Effect of exercise based cardiac rehabilitation on heart rate variability, functional exercise capacity and quality of life in patients with heart failure.

Cardiovascular diseases are the leading cause of death and disability in India. Marked reduction in exercise capacity has detrimental effects on activities of daily living, health-related quality of life. This leads to increased risk of mortality and hospital admission rate is high following a heart failure (HF), which may be due to gaps in secondary prevention in general and a lack of cardiac rehabilitation (CR) services in particular. Numerous cardiac rehabilitation studies have demonstrated functional benefits, improvement in quality of life, and clinical outcomes from exercise training in patients with heart failure. Autonomic dysfunction is an independent predictor of cardiovascular disease and mortality after heart failure. Heart rate variability (HRV) is a widely used, easy, non-invasive method that is reproducible and cost-effective for estimating cardiac autonomic modulation. A depressed HRV is a valuable indicator of autonomic dysfunction. Depressed HRV suggests poor functioning of cardiac autonomic modulation and thus impaired ability of the heart to adapt to a range of physiological and environmental stimuli. Low heart rate variability (HRV) is an indicator of increased risk of sudden cardiac death in patients with chronic heart failure.