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Introduction: Atrioventricular node reentry tachycardia (AVNRT) ablation is typically performed with solid tip catheters set to temperature control (TC) mode. Radiofrequency (RF) output, tip temperature (T), and junctional rhythm response (JRR) during RF application have been well defined. JRR in an intermittent burst, sinus-junction-junction, or sinus-junction-sinus pattern is associated with successful modification of the AV nodal slow pathway (SP). Irrigated force-sensing catheters (IFSC) are often utilized for mapping and ablation of the SP. Despite this, parameters for IFSC used in TC mode resulting in JRR have not been well described. Hypothesis: Parameters predicting JRR and successful SP modification with IFSC include power (P), force (F), impedance drop (I), and target temperature (T). Methods: Consecutive patients that underwent electrophysiologic study and successful ablation of typical AVNRT with an IFSC were studied. Lesion parameters including P, T, F, time and I change were analyzed. Lesions producing JRR were considered efficacious. Independent T-Test and ANOVA were used to determine significance between the two groups (efficacious and non-efficacious lesions). Results: 296 lesions in 39 patients (age 52+/-14) were analyzed. All patients had successful SP modification without complication. Average F producing JRR was 8g, average T producing JRR was 41 o C, average I drop producing JRR was 9 Ohms, and average P producing JRR was 28W. Only RF lesion time was a significant predictor of JRR (p=0.009). (Table 1). Conclusions: Successful SP modification with IFSC was accomplished with catheter contact force as low as 2g. Lower average tip T, and lower average P settings compared to parameters typically used with solid tip catheters were observed. Parameters including P, F, T, and I change were not predictive of JRR. Additional studies controlling for catheter location while varying parameters are indicated.

Introduction: Wellens’ sign is a characteristic finding on ECG, often found to be indicative of severe proximal Left anterior descending artery (LAD) stenosis. Our study sought to identify the prevalence of the Wellens’ sign in the ethnically diverse population of the Bronx, NY and elucidate its relationship to the presence of significant CAD. Methods: We retrospectively analyzed an ECG database at Montefiore Medical Center of over 1.7 million ECGs, using six diagnostic codes for anterior ischemia to identify ECGs that resemble the Wellens’ sign. Of the six diagnostic codes, the ECGs of the two highest yielding codes, were identified, then manually reviewed by an electrophysiologist. Patient’s charts and demographics were reviewed and Chi Square test was used to test statistical significance of the data. Results: Of the 1,756,742 ECGs done on 433,218 patients between 2012-2019, 26,624 ECGs were isolated. Subsequently, 2186 of these ECGs were manually reviewed. Wellens’ sign was identified in 448 (0.1%) patients, of which, 229 patients underwent cardiac catheterization, while 219 patients were managed medically. There was no statistical difference seen in the prevalence of Wellens’ Type A and B pattern across various ethnic groups (P = 0.213). Significant LAD stenosis was seen in 80 (35%) patients of whom 22 (10%) had proximal, 40 (17%) had mid, 4 (1%) had distal stenosis, while 14 (6%) patients had diffuse LAD disease. Two-vessel disease was seen in 46 (20%) of the patients, and triple-vessel disease was seen in 23 (10%) of the patients. Most common indication for cardiac catheterization was NSTEMI. Takotsubo cardiomyopathy was diagnosed in 19 (8%) patients who had either no or non-obstructive CAD. Among patients with the Wellens’ sign on the ECG but did not undergo cardiac catheterization, majority had a non-ACS presentation. Conclusions: No statistical difference in the prevalence of Wellens’ sign was seen among the various ethnic groups. In our study population, Wellens’ sign was a rare ECG pattern with a prevalence of 0.1%. When seen in conjunction with a clinical setting suggestive of angina there is a high probability of underlying CAD. Although significant LAD stenosis is the known most common underlying pathology, multivessel CAD may also occur.

