Impaired right ventricular functions in metabolic syndrome patients with preserved left ventricular ejection fraction

OBJECTIVES
Metabolic syndrome (MetS) has been shown to be independently associated with increased risk for incident heart failure and coronary artery disease. We investigated whether there is deterioration in right ventricular functions in MetS patients with preserved left ventricular functions and its association with the number of MetS components.

STUDY DESIGN
The study included 192 consecutive patients (148 women, 44 men; mean age 54.3±8.5 years) with the diagnosis of MetS based on the NCEP-ATP III criteria and 20 healthy controls (12 women, 8 men; mean age 51.6±8.4 years). All subjects underwent conventional and tissue Doppler (TDI) echocardiography to assess left and right ventricular functions, including right ventricular myocardial performance index (MPI) and tricuspid annular plane systolic excursion (TAPSE).

RESULTS
The number of MetS components were three in 43.8%, four in 31.3%, and five in 25% of the patients. Right ventricular TDI-derived MPI was higher in patients with MetS compared to controls [median 0.5 (range 0.2-3.3) vs. 0.3 (0.1-0.7), p=0.000]. This was possibly due to significantly shortened right ventricular ejection time in MetS patients (p<0.05). Although TAPSE was within the normal range in MetS patients, it was significantly decreased compared to controls (p=0.000), accompanied by significantly lower TDI-derived S wave, E wave, and E/A ratio (p=0.000). None of the MetS components were significantly correlated with right ventricular TDI-derived MPI. There was no association between the number of MetS components and echocardiographic parameters.

CONCLUSION
Our findings show that, despite preserved left ventricular systolic functions, both systolic and diastolic functions of the right ventricle deteriorate in MetS patients.