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Background: Recent studies have demonstrated relatively high rates of percutaneous coronary interventions (PCIs) classified as "inappropriate." The New York State Department of Health shared rates with hospitals and announced the intention of withholding reimbursement pending demonstration of clinical rationale for Medicaid patients with inappropriate PCIs., Objectives: The objective was to examine changes over time in the number and rate of inappropriate PCIs., Methods: Appropriate use criteria were applied to PCIs performed in New York in patients without acute coronary syndromes or previous coronary artery bypass graft surgery in periods before (2010 through 2011) and after (2012 through 2014) efforts were made to decrease inappropriateness rates. Changes in the number of appropriate PCIs were also assessed., Results: The percentage of inappropriate PCIs for all patients dropped from 18.2% in 2010 to 10.6% in 2014 (from 15.3% to 6.8% for Medicaid patients, and from 18.6% to 11.2% for other patients). The total number of PCIs in patients with no acute coronary syndrome/no prior coronary artery bypass graft surgery that were rated as inappropriate decreased from 2,956 patients in 2010 to 911 patients in 2014, a reduction of 69%. For Medicaid patients, the decrease was from 340 patients to 84 patients, a decrease of 75%. For a select set of higher-risk scenarios, there were higher numbers of appropriate PCIs per year in the period from 2012 to 2014., Conclusions: The inappropriateness rate for PCIs and the use of PCI for elective procedures in New York has decreased substantially between 2010 and 2014. This decrease has occurred for a large proportion of PCI hospitals., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Many studies have shown that drug-eluting stents (DESs) are associated with better outcomes for patients receiving coronary stents, and earlier studies showed disparities in use by race and payer. It is of interest to know whether these differences persist in an era of higher use of DESs and to examine DES use differences across providers., Methods: New York State's percutaneous coronary intervention registry was used to identify significant predictors of DES vs bare-metal stent use among patients receiving stents, including race, ethnicity, sex, payer, and numerous patient clinical risk factors in 2011-2012. Variations in DES use across hospitals and operators were also examined., Results: African Americans (adjusted odds ratio [AOR], 0.70; 95% confidence interval [CI], 0.66-0.75) and Hispanics (AOR, 0.80; 95% CI, 0.74-0.85) were less likely to receive DESs than their counterparts. Patients with private insurance were more likely to receive DESs than patients in all other payer categories. More than one third of the 60 hospitals in the study had significantly lower adjusted use of DESs than the mean rate of 83%. For these hospitals, adjusted rates ranged from 52%-80%, and 5 of these hospitals had adjusted rates < 70%. Twenty-five percent of the total variation in the use of DESs was related to differences across hospitals that were unrelated to patient characteristics., Conclusions: Disparities by race, ethnicity, and insurance status persist in the use of DESs among patients receiving coronary stents. There are also large differences in use among hospitals that are unrelated to patient clinical characteristics and demographics., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Hospitals' risk-standardized mortality rates and outlier status (significantly higher/lower rates) are reported by the Centers for Medicare and Medicaid Services (CMS) for acute myocardial infarction (AMI) patients using Medicare claims data. New York now has AMI claims data with blood pressure and heart rate added., Objective: The objective of this study was to see whether the appended database yields different hospital assessments than standard claims data., Methods: New York State clinically appended claims data for AMI were used to create 2 different risk models based on CMS methods: 1 with and 1 without the added clinical data. Model discrimination was compared, and differences between the models in hospital outlier status and tertile status were examined., Results: Mean arterial pressure and heart rate were both significant predictors of mortality in the clinically appended model. The C statistic for the model with the clinical variables added was significantly higher (0.803 vs. 0.773, P<0.001). The model without clinical variables identified 10 low outliers and all of them were percutaneous coronary intervention hospitals. When clinical variables were included in the model, only 6 of those 10 hospitals were low outliers, but there were 2 new low outliers. The model without clinical variables had only 3 high outliers, and the model with clinical variables included identified 2 new high outliers., Conclusion: Appending even a small number of clinical data elements to administrative data resulted in a difference in the assessment of hospital mortality outliers for AMI. The strategy of adding limited but important clinical data elements to administrative datasets should be considered when evaluating hospital quality for procedures and other medical conditions.

Background: Percutaneous coronary intervention (PCI) for chronic total occlusions (CTO) has been identified as a beneficial treatment, but there is limited information about its use in everyday practice., Methods and Results: Data from New York's PCI registry between July 1, 2009, and June 30, 2012, were used to examine the utilization and variation in use of CTO PCI, the success rates across providers, the multivariable correlates of success, and the mortality of successful CTO PCI. A total of 4030 (3.1%) patients undergoing PCI underwent CTO PCI with a success rate of 61.3%. Patients with successful CTO PCIs were younger; had higher ejection fractions; were less likely to have had previous revascularization or carotid/cerebrovascular disease; and were more likely to have the CTO in the left anterior descending artery. Operators with annual CTO PCI volumes of at least 48 per year (the top volume quartile) had odds of achieving success that were more than twice as high as the half of all operators who performed <9 CTO PCIs per year. Patients with unsuccessful CTO PCIs had significantly higher 2.5-year mortality (adjusted hazard ratio, 1.63; 95% confidence interval, 1.28-2.08) than patients who had complete revascularization (CR) for all CTOs and other diseased lesions., Conclusions: The success rate for CTO is low compared with the rate for other lesions. Successful revascularization of CTO is associated with improved survival compared with procedures with unsuccessful CTO, and higher-volume CTO operators are more successful., (© 2016 American Heart Association, Inc.)

