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Left atrial appendage closure (LAAC) is an intervention aimed at stroke prevention in nonvalvular atrial fibrillation (AF). There is a three-fold increased risk of stroke in patients with concomitant presence of AF and heart failure (HF). While anticoagulation is effective, only 60% receive it. We aimed at studying the safety of LAAC in HF patients using a national all-payer database.We queried the National Inpatient Sample for the year 2016-2018 for WATCHMAN device insertion using ICD 10 procedure codes. We divided the study population into HF and non-HF groups. Outcomes were compared using appropriate statistical tests, p .05 was considered significant.34 385 LAAC procedures were identified of which 8530 (24.8%) were done in patients with HF. The mean (SD) age of the study population was 76 (7.9) years and 42% were female. There was no difference in mean age between HF and non-HF groups. Our findings indicate that there is no difference in inpatient mortality and cardiac complications between the HF and non-HF groups. However, noncardiac complications including acute kidney injury and respiratory failure were higher in the HF group.LAAC appears to be a safe procedure in patients with HF. The study is limited by a short follow up period and long-term follow-up is required before definitive conclusions can be made.

Remote monitoring of cardiac implantable electronic devices (CIEDs) has become routine practice as a result of the advances in biomedical engineering, the advent of interconnectivity between the devices through the Internet, and the demonstrated improvement in patient outcomes, survival, and hospitalizations. However, this increased dependency on the Internet of Things comes with risks in the form of cybersecurity lapses and possible attacks. Although no cyberattack leading to patient harm has been reported to date, the threat is real and has been demonstrated in research laboratory scenarios and echoed in patient concerns. The CIED universe comprises a complex interplay of devices, connectivity protocols, and sensitive information flow between the devices and the central cloud server. Various manufacturers use proprietary software and black-box connectivity protocols that are susceptible to hacking. Here we discuss the fundamentals of the CIED ecosystem, the potential security vulnerabilities, a historical overview of such vulnerabilities reported in the literature, and recommendations for improving the security of the CIED ecosystem and patient safety.

Electrophysiology (EP) procedures carry the risk of kidney injury due to contrast/hemodynamic fluctuations. We aim to evaluate the national epidemiology of acute kidney injury requiring dialysis (AKI-D) in patients undergoing EP procedures. Using the National Inpatient Sample, we included 2,747,605 adult hospitalizations undergoing invasive diagnostic EP procedures, ablation and implantable device placement from 2006 to 2014. We examined the temporal trend of AKI-D and outcomes associated with AKI-D. The rate of AKI-D increased significantly in both diagnostic/ablation group (8-21/10,000 hospitalizations from 2006 to 2014, P = 0.02) and implanted device group (19-44/10,000 hospitalizations from 2006 to 2014, P < 0.01), but it was explained by temporal changes in demographics and comorbidities. Cardiac resynchronization therapy and pacemaker placement had higher risk of AKI-D compared to implantable cardioverter-defibrillator placement (23 vs. 31 vs. 14/10,000 hospitalizations in cardiac resynchronization therapy, pacemaker placement, and implantable cardioverter-defibrillator group, respectively). Development of AKI-D was associated with significant increase in in-hospital mortality (adjusted odds ratio, 9.6 in diagnostic/ablation group, P < 0.01; adjusted odds ratio, 5.1 in device implantation group, P < 0.01) and with longer length of stay (22.5 vs. 4.5 days in diagnostic/ablation group, 21.1 vs. 5.7 days in implanted device group) and higher cost (282,775 vs. 94,076 USD in diagnostic/ablation group, 295,660 vs. 102,007 USD in implanted device group). The incidence of AKI-D after EP procedures increased over time but largely explained by the change of demographics and comorbidities. This increasing trend, however, was associated with significant increase in resource utilization and in-hospital mortality in these patients.

Heart transplantation is the most effective long-term therapy for end-stage heart disease. There is limited data related to sudden cardiac arrest (SCA) in postheart transplant recipients. We aimed to describe the trends, and rate of SCA following heart transplantation and thereby identify clinical predictors as well as outcomes of SCA in patients post-transplant. We queried the National Inpatient Sample (NIS) with administrative codes for SCA and heart transplant. We assessed baseline differences between SCA and non-SCA admissions, with hazard ratios adjusted for age, gender, CCI, and race. Multivariable logistic regression models were generated to identify the independent predictors for SCA. There was a total of 30,020 hospitalizations of heart transplant recipients between 1999 and 2014 in the United States and among these 1,953 patients (6.5%) suffered SCA with an increasing trend of admissions for SCA. Among the patients who suffered from SCA, 18.83% died during the same hospitalization, 19.29% were discharged to a long-term facility, and 61.38% were discharged home. Multivariate analysis demonstrated that conduction system disorders (Hazard ratio [95% confidence interval]; 7.1 [4.5-11.1]), female gender (HR:1.2 [1.1-1.3]), diabetes (HR:1.4 [1.2-1.6]), and hypertension (HR:1.2 [1.1-1.4]) were the strongest predictors for SCA. SCA hospitalizations occur in 6.5% of patients post cardiac transplant and have been increasing from 1999 to 2014. Conduction block, graft rejection, female gender, hypertension, diabetes are independent predictors for SCA in heart transplant recipients.

Cardiac sarcoidosis is a component of an often multiorgan granulomatous disease of still uncertain cause. It is being recognized with increasing frequency, mainly as the result of heightened awareness and new diagnostic tests, specifically cardiac magnetic resonance imaging and18F-fluorodeoxyglucose positron emission tomography scans. The purpose of this case-based review is to highlight the potentially life-saving importance of making the early diagnosis of cardiac sarcoidosis using these new tools and to provide a framework for the optimal care of patients with this disease. We will review disease mechanisms as currently understood, associated arrhythmias including conduction abnormalities, and atrial and ventricular tachyarrhythmias, guideline-directed diagnostic criteria, screening of patients with extracardiac sarcoidosis, and the use of pacemakers and defibrillators in this setting. Treatment options, including those related to heart failure, and those which may help clarify disease mechanisms are included.

