• Stroke
• Atrial Fibrillation
• Bradycardia

The increasing burden of atrial fibrillation (AF) and significant morbidity/mortality associated with this arrhythmia encourage screening it in clinical practice, as recommended in current guidelines. It means opportunistic screening (in patients over 65 years) or systematic screening (in people above 75 years) by using clinical examination, followed by an ECG, 24-hour ECG monitoring or continuous rhythm monitoring by a screening tool (including mobile or wearable device). In screen-positive cases, a definitive diagnosis of AF should always be obtained before providing an appropriate management.1 Symptomatic or asymptomatic AF is described as either clinical or atrial high-rate episode/subclinical AF; the last one may represent a marker rather than a risk factor for stroke, with these complications probably at lower rates than those of clinical AF. From this point of view, in the current guidelines, bradyarrhythmias in patients with AF were less discussed, being less studied in clinical trials.1

Until now, clinical studies have mainly focused on episodes with AF, symptomatic or asymptomatic, clinical or subclinical. Apart from the episodes of bradyarrhythmias in sinus node disease, those associated with the evolution of AF have been neglected from either incidence, diagnostic, clinical significance, therapeutic or prognostic point of view.

Recently, the RACE V trial investigators assessed the prevalence and characteristics of severe bradyarrhythmia and tachyarrhythmia episodes in patients with self-terminating paroxysmal AF.2 They found a higher than anticipated prevalence of bradyarrhythmias in patients with self-terminating paroxysmal AF. Sixty-nine out of 217 patients (nearly one-fifth) experienced ‘at least one episode of pauses ≥5 seconds or bradycardias ≤30 beats per minute’. Twenty-two patients with bradyarrhythmia episodes were part of the patients with concomitant tachyarrhythmias; 74% of bradyarrhythmia episodes were pauses ≥5 s; 47% of bradyarrhythmias occurred during the night, with exclusively nocturnal episodes observed in only 19% of patients …