This expert consensus document was developed by the American College of Cardiology Foundation (ACCF), the American College of Gastroenterology (ACG), and the American Heart Association (AHA). Expert consensus documents inform practitioners, payers, and other interested parties of the opinion of ACCF and document cosponsors concerning evolving areas of clinical practice or medical technologies. Expert consensus documents cover topics for which the evidence base, experience with technology, or clinical practice is not considered sufficiently well developed to be evaluated by the formal ACCF/AHA Practice Guidelines process. Often, the topic is the subject of considerable ongoing investigation. Thus, the reader should view the expert consensus document as the best attempt of the ACCF and document cosponsors to inform clinical practice in areas where rigorous evidence may not yet be available. To avoid actual, potential, or perceived conflicts of interest that may arise as a result of industry relationships or personal interests among the writing committee, all members of the writing committee, as well as peer reviewers of the document, are asked to disclose all current healthcare-related relationships and those existing 12 months before initiation of the writing effort. The ACCF Task Force on Clinical Expert Consensus Documents (CECD) reviews these disclosures to determine which companies make products (on market or in development) that pertain to the document under development. Based on this information, a writing committee is formed to include a majority of members with no relevant relationships with industry (RWI), led by a chair with no relevant RWI. Authors with relevant RWI are not permitted to draft or vote on text or recommendations pertaining to their RWI. RWI are reviewed on all conference calls and updated as changes occur. Author and peer reviewer RWI pertinent to this document are disclosed in Appendixes 1 and 2, respectively. Additionally, to ensure complete transparency, …

Introduction: Atrial fibrillation (AF) is the most common arrhythmia and is associated with significant morbidity and mortality. Despite having a higher burden of traditional AF risk factors, African American and Hispanic minorities have a lower incidence of AF when compared to non-Hispanic Whites, referred to as the “racial paradox.” Hypothesis: We investigated if socioeconomic status (SES) could be an explanatory factor for the “racial paradox.” Methods: An ECG/EMR database from a tertiary-care center in New York State was interrogated for individuals free of AF for development of subsequent AF from 2000-2013. SES was assessed per zip code via a log composite of six measures Z-scored to the New York State average (income; value of housing unit; percentage of receiving interest/dividend/rental income; education; percentage completed college; individuals in professional positions). SES was reclassified into decile groups (1 lowest and 10 highest). The Log-Rank test was used to determine difference in survival times to develop AF by race/ethnicity stratified by SES decile. Cox regression analysis controlling for all baseline differences was used to estimate the independent predictive ability of SES for AF. P-trend was calculated by race/ethnicity to determine if there was a trend by SES decile to develop AF. Results: We identified 48,631 persons (43% Hispanic, 37% African Americans and 20% non-Hispanic White, mean age 59 years, mean follow-up of 3.2 years) of which 4,556 AF cases occurred. Hispanics and African Americans had lower AF risk than Whites in all SES deciles (p-value < 0.001 by Log Rank Test). Higher SES was borderline associated with lower AF risk (HR=0.990, 95% CI 0.980-1.001, p=0.061). P-trend analysis was not significant by any race/ethnic group by SES deciles for AF (Figure 1). Conclusions: Our study suggests that non-Hispanic Whites are at higher risk for AF compared to non-Whites, and this is independent of socioeconomic status.

Background: Atrial fibrillation (AF) and isthmus dependent atrial flutter (AFL) are two separate entities that in many patients coexist. We sought to investigate whether AF inducibility (spontaneous or drug induced) during isthmus AFL ablation predicted the occurrence of AF at follow up after successful AFL ablation. Methods: Two hundred seventy three consecutive patients with isthmus dependent AFL undergoing ablation of AFL at our institution were enrolled in this study. 119 (43%) patients were excluded since they had evidence of AF prior to AFL ablation. Univariate and multivariate analyses were performed. Results: A total of 154 patients (male: 72%, age: 61 ±13) with AFL and without history of AF composed our patient population. All patients underwent successful AFL ablation. During ablation, AF was induced in 28 (18%) patients. After a mean follow up of 34 ± 23.5 months a total of 50 (32%) experienced AF. Univariate and multivariate analyses showed that only age and AF inducibility during AFL ablation were predictors of AF. Univariate analysis (age: p=0.038 and inducible AF p=0.032 and multivariate analysis (age: p=0.011 inducible AF: p=0.016) ) with and adjusted odds ratio of 3.3 [95% CI (1.250-8.676)] (Table 1). A total of 169 (62%) patients experienced AF before or after AFL ablation. Conclusion: AF inducibility in patients undergoing isthmus dependent AFL without history of AF is a strong predictor of AF recurrence. This has an important clinical relevance on anticoagulation management of these patients.