Objectives The present study investigated whether regional anesthetic techniques, especially truncal blocks, can provide adjunct anesthesia without the additional risk of general anesthesia and neuraxial techniques for subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. Design Single-center, prospective, randomized study. Setting Holding area and operating room at a single-center tertiary care hospital. Participants The study comprised 22 American Society of Anesthesiologists (ASA) physical status 3 or 4 patients with severe cardiac disease undergoing S-ICD implantation. Interventions Patients received either a combination of serratus anterior plane block and transversus thoracis plane block or surgical infiltration of local anesthetics. Measurements and Main Results Perioperative analgesic medication in the fascial plane block group versus the surgical wound infiltration group, visual analog pain scale score (0-10), intraoperative vital signs, total procedure time, and length of stay in the intensive care unit were measured. Total intraoperative fentanyl requirements (µg) were significantly less in the truncal block group versus the surgical infiltration group (45 [25-50] v 90 [50-100]; p = 0.026), and no patients had any adverse sequelae related to the study. Median intraoperative propofol use in the surgical infiltration group was 66.48 (47.30-73.73) µg/kg/min, and 65.95 (51.86-104.86) µg/kg/min for the truncal block group. This difference between the groups was not statistically significant (p = 0.293). Conclusions The performance of both the serratus anterior plane block and transversus thoracis plane blocks for S-ICD implantation are appropriate and may have the benefit of decreasing intraoperative opioid requirements.

Intracardiac echocardiography (ICE) use during catheter ablation of atrial fibrillation (AF) provides real-time information to guide transseptal access, for monitoring the ablation and recognition of pericardial bleed. We describe trends of ICE use, impact on complications, and its in-hospital outcomes.The national in-patient sample database was queried from 2001 to 2014 for diagnosis of AF based on ICD-9-CM 427.31 with a catheter ablation procedure code (37.34) in the same hospitalization and its associated complications. ICE was identified using ICD-9-CM procedure code (37.28). Statistical Analysis System (SAS) was used for analysis.There was an estimated total 299,152 patients who underwent AF ablation from 2001 to 2014 of which ICE was used in 46,688 (15.6%) patients. The use of ICE significantly increased from 0.08% in 2001 to 15.7% in 2014. In-hospital mortality was significantly lower in patients in whom ICE was used (0.11% vs 0.54%, p 0.0001). Complications were 52% lower in procedures using ICE vs without ICE (HR [95%CI]; 0.48 [0.44-0.51]). The rate of cardiac complications was also lower in ICE users (3.67% vs 4.51%; p = 0.025). The use of ICE during AF ablation resulted in significantly higher cost of hospitalization ($98,436 ± 597 vs $81,300 ± 310; p 0.0001), but this was offset by a decreased length of hospital stay (2.1 ± 0.02 vs 4 ± 0.02 days; p 0.0001).The use of ICE during AF ablation has increased over the years and is associated with lower in-hospital mortality and procedural complications, shorter LOS but an increased cost of hospitalization.

The atrioventricular node (AV) is considered the electrical connection between the atria and ventricles. There is an electrical pause between activation of the atria and the ventricles (PR segment), but to date the mechanism responsible for this interruption remains unclear. The present communication focuses on the hypothesis that magnetic field dynamics could provide the answer. Proof of this hypothesis is that in Wolff-Parkinson-White syndrome, where there is physical connection between the atria and ventricles (bundle of Kent), there is electrical AV continuity, no PR segment is detected, and catheter ablation of the abnormal bundle restores AV discontinuity. Spontaneous initiation of the heart at the level of the sinus node, the pacemaker of the heart, could also be explained via field dynamics. The known transmembrane pacemaker protein CHN4, present in both sinoatrial and AV nodal cells, could interact with field information to provide specificity in an electronic key-to-lock mechanism interaction.

Surgical site bleeding and infection are potential complications after electrophysiology (EP) device implantation procedures. To date, there is a wide variety of tools for management of intraoperative bleeding but it still remains unclear what methods are preferred.The aim of our study is to compare the rate of complications in patients who underwent cardiac implantable electronic device (CIED) implantation utilizing MPH hemostatic powder to the rate of complications in those patients who underwent standard procedure protocol without MPH hemostatic powder.In our study, a new plant-derived microporous polysaccharide hemostatic powder (Arista) was used. A total of 283 consecutive patients were retrospectively studied to assess the rate of complications in patients who underwent CIED implantation with MPH hemostatic powder (n = 77, MPH hemostatic powder) and without (n = 206, no MPH hemostatic powder). Patients were followed for 12 months.The MPH hemostatic powder group of patients had a lower complication rate when compared to no MPH hemostatic powder, 0.3% vs. 1.7% (p .05), respectively. The rate of device implantation site MPH hematoma in the MPH hemostatic powder group was 0.4%, versus 0.9% in the other group. There were no postoperative infections in the MPH hemostatic powder group versus 3.2% infections in the other group. The main predictor of increased risk of post-procedural complication was the usage of anticoagulation with a hazard ration of 2.7.Using MPH hemostatic powder for post-procedural hemostasis was shown to result in a significant reduction in the rate of overall post-procedural complications (a composite endpoint of hematoma and infections), and a trend in reduction of the infections rates and device implantation site hematoma rates.

Background— Cardiac involvement in sarcoidosis is often silent and may lead to sudden death. This study was designed to assess the value of programmed electric stimulation of the ventricle (PES) for risk stratification in patients with sarcoidosis and evidence of preclinical cardiac involvement on imaging studies. Methods and Results— Patients with biopsy-proven systemic sarcoidosis but without cardiac symptoms who had evidence of cardiac sarcoidosis on positron emission tomography (PET) or cardiac MRI (CMR) were included. All patients underwent baseline evaluation, echocardiographic assessment of left ventricular function, and programmed electric stimulation of the ventricle. Patients were followed for survival and arrhythmic events. Seventy-six patients underwent PES of the ventricle. Eight (11%) were inducible for sustained ventricular arrhythmias and received an implantable defibrillator. None of the noninducible patients received a defibrillator. Left ventricular ejection fraction was lower in patients with inducible ventricular arrhythmia (36.4±4.2% versus 55.8±1.5%, P P Conclusions— In patients with biopsy-proven sarcoidosis and evidence of cardiac involvement on PET or CMR alone, positive PES may help to identify patients at risk for ventricular arrhythmia. More importantly, patients in this cohort with a negative PES appear to have a benign course within the first several years following diagnosis. PES may help to guide the use of implantable cardioverter defibrillators in this population.

Periprocedural thromboembolic and hemorrhagic events are complications of percutaneous radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The management of anticoagulation before and after RFA could play an important role in the prevention of these complications. The incidence of thromboembolic events varies from 1% to 5%, depending on the ablation and the anticoagulation strategy used in the periprocedural period. The scientific evidence behind the management of anticoagulation in patients with AF undergoing RFA is scarce and is mostly based on small studies and experts' consensus. It remains unclear whether catheter ablation for AF reduces the risk of stroke and obviates the need for anticoagulation after the procedure. Limited data are available regarding the risk of thromboembolism with and without warfarin after AF ablation. In this review we will review the most current evidence supporting the different strategies to reduce thromboembolic risk before, during, and after catheter ablation for AF.