Objectives: The purpose of this study was to investigate changes in the use of transcatheter aortic valve replacement (TAVR) relative to surgical aortic valve replacement (SAVR) and to examine relative 1-year TAVR and SAVR outcomes in 2011 to 2012 in a population-based setting., Background: TAVR has become a popular option for patients with severe aortic stenosis, particularly for higher-risk patients., Methods: New York's Cardiac Surgery Reporting System was used to identify TAVR and SAVR volumes and to propensity match TAVR and SAVR patients using numerous patient risk factors contained in the registry to compare 1-year mortality rates. Mortality rates were also compared for different levels of patient risk., Results: The total number of aortic valve replacement patients increased from 2,291 in 2011 to 2,899 in 2012, an increase of 27%. The volume of SAVR patients increased by 7.1% from 1,994 to 2,135 and the volume of TAVR patients increased 157% from 297 to 764. The percentage of SAVR patients that were at higher risk (≥3% New York State [NYS] score, equivalent to a Society of Thoracic Surgeons score of about 8%) decreased from 27% to 23%, and the percentage of TAVR patients that were at higher risk decreased from 83% to 76%. There was no significant difference in 1-year mortality between TAVR and SAVR patients (15.6% vs. 13.1%; hazard ratio [HR]: 1.30 [95% confidence interval (CI): 0.89 to 1.92]). There were no differences among patients with NYS score <3% (12.5% vs. 10.2%; HR: 1.42 [95% CI: 0.68 to 2.97]) or among patients with NYS score ≥3% (17.1% vs. 14.5%; HR: 1.27 [95% CI: 0.81 to 1.98])., Conclusions: TAVR has assumed a much larger share of all aortic valve replacements for severe aortic stenosis, and the average level of pre-procedural risk has decreased substantially. There are no differences between 1-year mortality rates for TAVR and SAVR patients., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Several randomized controlled trials and observational studies have compared outcomes for coronary artery bypass graft (CABG) surgery and drug-eluting stents (DES), but these studies have not thoroughly investigated the relative difference in outcomes by sex. We aimed to compare 3-year outcomes (mortality, mortality/myocardial infarction/stroke, and repeat revascularization) for CABG surgery and percutaneous coronary interventions with DES by sex., Methods: A total of 4,532 women (2,266 pairs of CABG and DES patients) and 11,768 men (5,884 pairs) were propensity matched separately using multiple patient risk factors and were compared with respect to 3-year outcomes., Results: Both women and men receiving DES had significantly higher mortality rates (adjusted hazard ratio, 1.28; 95% confidence interval, 1.06 to 1.54 and adjusted hazard ratio, 1.22; 95% confidence interval, 1.06 to 1.41, respectively) and myocardial infarction/mortality/stroke rates (adjusted hazard ratio, 1.40; 95% confidence interval, 1.19 to 1.64 and adjusted hazard ratio, 1.36; 95% confidence interval, 1.20 to 1.54, respectively) with DES. The advantage for CABG surgery was also present for several preselected patient subgroups. Men had consistently lower adverse outcome rates than women for both procedures. For example, the mortality rates for CABG and DES for men were 8.0% and 9.1%, compared with respective rates of 11.8% and 13.7% for women., Conclusions: For women, the advantage of CABG surgery over DES is very similar to what was found for men, and this advantage persisted for patients with and without high-risk characteristics., (Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Several studies have compared short-term and medium-term mortality rates for patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR), but no studies have compared short-term readmission rates for the 2 procedures., Methods and Results: New York's Cardiac Surgery Reporting System was used to propensity match 617 TAVI and 1981 SAVR patients using numerous patient risk factors contained in the registry. The 389 propensity-matched pairs were then used to analyze differences in readmission rates between the 2 groups. TAVI and SAVR readmission rates were also compared for patients with a history of congestive heart failure and for patients aged ≥80. Also, reasons for readmission for TAVI and SAVR patients were examined and compared. Readmission rates were not statistically different for all propensity-matched TAVI and SAVR patients (respective rates, 18.8% and 19.3%; P=0.86). After further adjustment using a logistic regression model, there was still no significant difference (adjusted odds ratio, 0.97; 95% confidence interval [0.68-1.39]). For patients aged ≥80, the 30-day readmission rates were 19.9% and 22.0% (P=0.59), and when further adjusted using the logistic regression model, adjusted odds ratio=0.89 (0.55-1.45). For patients with a history of congestive heart failure, the respective rates were 22.8% and 20.4% (P=0.56), and with further adjustment, adjusted odds ratio became 1.15 (0.72-1.82)., Conclusions: There are no statistically significant differences between TAVI and SAVR patients in short-term readmission rates., (© 2015 American Heart Association, Inc.)

Background: Few recent studies have compared the outcomes of coronary artery bypass graft (CABG) surgery with percutaneous coronary interventions (PCIs) in patients with isolated (single vessel) proximal left anterior descending (PLAD) coronary artery disease in the era of drug-eluting stents (DES)., Objectives: The goal of this study was to compare outcomes in patients with PLAD who underwent CABG and PCI with DES., Methods: New York's Percutaneous Coronary Interventions Reporting System was used to identify and track all patients who underwent CABG surgery and received DES for isolated PLAD disease between January 1, 2008 and December 31, 2010, and who were followed-up through December 31, 2011. A total of 5,340 of 6,064 (88%) patients received DES. Patients were matched to vital statistics data to obtain mortality after discharge and matched to New York's administrative data to obtain readmissions for myocardial infarction (MI) and stroke. To minimize selection bias, patients were propensity matched into 715 CABG and/or DES pairs, and 3 outcome measures were compared across the pairs., Results: Kaplan-Meier estimates for CABG and DES did not significantly differ for mortality or mortality, MI, and/or stroke, but repeat revascularization rates were lower for CABG (7.09% vs. 12.98%; p = 0.0007). After further adjustment with Cox proportional hazards models, there were still no significant differences in 3-year mortality rates (CABG and/or DES adjusted hazard ratio (AHR): 1.14; 95% confidence interval [CI]: 0.70 to 1.85) or mortality, MI, and/or stroke rates (AHR: 1.15; 95% CI: 0.76 to 1.73), and the repeat revascularization rate remained significantly lower for CABG patients (AHR: 0.54; 95% CI: 0.36 to 0.81)., Conclusions: Despite the higher rating in current guidelines of CABG (Class IIa vs. Class IIb) for patients with isolated PLAD disease, there were no differences in mortality or mortality, MI, and/or stroke, although CABG patients had significantly lower repeat revascularization rates., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to determine the utilization and outcomes for radial access for percutaneous coronary intervention (PCI) for ST-segment elevation acute myocardial infarction (STEMI) in common practice., Background: Radial access for PCI has been studied considerably, but mostly in clinical trials., Methods: All patients undergoing PCI for STEMI in 2009 to 2010 in New York were studied to determine the frequency and the patient-level predictors of radial access. Differences in in-hospital/30-day mortality between radial and femoral access were also studied., Results: Radial access increased from 4.9% in the first quarter of 2009 to 11.9% in the last quarter of 2010. Significant independent predictors were higher body surface area, non-Hispanic ethnicity, Caucasian race, stable hemodynamic state, ejection fraction <30% and ≥50% onset of STEMI from 12 to 23 h before the index procedure, and peripheral vascular disease. Mortality was not related to access site after adjustment for covariates (for radial vs. femoral access, adjusted odds ratio: 0.86, 95% confidence interval: 0.59 to 1.25), but the radial access site was trending toward lower mortality for the 9 hospitals that used it for more than 10% of their patients (adjusted odds ratio: 0.61, 95% confidence interval: 0.36 to 1.02)., Conclusions: The use of a radial access site for PCI in STEMI patients increased between 2009 and 2010, but was still infrequent in 2010, and was used for lower-risk STEMI patients. There was no significant difference in mortality by access site, but there was a trend toward a mortality advantage for patients with a radial access site among hospitals that used it relatively frequently., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Appropriate use criteria for diagnostic catheterization (DC) were recently published. These criteria are yet to be examined for a large population of patients undergoing DC., Methods and Results: New York State's Cardiac Diagnostic Catheterization Database was used to identify patients undergoing DC for coronary artery disease between 2010 and 2011 for suspected coronary artery disease. Patients were rated by the appropriate use criteria as appropriate, uncertain, and inappropriate for DC. The relationships between various patient characteristics and the appropriateness ratings were examined, along with the relationships between hospital-level inappropriateness, for DC and 2 other hospital-level variables (hospital DC volume and percutaneous coronary intervention inappropriateness). Of the 8986 patients who could be rated for appropriateness, 35.3% were rated as appropriate, 39.8% as uncertain, and 24.9% as inappropriate. Of the 2240 patients rated as inappropriate, 56.7% were asymptomatic/had no previous stress test/had low or intermediate global coronary artery disease risk, 36.0% had a previous stress test with low-risk findings and no symptoms, and 7.3% were symptomatic/had no previous stress test/had low pretest probability. The median hospital-level inappropriateness rate was 28.5%, with a maximum of 48.8% and a minimum of 8.6%. Hospital-level inappropriateness was not related to hospital volume or inappropriateness for percutaneous coronary intervention., Conclusions: One quarter of patients undergoing DC for suspected coronary artery disease were rated as inappropriate for the procedure, approximately two thirds of these inappropriate patients had no previous stress test, and ≈90% of inappropriate patients with no previous stress test were asymptomatic with low or intermediate global risk scores.

