Naga Venkata Pothineni’s research while affiliated with University of Pennsylvania and other places

Background: The subcutaneous implantable-cardioverter defibrillator (S-ICD) is an appealing alternative to transvenous ICD systems. However, data on indications for S-ICD explantations are sparse. Objectives: To assess incidence and indications for S-ICD explantation at a large tertiary referral center. Methods: We conducted a retrospective study of all S-ICD explantations performed from 2014 to 2020. Data on demographics, comorbidities, implantation characteristics, and indications for explantation, were collected. Results: A total of 64 patients underwent S-ICD explantation during the study period. During that time, there were 410 S-ICD implantations at our institution of which 53 (12.9%) were explanted with a mean duration from implant to explant of 19.7±20.1 months. The mean age of the patients at explantation was 44.8±15.3 years, and 42% (n=27) were female. The indication for S-ICD implantation was primary prevention in 58% and secondary prevention in 42% of the patients. The most common reason for explantation was infection (32.8%) followed by abnormal sensing (25%) and need for pacing (18.8%). Those who underwent S-ICD explantation for pacing indications were significantly older (55.7±13.6 vs 42.3± 14.6 years, p = 0.005) with a wider QRS duration (111±19 ms vs 98±19 ms, p = 0.03) at device implantation compared to patients who underwent explantation for other indications. Conclusion: Incidence of S-ICD explantation in a large tertiary practice was 12.9%. While infection was the indication for a third of the explantations, a significant number were due to sensing abnormalities and need for pacing. These data may have implications for patient selection for S-ICD implantation.

Idiopathic ventricular arrhythmias are ventricular tachycardias or premature ventricular contractions presumably not related to myocardial scar or disorders of ion channels. Of the ventricular arrhythmias (VAs) without underlying structural heart disease, those arising from the ventricular outflow tracts (OTs) are the most common. The right ventricular outflow tract (RVOT) is the most common site of origin for OT-VAs, but these arrhythmias can, less frequently, originate from the left ventricular outflow tract (LVOT). OT-VAs are focal and have characteristic ECG features based on their anatomical origin. Radiofrequency catheter ablation (RFCA) is an effective and safe treatment strategy for OT-VAs. Prediction of the OT-VA origin according to ECG features is an essential part of the preprocedural planning for RFCA procedures. Several ECG criteria have been proposed for differentiating OT site of origin. Unfortunately, the ECG features of RVOT-VAs and LVOT-VAs are similar and could possibly lead to misdiagnosis. The authors review the ECG criteria used in clinical practice to differentiate RVOT-VAs from LVOT-VAs.

A woman in her 60s presented to the emergency department with symptoms of worsening dyspnea on exertion and pedal edema. She reported being at her baseline functional status about 2 months ago with a gradual progression of her symptoms. She had no medical history and had not been taking any medications other than over-the-counter vitamin supplements. Her heart rate on admission was 125 beats/min and blood pressure was 100/70 mm Hg. Physical examination findings revealed jugular venous distention and bilateral pedal edema. The initial 12-lead electrocardiogram (ECG) obtained in the emergency department (Figure, A) was interpreted as sinus tachycardia. Brain-type natriuretic peptide level on admission was 1700 pg/mL (to convert to nanograms per liter, multiply by 1). She was admitted for concern of a new diagnosis of heart failure. She had a prior ECG during a routine primary care visit, which was similar to her admission ECG.

Background Radiofrequency ablation (RFA) of ventricular arrhythmias (VAs) arising from the inaccessible basal region of the left ventricular summit (LVS) is challenging due to proximity to coronary vessels, epicardial fat and poor RF delivery within the distal coronary venous system. Objective We describe the outcomes of an anatomical approach for inaccessible LVS-VAs using bipolar RF (Bi-RFA) delivered from the anatomically adjacent left pulmonic cusp (LPC) to the opposite LV outflow tract (LVOT). Methods From 3 centers we reviewed patients (pts) who underwent Bi-RFA for inaccessible LVS-VAs refractory to conventional RFA using an anatomical approach targeting the adjacent LPC (“reversed U” approach) with catheter tip pointing inferiorly within the LPC and LVOT. Results A total of 7 pts (59±12 years, 3 females) underwent Bi-RF from the LPC to the LVOT for LVS-VAs after ≥1 failed conventional RFA. Bi-RFA (power 36±7 W, duration 333±107s) resulted in VAs suppression in 5 out of 7 pts. In 2 cases Bi-RFCA was successfully performed using dextrose-5% in water (D5W). No complications occurred. After a mean follow-up of 14±6 months, no recurrent VT was documented in 2/2 pts with baseline VT and a mean 84% reduction in PVC burden (31±13% vs 4±5% PVC/d; p=0,0027) was documented in others. Conclusion In pts with LVS-VAs arising from the inaccessible region and refractory to conventional RFA, an anatomical approach utilizing Bi-RFA from the LPC and opposite LVOT is an effective alternative approach.