Aim: This study used phonocardiography to investigate maternal cardiac reserve function in gestational hypertension and pre-eclampsia.
Method: Ninety-nine pregnant women with gestational hypertension (50 cases) and pre-eclampsia (49 cases) were included in the study; 99 normotensive pregnant women acted as controls. Using phonocardiography, cardiac reserve function parameters for all participants were recorded: heart rate, the ratio of the first heart sound magnitude to the second heart sound magnitude (S1/S2) and the ratio of the diastolic duration to the systolic duration (D/S).
Results: The average values for S1/S2 in the pre-eclampsia and gestational hypertension groups were 4.3 ± 2.2 and 2.2 ± 1.1 respectively. The average D/S of the pre-eclampsia and gestational hypertension groups were 1.1 ± 0.3 and 1.4 ± 0.3 respectively. Cases of postnatal adverse maternal outcomes were only observed in the pre-eclampsia group. A small proportion (2 out of 28) suffered cardiac-related complications, with one of these two patients dying from cardiac failure. Both these cases had notably poor cardiac reserve function (S1/S2 > 5.00 and D/S < 1) before delivery. The index S1/S2 increases and the index D/S decreases with increasing severity of hypertension-complicated pregnancies.
Conclusions: Our findings indicate that cardiac reserve function declines with the increasing severity of hypertension during pregnancy. Phonocardiography is a useful, convenient and clinically worthwhile technique to monitor cardiac reserve function parameters of pregnant women with pre-eclampsia.