Heart patients with depression are at a higher risk of developing heart failure regardless of whether they take antidepressants, according to US researchers who studied 14,000 people.

Their study is the first to look into how depression affects risk for heart failure, a chronic condition affecting 5 million Americans. The condition leads to a gradual weakening of the heart's ability to pump blood efficiently. The data suggest that depression is an important risk factor for heart failure among patients with coronary heart disease.

According to previous studies depression is about three times more common in heart attack patients and depressed patients are at higher risk of a second heart attack.

Nearly 14,000 people with no depression at the time of diagnosis but with clogged heart arteries were studied. They were tracked till they developed heart failure or died. Researchers found that of the 1,377 patients who developed depression, the heart failure rates in the group were much higher than among those who were not depressed.

While the heart failure rate was 3.6 per cent among people who were not depressed, it was 16.4 per cent in the group that developed depression. Researchers also observed that though many patients took anti-depressants it did nothing to reduce heart failure risks.

Studies have also shown that depressed patients are more likely to stop taking their heart mediations. They are also less likely to stay on prescribed diets or exercise on a regular basis.

Depression is also implicated in triggering changes in the body including reduced heart rate and elevated blood factors that encourage formation of blood clots.

Researchers say that the findings suggest that though symptoms of depressions may improve, depression related heart risks might not.

Another independent study has implicated higher waist size in both men and women across all levels of body mass index (BMI). In a study on 36, 873 women aged 48 t0 83 years and 43,487 men aged 45 to 79 years researchers examined the strength of the association of BMI with heart failure by age and joint associations of BMI and waist circumference (WC).

Researchers observed 15 per cent and 18 per cent higher rates of HF in women with BMIs of 25 kg/m2 and 30 kg/m2 and 10cm higher WC.

Among men, of BMI 25 kg/m2 and 30 kg/m2 and 10 cm higher WC, researchers observed a 16 per cent and 18 per cent higher rates of HF. A 1-kg/m2 higher BMI was associated with 4 per cent higher HF rates regardless of WC.

Researchers concluded that higher WC was associated with HF at all levels of BMI in women while both BMI and WC were predictors in men. They say measures of both overall and abdominal adiposity were associated with HF hospitalization or mortality in middle-aged and older population.