Prevalence of bradycardic arrhythmias in sleep apnoea

In the early days of sleep research it was thought that heart block (second and third degree atrioventricular block), sinus arrest, or sinoatrial block were frequent findings in patients with sleep apnoea. Tilkian and co-workers1 reported that more than 50% of patients with sleep apnoea develop episodes of heart block during sleep. In 400 patients studied by Guilleminault et al 2 bradycardic arrhythmias were reported in almost 18% of the patients and later studies found heart block in 9–13% of patients with sleep apnoea.3 ,4 Due to ventricular asystoles of up to 13 seconds in duration it was hypothesised that heart block might lead to an increased mortality risk in these patients.2 A recent publication challenged previous results in that no increased prevalence of bradycardic arrhythmias was seen in patients with sleep apnoea compared with those without sleep apnoea.5

To examine these seemingly discrepant results further we performed Holter monitoring in 239 consecutive patients diagnosed as having sleep apnoea (apnoea/hypopnoea index >10/h) using a validated ambulatory recording device based on the measurement of heart rate, Sao ₂, snoring sound, and body position. Episodes of second and third degree atrioventricular (AV) block and/or sinus arrest of more than two seconds in duration occurred in 17 of the 239 patients.6 There was no significant difference in age between patients with and without heart block (mean (SD) 50.7 (12.8) versus 52.1 (9.8) years), but those with heart block were significantly more obese (38.7 (7.3) versus 30.7 (4.6)).

Twelve of the 17 patients (70.6%) had arterial hypertension, seven (41.1%) suffered from heart failure (NYHA II–III), and four (23.5%) had pulmonary hypertension. None of the patients reported a myocardial infarction in their medical history, and in only one (5.9%) exercise testing showed signs of coronary heart disease. …