Background: A simple risk score to predict long-term mortality after percutaneous coronary intervention (PCI) using preprocedural risk factors is currently not available. In this study, we created one by simplifying the results of a Cox proportional hazards model., Methods and Results: A total of 11,897 patients who underwent PCI from October through December 2003 in New York State were randomly divided into derivation and validation samples. Patients' vital statuses were tracked using the National Death Index through the end of 2008. A Cox proportional hazards model was fit to predict death after PCI using the derivation sample, and a simplified risk score was created. The Cox model identified 12 separate risk factors for mortality including older age, extreme body mass indexes, multivessel disease, a lower ejection fraction, unstable hemodynamic state or shock, several comorbidities (cerebrovascular disease, peripheral vascular disease, congestive heart failure, chronic obstructive pulmonary disease, diabetes mellitus, and renal failure), and a history of coronary artery bypass graft surgery. The C statistics of this model when applied to the validation sample were 0.787, 0.785, and 0.773 for risks of death within 1, 3, and 5 years after PCI, respectively. In addition, the point-based risk score demonstrated good agreement between patients' observed and predicted risks of death., Conclusions: A simple risk score created from a more complicated Cox proportional hazards model can be used to accurately predict a patient's risk of long-term mortality after PCI.

Background: Appropriate use criteria (AUC) for diagnostic catheterization (DC) developed by the American College of Cardiology Foundation (ACCF) and other professional societies were recently published. These criteria have yet to be examined thoroughly using existing DC databases., Methods and Results: New York State's Cardiac Diagnostic Catheterization Database was used to identify patients undergoing DC "for suspected coronary artery disease (CAD)" in 01/2010-06/2011 who underwent noninvasive stress testing. Patients rated for appropriateness using symptoms and stress test results were examined to determine the percentage with obstructive CAD and to explore the benefit of adding Global Risk Score (GRS) to the AUC. Of the 4432 patients who could be rated, 1530 (34.5%) had obstructive CAD, which varied from 22% for patients rated inappropriate to 47% for patients rated appropriate. Of all patients with low risk stress test results/no symptoms, all of whom were rated "inappropriate" for DC, only 8% of those patients with low GRS had obstructive CAD, whereas 44% of the patients with high GRS had obstructive CAD., Conclusions: Global Risk Score improved the ability of symptoms and stress test results to identify obstructive CAD in patients with "suspected CAD" with prior stress tests, and it might be helpful to add GRS to the DC AUC for those patients. These findings should be regarded as hypothesis generating unless/until they can be confirmed by other data bases., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Objective: To determine whether disparities in access to invasive cardiac procedures still exist for Medicaid patients, given how old earlier studies are and given changes in the interim in appropriateness guidelines., Patients and Methods: A total of 5,022 Medicaid and private insurance patients in New York from January 1, 2008 through December 31, 2009 under age 65 with ST-elevation myocardial infarction (STEMI) were compared with regard to their access to percutaneous coronary interventions (PCI) before and after controlling for numerous patient characteristics and other important factors., Results: Medicaid patients were significantly less likely to be admitted initially to a hospital certified to perform PCI (90.4% vs. 94.3%, P < 0.001). Also, Medicaid patients were found to be significantly less likely to undergo PCI than other patients (adjusted odds ratio [AOR] = 0.81, 95% CI 0.66, 0.98, P = 0.03). When the probability of each hospital performing PCI for STEMI patients was controlled for, Medicaid patients were still less likely to undergo PCI after controlling for other risk factors (AOR = 0.80, 95% CI 0.65, 0.99, P = 0.04)., Conclusions: Medicaid STEMI patients are significantly less likely to undergo PCI within the same day of admission as private pay patients even after adjusting for patient characteristics related to receiving PCI, and the strength of this relationship is not diminished when controlling for whether the admitting hospital has approval to perform PCI or controlling for the tendency of the admitting hospital to treat STEMI with PCI., (© 2013, Wiley Periodicals, Inc.)

The association between incomplete revascularization (IR) and long-term mortality after stenting in the era of drug-eluting stents is not well understood. In the present study, we test the hypothesis that IR is associated with a greater risk of long-term (5-year) mortality after stenting for multivessel coronary disease. Using data from the Percutaneous Coronary Intervention Reporting System of New York State, 21,767 patients with multivessel disease who underwent stenting during October 2003 to December 2005 were identified. Complete revascularization (CR) was achieved in 6,844 patients (31.4%), and 14,923 patients (68.6%) were incompletely revascularized. The CR and IR patients were propensity matched on a 1:1 ratio on the number of diseased vessels, the presence of total occlusion, type of stents, and the probability of achieving CR estimated using a logistic model with established risk factors as independent variables. Patients were followed for vital status until December 31, 2008 using the National Death Index. Differences in survival between the matched CR and IR patients were compared. Among the 6,511 pairs of propensity-matched patients, the 5-year survival rate for IR was lower compared with CR (79.3% vs 81.4%, p = 0.004), and the risk of death during follow-up was 16% greater for IR compared with CR (hazard ratio 1.16, 95% confidence interval 1.06 to 1.27, p = 0.001). In addition, subgroup analyses demonstrated that the association between IR and long-term mortality was not dependent on major patient risk factors. In conclusion, IR is associated with an increased risk of long-term mortality after stenting for multivessel disease in the era of drug-eluting stents., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objectives: This study sought to develop a percutaneous coronary intervention (PCI) risk score for in-hospital/30-day mortality., Background: Risk scores are simplified linear scores that provide clinicians with quick estimates of patients' short-term mortality rates for informed consent and to determine the appropriate intervention. Earlier PCI risk scores were based on in-hospital mortality. However, for PCI, a substantial percentage of patients die within 30 days of the procedure after discharge., Methods: New York's Percutaneous Coronary Interventions Reporting System was used to develop an in-hospital/30-day logistic regression model for patients undergoing PCI in 2010, and this model was converted into a simple linear risk score that estimates mortality rates. The score was validated by applying it to 2009 New York PCI data. Subsequent analyses evaluated the ability of the score to predict complications and length of stay., Results: A total of 54,223 patients were used to develop the risk score. There are 11 risk factors that make up the score, with risk factor scores ranging from 1 to 9, and the highest total score is 34. The score was validated based on patients undergoing PCI in the previous year, and accurately predicted mortality for all patients as well as patients who recently suffered a myocardial infarction (MI)., Conclusions: The PCI risk score developed here enables clinicians to estimate in-hospital/30-day mortality very quickly and quite accurately. It accurately predicts mortality for patients undergoing PCI in the previous year and for MI patients, and is also moderately related to perioperative complications and length of stay., (Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: To compare 2-year outcomes (mortality, mortality/myocardial infarction (MI), target vessel PCI (TVPCI), and target lesion PCI (TLPCI)) for patients receiving EES and ZES., Background: The utilization of drug-eluting coronary stents (DES) among patients undergoing percutaneous coronary interventions (PCI) has increased dramatically in the last decade. Everolimus-eluting stents (EES) and ENDEAVOR zotarolimus eluting stents (ZES) constitute the latest generation of approved DES in the United States, but little is known about their relative effectiveness., Methods: New York patients undergoing EES and ZES revascularization without any other type of stent between 7/08 and 12/08 were propensity matched at the hospital level using multiple patient, operator, and hospital characteristics, and matched patients were followed through the end of 2010 to obtain comparative 2-year outcomes., Results: A total of 3286 patients were propensity-matched. Patients receiving EES had a significantly lower TVPCI rate (9.0% vs. 11.9%, AHR = 1.31, 95% CI (1.04, 1.65)) and a significantly lower TLPCI rate (6.0% vs. 8.3%, AHR = 1.35, 95% CI (1.02, 1.79)). There was no significant difference between EES and ZES for mortality or MI/mortality., Conclusions: There were no significant differences in the hard endpoints of death or MI between patients who received EES versus those who received ZES (ENDEAVOR). Patients with EES experienced lower repeat revascularization rates than patients with ZES at 24 months., (Copyright © 2012 Wiley Periodicals, Inc.)