Background— Fifty percent of deaths in patients with coronary disease occur suddenly. Although many factors correlate with increased mortality, there is little information regarding the influence of these factors on mode of death. As such, optimum methods to determine patients most likely to benefit from implantable defibrillator therapy are unclear. Methods and Results— We analyzed the relation of ejection fraction and inducible ventricular tachyarrhythmias to mode of death in all 1791 patients enrolled in the Multicenter Unsustained Tachycardia Trial who did not receive antiarrhythmic therapy. Total mortality and arrhythmic deaths/cardiac arrests occurred more frequently in patients with ejection fraction P =0.004). The higher percentage of events that were arrhythmic among patients with inducible tachyarrhythmia appeared more distinct among patients with an ejection fraction ≥30% (61% of events were arrhythmic among inducible patients with ejection fraction ≥30% and only 42% among noninducible patients, P =0.002). Conclusions— Both low ejection fraction and inducible tachyarrhythmias identify patients with coronary disease at increased mortality risk. Ejection fraction does not discriminate between modes of death, whereas inducible tachyarrhythmia identifies patients for whom death, if it occurs, is significantly more likely to be arrhythmic, especially if ejection fraction is ≥30%.

Background — The Multicenter Unsustained Tachycardia Trial (MUSTT) was designed to evaluate an antiarrhythmic treatment strategy, including drugs and implantable defibrillators (ICDs), guided by electrophysiological (EP) testing. We performed several statistical analyses to assess the contribution of defibrillators to the observed treatment benefit. Methods and Results — First, the effects of defibrillators were indirectly examined by comparing the randomized treatment arms (EP-guided therapy versus no antiarrhythmic therapy) within subgroups that varied according to ICD usage. Use of ICDs increased during the trial; hence, the randomized treatments were compared according to date of enrollment. There were also site-specific differences in ICD use; hence, the randomized arms were compared within groups of sites defined by level of ICD use. There was a distinct “dose response” in relation to ICD use. Where ICD use was high, EP-guided therapy produced significant reductions in arrhythmic death or cardiac arrest ( P 70% in arrhythmic death or cardiac arrest and >50% in total mortality ( P Conclusions — The benefit of EP-guided antiarrhythmic therapy observed in MUSTT was due to improved outcomes among patients who received an ICD but not among patients who received antiarrhythmic drugs.

BACKGROUND The outcomes of patients treated with implantable defibrillators were compared between patients with left ventricular ejection fraction greater than or equal to 30% and less than 30%. METHODS AND RESULTS Of 68 consecutive patients treated with implantable defibrillators, 40 patients (group 1) had left ventricular ejection fraction greater than or equal to 30%, and 28 patients (group 2) had left ventricular ejection fraction less than 30%. Sudden death, surgical mortality, nonsudden arrhythmia-related death (death within 24 hours after an arrhythmic event despite initial termination of the arrhythmia by the implantable defibrillator), total arrhythmia-related death (including sudden death, surgical death, and nonsudden arrhythmia-related death), and total cardiac death were compared between the two groups. Surgical mortality was 4.4% (0% in group 1, 11% in group 2). During the follow-up of 31 +/- 27 months, actuarial survival rates free of events were 97%, 97%, and 97% in group 1 and 96%, 91%, and 82% in group 2 at 12, 24, and 36 months, respectively, for sudden death (p = NS); 97%, 97%, and 97% in group 1 and 85%, 81%, and 72% in group 2 at 12, 24, and 36 months, respectively, for sudden death and surgical mortality (p less than 0.05); 97%, 97%, and 97% in group 1 and 82%, 78%, and 70% in group 2 at 12, 24, and 36 months, respectively, for total arrhythmia-related death (p less than 0.05); and 95%, 95%, and 95% in group 1 and 82%, 69%, and 57% in group 2 at 12, 24, and 36 months, respectively, for total cardiac death (p less than 0.05). Four (57%) of seven nonsudden cardiac deaths during the initial 36-month follow-up period were causally related to arrhythmia (three surgical deaths and one arrhythmia-related nonsudden death). CONCLUSIONS The outcome of patients treated with implantable defibrillators is strongly influenced by the degree of left ventricular dysfunction. In group 1 patients, surgical mortality, sudden death, and total cardiac death are rare. In group 2, sudden death rate may not be markedly different from that of group 1 patients. However, the risk of therapy (surgical mortality) is high. Many nonsudden cardiac deaths are causally related to arrhythmia (surgical mortality or nonsudden arrhythmia-related death). Therefore, the survival rate free of total arrhythmia-related death is significantly lower in group 2 (70% versus 97% in group 1 at 3 years). Further studies are needed to determine the roles of defibrillator therapy and other therapies in various clinical settings.

