Usefulness of Sleep-Disordered Breathing to Predict Occurrence of Appropriate and Inappropriate Implantable Cardioverter-Defibrillator Therapy in Patients With Implantable Cardioverter-Defibrillator for Primary Prevention of Sudden Cardiac Death
Is sleep apnea (SA) a predictor of implantable cardioverter-defibrillator (ICD) therapies?
In this prospective observational study, 133 patients (mean age 63 years, mean ejection fraction 27%) with heart failure (HF) underwent a sleep study before receiving an ICD for primary prevention of sudden cardiac death. Patients already being treated for SA were excluded from the study, and no therapy for SA was instituted during the course of the study. The ICDs were interrogated at regular intervals during a mean of 24 months of follow-up.
SA was present in 62% of patients. Appropriate ICD therapies were significantly more prevalent among the patients with than without SA (54% vs. 34%). Inappropriate ICD therapies also were significantly more prevalent among the patients with than without SA (29% vs. 14%).
The authors concluded that SA identifies patients with HF who are most likely to receive appropriate and inappropriate ICD therapies.
Prior studies have demonstrated that SA increases the risk of ventricular arrhythmias and atrial fibrillation, explaining why both appropriate and inappropriate ICD therapies were more common among the patients in this study who had SA. The most likely mechanisms by which SA triggers or contributes to the genesis of arrhythmias include abrupt and wide swings in autonomic tone and hypoxia. The results emphasize the importance of identifying and treating SA in ICD recipients.
Keywords: Defibrillators, Death, Heart Failure, Primary Prevention, Sleep Apnea Syndromes
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