Background: There are evidence-based guidelines for staging of patients with ST-elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI), but we are not aware of any evidence comparing the strategy of complete revascularization (CR) with PCI in the index admission versus the strategy of staging in a subsequent admission for patients with coronary artery disease without STEMI., Methods and Results: PCI patients without STEMI undergoing PCI in New York between 2007 and 2009 were separated into 2 groups: those with acute coronary syndrome but no STEMI, and those without acute coronary syndrome. For each group, patients who underwent CR in the index admission were then propensity matched to patients staged within 60 days to obtain CR based on 17 patient risk factors related to longer-term mortality, and 3-year mortality rates were compared for the propensity-matched groups. Outcomes were also compared for preselected subgroups. For propensity-matched patients without acute coronary syndrome, the all-cause mortality rates at 3 years for patients who underwent CR in the index hospitalization and patients staged for CR within 60 days of discharge were 5.62% and 5.97%, P=0.93, respectively. For propensity-matched patients with acute coronary syndrome but without STEMI, the all-cause mortality rates at 3 years for patients who underwent CR in the index hospitalization and patients staged for CR within 60 days of discharge were 6.59% and 5.92%, P=0.41, respectively., Conclusions: Patients with coronary artery disease without STEMI do not have significantly lower 3-year mortality rates with staged PCI than when they undergo CR in the index admission.

Objectives: This study sought to report percutaneous coronary intervention (PCI) 30-day readmission rates, identify the impact of staged (planned) readmissions on overall readmission rates, determine the significant predictors of unstaged readmissions after PCI, and specify the reasons for readmissions., Background: Hospital readmissions occur frequently and incur substantial costs. PCI are among the most common and costly procedures, and little is known about the nature and extent of readmissions for PCI., Methods: We retrospectively analyzed 30-day readmissions after PCI using the nation's largest statewide PCI registry to identify 40,093 New York State patients who underwent PCI between January 1, 2007, and November 30, 2007. Demographic variables, pre-procedural risk factors, complications of PCI, and length of stay were considered as potential predictors of readmission, and reasons for readmission were identified from New York's administrative database using principal diagnoses., Results: A total of 15.6% of all PCI patients were readmitted within 30 days, and 20.6% of these readmissions were staged. Among unstaged readmissions, the most common reasons for readmission were chronic ischemic heart disease (22.5%), chest pain (10.8%), and heart failure (8.2%). A total of 2,015 patients (32.2% of readmissions) underwent a repeat PCI. Thirteen demographic and diagnostic risk factors, as well as longer lengths of stay, were all associated with higher readmission rates., Conclusions: Future efforts to reduce readmissions should be directed toward the recognition of patients most at risk, and the reasons they are readmitted. Staging also should be examined from a cost-effectiveness standpoint as a function of patients' unique risk factors., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: The impact of incomplete revascularization (IR) on adverse outcomes after percutaneous coronary intervention remains inconclusive, and few studies have examined mortality during follow-ups longer than 5 years. The objective of this study is to test the hypothesis that IR is associated with higher risk of long-term (8-year) mortality after stenting for multivessel coronary disease., Methods and Results: A total of 13 016 patients with multivessel disease who had undergone stenting procedures with bare metal stents in 1999 to 2000 were identified in the New York State's Percutaneous Coronary Intervention Reporting System. A logistic regression model was fit to predict the probability of achieving complete revascularization (CR) in these patients using baseline risk factors; then, the CR patients were matched to the IR patients with similar likelihoods of achieving CR. Each patient's vital status was followed through 2007 using the National Death Index, and the difference in long-term mortality between IR and CR was compared. It was found that CR was achieved in 29.2% (3803) of the patients. For the 3803 pair-matched patients, the respective 8-year survival rates were 80.8% and 78.5% for CR and IR (P=0.04), respectively. The risk of death was marginally significantly higher for IR (hazard ratio=1.12; 95% confidence interval, 1.01-1.26, P=0.04). The 95% bootstrap confidence interval for the hazard ratio was 0.98 to 1.32., Conclusions: IR may be associated with higher risk of long-term mortality after stenting with BMS in patients with multivessel disease. More prospective studies are needed to further test this association.

The outcomes for patients undergoing percutaneous coronary interventions (PCI) with drug-eluting stents (DESs) and bare metal stents (BMSs) have been compared in many studies for patients with ST-segment elevation myocardial infarction. However, little is known about the relative outcomes for patients with non-ST-segment elevation myocardial infarction (NSTEMI). The aim of the present study was to compare the NSTEMI outcomes for PCI with DESs and BMSs. New York's PCI registry was used to propensity-match 4,776 pairs of patients with NSTEMI who had received DESs and BMSs from January 1, 2003 to December 31, 2007. These patients were followed up through December 31, 2008 to test for differences in mortality, target vessel revascularization, and total repeat revascularization. The outcomes were also compared for various patient subsets. At a median follow-up period of 3.68 years, the patients receiving DESs had significantly lower mortality (16.58% vs 14.52%, difference 2.06%, p<0.001), target vessel revascularization (13.08% vs 11.04%, p=0.009), and total repeat revascularization (22.16% vs 18.77%, p<0.001). The patients receiving paclitaxel-eluting and sirolimus-eluting stents both experienced superior outcomes compared to patients receiving BMSs. The patients receiving DESs had significantly lower mortality rates than their propensity-matched counterparts receiving BMSs when they were ≥65 years (difference 2.29%, p=0.01) and male (difference 2.77%, p=0.003). In conclusion, patients with NSTEMI undergoing PCI experienced lower 4-year mortality, target vessel revascularization, and repeat revascularization rates when they had received DESs than when they had received BMSs, and patients who were >65 years old, and men received notable benefits., (Copyright © 2011 Elsevier Inc. All rights reserved.)

