Central sleep apnea in left ventricular dysfunction: prevalence and implications for arrhythmic risk

Area of Science:

• Cardiology
• Sleep Medicine
• Internal Medicine

Background:

• Sleep-disordered breathing (SDB) prevalence and characteristics in asymptomatic left ventricular (LV) dysfunction are largely unknown.
• Patients with LV dysfunction often have undiagnosed comorbidities.
• Understanding SDB in this population is crucial for comprehensive patient management.

Purpose of the Study:

• To determine the prevalence of SDB in patients with asymptomatic LV dysfunction.
• To investigate the association between SDB and hemodynamic/autonomic impairment in these patients.

Main Methods:

• Studied 47 patients with LV ejection fraction ≤40% and no history of heart failure.
• Assessed for central sleep apnea (CSA) and obstructive sleep apnea using standard criteria.
• Evaluated exercise tolerance, echocardiographic indices, heart rate variability, and arrhythmias.

Main Results:

• Central sleep apnea (CSA) was present in 55% of patients, with 36% having severe CSA.
• CSA prevalence was higher in ischemic cardiomyopathy compared to non-ischemic.
• Patients with CSA showed depressed heart rate variability and a higher incidence of ventricular tachycardia.

Conclusions:

• CSA is highly prevalent in asymptomatic LV dysfunction.
• Severe CSA is associated with impaired cardiac autonomic control and increased arrhythmias.
• The severity of CSA may not correlate with the degree of hemodynamic impairment.