Background: Lead extraction is an effective method for removing pacemaker and defibrillator leads and to obtain venous access when central veins are occluded. Objective: We report a series of patients who required lead extraction and preservation of vascular access requiring a vascular snare introduced from the femoral vein to provide traction on the lead. This technique allowed advancement of the extraction sheath beyond the level of vascular occlusion, preserving vascular access in all patients. Methods: All patients had peripheral contrast venography performed immediately prior to the procedure to identify the site(s) of venous occlusion. An extraction sheath was employed and with direct manual traction, the lead tip pulled free from the myocardial surface prior to advancement of the sheath beyond the occlusion. A transfemoral snare was used to grasp the distal portion of the lead and traction was used to immobilize the lead. Results: In all patients, transfemoral snaring of the leads was necessary to allow safe advancement of a sheath to open the occluded venous system. There were no complications in any of the patients. Conclusion: Our series demonstrates the simple and safe technique of transfemoral lead snaring to assist lead extraction and maintain vascular access in the setting of venous occlusion, when the distal lead tip pulls free of the myocardium before an extraction sheath is passed beyond the point of venous obstruction.

Cardiac resynchronization therapy (CRT) is a well-established therapy for patients with moderate-to-severe heart failure (HF), left ventricular dysfunction with an ejection fractionor= 35% and a QRS on the surface electrocardiogram ofor=130 msec. Device optimization is often performed, adjusting the timing of RV and LV stimulation to produce a pacing sequence that yields the best global cardiac performance. However, no standard guidelines exist for optimization and many invasive and non-invasive techniques have been employed with mixed results. The aim of the present study was to determine whether there are any clinical predictors of the optimal V-V settings in patients implanted with CRT devices.We prospectively evaluated 47 consecutive patients with HF who were referred to our device optimization clinic. The mean patient age was 64.9 +/- 12.7 years. Patients were in both sinus rhythm (83%) and atrial fibrillation. Prior to device implant, 51% of patients had left bundle branch block (LBBB), 17% had intra-ventricular conduction delay (IVCD) and 21% were RV paced. Sixty-two percent were male, the mean QRS duration was 152 +/- 29 ms, mean LVEF 26 +/- 8% and 60% had a non-ischemic cardiomyopathy. Overall, 82% of patients required sequential pacing with 69% requiring LV pre-excitation to produce the best global cardiac function as determined by aortic velocity time integrals (VTI). In our cohort, none of the clinical characteristics evaluated, including etiology of the cardiomyopathy, QRS duration, LVEF, pre-implant rhythm or AV delay were predictive of an optimal simultaneous or sequential V-V setting.None of the clinical variables tested in our analysis predicted optimal RV-LV settings. Our results suggest that individual optimization and programming of V-V settings is necessary. The inability to predict optimal settings likely reflects the unique characteristics of each patient and supports the need for individualized programming of each device.

Once used only as third-line therapy for chronic pain management, methadone is now being used as first- and second-line therapy in palliative care. The risks and stigma associated with methadone use are known, but difficulties with dosing methadone and lack of an established conversion protocol from other opiates have limited the access for patient populations who could potentially benefit from this medication. For palliative care patients, the benefits of methadone can far outweigh its risks. This article provides an overview and specific recommendations on the use of parenteral methadone in pain and palliative care, with a focus on the transition from hospital to home/hospice care. The goal of this consensus guideline is to assist clinicians who are providing chronic pain management in acute care hospital and nonhospital settings (i.e., hospice, long-term care facilities, and community) for patients with life-limiting illnesses, where the goals of care are focused on comfort (i.e., palliative care). The recommendations in this article intend to promote a standard of care involving the use of intravenous methadone with the aim of reaching a broader population of patients for whom this drug would provide important benefits.

A case of successful laser extraction of a defibrillator lead with baffle stenting in a 15-year-old boy with dextrocardia, L-transposition, ventricular septal defect, and pulmonic stenosis status-post Senning/Rastelli repair is presented. Six-month follow-up revealed a significant increase in exercise tolerance and maximum oxygen consumption (VO(2)max).

As Implantable Cardioverter Defibrillators (ICDs) have become more common, ethical issues have arisen regarding the deactivation of these devices. Goldstein et al., have shown that both patients and cardiologists consider ICD deactivation to be different from the discontinuation of other life-sustaining treatments. It cannot be argued ethically that ICDs raise new questions about the distinction between withholding and withdrawing treatment, and neither the fact that they are used intermittently, nor the duration of therapy, nor the mere fact that they are located inside the body can be considered unique to these devices and morally decisive. However, frequent allusions to the fact that they are located inside the body might provide a clue about what bothers patients and physicians. As technology progresses, some interventions seem to become a part of the patient as a unified whole person, completely replacing body parts and lost physiological functions rather than merely substituting for impaired structure and function. If a life-sustaining intervention can be considered a "replacement"--a part of the patient as a unified whole person--then it seems that deactivation is better classified as a case of killing rather than a case of forgoing a life-sustaining treatment. ICDs are not a "replacement" therapy in this sense. The deactivation of an ICD is best classified, under the proper conditions, as the forgoing of an extraordinary means of care. As technology becomes more sophisticated, however, and new interventions come to be best classified as "replacements" (a heart transplant would be a good example), "discontinuing" these interventions should be much more morally troubling for those clinicians who oppose euthanasia and assisted suicide.

Using cardiac magnetic resonance, the presence of myocardial delayed contrast enhancement (DCE) has been described in the ventricular septum at the level of the right ventricular insertion points in patients with pulmonary hypertension (PH). The aim of this study was to investigate the prevalence, extent, and correlates of this finding. Septal DCE was evaluated in 55 patients with known or suspected PH of various causes. The extent of DCE was estimated visually with an insertion enhancement score (range 0 to 4) and quantified as DCE mass. The results were correlated with cine magnetic resonance and right-sided cardiac catheterization. Predictors of DCE were investigated using multivariate analysis. PH at rest was present in 42 patients (group 1) and absent in 13 (group 2). DCE was noted in 41 patients (97%) in group 1 and 3 (23%) in group 2 (p

Despite improvements in therapy, sudden cardiac death still poses a major problem for cardiovascular patients. In very high-risk patients, half of premature deaths are sudden. Certain inotropic drugs can increase the risk of death, but mechanical devices can provide prophylactic benefits. Winslowet al. sum up the major issues and challenges in this review. Sudden cardiac death (SCD) is the leading cause of cardiac death in the US. In the past few years, intensive efforts have been made to expand public awareness of SCD and to increase our understanding of its pathophysiology, medical treatment options and device therapy. Significant advances have been made in our ability to prevent SCD in both primary and secondary health care. Two critical issues remain, however: the identification of patients who would benefit from such therapies, and how to achieve even greater prevention, especially primary prevention. The goal of this article is to provide a review of the topic of SCD in the setting of abnormal myocardial substrate, to outline the techniques that are useful in identifying patients at risk, and available treatment options.