It is important to identify the factors related to survival of patients undergoing primary percutaneous coronary intervention for ST-segment elevation acute myocardial infarction. Our objective was to determine the interactive effect of the door-to-balloon (DTB) time and onset-to-door (OTD) time on longer term mortality for patients with ST-segment elevation acute myocardial infarction. The present study was a retrospective cohort analysis of the effect of the DTB time and OTD time on longer term (median follow-up 413 days) mortality for patients undergoing primary percutaneous coronary intervention in New York from January 1, 2004 to December 31, 2006, adjusting for the effect of other important risk factors. The patients with ST-segment elevation acute myocardial infarction with a DTB time of <90 minutes and OTD time of <4 hours had the lowest longer term mortality (3.51%). Patients with a DTB time <90 minutes and OTD time of >or =4 hours had significantly greater mortality than patients with an OTD time of <4 hours and DTB time of <90 minutes (adjusted hazard ratio 1.54, 95% confidence interval 1.04 to 2.30), as did patients with a DTB time of > or =90 minutes and OTD time of > or =4 hours (adjusted hazard ratio 1.48, 95% confidence interval 1.05 to 2.09). For an OTD time of <4 hours and DTB time of > or =90 minutes, mortality showed a trend toward being greater compared to shorter OTD and DTB times (adjusted hazard ratio 1.29, 95% confidence interval 0.95 to 1.77). In conclusion, the combination of short (<90 minutes) DTB time and short (<4 hours) OTD time was associated with the lowest longer term mortality rate., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)

Background: The American College of Cardiology and the American Heart Association have issued guidelines for the use of coronary artery bypass graft surgery (CABG) and percutaneous coronary interventions (PCI) for many years, but little is known about the impact of these evidence-based guidelines on referral decisions., Methods and Results: A cardiac catheterization laboratory database used by 19 hospitals in New York State was used to identify treatment (CABG surgery, PCI, medical treatment, or nothing) recommended by the catheterization laboratory cardiologist for patients undergoing catheterization with asymptomatic/mild angina, stable angina, and unstable angina/non-ST-elevation myocardial infarction between January 1, 2005, and August 31, 2007. The recommended treatment was compared with indications for these patients based on American College of Cardiology/American Heart Association guidelines. Of the 16 142 patients undergoing catheterization who were found to have coronary artery disease, the catheterization laboratory cardiologist was the final source of recommendation for 10 333 patients (64%). Of these 10 333 patients, 13% had indications for CABG surgery, 59% for PCI, and 17% for both CABG surgery and PCI. Of the patients who had indications for CABG surgery, 53% were recommended for CABG and 34% for PCI. Of the patients with indications for PCI, 94% were recommended for PCI. For the patients who had indications for both CABG surgery and PCI, 93% were recommended for PCI and 5% for CABG surgery. Catheterization laboratory cardiologists in hospitals with PCI capability were more likely to recommend patients for PCI than hospitals in which only catheterization was performed., Conclusions: Patients with coronary artery disease receive more recommendations for PCI and fewer recommendations for CABG surgery than indicated in the American College of Cardiology/American Heart Association guidelines.

Objectives: The purpose of this study was to examine the differences in in-hospital and longer-term mortality for ST-segment elevation myocardial infarction (STEMI) patients with multivessel disease as a function of whether they underwent single-vessel (culprit vessel) percutaneous coronary interventions (PCIs) or multivessel PCI., Background: The optimal treatment of patients with STEMI and multivessel disease is of continuing interest in the era of drug-eluting stents., Methods: STEMI patients with multivessel disease undergoing PCIs in New York between January 1, 2003, and June 30, 2006, were subdivided into those who underwent culprit vessel PCI and those who underwent multivessel PCI during the index procedure, during the index admission, or staged within 60 days of the index admission. Patients were propensity-matched and mortality rates were calculated at 12, 24, and 42 months., Results: A total of 3,521 patients (87.5%) underwent culprit vessel PCI during the index procedure. A total of 259 of them underwent staged PCI during the index admission and 538 patients underwent staged PCI within 60 days of the index procedure. For patients without hemodynamic compromise, culprit vessel PCI during the index procedure was associated with lower in-hospital mortality than multivessel PCI during the index procedure (0.9% vs. 2.4%, p = 0.04). Patients undergoing staged multivessel PCI within 60 days after the index procedure had a significantly lower 12-month mortality rate than patients undergoing culprit vessel PCI only (1.3% vs. 3.3%, p = 0.04)., Conclusions: Our findings support the American College of Cardiology/American Heart Association (ACC/AHA) recommendation that culprit vessel PCI be used for STEMI patients with multivessel disease at the time of the index PCI when patients are not hemodynamically compromised. However, staged PCI within 60 days after the index procedure, including during the index admission, is associated with risk-adjusted mortality rates that are comparable with the rate for culprit vessel PCI alone., (Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: We explored the association between renal insufficiency (RI) and mortality among patients treated with an implantable cardioverter defibrillator (ICD)., Background: Randomized trials have shown improvements in survival among select patients treated with an ICD. Renal insufficiency patients have a high risk of cardiac death; however, it is not clear whether the ICD has a positive effect on survival in this group of patients., Methods: This was a retrospective review of a single-center experience of 346 patients treated with an ICD. Patients were stratified into 4 groups according to their glomerular filtration rate (eGFR; expressed as mL/min/ -1.73 m(2)) at implantation: group I, > 75.0; group II, - 60.0 to 74.9; group III, - 45.0 to 59.9; and group IV, - < or = 45.0. All-cause mortality was the primary end point, with differences in survival times among the 4 groups of patients expressed in Kaplan-Meier curves., Results: Mean follow-up was 3.5 y (range 0.1 to 12.9 y), during which 67 patients died (19%). Mortality in each eGFR group was: I - 6.8%, II - 13.8%, III - 11.5%, IV - 45.8% (p < 0.001). Survival times (mean, y) were I, 3.74; II, 3.66; III, 3.38, and IV, 2.82. The presence of diabetes was not a factor in the outcomes., Conclusions: Patients treated with an ICD with an eGFR of < or = 45.0 mL/min/1.73 m(2) have a significantly shorter survival time than those patients with an eGFR > 45.0 mL/min/1.73 m(2). Patients with an eGFR > 45.0 mL/min/1.73 m(2) appear to have equally good outcomes when treated with an ICD. This may have implications for patient selection for ICD therapy.

