The relationship between insulin resistance and left ventricular systolic and diastolic functions and functional capacity in patients with chronic heart failure and metabolic syndrome

OBJECTIVES
The relationship between chronic heart failure (CHF) and insulin resistance (IR) has long been recognized. We examined the relationship of IR with left ventricular (LV) systolic and diastolic functions and functional capacity of CHF patients with metabolic syndrome.

STUDY DESIGN
The study included 50 nondiabetic CHF patients with metabolic syndrome (NYHA class I-III; 40 men, 10 women; mean age 60±10 years). Metabolic syndrome was diagnosed according to the AHA/NHLBI (American Heart Association/National Heart, Lung, Blood Institute) criteria. Insulin resistance was determined by the homeostasis model assessment (HOMA). Pulse-wave Doppler echocardiography and tissue Doppler imaging were performed to assess LV structure and functions.

RESULTS
Patients with LV ejection fraction ≤%40 (n=25) had significantly higher NYHA functional class (p<0.001) compared to those with EF >%40 (n=25). Fasting plasma insulin concentrations and HOMA-IR did not differ significantly in this respect. No significant differences were found in LV geometrical patterns, diastolic and systolic functions in patients with (HOMA ≥2.7; n=19) or without (HOMA <2.7; n=31) HOMA-IR. However, patients with HOMA-IR had a lower NYHA functional capacity (p<0.0001). HOMA-IR showed significant increases in parallel with NYHA functional class.

CONCLUSION
Our findings suggest that IR in CHF patients with metabolic syndrome is not associated with LV systolic and diastolic functions, but is strongly linked with worsening in NYHA functional capacity.