A37-year-old man with frequent episodes of paroxysmal atrial fibrillation refractory to antiarrhythmic therapy (and no other documented arrhythmias on multiple Holter examinations) underwent an attempt at radiofrequency ablation of the atrial fibrillation. Catheter positions are shown in the left anterior oblique view in Figure 1⇓ and include 2 catheters in the left and right upper pulmonary veins. During mapping, the patient developed atrioventricular node reentry tachycardia (AVNRT) both spontaneously and with atrial extrastimuli; this AVNRT was later ablated. Before ablation, the patient’s rhythm spontaneously …

SUMMARY The production of atrioventricular block by intracardiac discharges at up to 300 W-sec delivered through standard electrophysiologic catheters is a safe and effective treatment for some patients with supraventricular tachycardias. We evaluated the possibility that a similar technique using a catheter in the coronary sinus might be useful in ablating left-sided bypass tracts associated with the Wolff-Parkinson- White syndrome. Acute studies involved one discharge of 35–45 J in the coronary sinus of five dogs; a sixth dog served as a control. These dogs were killed after 6 hours of observation, during which they remained stable. Two and three discharges of 240 J were used in two dogs and caused profound local damage, including exsanguinating hemorrhage in one. Chronic experiments also were conducted. Sixteen dogs received one to four 35–45-J discharges in the middle coronary sinus and two dogs received four 240-J discharges near the ostium of the coronary sinus. One dog suffered a small perforation of the coronary sinus; there was no significant hemorrhage, and the perforation was promptly sealed by thrombus formation. There were no clinical complications. All dogs recovered uneventfully and regained their usual vigor. Before sacrifice 2–11 weeks later, cardiac catheterization, including coronary arteriography, biplane left ventricular angiography and pressure measurements, was performed; the results were normal in each dog. Gross and microscopic examination revealed fibrosis in the atrioventricular sulcus and atrial wall, and preservation of normal coronary anatomy in all but three dogs. The extent and distribution of the fibrosis suggested the possibility of adapting this technique for the ablation of left-sided bypass tracts in patients with Wolff-Parkinson-White syndrome.

A 3-year study by three medical centers has revealed a 1-year electrode malfunction rate of 7.4%; most malfunctions occurred within the first 30 days. The incidence of unavoidable early malfunction (3.2%) fell within the 5% standards suggested by the committee report of the Inter-Society Committee on Heart Diseases. Incidences of obscure cause (3.2%) may be difficult to identify prospectively and may be, to a certain extent, unavoidable. The majority of the malfunctions (4.2%) showed specific clues that indicated that they were preventable. Successful repositioning was achieved on the first attempt in 80.6% of the cases with malfunction, and only 0.7% required ultimate myocardial electrode implantation. The principal clues to potentially unsatisfactory positioning included the presence of a large right ventricle with or without tricuspid insufficiency, current thresholds greater than 0.5 mA and ST-segment deviations on the intracardiac electrogram of less than 2 mV. Electrode malfunction may be more common with bipolar than with unipolar electrodes; but significant differences in the incidence of malfunction among different unipolar electrodes were observed. These data indicate that further developments in transvenous electrode design are warranted.