A 37-year-old woman with a history of incomplete atrioventricular canal and an extensive history of corrective cardiac surgeries presented with recurrent episodes of acute decompensated heart failure in the presence of junctional bradycardia with chronotropic incompetence. The initial plan was to proceed with implantation of a dual chamber pacemaker but given high index of suspicion for the presence of atrial standstill in the context of her extensive cardiac surgical history, we performed electroanatomical mapping and echocardiography at the time of pacemaker implantation that confirmed atrial standstill. Islands of electrically functional atrial myocardium were detected. Pacing from these locations resulted in local atrial capture, but failed to result in global atrial electrical capture, mechanical atrial contraction, or atrioventricular conduction. In light of the dismal outcomes of right ventricular pacing in patients with atrial standstill, we implanted a left bundle branch pacing lead that resulted in improvement of patient's cardiac output and prevented future admissions for decompensated heart failure in one year follow up.

Introduction: There are limited data describing the experience of index radiofrequency (RF) vs. cryoballoon (CB) ablation for atrial fibrillation (AF) among elderly patients in the United States. Methods: We conducted a retrospective analysis of patients > 75 years of age undergoing index AF ablation between January 2010 and March 2019 at our center. Major complications and efficacy, defined as freedom from any atrial tachyarrhythmia (ATA) lasting ≥30 seconds after one year of follow-up, were assessed in patients with index RF vs. CB ablation. Predictors of ATA recurrence at 1 year follow-up were also evaluated. Results: In our cohort of 194 patients, the mean age was 78 ± 3.1 years, 58.2% were men, and 39.4% had persistent AF. The mean left atrial (LA) diameter was 4.5 ± 0.7, while the mean CHA2DS2-VASc score was 3.5 ± 1.2. The majority (n=149, 76.8%) underwent RF ablation. The incidence of complications was similar in the two sub-groups (RF: 1.3% vs. CB: 2.2%, p=0.67). No significant difference in success rate at 1-year follow-up was found between patients receiving RF vs. CB ablation (59.7% vs. 66.7%, p=0.68). In a multivariable model adjusting for the relevant covariates only LA size [HR=1.64, CI: 1.15-2.34, p<0.01] was independently associated with ATA recurrence at 1year follow-up. Conclusion: In our cohort of elderly patients undergoing index CA for AF, RF ablation was the predominant modality with similar safety and efficacy relative to CB ablation. LA size was a significant predictor of ATA recurrence at 1year independent of index ablation modality.