The utility of programmed ventricular stimulation to predict future arrhythmic events in patients with cardiac sarcoidosis is unknown. Similarly, the long-term benefit of implantable cardioverter-defibrillators (ICDs) in cardiac sarcoidosis has not been established. Thirty-two consecutive patients with cardiac sarcoidosis underwent programmed ventricular stimulation. Patients with spontaneous or inducible sustained ventricular arrhythmias (n = 12) underwent ICD insertion. All study patients were followed for the combined arrhythmic event end point of appropriate ICD therapies or sudden death. Mean length of follow-up to sustained ventricular arrhythmia or sudden death was 32 +/- 30 months. Five of 6 patients (83%) with spontaneous sustained ventricular arrhythmias and 4 of 6 patients (67%) without spontaneous but with inducible sustained ventricular arrhythmias received appropriate ICD therapy. Two of 20 patients (10%) with neither spontaneous nor inducible sustained ventricular arrhythmias experienced sustained ventricular arrhythmias or sudden death. Programmed ventricular stimulation predicted subsequent arrhythmic events in the entire population (relative hazard 4.47, 95% confidence interval [CI] 1.30 to 15.39) and in patients who presented without spontaneous sustained ventricular arrhythmias (relative hazard 6.97, 95% CI 1.27 to 38.27). No patient with an ICD died of a primary arrhythmic event. In patients with spontaneous or inducible sustained ventricular arrhythmias, mean survival from first appropriate ICD therapy to death or cardiac transplant was 60 +/- 46 months, with only 2 patients dying or reaching transplant at study end. In conclusion, programmed ventricular stimulation identifies patients with cardiac sarcoidosis at high risk for future arrhythmic events. ICDs effectively terminate life-threatening arrhythmias in high-risk patients, with significant survival after first appropriate therapy.

OBJECTIVES The purpose of this study was to evaluate the transfemoral venous approach for electrophysiologic interventions in patients with inferior vena cava filters. BACKGROUND Reports have detailed complications associated with obtaining central venous access in patients with inferior vena cava filters. Accordingly, electrophysiologic interventions have been modified or deferred altogether in such patients. METHODS Patients requiring interventions with a transfemoral approach who were at least 3 months post filter insertion underwent fluoroscopically guided insertion and withdrawal of electrode catheters with appropriate follow-up. RESULTS Five patients underwent successful pacing, electrophysiologic study, or radiofrequency ablation using one to three catheters, with no complications attributable to filter placement. CONCLUSIONS Transfemoral electrophysiologic interventions can be safely undertaken across vena cava filters provided appropriate precautions are taken.

Cardiac sarcoidosis (CS) patients are at increased risk for sudden death. Isolated CS is rare and can be difficult to diagnose.In this multicenter retrospective review, patients with CS and an implantable cardiac defibrillator (ICD) were identified.Of 235 patients with CS and ICD, 13 (5.5 %) had isolated CS, including 7 (3.0 %) with definite isolated CS (biopsy or necropsy-proven) and 6 (2.6 %) with suspected isolated CS based on a constellation of clinical, ECG, and imaging findings. Among 13 patients with isolated CS, 10 (76.9 %) were male, mean age was 53.8 ± 7.6 years, and mean left ventricular ejection fraction was 38.3 ± 16.5. Diagnosis was made by cardiac magnetic resonance (CMR) (n = 2), biopsy (n = 3), CMR and biopsy (n = 2), CMR and positron emission tomography (PET) (n = 2), PET (n = 1), late enhanced cardiac CT (n = 1), pathology at heart transplant (n = 1), and autopsy (n = 1). Eight of 13 (61.5 %) patients with isolated CS had a secondary prevention indication (VT in 6 and VF in 2) vs. 80 of 222 (36.0 %) with sarcoidosis in other organs (p = 0.04). Over a mean of 4.2 years, 9 of 13 (69.2 %) patients with isolated CS received appropriate ICD therapy, including anti-tachycardia pacing (ATP) and/or shock, compared with 75 of 222 (33.8 %) patients with cardiac and extracardiac sarcoidosis (p = 0.0150). Six of 7 (85.7 %) patients with definite isolated CS received appropriate ICD intervention, compared with 78 of 228 patients (34.2 %) without definite isolated CS (p = 0.0192.)In this retrospective study, patients with isolated CS had very high rates of appropriate ICD therapy. Prospective, long-term follow-up of consecutive patients with isolated CS is needed to determine the true natural history and rates of ventricular arrhythmias in this rare and difficult-to-diagnose disease.

We previously reported on the incidence and clinical implications of supraventricular arrhythmia in patients with cardiac sarcoidosis (CS). The role of catheter ablation for the management of atrial arrhythmia (AA) in this patient population is unknown.One hundred consecutive patients with CS were monitored for the incidence of supraventricular arrhythmias. Those with persistent symptoms despite optimal medical therapy proceeded to catheter ablation. Following ablation, all patients were followed serially with Holter monitoring or device interrogation. Thirty-two (32%) patients had symptomatic supraventricular arrhythmias. Nine (28%) patients had symptomatic AA requiring catheter ablation for clinical indications. Mean age was 55 ± 11.6 years. Five (56%) patients had atrial fibrillation (AF), of whom 2 also had cavotricuspid isthmus ablation. Four patients had isolated atrial flutter: 2 patients with left atrial flutter, and 2 patients with cavotricuspid flutter. All other arrhythmias were ablated in the left atrium. Mean duration of follow-up was 1.8 ± 1.9 years. One patient with atypical atrial flutter, and one patient with AF have had recurrence; the remaining patients remain in sinus rhythm.Our study suggests that AA in CS is frequently left atrial in origin. Catheter ablation appears to be effective and safe for the maintenance of sinus rhythm in patients with CS.

