Brady- and tachyarrhythmias detected by continuous rhythm monitoring in paroxysmal atrial fibrillation

Abstract

Objective: Atrial fibrillation (AF) is associated with adverse events including conduction disturbances, ventricular arrhythmias and sudden death. The aim of this study was to examine brady- and tachyarrhythmias using continuous rhythm monitoring in patients with paroxysmal self-terminating AF (PAF).

Methods: In this multicentre observational substudy to the Reappraisal of Atrial Fibrillation: interaction between hyperCoagulability, Electrical remodelling and Vascular destabilisation in the progression of AF (RACE V), we included 392 patients with PAF and at least 2 years of continuous rhythm monitoring. All patients received an implantable loop recorder, and all detected episodes of tachycardia ≥182 beats per minute (BPM), bradycardia ≤30 BPM or pauses ≥5 s were adjudicated by three physicians.

Results: Over 1272 patient-years of continuous rhythm monitoring, we adjudicated 1940 episodes in 175 patients (45%): 106 (27%) patients experienced rapid AF or atrial flutter (AFL), pauses ≥5 s or bradycardias ≤30 BPM occurred in 47 (12%) patients and in 22 (6%) patients, we observed both episode types. No sustained ventricular tachycardias occurred. In the multivariable analysis, age >70 years (HR 2.3, 95% CI 1.4 to 3.9), longer PR interval (HR 1.9, 1.1-3.1), CHA₂DS₂-VASc score ≥2 (HR 2.2, 1.1-4.5) and treatment with verapamil or diltiazem (HR 0.4, 0.2-1.0) were significantly associated with bradyarrhythmia episodes. Age >70 years was associated with lower rates of tachyarrhythmias.

Conclusions: In a cohort exclusive to patients with PAF, almost half experienced severe bradyarrhythmias or AF/AFL with rapid ventricular rates. Our data highlight a higher than anticipated bradyarrhythmia risk in PAF.

Trial registration number: NCT02726698.

Keywords: arrhythmias, cardiac; atrial fibrillation; bradycardia; electrophysiology; tachycardia, supraventricular.

Figure 1

Central illustration. Study overview and main findings. AF, atrial fibrillation; AFL, atrial flutter; BPM, beats per minute; RACE V, Reappraisal of Atrial Fibrillation: interaction between hyperCoagulability, Electrical remodelling, and Vascular destabilization in the progression of AF.

Figure 2

Sankey diagram showing changes in rate and rhythm control drug use over follow-up for all patients included in this study (n=392). Patients who underwent an atrial fibrillation (AF) ablation were listed as such regardless of underlying pharmacological AF therapy. 12m FU=12-month follow-up visit; 30m FU=30-month follow-up visit.

Figure 3

Pacemaker implantations and rate control strategy at baseline, 1-year and 2.5-year follow-up visits in patients with pauses ≥5 s or bradycardias ≤30 BPM (n=69). In 22 patients, both bradyarrhythmia and tachyarrhythmia episodes were detected. Dots indicate days with episode registrations. AF, atrial fibrillation; AFL, atrial flutter; AVN, atrioventricular node; BPM, beats per minute; ILR, implantable loop recorder; PM, pacemaker.

Figure 4

Results from the multivariable analyses in patients with bradyarrhythmia and tachyarrhythmia episodes. Bold text indicates statistical significance. (A) Risk factors for bradyarrhythmia episodes and (B) risk factors for tachyarrhythmia episodes. AADs, antiarrhythmic drugs; BB, beta-blocker; IRR, incidence rate ratio.