[Obstructive sleep apnea as a cause of dysrhythmia in sudden cardiac death]

Sleep apnoea is often accompanied by severe disturbances in heart rate and cardiac rhythm.

Various respiratory parameters were continuously recorded 6-9 hours during sleep in ten patients with sleep apnoea syndrome, paralley with direct ECG recording (8 cases) or Holter monitoring (2 cases). The rate, development and reversibility of various dysrrhythmias were evaluated.

Obstructive, central and mixed sleep apnoeas (OSA, CSA, MSA) and hypopnoea occurred in each patient (52.5%, 3.5%, 10% and 34%, respectively). Lighter dysrrhythmias (sinus arrest, atrioventricular block and occasional supraventricular premature contractions) were in patients with frequent CSA, whereas the most severe ones (higher degrees of AVCB, premature ventricular contractions and tachyarrhythmias) occurred during OSA. Stronger hypoxaemia and myocardial acidosis, as well as severe alteration in sympathetic and vagal tone probably contributed to the development of life-threatening brady- and tachyarrhythmias in OSA, based on alteration in effective refractory period and reentry phenomenon.

Dysrrhythmias often occur during OSA and they may result in acute cardiovascular complications. Due to their functional character and reversibility, the development of nocturnal dysrrhythmias can be prevented by early diagnosis and effective treatment of sleep related breathing disorders, which at the same time decreases, the risk of both cardiovascular complications and diseases.