Atrial fibrillation (Afib) has been associated with abnormal signal-averaged P wave (SAPW) parameters but whether SAPW is associated with the time course of these arrhythmias (persistent vs. paroxysmal, frequent vs. rare episodes) remains unknown. This article assesses the significance of SAPW duration in distinguishing patients with paroxysmal from those with persistent Afib. SAPW electrocardiogram was performed with a "double triggering" software system for acquisition and analysis of data. SAPW total duration (TD), X, Y, and Z leads magnitudes and vector signal magnitudes were measured offline. Optimal cutoff value between control and patient groups was determined by using a receiver operator characteristic curve. Data were analyzed to compare controls with patients groups and between patient groups according to time course of the arrhythmic history. Fifteen age-matched patients without a history of Afib and 55 patients with a history of Afib (33 with paroxysmal and 22 with persistent arrhythmia) were studied off antiarrhythmic drugs. Patients with history of persistent arrhythmia were studied within 2 days after electrical cardioversion to sinus rhythm. SAPW TD was the only parameter consistently associated with Afib. SAPW TD was 98 +/- 6 ms (mean +/- SD) in the control group, 127 +/- 19 ms in the pooled patients group (P =.0001); 122 +/- 20 ms for paroxysmal and 133 +/- 17 ms for the persistent Afib group (P =.04). Analysis of other SAPW parameters were not statistically significant. SAPW duration is a simple method to identify patients with history of Afib. A significantly longer SAPW TD characterizes patients with a history of persistent as opposed to paroxysmal Afib. Prolongation of SAPW TD possibly reflects more advanced electrophysiological changes, creating a more stable substrate that leads to persistence of the arrhythmia.

Fabry disease results from deficient alpha-galactosidase A (alpha-Gal A) activity and the pathologic accumulation of the globotriaosylceramide (GL-3) and related glycosphingolipids, primarily in vascular endothelial lysosomes. Treatment is currently palliative, and affected patients generally die in their 40s or 50s. Preclinical studies of recombinant human alpha-Gal A (r-halphaGalA) infusions in knockout mice demonstrated reduction of GL-3 in tissues and plasma, providing rationale for a phase 1/2 clinical trial. Here, we report a single-center, open-label, dose-ranging study of r-halphaGalA treatment in 15 patients, each of whom received five infusions at one of five dose regimens. Intravenously administered r-halphaGalA was cleared from the circulation in a dose-dependent manner, via both saturable and non-saturable pathways. Rapid and marked reductions in plasma and tissue GL-3 were observed biochemically, histologically, and/or ultrastructurally. Clearance of plasma GL-3 was dose-dependent. In patients with pre- and posttreatment biopsies, mean GL-3 content decreased 84% in liver (n=13), was markedly reduced in kidney in four of five patients, and after five doses was modestly lowered in the endomyocardium of four of seven patients. GL-3 deposits were cleared to near normal or were markedly reduced in the vascular endothelium of liver, skin, heart, and kidney, on the basis of light- and electron-microscopic evaluation. In addition, patients reported less pain, increased ability to sweat, and improved quality-of-life measures. Infusions were well tolerated; four patients experienced mild-to-moderate reactions, suggestive of hypersensitivity, that were managed conservatively. Of 15 patients, 8 (53%) developed IgG antibodies to r-halphaGalA; however, the antibodies were not neutralizing, as indicated by unchanged pharmacokinetic values for infusions 1 and 5. This study provides the basis for a phase 3 trial of enzyme-replacement therapy for Fabry disease.

Thirty-seven patients with atrial flutter were studied with catheter mapping and radiofrequency ablation. Uncommon atrial flutter occurred in 20 out of 37 (54%) patients. Atrial endocardial mapping showed two types of uncommon atrial flutter. In 15 patients (group I) it was characterized by a single clockwise circuit whereas in 5 patients (Group II) it was characterized by the presence of more than one circuit and/or localized atrial fibrillation. RFA ablation was acutely successful in 14 out of 15 patients (93%) in Group I and in 2 out of 5 (40%) patients in Group II. On long-term follow-up a significantly larger number of patients in Group I versus Group II (86% vs 20%) remained free of atrial flutter recurrence. We conclude that uncommon atrial flutter is a heterogeneous entity involving one or more reentrant circuits. Uncommon atrial flutter with multiple circuits may not be suitable for RFA.

Adenosine has been demonstrated to reliably produce transient block of atrioventricular nodal (AVN) conduction, and has been advocated as a method of differentiating retrograde conduction via the atrioventricular node from accessory pathway conduction. However, the response of retrograde AVN to adenosine in patients with typical atrioventricular nodal reentry tachycardia (AVNRT) remains unclear. We evaluated 13 patients (mean age 45 +/- 20 years) with typical AVNRT prior to AVN modification. During right ventricular pacing, a rapid bolus of adenosine (0.2 mg/kg; maximum 18 mg) was administered. Adenosine sensitivity, defined by transient ventriculoatrial block, was observed in six patients, while in seven patients ventriculoatrial conduction was unaffected. An adenosine bolus administered during sinus rhythm or atrial pacing resulted in antegrade atrioventricular block in all the adenosine resistant patients in whom this was performed (n = 6). Comparisons of AVN electrophysiological characteristics between the adenosine sensitive and adenosine resistant patients were performed. There was no difference with respect to ventriculoatrial effective refractory period, ventriculoatrial Wenckebach, AVNRT cycle length, and His to atrial echo interval in AVNRT. However, there was a trend toward a longer antegrade fast pathway ERP in the adenosine sensitive group (P = 0.07). Electrophysiological properties do not predict retrograde AVN adenosine sensitivity. Adenosine does not cause retrograde AVN block in all patients with AVNRT, and therefore cannot reliably distinguish between retrograde conduction via the AVN or an accessory pathway.

Preexcitation developed post-operatively in a cardiac transplant recipient whose donor electrocardiogram was normal. An electrophysiology study revealed evidence of a mid-septal atrioventricular (AV) bypass tract. The patient is clinically well fourteen months after transplant and has intermittent preexcitation.

adiofrequency catheter ablation of accessory pathways has ecome a well-established therapy with a high rate of success. ntracardiac electrophysiologic study, mapping, and ablation of he pathway are typically performed either in sinus rhythm or uring AV reentrant tachycardia. However, atrial fibrillation ccurs commonly in these patients (11.5%–39%). It may be he presenting arrhythmia and can occur during the electrohysiologic study. Atrial fibrillation during electrophysiologic tudy makes mapping and catheter ablation difficult. Previous eports have described ablation of AV accessory pathways uring atrial fibrillation using an accessory pathway potential r earliest ventricular activation as a guide. Pathway potenial localization can be used to guide ablation of an atriofasicular (Mahaim) pathway during atrial fibrillation. However, ocalization of these potentials is different compared with AV athways, as illustrated in the following case.

