Mechanisms of cardiac dysfunction in obstructive sleep apnea

Area of Science:

• Cardiology
• Sleep Medicine
• Internal Medicine

Background:

• Obstructive sleep apnea (OSA) is linked to significant cardiovascular morbidity and mortality.
• Myocardial anomalies and damage are key contributors to OSA-related cardiovascular complications.
• Chronic, intermittent hypoxia resulting from OSA initiates numerous pathways of myocardial injury.

Purpose of the Study:

• To elucidate the mechanisms of OSA-induced myocardial damage.
• To explore the association between OSA, hypertension, and various cardiomyopathies.
• To evaluate the potential benefits of continuous positive airway pressure (CPAP) on cardiac health in OSA patients.

Main Methods:

• Review of mechanisms linking OSA to myocardial damage, including sympathetic activity, inflammation, oxidative stress, and metabolic dysfunction.
• Analysis of OSA's role in hypertension and specific cardiomyopathies (hypertensive, coronary heart disease, obesity-related, diabetic, tachycardia-induced).
• Examination of cardiac structural and functional changes in OSA, such as left ventricular hypertrophy, fibrosis, and diastolic/systolic dysfunction.

Main Results:

• Key mechanisms driving OSA-related cardiac damage include increased sympathetic activity, endothelial dysfunction, systemic inflammation, oxidative stress, and metabolic anomalies.
• These factors contribute to hypertension, a common comorbidity in OSA patients.
• OSA is associated with left ventricular hypertrophy, myocardial fibrosis, atrial dilatation, and impaired ventricular function, explaining clinical outcomes.

Conclusions:

• OSA significantly impacts cardiac structure and function through multiple pathophysiological pathways.
• Nasal continuous positive airway pressure (CPAP) shows potential for improving cardiac symptoms and hemodynamics in OSA patients.
• Further large-scale clinical trials are essential to fully understand OSA's cardiac consequences and the therapeutic effects of CPAP on myocardial damage and cardiovascular prevention.