Circulation: Arrhythmia and Electrophysiology June 2020 Issue

Paul J. Wang:

Welcome to the monthly podcast, On the Beat for Circulation: Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, editor in chief, with some of the key highlights from this month's issue.

 

In our first paper, Vivek Reddy and associates studied a novel, 7.5, French lattice tip catheter with the compressible 9 mm nitinol tip that is able to deliver either focal radio frequency ablation [RFA] or pulsed field ablation [PFA], 2 to 5 second lesions. In a 3 center, single-arm, first in human trial, the catheter was used with a custom mapping system to treat paroxysmal or persistent atrial fibrillation. Toggling between energy sources, point by point, pulmonary vein [PV] encirclement was performed using biphasic pulsed field ablation, posteriorly, and either temperature controlled irrigated RFA or pulse field ablation, anteriorly (RF/PF or PF/PF) respectively. Linear lesions were created with either PFA or RFA. The 76 patient cohort included 55 paroxysmal and 21 persistent atrial fibrillation [AF] patients undergoing either RF/PF [pulse field ablation] 40 patients or PF/PF ablation in 36 patients, pulmonary vein isolation therapy duration was 22.6 minutes per patient with a mean of 50.1 RF/PF ablation lesions per patient. Linear lesions included 14 mitral, 34 left atrial roof and 44 cavo-tricuspid isthmus lines with therapy duration times of 5.1, 1.8 and 2.4 min/patient respectively. All lesion sets were acutely successful using 4.7 minutes of fluoroscopy. There were no device-related complications, including no strokes. Post-procedure esophagogastroduodenoscopy revealed minor mucosal thermal injury in two of the 36 RF/PF and zero of the 24 PF/PF patients. Post-procedure brain MRI revealed DWI positive flair, negative and DWI positive flare positive asymptomatic lesions in 5 and 3 of the 51 patients respectively.

 

In our next paper, Moussa Saleh and associates examined whether chloroquine, hydroxychloroquine plus or minus azithromycin lead to a prolongation of the QT interval, possibly increasing the risk of torsades de pointes and sudden death in a hospitalized population of patients with COVID-19. 201 patients were treated for COVID-19 with chloroquine/hydroxychloroquine. 10 patients or 5% received chloroquine, and 191 or 95% received hydroxychloroquine and 119 or 59% also received azithromycin. The primary outcome of Torsades de pointes was not observed in the entire population. Baseline QTC interval did not differ between patients treated with chloroquine or hydroxychloroquine monotherapy versus those treated with combination group chloroquine/hydroxychloroquine and azithromycin (440 ms versus 439.9 ms). The maximum QT during treatment was significantly longer in the combination versus the monotherapy group, 470 ms versus 453 ms (P = 0.004). Seven patients (3.5%) required discontinuation of these medications due to QTC prolongation. No arrhythmic deaths were reported.

 

In our next paper, Mikko Tulppo and associates examine whether the association between leisure time physical activity and the risk of sudden death and non-sudden cardiac death in coronary artery disease patients. 1,946 patients with angiographically verified coronary artery disease were classified into four groups: inactive, irregularly active, active exercise regularly two to three times per week, and highly active, exercise four times or more weekly. During follow-up, median 6.3 years, 52 sudden cardiac death and 49 non-sudden cardiac deaths occurred. Inactive patients had increased risk for sudden cardiac death compared to active patients, hazard ratio 2.45. Leisure time was not associated with sudden cardiac death in patients with Canadian cardiovascular class one, 18 events in 1,107 patients. Among patients with Canadian cardiovascular society, class two or higher, 34 events in 839 patients. An increased risk for sudden cardiac death encountered in highly active patients, hazard ratio 7.46 (P < 0.001). In inactive patients hazard ratio 3.64 as compared to active patients. A linear association was observed between leisure time, physical activity and non-sudden cardiac death. Those with high leisure time physical activity had the lowest risk for non sudden cardiac death.

 

In our next paper, Jacob Koruth and associates examined the preclinical feasibility and safety of a 9mm lattice tip catheter with focal biphasic pulse field [PF] based thoracic vein isolation and linear ablation combined focal biphasic pulse field and radio-frequency [RF] focal ablation and vocal biphasic pulse field delivered directly on top of the esophagus. They treated two cohorts of six swine with pulse fields at low dose and high dose followed for four weeks and two weeks, respectively to isolate 25 thoracic veins and to create five right atrial low dose PF, six mitral high dose PF, and six roof lines with combined RF and high dose PF. Baseline and follow-up voltage mapping, venus potent