Introduction: Previous studies have demonstrated gender differences in risk of sudden death in patients with ischemic heart disease. The Multicenter UnSustained Tachycardia Trial (MUSTT) evaluated the ability of therapy guided by electrophysiologic (EP) testing to reduce mortality in patients with coronary disease, ejection fraction < or =40%, and spontaneous nonsustained ventricular tachycardia., Methods and Results: We analyzed the influence of gender on results of EP testing and outcome of patients enrolled in MUSTT. Women made up 14% of the overall MUSTT population and were less likely than men to have inducible sustained randomizable ventricular arrhythmias (24% vs 36%, P < 0.001). Baseline characteristics differed between men and women. In randomized patients, women were older, more likely to have had an infarction within 6 months, more likely to have a history of heart failure, and more likely to have recent angina prior to enrollment than men (P < 0.05). In the EP-guided therapy group, there was no difference in implantable cardioverter defibrillator implantation rate in men and women (45% vs 53%, P = 0.38). There also were no significant gender influences on risk of arrhythmic death or cardiac arrest (2-year event rate 9% in women and 12% in men, adjusted hazard ratio 0.88) or overall mortality (2-year event rate 32% in women vs 21% in men, adjusted hazard ratio 1.51)., Conclusion: The outcome and benefit of EP-guided therapy in this trial did not appear to be influenced by gender. However, due to the small numbers of women in the trial, small differences in outcome may not be apparent. Plans for future primary prevention trials should include careful risk stratification of women who less often have inducible sustained ventricular arrhythmias and better left ventricular function despite more frequent heart failure.

Emerging evidence suggests that atrial fibrillation is not a benign arrhythmia. It is associated with increased risk of death. The magnitude of association is controversial and potential causes remain unknown. Patients in the registry of the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial form the basis for this report. Baseline variables, in particular the presence or absence of a history of atrial fibrillation/flutter, were examined in relation to survival. Multivariate Cox regression was used to adjust for differences in important baseline co-variables using 27 pre-selected variables. There were 3762 subjects who were followed for an average of 773+/-420 days; 1459 (39 %) qualified with ventricular fibrillation and 2303 (61 %) with ventricular tachycardia. A history of atrial fibrillation/flutter was present in 24.4 percent. There were many differences in baseline variables between those with and those without a history of atrial fibrillation/flutter. After adjustment for baseline differences, a history of atrial fibrillation/flutter remained a significant independent predictor of mortality, (relative risk=1.20; 95 % confidence intervals=1.03-1.40; p=0.020). Antiarrhythmic drug use, other than amiodarone or sotalol, was also a significant independent predictor of mortality (relative risk 1.34; 95 % confidence intervals 1.07-1.69, p=0.011. Atrial fibrillation/flutter is a significant independent risk factor for increased mortality in patients presenting with ventricular tachyarrhythmias. This risk may have been overestimated in previous studies that could not adjust for the proarrhythmic effects of antiarrhythmic drugs other than amiodarone or sotalol.

Introduction: New defibrillation techniques are often compared to standard approaches using the defibrillation threshold. However, inference from thresholding data necessitates extrapolation from reactions to relatively ineffective shocks, an error prone procedure requiring large sample sizes for hypothesis testing and large safety margins for defibrillator implantation. In contrast, this article presents a clinically validated statistical model of a minimum error, four-shock defibrillation testing protocol for estimating the 80% effective defibrillation strength for a given patient (ED80)., Methods and Results: A Bayesian statistical model was constructed assuming that the defibrillation dose-response curve is sigmoidal, and the ED80 is between 150 and 750 V. The model was used to design a minimum predicted error testing protocol and estimates. To prospectively validate the testing protocol and estimates, 170 patients received voltage-programmed biphasic testing. Four fibrillation episodes were induced and terminated in each patient according to the Bayesian up-down protocol. In addition, a validation attempt was made at the estimated ED80 rounded up to the nearest 50 V. In order to estimate the safety margin, in 136 patients, a defibrillation attempt was made at the rounded ED80 + 100 V. Of the 170 attempts at the rounded ED80, 143 (84%) attempts terminated fibrillation. Of the 136 attempts at the rounded ED80 + 100 V, 133 (98%) were effective., Conclusions: The four-shock Bayesian up-down protocol is the first clinical protocol to accurately predict an ED80 voltage. A 100 V increment above the ED80 provides an adequate safety margin. This simple and accurate method for estimating a highly effective defibrillation dose may be a valuable tool for population-based clinical hypothesis testing, as well as defibrillator implantation.

Background: Cardiologists often use clinical variables to determine the need for electrophysiological studies to stratify patients for risk of sudden death. It is not clear whether this is rational in patients with coronary artery disease, left ventricular dysfunction, and nonsustained ventricular tachycardia., Methods and Results: We analyzed the first 1721 patients enrolled in the Multicenter UnSustained Tachycardia Trial to determine whether clinical variables could predict which patients would have inducible sustained monomorphic ventricular tachycardia. The rate of inducibility of sustained ventricular tachycardia was significantly higher in patients with a history of myocardial infarction and in men compared with women. There was a progressively increased rate of inducibility with increasing numbers of diseased coronary arteries. There was a significantly lower rate of inducibility in patients with prior coronary artery bypass surgery and in patients who also had noncoronary cardiac disease. The rate of inducibility was higher in patients of white race, patients with recent (

RF catheter ablation of accessory bypass tracts associated with the Wolff-Parkinson-White syndrome has become an accepted and widespread therapy. When bypass tracts are located in the free wall of the left ventricle, a single catheter technique may be utilized. A single catheter is placed via the femoral artery, across the aortic valve into the left ventricle. Mapping is performed during sinus rhythm, and ablation performed at the site of recording of Kent bundle activation. We describe a case of a patient with Wolff-Parkinson-White syndrome presenting with rapid atrial fibrillation requiring cardioversion. This patient subsequently underwent catheter ablation of a left free-wall bypass tract using the single catheter technique. At baseline, preexcitation and right bundle branch block (RBBB) were present on the ECG. During catheter ablation of the accessory pathway, transient complete AV block was seen. This was felt likely to be due to trauma to the His bundle, or more likely to the left bundle branch, as the ablation catheter crossed the aortic valve. The bypass tract was successfully ablated after placement of a temporary right ventricular pacemaker. AV conduction resumed with a pattern of RBBB. A temporary right ventricular pacing catheter should be placed prior to RF ablation of left-sided bypass tracts when the ECG is also suggestive of RBBB.

Permanent pacemakers may be implanted in operating rooms, special procedure laboratories, or cardiac catheterization laboratories. Previous investigators have shown no difference in efficacy or complications in the operating room versus the cardiac catheterization laboratory. We retrospectively analyzed the hospital bills of 30 patients undergoing permanent pacemaker implantation at our institution. Group I was 15 consecutive patients implanted in the operating room and group II was 15 consecutive patients implanted in the cardiac catheterization laboratory, all by the same operators. Hospital charges that were specific to the site of implantation were analyzed. Physician charges for implantation, anesthesiologist, and radiologist charges were not analyzed. There were no in-hospital complications in either group. The mean charges for group I were $1,856.00 and group II were $1,075.00 (P < 0.001). We conclude that implantation of permanent pacemakers in the cardiac catheterization laboratory is associated with significantly lower hospital charges compared to implantation in the operating room and has an equally low complication rate.

