Introduction Myriad cardiovascular manifestations have been reported with COVID‐19. We previously reported that failure of PR interval shortening with increasing heart rate (HR) in patients with COVID‐19 is associated with adverse outcomes. Here, we report on heart rate variability (HRV) and clinical outcomes in patients with chronic atrial fibrillation (cAF) hospitalized for COVID‐19. Methods A retrospective review of admitted COVID‐19 patients with cAF between 1 March 2020 to 30 June 2020 was performed. HRV in cAF was compared during pre‐COVID‐19 and COVID‐19 admissions; we selected pre‐COVID‐19 ECGs with HRs that were within 10 beats per minute of the COVID‐19 ECGs. Mean HR and each RR interval were recorded. Time‐domain measurements of HR variability were then calculated (SDSD, RMSSD, pNN50). Clinical outcomes during COVID‐19 were correlated to indices of HRV. Results A total of 184 ECGs (95 pre‐COVID‐19, 89 COVID‐19) from 38 cAF in‐patients were included. Mean age 78.6 ± 11.4 years, male 44.7%. The mean number of ECGs analyzed per patient pre‐COVID‐19 was 2.50 and during COVID‐19 was 2.34. Comparing pre‐COVID‐19 versus COVID‐19 ECGs showed: mean HR (95.9 ± 24.3 vs. 101.6 ± 22.8 BPM; P = .10), SDSD (109.0 ± 50.6 vs. 90.3 ± 37.2 ms; P < .01), RMSSD (184.1 ± 80.4 vs. 147.3 ± 59.8 ms; P < .01), pNN50 (73.8 ± 16.3 vs. 65.6 ± 16.6%; P < .01). Patients who had a smaller pNN50 during a COVID‐19 admission had increased mortality (50.0% vs. 14.3%; log‐rank test P = .02). Conclusion In patients with cAF, the HRV was reduced during COVID‐19 compared with prior illnesses at similar average heart rates. Patients with the most depressed HRV as measured by pNN50 had an associated increase in mortality compared with patients whose HRV was preserved.

BACKGROUND Myriad manifestations of cardiovascular involvement have been described in patients with coronavirus disease 2019 (COVID-19), but there have been no reports of COVID-19 affecting the cardiac conduction system. The PR interval on the electrocardiogram (ECG) normally shortens with increasing heart rate (HR). The case of a patient with COVID-19 manifesting Mobitz type 1 atrioventricular (AV) block that normalized as the patient's condition improved prompted us to investigate PR interval behavior in patients with COVID-19.OBJECTIVE The purpose of this study was to characterize PR interval behavior in hospitalized patients with COVID-19 and to correlate that behavior with clinical outcomes.METHODS This study was a cross-sectional cohort analysis of confirmed COVID-19 cases (March 26, 2020, to April 25, 2020. We reviewed pre-COVID-19 and COVID-19 ECGs to characterize AV conduction by calculating the PR interval to HR (PR:HR) slope. Clinical endpoints were death or need for endotracheal intubation.RESULTS ECGs from 75 patients (246 pre-COVID-19 ECGs and 246 COVID-19 ECGs) were analyzed for PR:HR slope. Of these patients, 38 (50.7%) showed the expected PR interval shortening with increasing HR (negative PR:HR slope), whereas 37 (49.3%) showed either no change (8 with PR:HR slope 5 0) or paradoxical PR interval prolongation (29 with positive PR:HR slope) with increasing HR. Patients without PR interval shortening were more likely to die (11/37 [29.7%] vs 3/38 [7.9%]; P 5 .019) or require endotracheal intubation (16/37 [43.2%] vs 8/38 [21.1%]; P 5 .05) compared to patients with PR interval shortening.CONCLUSION Half of patients with COVID-19 showed abnormal PR interval behavior (paradoxical prolongation or lack of shortening) with increasing HR. This finding was associated with increased risk of death and need for endotracheal intubation.

Aims The value of additional ablation beyond pulmonary vein isolation for atrial fibrillation (AF) ablation is unclear, especially for persistent AF. The optimal target for substrate modification to improve outcomes is uncertain. We investigate the utility of low-voltage area (LVA) substrate modification in patients undergoing catheter ablation for AF. Methods This meta-analysis was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Medline, Scopus and Cochrane Central Register of Controlled Trials were systematically searched to identify relevant studies. Risk of bias was assessed using the Cochrane risk of bias tool. Only randomized studies were included. AF patients who underwent catheter ablation with voltage-guided substrate modification targeting LVA (LVA group) vs. conventional ablation approaches not targeting LVA (non-LVA group) were compared. Results Four studies comprising 539 patients were included (36% female). Freedom from arrhythmia (FFA) in patients with persistent AF was greater in the LVA group [risk ratio (RR) 1.30; 95% confidence interval (CI) 1.03–1.64]. There was no difference in FFA in patients with paroxysmal AF between groups (RR 1.30; 95% CI 0.89–1.91). There was no difference in total procedural time (mean difference −17.54 min; 95% CI −64.37 to 29.28 min) or total ablation time (mean difference −36.17 min; 95% CI −93.69 to 21.35 min) in all included patients regardless of AF type between groups. There was no difference in periprocedural complications between groups in all included patients regardless of AF type (RR 0.93; 95% CI 0.22–3.82). Conclusion This meta-analysis demonstrates improved FFA in persistent AF patients who underwent voltage-guided substrate modification targeting LVA.

Background Catheter ablation for atrial fibrillation (AF) is a proven alternative to pharmacologic rhythm control in patients with heart failure with reduced ejection fraction (HFrEF). Whether outcomes differ in patients with heart failure with preserved ejection fraction (HFpEF) is of interest. Methods Medline, Scopus, and Cochrane Central Register of Controlled Trials were systematically searched to identify relevant studies. Primary efficacy outcomes of interest include atrial arrythmia recurrence and repeat ablation. Harm outcomes of interest include all‐cause mortality, all‐cause hospitalizations, cardiovascular hospitalizations, stroke/transient ischemic attack, and cardiac tamponade. Results We included 7 observational studies comprising 2554 patients with HFpEF who underwent catheter ablation for AF. When comparing patients with HFpEF versus without HF, there was no significant difference in atrial arrhythmia recurrence (risk ratio [RR] 1.39; 95% confidence interval [CI] 0.91–2.13), stroke or transient ischemic attack (TIA) (RR 0.47; 95% CI 0.03–6.54), or cardiac tamponade (RR 1.20; 95% CI 0.12–12.20). When comparing patients with HFpEF versus HFrEF, there was no significant difference in atrial arrhythmia recurrence (RR 1.12; 95% CI 0.92–1.37), repeat ablation (RR 1.19; 95% CI 0.74–1.93), all‐cause mortality (RR 0.87; 95% CI 0.67–1.13), all‐cause hospitalizations (RR 1.10; 95% CI 0.94–1.30), cardiovascular hospitalizations (RR 0.83; 95% CI 0.69–1.01), stroke or TIA (RR 0.81; 95% CI 0.29–2.25), or cardiac tamponade (RR 0.98; 95% CI 0.19–5.16). Conclusions Non‐randomized studies suggest that catheter ablation for AF in patients with HFpEF is associated with similar arrythmia‐free survival and safety profile when compared to patients with HFrEF or without heart failure.