[Influence of myocardial mass of the univentricular heart on exercise capacity in patients with functional single ventricle and Fontan surgery].

BACKGROUND

The Fontan operation causes an acute decrease of volume overload of the univentricular heart followed by changes in ventricular geometry. The postoperative increase of myocardial mass-volume-index (MVI) may alter ventricular diastolic function. In this study, we analysed whether the increase in MVI and changes of the ventricular geometry have an effect on the decrease of the exercise capacity in patients with Fontan surgery.

METHODS

We examined the cardiopulmonary function of 24 patients with functional single ventricle and Fontan operation 3.63 +/- 1.97 years after surgery (m = 14, w = 10, age: 14.57 +/- 9.74 years) using a bicycle cardiopulmonary exercise testing. The parameters of exercise capacity and cardiopulmonary function were correlated with Magnetic Resonance Imaging (MRI) parameters such as the MVI, enddiastolic ventricular muscle mass (EDMM) und endsystolic volume (ESV).

RESULTS

The exercise capacity was 2.06 +/- 0.54 W/kg (60.63 +/- 15.75% of the norm) and VO(2)max was 27.41 +/- 8.87 ml/min/kg (60.91 +/- 19.7% of the norm). There was a positive correlation of exercise capacity and VO(2)max with ESV (r(2) = 0.2572, p = 0.033) and EDMM (r(2) = 0.2544, p = 0.024), but none with the MVI.

CONCLUSION

Myocardial hypertrophy may influence the myocardial performance of the univentricular heart and thereby the physical performance in children and adults with Fontan circulation.