Nonphysiological prolongation of PR intervals can lead to palpitations and shortness of breath similar to those seen with pacemaker syndrome. This has been shown to be related to diastolic mitral regurgitation.1 We present a case of intermittent first-degree AV block that was caused by premature ventricular contraction (PVC)–induced slow pathway conduction. Catheter ablation of the slow pathway and the PVC focus normalized the PR interval and abolished all symptoms. The patient is a 74-year-old women with a structurally normal heart who presented with palpitations, shortness of breath, dizziness, and decreased exercise tolerance. Event monitoring disclosed no sustained arrhythmia but revealed frequent PVCs. The PVCs had left bundle-branch block morphology and a normal QRS axis. The baseline PR interval was normal; however, prolonged periods of first-degree AV block (PR>500 ms) were noted. First-degree AV block was consistently initiated by PVCs (Figure 1A). Interestingly, appropriately timed PVCs just as consistently led to normalization of the PR interval (Figure 1B). In the absence of such appropriately timed PVCs, slow pathway conduction persisted. She did …

Cardiac sarcoidosis (CS) is known to be associated with congestive heart failure, conduction disorders, and tachyarrhythmias. Ventricular arrhythmias are the most feared cardiac manifestation because they often are unpredictable, may be the fi rst manifestation of the disease, and may be fatal. The propensity for the development of supraventricular arrhythmias (SVAs) in patients with CS has not been described. The aim of this study was to assess the prevalence as well as the predictors of SVA.We retrospectively investigated 100 patients with biopsy specimen-proven systemic sarcoidosis and evidence of cardiac involvement (defi ned by cardiac biopsy specimen, PET scan, or cardiac MRI). The mean follow-up was 5.8 3.6 years. ECG, Holter monitoring, implantable cardioverter defibrillator interrogations, or electrophysiology studies were used to document SVA. Echocardiographic data, demographics, and extracardiac involvement were recorded, and univariate and Poisson regressions were performed to compare characteristics of patients with and without documented SVA.The prevalence of SVA was 32%, and atrial fibrillation was the most common arrhythmia, comprising 18% of the total burden, followed by atrial tachycardias (7%), atrial fl utter (5%), and other supraventricular tachycardias (2%). Of the patients with SVA, 96% were symptomatic. Left atrial enlargement (LAE) was more frequent in the group with SVA, with an incidence of 267.8 per 1,000 person-years, and it significantly increased the likelihood of SVA on multivariate analysis (risk ratio, 6.12; 95% CI, 2.19-17.11). Diastolic dysfunction, systemic hypertension, and right atrial enlargement were predictors of SVA on univariate analysis. Left ventricular hypertrophy, right ventricular dysfunction, tricuspid valve disease, pulmonary hypertension, and pulmonary sarcoidosis were not associated with SVA on univariate analysis.The study systematically evaluated the frequency of SVA in a large number of patients with CS. SVA in patients with CS is frequent and associated with symptoms. LAE was clearly associated with the development of SVA in this patient population. The extent to which LAE predicts the occurrence of SVA in larger, more diverse CS populations should be evaluated prospectively.

Heart disease is the leading cause of death in the United States. Probably the most feared complication of this disease is sudden cardiac death, which accounts for 350,000 to 400,000 deaths annually. Despite the large number of out-of-hospital cardiac arrests, only a small proportion of such patients will survive long enough to receive medical care and, of those, only a percentage will survive to hospital discharge. 1 Patients at particular risk of ventricular tachyarrhythmias and therefore sudden cardiac death (SCD) are those with congestive heart failure (CHF). An analysis of the Framingham data revealed an age-adjusted rate of SCD of 31.4 per 1000 for men with heart failure versus 5.7 per 1000 for men without heart failure (9.9/1000 and 1.8/1000, respectively, for women). 2 Although revascularization, ablation, surgery, or transplantation are options for certain patients, most do not qualify for such procedures. Therefore essentially only two widespread options exist: arrhythmia suppression by using available drug therapy or implantation of a cardiac defibrillator (ICD). Medical therapy. Large studies such as CONSENSUS and V-HEFT have demonstrated the usefulness ofvasodilators, particularly the angiotensin-converting enzyme inhibitors, in reducing mortality in patients with poor ventricular function, a, 4 In addition, past studies have suggested a possible role for beta blockers in reducing cardiac mortality in these patients.5, 6 However, neither of these agents has gained acceptance for sustained ventricular arrhythmias. As for the available class 1 agents, several

Appropriate medical therapy and revascularization play a pivotal role in preventing or treating myocardial infarction and left ventricular systolic dysfunction, thereby reducing the incidence of SCD. Nevertheless, the ever-growing population of diabetic patients with coronary artery disease, prior myocardial infarction, and left ventricular systolic dysfunction continue to comprise a high-risk population. Thus, appropriate screening and utilization of ICD therapy will remain essential modalities in the ongoing battle against SCD. The use of devices capable of both biventricular pacing and ICD therapy will continue to grow in the ongoing effort to improve both quality of life and mortality in patients with systolic congestive heart failure.

This review article discusses the electrophysiological basis of sinus node reentry, clinical features of sinus node reentry, and the management of this uncommon tachycardia with drugs and ablative therapy. It also proposes the use of the term "sinoatrial reentrant tachycardia" for this form of tachycardia.

Aims Implantable cardiac defibrillator (ICD) implantation is a class IIA recommendation for patients with cardiac sarcoidosis (CS). However, little is known about the efficacy and safety of ICDs in this population. The goal of this multicentre retrospective data review was to evaluate the efficacy and safety of ICDs in patients with CS. Methods and results Electrophysiologists at academic medical centres were asked to identify consecutive patients with CS and an ICD. Clinical information, ICD therapy history, and device complications were collected for each patient. Data were collected on 235 patients from 13 institutions, 64.7% male with mean age 55.6 ± 11.1. Over a mean follow-up of 4.2 ± 4.0 years, 85 of 234 (36.2%) patients received an appropriate ICD therapy (shocks and/or anti-tachycardia pacing) and 67 of 226 (29.7%) received an appropriate shock. Fifty-seven of 235 patients (24.3%) received a total of 222 inappropriate shocks. Forty-six adverse events occurred in 41 of 235 patients (17.4%). Patients who received appropriate ICD therapies were more likely to be male (73.8 vs. 59.6%, P = 0.0330), have a history of syncope (40.5 vs. 22.5%, P = 0.0044), lower left ventricular ejection fraction (38.1 ± 15.2 vs. 48.8 ± 14.7%, P ≤ 0.0001), ventricular pacing on baseline electrocardiogram (16.1 vs. 2.1%, P = 0.0002), and a secondary prevention indication (60.7 vs. 24.5%, P < 0.0001) compared with those who did not receive appropriate ICD therapies. Conclusion Patients with CS and ICDs are at high risk for ventricular arrhythmias. This population also has high rates of inappropriate shocks and device complications.

