ImportanceThe emergence of novel programming guidelines that reduce premature and inappropriate therapies along with the availability of new implantable cardioverter-defibrillator (ICD) technologies lacking traditional endocardial antitachycardia pacing (ATP) capabilities requires the reevaluation of ATP as a first strategy in terminating fast ventricular tachycardias (VTs) in primary prevention ICD recipients.ObjectiveTo assess the role of ATP in terminating fast VTs in primary prevention ICD recipients with contemporary programming.Design, Setting, and ParticipantsThis global, prospective, double-blind, randomized clinical trial had an equivalence design with a relative margin of 35%. Superiority tests were performed at interim analyses and the final analysis if equivalence was not proven. Patients were enrolled between September 2016 and April 2021 at 134 sites in 8 countries, with the last date of follow-up on July 6, 2023. Patients were required to have an indication for a primary prevention ICD, including left ventricular ejection fraction less than or equal to 35%.InterventionsPatients were randomized in a 1:1 ratio to receive ATP plus shock vs shock only.Main Outcomes and MeasuresThe primary end point was time to first all-cause shock. Secondary end points included time to first appropriate shock, time to first inappropriate shock, all-cause mortality, and the composite of time to first all-cause shock plus all-cause mortality.ResultsA total of 2595 patients were randomized (mean age, 63.9 years; 22.4% were females). At a mean follow-up of 38 months, first all-cause shock occurred in 129 participants in the ATP plus shock group and 178 participants in the shock only group. The hazard ratio (HR) for the primary end point was 0.72 (95.9% CI, 0.57-0.92), with P = .005 for superiority of the ATP plus shock group over the shock only group. During follow-up in an intention-to-treat analysis, the total shock burden per 100 patient-years was not statistically different, at 12.3 and 14.9, respectively (P = .70).Conclusions and RelevanceThe use of a single burst of ATP prior to shock in primary prevention ICD recipients with modern ICD detection programming prolonged the time to first all-cause ICD shock.Trial RegistrationClinicalTrials.gov Identifier: NCT02923726

Atrial fibrillation is the most common arrhythmia in clinical practice with indication for anticoagulation in those patients whose annual risk for thromboembolism is >2%. Left atrial appendage closure is growing as an alternative to anticoagulation. We present a case of pulmonary artery-left atrial appendage fistula seen after left atrial appendage closure. (Level of Difficulty: Intermediate.)

Permanent pacemaker implantation is a common procedure with a low complication risk. However, congenital heart anomalies can lead to devastating and unusual complications. Partial anomalous pulmonary vein return (PAPVR) is rare anomaly in which a pulmonary vein (PV) drains into right atrium or

New Endpoint for Ablation of Ventricular Tachycardia. Introduction: Endpoints confirming block in the critical isthmus in sinus rhythm and with pace mapping have not been established. Methods and Results: A 44‐year‐old man with a history of Tetralogy of Fallot presented with recurrent ventricular tachycardia (VT). Entrainment mapping was consistent with a macroreentrant circuit rotating in a clockwise fashion under the pulmonic valve. After termination of the VT in a critical isthmus located on the conal free wall, a pace map proximal to the site of successful ablation was consistent with a change in QRS morphology. This change in QRS morphology suggested critical isthmus block and successful ablation, which was confirmed by noninducibility with programmed stimulation. Conclusion: Evidence of conduction block can be used as an additional endpoint for successful ablation of VT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 320–324, March 2010)

BACKGROUND Ventricular arrhythmias are known to originate from the aortic sinus of Valsalva. OBJECTIVE The purpose of this study was to identify the characteristics associated with ventricular arrhythmias originating from the right coronary cusp-left coronary cusp (RCC-LCC) commissure.METHODS Thirty-seven consecutive patients with ventricular arrhythmias originating from the aortic cusp region were studied. Intracardiac echocardiography and electroanatomic mapping were used to define coronary cusp anatomy and catheter position. Ventricular arrhythmias from the RCC-LCC commissure were compared with ventricular arrhythmias originating from other sites in the aortic cusp region.RESULTS Nineteen (51%) ventricular arrhythmias had an anatomic origin at the RCC-LCC commissure. Eighteen ventricular arrhythmias originated from other aortic cusp sites (4 right cusp, 7 left cusp, 3 left ventricular endocardium, 4 left ventricular epicardium anterior to aortic valve). A QS morphology in lead V(1) with notching on the downward deflection was present in 15 of 19 ventricular arrhythmias originating from the RCC-LCC commissure compared to 2 of 18 ventricular arrhythmias from other aortic cusp sites (P <.01). At the site of earliest activation, 13 of 19 patients with RCC-LCC ventricular arrhythmias had late potentials in sinus rhythm compared to 1 of 18 ventricular arrhythmias from other aortic cusp sites (P <.01). The site of successful ablation was confirmed to be above the aortic valve plane in 15 (79%) of 19 patients with RCC-LCC ventricular arrhythmias.CONCLUSION RCC-LCC aortic cusp ventricular arrhythmias are common and have a QS morphology in lead V(1) with notching on the downward deflection with precordial transition at lead V(3). In the majority of cases, the site of successful ablation has late potentials in sinus rhythm.

To identify the prevalence of adrenergically mediated ventricular premature depolarizations (VPDs) and characterize their electrocardiographic (ECG) features and specific anatomically determined sites of origin within the ventricles.