We report the use of a steerable hydrophilic guidewire for permanent pacemaker implantation. This wire, previously used for peripheral vascular and cardiac angiography, is able to be steered and passed in many situations when a standard guidewire cannot be used. We report three cases where the standard J-tipped guidewire could not be passed by either the cephalic or subclavian route and the hydrophilic guidewire allowed for successful atraumatic placement of a sheath and pacemaker lead.

Steroid eluting leads may allow for lower chronic pacing thresholds and therefore lower pacing outputs. Twenty-two patients (15 presenting with syncope) were implanted with VVI or VVIR pacemakers and transvenous steroid eluting leads and followed for a mean of 20.6 months while being paced at 1.6 V and 0.6 msec. Mean acute voltage pacing thresholds were 0.40 V at 0.5 msec and chronic pulse width thresholds were 0.21 msec at 0.8 V. Pacemaker function was documented with one to three 24-hour Holter monitors, attached during the 2-6 week postimplant period, bimonthly transtelephonic monitoring, and monthly pacemaker clinic visits. No patient developed recurrent symptoms and consistent capture was verified in all patients on every 24-hour Holter recording and transtelephonic monitor. Chronic ventricular pacing at an output of 1.6 V at 0.6 msec is safe and effective when using a steroid eluting lead and potentially has implications for pacemaker longevity.

Fifty-four patients presenting with stenotic lesions in a major coronary artery visually estimated by diagnostic angiography to be greater than 90% but less than 100% were randomized to one of two angioplasty regimens, predilatation (group 1) or no predilatation (group 2). In group 1, the artery was initially dilated with a 2 mm balloon followed by a balloon that was considered by the operator to be the definitive size to fully dilate the target vessel. In group 2, the artery was dilated with a balloon deemed the definitive size to complete the angioplasty procedure. There were no statistical differences between groups with respect to age, sex, history of unstable angina, or prior acute myocardial infarction. There were also no significant differences in the angiographic characteristics of the coronary lesions including artery location, lesion length, concentric or eccentric morphology, tubular versus discrete stenosis, calcium in lesions, or lesions on a bend. Following angioplasty, luminal filling defects were present in 5% of the predilated group and in 9% of the nonpredilated group (p = NS). The incidence of luminal border haziness at the dilatation site did not differ between groups, seven (35%) in group 1 versus eight (24%) in group 2. Angiographic evidence of a linear dissection at the angioplasty site was also similar between groups, one (5%) in group 1 versus five (15%) in group 2. Occlusive complications were witnessed in 10% of the predilated group and 12% of the nonpredilated group (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic occlusion of saphenous vein aortocoronary bypass grafts is a common problem. Although percutaneous transluminal angioplasty of a saphenous vein with a stenotic lesion is feasible, angioplasty alone of a totally occluded vein graft yields uniformly poor results. Patients with such occlusion are often subjected to repeat aortocoronary bypass surgery. Experience with a new technique that allows angioplasty to be performed in a totally occluded saphenous vein bypass graft is reported. This technique utilizes infusion of prolonged low dose urokinase directly into the proximal portion of the occluded graft. Forty-six consecutive patients with 47 totally occluded grafts were studied. Patients had undergone end to side saphenous vein bypass grafting 1 to 13 (mean 7) years previously. All patients presented with new or worsening angina pectoris with ST-T changes or non-Q wave acute myocardial infarction and all had a totally occluded saphenous vein bypass graft. The new technique entailed the positioning of an angiographic catheter into the stub of the occluded graft and the advancement of an infusion wire into the graft. Patients were returned to the coronary care unit, where urokinase was delivered at a dose of 100,000 to 250,000 U/h. The total dose of urokinase ranged from 0.7 to 9.8 million U over 7.5 to 77 h (mean 31). After therapy, recanalization was seen in 37 (79%) of the 47 grafts. In 20 successfully treated patients, angiography was performed 1 to 24 (mean 11) months after treatment; 13 (65%) of these grafts were patent.(ABSTRACT TRUNCATED AT 250 WORDS)

Programmed ventricular stimuli introduced during sustained monomorphic ventricular tachycardia frequently reset the tachycardia, resulting in a less than fully compensatory pause. A resetting response curve is generated when the set of return cycles is evaluated as the function of the coupling intervals of the extrastimuli delivered during the ventricular tachycardia. If the stimulated wave front encounters tissue within the tachycardia circuit that is not fully recovered, interval-dependent conduction changes should occur producing an increasing resetting response pattern. We quantified the magnitude of this interval-dependent conduction slowing in 17 morphologically distinct ventricular tachycardias. The slope of the increasing limb of the resetting response curve was determined by linear regression analysis and ranged from -0.30 to -1.14 (mean +/- SD, 0.70 +/- 0.25). Seven of the 17 ventricular tachycardias (41%) terminated during introduction of ventricular extrastimuli. The slope of the resetting response pattern in those ventricular tachycardias that terminated were significantly steeper than in those that did not terminate (-0.85 +/- 0.15 versus -0.61 +/- 0.21, respectively, p = 0.025). Six of the seven ventricular tachycardias terminated with programmed ventricular stimuli had a slope steeper than -0.75, whereas only one of 10 ventricular tachycardias that did not terminate exceeded this value. In conclusion, the slope of the increasing portion of the resetting response curve correlates with ability to terminate uniform sustained ventricular tachycardia by timed extrastimuli. This slope is the quantification of the magnitude of interval-dependent conduction slowing. Additionally, tissue within the reentrant circuit displaying greater degrees of interval-dependent conduction slowing may also have relatively longer effective refractory periods.

The incidence and significance of fusion of the QRS complex during resetting of sustained ventricular tachycardias (VTs) was determined in 53 VTs induced by programmed stimulation in 46 patients with prior myocardial infarction. All 53 VTs were reset with one or two extrastimuli delivered at the right ventricular apex (RVA); 29 (54.7%) demonstrated fusion of the VT QRS complex coincident with the extrastimulus resetting the VT. Activation time at the RVA during VT (measured from the onset of the VT QRS complex to the first rapid deflection of the RVA electrogram) was longer in VT reset with fusion compared with those without fusion (91 +/- 30 vs 33 +/- 32 msec; p less than .001). A right bundle branch block VT QRS morphology and a rightward and inferior axis were more common in VT reset with electrocardiographic (ECG) fusion. Additionally, the shortest return cycle following the extrastimulus resetting the VT was shorter in VT reset with ECG fusion compared with those without (327 +/- 66 vs 423 +/- 84 msec; p less than .001). Fusion of the endocardial electrogram recorded at the site of VT origin was noted in 11 of 15 VTs that were reset while a recording catheter was positioned at this site, including all eight VTs with evidence of surface ECG fusion and three of seven VTs without fusion. Seventeen VTs were reset from the right ventricular outflow tract as well as the RVA; eight demonstrated QRS fusion at both sites, five from the right ventricular outflow tract only, and four from neither site.(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate the mechanism of slowing of the rate of ventricular tachycardias (VTs) by procainamide, resetting response patterns were characterized in 24 VTs in 22 patients. All patients had coronary artery disease and inducible sustained VT during procainamide therapy. Only tachycardias with the same surface QRS morphology before and after procainamide were studied: all were slowed by procainamide. The mean cycle length was 292 +/- 61 ms before and 374 +/- 61 ms after procainamide (p less than 0.05). The mean effective refractory period, measured at the right ventricle, was 241 +/- 21 ms before and 261 +/- 24 ms after procainamide (p less than 0.05). During procainamide therapy, single and double extrastimuli were delivered during VT and resetting response patterns identified. Patterns were characterized as flat, increasing or flat plus increasing. Resetting was seen in 17 (71%) of these VTs and resetting response patterns were identified in 16 (94%) of these. The resetting response pattern was flat in 7, flat plus increasing in 5 and increasing in 4. The finding of some flat portion at the end of resetting response patterns in 12 VTs after procainamide indicates that the reentrant impulse conducts through fully recovered tissue within the circuit. It suggests that procainamide slowed these VTs by slowing conduction velocity in fully recovered tissue due to sodium channel blockade and not by prolongation of action potentials and refractory periods.