The diagnosis of subclinical myocardial disease in patients with ventricular tachycardias of right ventricular (RV) origin and no overt cardiac abnormalities is important, inasmuch as the presence of RV cardiomyopathy or arrhythmogenic dysplasia can be associated with a poor prognosis. To this end the relative value of symptoms, ECG features of ventricular tachycardia, signal-averaged ECGs, and RV echocardiograms as compared with endomyocardial biopsy findings was prospectively evaluated. Twenty-seven patients with chronic ventricular tachycardias with a left bundle branch block-like morphology, presumed to be of RV origin, were studied. Clinical examination findings, 12-lead ECGs in sinus rhythm, radiographs of the chest, coronary angiograms, and left ventricular cineangiograms were normal in all patients. RV biopsies were abnormal in 11 patients (41%) with findings suggestive of RV dysplasia or cardiomyopathy. A multivariate analysis showed a significant correlation between an abnormal biopsy and sustained ventricular tachycardia (p0.05), tachycardia with a superior frontal plane axis (p0.001), an abnormal signal-averaged ECG (p0.05), and an abnormal RV echocardiogram (p0.001). An abnormal RV echocardiogram was both a sensitive (73%) and a specific (94%) indicator of an abnormal RV biopsy. Sustained tachycardia although sensitive (90%) had a low specificity (56%). In comparison, a superior frontal plane axis of ventricular tachycardia and an abnormal signal-averaged ECG were indicative of high specificity and low sensitivity for abnormal myocardial histologic findings.(ABSTRACT TRUNCATED AT 250 WORDS)

The treatment of supraventricular tachyarrhythmias has recently changed substantially. Although the true prevalence of paroxysmal supraventricular tachycardia in the population is unknown, it is nonetheless the most common cause of tachyarrhythmia in children and young adults. Given the spectrum of newly available medications and procedures for these arrhythmias, clinicians can find themselves unsure as to the best treatment for their patients. This overview will serve to examine the currently available options for the treatment of paroxysmal supraventricular tachyarrhythmias, namely atrioventricular (AV) nodal reentrant, AV reciprocating, and accessory pathway mechanisms (including the Wolff -Parkinson-white syndrome). This discussion will not include the more common atria1 fibrillation and flutter tachycardias or the automatic and multifocal atria1 tachycardias. Mechanisms. The classic paroxysmal supraventricular tachycardias (PSVT), AV nodal reentrant (tachycardia contained within the AV node and possibly a small rim of perinodal atria1 tissue) and the AV reciprocating tachycardia (tachycardia involving the AV node and an extranodal bypass tract) are two clinically similar but etiologically distinct forms of tachyarrhythmias. Both are usually regular tachycardias with rates between 120 and 300 beatslmin, of sudden onset and offset. Most patients are young adults and have no structural heart disease, although exceptions exist. AV nodal reentrant tachycardia (AVNRT) involves a reentrant circuit that uses slow and fast

In an effort to enhance patient safety in opioid treatment programs, the Substance Abuse and Mental Health Saervices Administration convened a multi-disciplinary Expert Panel on the Cardiac Effects of Methadone. Panel members (Appendix A) reviewed the literature, regulatory actions, professional guidances, and opioid treatment program experiences regarding adverse cardiac events associated with methadone. The Panel concluded that, to the extent possible, every opioid treatment program should have a universal Cardiac Risk Management Plan (incorporating clinical assessment, electrocardiogram assessment, risk stratification, and prevention of drug interactions) for all patients and should strongly consider patient-specific risk minimization strategies (such as careful patient monitoring, obtaining electrocardiograms as indicated by a particular patient's risk profile, and adjusting the methadone dose as needed) for patients with identified risk factors for adverse cardiac events. The Panel also suggested specific modifications to informed consent documents, patient education, staff education, and methadone protocols.

The beneficial effects of implanted cardioverter defibrillator (ICD) therapy in patients with malignant ventricular tachyarrhythmias and variable degrees of left ventricular (LV) dysfunction are debated. ICD use and patient survival were examined in 128 patients with malignant ventricular arrhythmias and moderate or severe LV dys function. Group I included 64 patients with moderate LV dysfunction (LV ejection fraction of > 30%) and group H, 64 patients with severe LV dysfunction (LV ejection fracfion of ≤ 30%). Follow-up period ranged from 1 to 78 months. The two groups were similar in age, incidence of coronary artery disease and presenting arrhythmia. The mean LV ejection fraction in group I was 44%± 8% and group II was 22%± 5% (P < 0.0001). At 4 years of follow-up, 66% of patients from group I and 62% from group II (P = NS) had ICD activation for presumed ventricular tachyarrhythmia. Survival was calculated using actuarial analysis. Arrhythmic or sudden death mortality at 4 years of follow-up was 4% in group I and 7% in group II (P = NS). Cardiac mortality was for group I, 7% (P < 0.05), 12% (fP < 0,01), 15% (P < 0.01), and 15% (P < 0.01) for follow-up years 1, 2, 3, and 4, respectively. For group II, cardiac mortality was 27%, 36%, 41%, and 41% for follow-up years for 1, 2, 3, and 4, respectively. The majority of cardiac deaths in both groups was observed in the first 2 years of follow-up. However, in both groups, cardiac mortality was comparable in patients who did (users) and did not (nonusers) experience appropriate ICD shocks. Thus, the incidence of long-term ICD use is comparable in patients with moderate and severe LV dysfunction. Cardiac mortality is higher in patients with severe LV dysfunction in the first 4 years of follow-up irrespective of device use. The comparable long-term clinical outcome of ICD users and non users in patients with moderate or severe LV dysfunction can be related to elimination of arrhythmic mortality. Long-term patient survival in ICD recipients with severe LV dysfunction remains substantial even at 4 years of follow-up.

The recent advisory of Medtronic Sprint Fidelis leads has resulted in significant controversy over proper management of patients. The current manufacture's guidelines recommend programming specific device alerts with close follow-up and implantable cardioverter-defibrillator lead replacement in patients with evidence of breach in lead integrity. Recently, several studies have identified significant limitations in this method of surveillance. We report the case of a pacemaker-dependent patient with an ischemic cardiomyopathy, who presented with cardiac arrest and evidence of fracture of the pace/sense portion of a Sprint Fidelis lead during postmortem interrogation. Likely mechanisms leading to his ultimate demise are discussed.

Stroke prevention in atrial fibrillation presents a challenge for many clinicians. A considerable amount of research has gone into creating scoring systems that can accurately predict thromboembolic risk. Patients at low enough risk are best treated with aspirin, whereas higher-risk patients require anticoagulation with warfarin despite its shortcomings. Antithrombotic regimens for moderate-risk patients require careful consideration based on bleeding risk, age, and the ability to undergo frequent serum monitoring. Oral drugs may soon be available to replace warfarin. While this may simplify dosing and monitoring, it will still be necessary to weigh the risks and benefits of therapy.

