Background: Understanding to what extent genetic factors influence diastolic Doppler indexes is an important issue in view of the relation of left ventricular diastolic dysfunction with outcome. We, therefore, investigated the heritability of left ventricular diastolic traits and the composite diastolic score in nuclear families recruited from the general population.
Methods: In a random sample of 316 nuclear families (452 parents and 600 offspring, mean age, 58.5 and 33.3 years), we measured transmitral early and late diastolic velocities (E and A) by pulsed wave Doppler, and mitral annular velocities (e' and a') by tissue Doppler. Using principal component analysis, we summarized seven Doppler indexes - namely, E, A, e' and a' velocities, and their ratios - into a single diastolic score. To calculate the heritability of diastolic indexes, we used variance decomposition in nuclear families and offspring as implemented in SOLAR and SAS, and the regression slope of offspring on mid-parent residual values.
Results: In variance decomposition analyses in nuclear families, the abovementioned traits with adjustment for covariables had moderate heritability ranging from 0.27 to 0.43 (P < 0.0001 for all). The parent-offspring concordances of all diastolic indexes were significant and ranged from 0.17 for A (P = 0.009) to 0.42 for e' (P < 0.0001). In nuclear families and offspring, the heritability estimates of the composite diastolic score were 0.42 and 0.64, respectively (P < 0.0001).
Conclusion: Our study demonstrated moderate heritability of various indexes reflecting left ventricular diastolic function in nuclear families. The observation highlights the necessity of further research into the genes that affect left ventricular diastolic function.