A prospective study was undertaken to assess the response of patients with idiopathic dilated cardiomyopathy to programmed electrical stimulation (PES). Fifteen patients undergoing evaluation of congestive heart failure were studied. All patients underwent cardiac catheterization and coronary angiography as well as endomyocardial biopsy to exclude known causes of heart failure. No patient had a history of syncope or sustained ventricular arrhythmias. All patients were found to have severe left ventricular dysfunction (mean ejection fraction 17%), as well as nonsustained ventricular tachycardia on ambulatory monitoring or exercise testing. A protocol using up to two premature stimuli and burst pacing, from two right ventricular sites, induced up to four repetitive ventricular responses but failed to induce a sustained ventricular arrhythmia in any patient. Patients with dilated cardiomyopathy, advanced ventricular arrhythmias, and depressed left ventricular function respond differently than do patients with coronary artery disease, advanced ventricular arrhythmias, and depressed left ventricular function, to PES. PES appears to have limited value in the evaluation of patients with dilated cardiomyopathy and nonsustained ventricular arrhythmias.

Unlabelled: To evaluate the influence of local tissue refractoriness and delay in intervening tissue on the ability of single ventricular extrastimuli to reset and characterize a resetting response pattern in ventricular tachycardia (VT), single ventricular extrastimuli were delivered during 81 VTs and double ventricular extrastimuli in 45 of the 81 VTs. Resetting of VT was recognized as a less than fully compensatory pause after stimulation and was seen in 43 of 81 VTs (53%) with single ventricular extrastimuli and 35 of 45 (78%) with double ventricular extrastimuli. Double ventricular extrastimuli reset 16 VTs not reset by single ventricular extrastimuli. The return cycle, the interval from the extrastimulus to the first VT beat after extrastimuli, has 1 of 3 distinct response patterns: flat, increasing, and flat plus increasing. In 19 VTs, resetting was seen with both single ventricular extrastimuli and double ventricular extrastimuli; 4 flat responses with single ventricular extrastimuli became flat plus increasing with double ventricular extrastimuli. All other patterns were unchanged. In the 19 VTs reset by both single and double ventricular extrastimuli, the estimate of both the total reset zone (94 +/- 36 vs 56 +/- 32 ms) and the flat portion of the reset zone (52 +/- 42 vs 42 +/- 28 ms) was significantly longer with double ventricular extrastimuli (p less than 0.001 and p less than 0.02, respectively)., In Conclusion: (1) when single ventricular extrastimuli failed to reset a VT, double ventricular extrastimuli from the same site may reset the VT.

Uniform, sustained ventricular tachycardia (VT) in the setting of prior myocardial infarction is believed to be due to reentry. The ability to reset VT with programmed extrastimuli requires that the premature impulse reach and enter the reentrant circuit. To evaluate the importance of the site of pacing on the ability to reset VT, single ventricular extrastimuli were delivered during 32 morphologically distinct, uniform VTs from both the right ventricular (RV) apex and RV outflow tract. Single ventricular extrastimuli resulted in resetting of VT from the RV apex only in 6 VTs, from the RV outflow tract only in 2, from both sites in 11 VTs and neither site in 13. When VT reset at both RV sites, 1 RV site or neither RV site was compared, a left bundle branch block VT QRS morphologic pattern was found to be more common in VT reset at both sites than at neither site (8 of 11 vs 4 of 13, p less than 0.05). No other differences in VT characteristics analyzed were found between these groups. Multiple ventricular extrastimuli were delivered in 16 VTs; in 6 of these, resetting was shown from at least 1 additional site, as compared to the response with single ventricular extrastimuli. In summary, site of stimulation can influence the ability of premature extrastimuli to reset uniform VT, and site dependence of VT resetting diminishes when multiple extrastimuli are used. This suggests that refractoriness or conduction delay in tissue between the pacing site and tachycardia circuit are important determinants of ability to reset VT from a particular site.

Transient entrainment was demonstrated during 59 pacing events in 18 episodes of sustained uniform ventricular tachycardia (VT) while recording electrograms from the site of origin of tachycardia (LE-SOO). During entrainment, the morphology of the initial component of the LE-SOO was identical to the morphology observed during the tachycardia in 13 VTs (group I), but in five VTs (group II), the initial component changed at a "critical" paced cycle length. The presence of the proposed surface electrocardiographic criteria for entrainment--fixed fusion and a first postpacing complex without fusion but occurring at the paced cycle length--were integrally dependent on the morphologic changes in the local presystolic electrogram. Fixed fusion of the surface electrocardiogram at one or more paced cycle lengths was detected during entrainment at 35 of 59 paced cycle lengths in 12 of 18 tachycardias, 10 of which were group I and two of which were group II VTs. Fixed fusion demonstrated by analysis of the LE-SOO was observed at one or more pacing cycle lengths in 17 of 18 VTs. In five tachycardias in which surface electrocardiographic fusion was not observed, fixed fusion was evident on analysis of the left ventricular LE-SOO during right ventricular pacing. The first postpacing interval, as measured at the surface electrocardiogram, was consistently equal to the paced cycle length in only one of 18 tachycardias and was greater than the VT cycle length in eight of 17 tachycardias. A pathway with a long conduction time was demonstrated during entrainment. However, in those 12 VTs in patients in whom pacing was performed at more than one cycle length and there was preservation of the LE-SOO morphology, the conduction time between the stimulus and presystolic electrogram remained constant. Thus, no evidence for "atrioventricular nodal-like" decremental conduction was observed over a wide range of pacing cycle lengths. We conclude that: (1) two of the previously proposed criteria for diagnosis of entrainment (fixed fusion on the surface electrocardiogram and a first postpacing interval equal to the paced cycle length) are overly restrictive criteria for definition of "entrainment" of VT, (2) analysis of endocardial recordings from the site of origin of tachycardia during attempted entrainment of VT is useful for documenting the presence of entrainment, and (3) such analysis provides a basis for the understanding of surface electrocardiographic phenomenon associated with entrainment.