Background:In the past 2 years, multiple implantable cardioverter-defibrillator (ICD) manufacturers have issued recalls on ICD models due to the potential for serious malfunction and even patient death. Previous studies examining the relationship between these recalls and patients' psychological well-being have been limited by small sample size and conflicting results. The purpose of this study is to examine the association between ICD recalls and patients' anxiety, depression, and quality of life. Methods:Patients were drawn from an outpatient electrophysiology clinic at a tertiary care hospital in New York City. Patients who had devices subject to a recall (cases) were identified from lists provided by device manufacturer and controls (patients with ICDs not subjected to a recall) were drawn from a convenience sample of outpatients. The survey instrument consisted of two validated questionnaires–-Hospital Anxiety and Depression Score (HADS) and MacNew heart disease health-related quality of life (QOL) instrument. In addition, a series of Likert-type scales were designed to elucidate patients' concerns related to the following domains: anger, trust, hope, concerns regarding ICD shock, fear of death (FOD), and physicians' ability to reduce their concern about the ICD recall. Data were analyzed using simple descriptive statistics and bivariate analyses (χ2 and t-test) as appropriate. Result:Sixty-one cases and 43 control patients were enrolled. Thirty-two patients (52%) with devices subject to a recall opted for a generator replacement. There were no significant differences in the mean scores on the HADS scale, or the MacNew QOL scale between these two groups of patients (cases and controls). Subgroup analysis within the group of patients whose ICDs were recalled (cases) revealed a reduced QOL among patients with a class I recall (reasonable probability that the product will cause serious adverse health consequences or death) as compared to those with a class II recall (product may cause temporary or medically reversible adverse health consequences) (P = 0.01). Both cases and control patients reported having reduced trust in the health-care system. On the whole, however, patients were satisfied with the way their physicians dealt with the recall. There was no significant change in the overall concern of ICD shocks or FOD between the two groups. Conclusion:In this study of ICD recall, we found no difference in the levels of anxiety, depression, or QOL expressed by patients with an ICD subject to a recall as compared to those without. These findings may be a reflection of good physician-patient communication, which might have reduced any anxiety associated with recalls.

Sarcoidosis, scleroderma, amyloidosis, and hemachromatosis are systemic infiltrative disorders that commonly affect the heart. Owing to their potential for diffuse organ involvement, these diseases may present with myriad clinical manifestations. Conduction system abnormalities are common, and each of these disorders has been associated with sudden cardiac death. In this review, we summarize the epidemiology, clinical features, diagnosis, and treatment of each of these entities. We place special emphasis on existing literature as it pertains to risk stratification and therapy aimed at the prevention of sudden cardiac death in these infiltrative cardiomyopathies.

Cardiac sarcoidosis (CS) causes substantial morbidity and sudden death. Early diagnosis and risk stratification are warranted.Ambulatory patients with sarcoidosis were interviewed to determine whether they experienced palpitations, syncope, or presyncope, and were evaluated with ECG, Holter monitoring, and echocardiography (transthoracic echocardiogram [TTE]). Those with symptoms or abnormal results were studied with cardiac MRI (CMRI) or positron emission tomography (PET) scanning. The diagnosis of CS was based on abnormalities detected by these imaging studies. Patients with CS were referred for risk stratification by electrophysiology study (EPS).Among the 62 patients evaluated, the prevalence of CS was 39%. Patients with CS had more cardiac symptoms than those without CS (46% vs 5%, respectively; p0.001), and were more likely to have abnormal Holter monitoring findings (50% vs 3%, respectively; p0.001) and TTE findings (25% vs 5%, respectively; p = 0.02). The degree of pulmonary impairment did not predict CS. Two of the 17 patients who underwent EPS had abnormal test findings and received implantable cardioverter-defibrillators. No patients died, had ventricular arrhythmias that triggered defibrillator therapy, or had heart failure develop during almost 2 years of follow-up. This diagnostic approach was more sensitive than the established criteria for identifying CS.CS is common among patients with sarcoidosis. A structured clinical assessment incorporating advanced cardiac imaging with PET scanning or CMRI is more sensitive than the established criteria for the identification of CS. Sarcoidal lesions seen on CMRI or PET scanning do not predict arrhythmias in ambulatory patients with preserved cardiac function, who appear to be at low risk for short-term mortality.

All eight stages of a stimulation protocol that used one then two extrastimuli from the right ventricular apex in sinus rhythm and three ventricular drive rates (100, 120, and 140 beats/min) were performed in 24 patients with recurrent spontaneous sustained ventricular tachycardia despite drug treatment. Twenty two of the patients had sustained a previous myocardial infarct and 18 were on long term treatment with amiodarone. Sustained (greater than 30 s) ventricular tachycardia was induced in all patients. Two extrastimuli were significantly more likely to induce sustained ventricular tachycardia than one extrastimulus, both overall and individually for the three ventricular drive rates. A ventricular drive rate of 140 beats/min was significantly more likely to induce ventricular tachycardia than ventricular drive rates of 100 and 120 beats/min which were significantly more effective than sinus rhythm. A ventricular drive rate of 140 beats/min with one or two extrastimuli induced ventricular tachycardia in 23/24 (95%) of the patients in this study. The full eight stage protocol was progressive separately for both extrastimuli and ventricular drive rate but the last two stages (ventricular drive rate of 140 beats/min with one or two extrastimuli) were as effective as the entire protocol in inducing ventricular tachycardia.

OBJECTIVES: This study was designed to determine whether the signal-averaged electrocardiogram of the P-wave (SAPW) is an independent predictor of recurrence of atrial fibrillation (AF) post cardioversion (CV), and to assess atrial remodeling using SAPW. BACKGROUND: There are limited electrophysiologic data to predict the recurrence of AF post-CV. The electrical remodeling that occurs post-CV is poorly understood. METHODS: Sixty-four patients with persistent AF undergoing CV were prospectively enrolled. SAPW parameters were measured the day of CV and repeated at 1 month. These SAPW parameters were compared to other baseline indices for the recurrence of AF. RESULTS: Sixty patients (94%) had successful CV. At 1 month, 22 (37%) maintained sinus rhythm (SR). The SAPW total duration decreased significantly in those who remained in SR (159 ms +/- 19 to 146 ms +/- 17; P < 0.0001). Only the duration of AF (46 +/- 50 days vs 147 +/- 227 days, P = 0.03) and the presence of left ventricular hypertrophy (LVH, 12% vs 65%, P = 0.0006) were significantly associated with recurrence of AF. Atrial size strongly correlated with the SAPW duration in patients who remained in SR (R(2)= 0.67, P = 0.003) but not in those who returned to AF (R(2)= 0.11, P = 0.65). CONCLUSIONS: Atrial electrical reverse remodeling occurs in patients with AF who maintain SR post-CV. This remodeling is likely inversely related to the duration of AF and LVH. SAPW duration does not predict recurrence of AF post-CV.