OBJECTIVES:This study sought to identify the origin within the pulmonary vein (PV) of reproducible atrial fibrillation (AF) triggers. BACKGROUND:Triggers for AF frequently originate from PVs. However, a systematic evaluation of the location of origin within the PV orifice and associated techniques for eliciting triggers has not been performed. METHODS:Spontaneous triggers and those provoked with isoproterenol (up to 20 microg/min) and/or cardioversion in 45 patients with AF were identified using multipolar catheter recordings. In identifying origin, PVs were divided into 17 equal segments from ipsilateral PVs with "carina zone" (CZ) (7 segments between the PVs) and 10 "noncarina zone" (NCZ) segments. RESULTS:Sixty-three reproducible triggers were noted in 37 of the 45 (82%) patients with 57 from PV and 6 (10%) from non-PV sites. Although triggers were identified from 26 of 34 distinct PV segments, most PV triggers (36, 63%) originated from CZ segments (p < 0.05) from both right (17 triggers) and left (19 triggers) PVs. The CZ triggers were more often spontaneous (11 of 36 in CZ vs. 2 of 21 in NCZ; p < 0.05) or elicited with CV (17 of 36 in CZ vs. 6 of 21 in NCZ; p < 0.05). In contrast, NCZ triggers were more likely to require isoproterenol to be provoked (13 of 21 [62%] vs. 8 of 36 [22%], p < 0.05). CONCLUSIONS:Reproducible spontaneous and provoked PV triggers initiating AF can be observed in most patients undergoing AF ablation. These triggers most commonly originate from the carina region of both right and left PVs. Noncarina PV triggers more commonly require provocation with isoproterenol infusion.

Ablation is an important management tool for the treatment of ventricular arrhythmias. Even at experienced centers ventricular tachycardia ablation carries a minor but significant risk for potential complications, including vascular and thomboembolic complications, air embolism, volume overload and the precipitation of congestive heart failure, cardiac tamponade from catheter perforation or from steam pop with RF energy delivery, valve or subvalvular support structure disruption, conduction system disruption with development of heart block, coronary artery injury when ablating in the coronary cusps region or trying to gain access to the LV chamber, precipitation of cardiogenic shock from ablation of viable myocardium in patients with marginal reserve and failure to resuscitate or precipitation of cardiogenic shock from repeated VT induction, and with epicardial ablation the potential complications of epicardial access, coronary arteries and phrenic nerve damage. Recognition of these risks is paramount for their avoidance with careful pre-procedure planning and intraprocedural technique being essential to minimize the potential for complications.

Background: Brief atrial high rate episodes (AHREs) of even 5 minutes duration, as detected by pacemaker (PPM) diagnostics, are a reliable surrogate for atrial fibrillation (AF) and potentially identify patients at increased risk for stroke and death. However, the incidence and predictors of de novo AF following dual chamber PPM implantation are unknown. Methods : We retrospectively evaluated 127 patients (71 male; 76 ± 11 years) without documented AF who underwent PPM implantation for management of sinus node dysfunction. Information regarding patient demographics, cardiovascular diseases, and medication history was obtained. The cumulative percentage of right ventricular pacing (Cum VP) was determined. Results : During a mean follow-up of 599 ± 353 days, 33 (26%) patients had an AHRE ≥ 5 minutes. Age, gender, ejection fraction, co-morbid medical conditions, use of medications, and burden of atrial pacing were similar between patients with and without AHREs during the follow-up period. The only significant predictor of an AHRE was ≥ 50% Cum VP (RR 2.2; CI [1.1–4.8]; p = 0.03, Figure). The 1- and 2-year incidence of an AHRE Conclusions: Cumulative right ventricular pacing ≥ 50% was the sole significant predictor of de novo AF (defined as an AHRE ≥ 5 minutes) in patients with sinus node dysfunction following dual chamber PPM implantation and is associated with a more than two-fold increased risk of AF. The routine use of novel pacing strategies that minimize right ventricular pacing merits prospective investigation as a means of reducing the incidence of de novo AF in this population.

Introduction : Multiple randomized clinical trials have shown that an ICD improves survival in patients (pts) with an ischemic cardiomyopathy. Although a life expectancy ≤ 1 year is considered a contraindication to ICD implantation, the incidence and predictors of early mortality remain undefined. Methods : We evaluated consecutive pts with ischemic heart disease and depressed left ventricular ejection fraction (LVEF ≤ 35%) who underwent prophylactic ICD implantation between February 2002 and December 2004. No pt underwent pre-implant electrophysiologic testing. Predictors of mortality within one year of ICD implantation were determined using Cox-regression analysis. Results : The study population consisted of 123 pts (103 male, age 70 ± 11 years) with a mean EF of 25 ± 6 %. The mean QRS duration was 149 ± 29 msec and 75 (61%) pts had class III CHF. Sixty-two (50%) pts received a LV lead. During a follow-up of 2.1 ± 1.1 years, 34 (28%) pts died. Overall, 22 (65%) of these 34 pts died ≤ 1 year post-ICD implantation. Pts who died within a year were less likely to be taking a β-blocker (73 vs 93%, p=0.005) and more likely to have unrevascularized coronary artery disease (32 vs 15%, p=0.06). No other predictor of early mortality was identified. In multivariate analysis, lack of β-blocker use was the only predictor of early mortality (RR 3.6, 95% CI: 1.4–9.3, p=0.007). The 1-year mortality in pts not taking a β-blocker was 43%. Conclusions : In a real world population of pts with an ischemic cardiomyopathy, overall mortality is high in the first year after ICD implantation. Lack of β-blocker use significantly increases the likelihood of early mortality in these pts.

Background: Recent studies suggest that a normal T-wave alternans test (TWA) identifies a group of “MADIT-2 type” pts with low mortality who are unlikely to benefit from prophylactic ICD implantation.