Influence of hypertension on systolic and diastolic left ventricular function including segmental strain and strain rate.

ABSTRACT

BACKGROUND: Left ventricular (LV) systolic and diastolic functions are important cardiovascular risk predictors in patients with hypertension. However, data on segmental, layer-specific strain, and diastolic strain rates in these patients are limited. The aim of this study was to investigate segmental two-dimensional strain rate imaging (SRI)-derived parameters to characterize LV systolic and diastolic function in hypertensive individuals compared with that in normotensive individuals. METHODS: The study sample comprised 1194 participants from the population-based Know Your Heart study in Arkhangelsk and Novosibirsk, Russia, and 1013 individuals from the Seventh Tromsø Study in Norway. The study population was divided into four subgroups (A) healthy individuals with normal blood pressure (BP), (B) individuals on antihypertensive medication with normal BP, (C) individuals with systolic BP 140-159 mmHg and/or diastolic BP > 90 mm HG, and (D) individuals with systolic BP ≥160 mmHg. In addition to conventional echocardiographic parameters, global and segmental layer-specific strains and strain rates in early diastole and atrial contraction (SR E, SR A) were extracted. The strain and SR (S/SR) analysis included only segments without strain curve artifacts. RESULTS: With increasing BP, the systolic and diastolic global and segmental S/SR gradually decreased. SR E, a marker of impaired relaxation, showed the most distinctive differences between the groups. In normotensive controls and the three hypertension groups, all segmental parameters displayed apico-basal gradients, with the lowest S/SR in the basal septal and highest in apical segments. Only SR A did not differ between the segmental groups but increased gradually with increasing BP. End-systolic strain showed incremental epi-towards endocardial gradients, irrespective of the study group. CONCLUSION: Arterial hypertension reduces global and segmental systolic and diastolic left ventricular S/SR parameters. Impaired relaxation determined by SR E is the dominant factor of diastolic dysfunction, whereas end-diastolic compliance (by SR A) does not seem to be influenced by different degrees of hypertension. Segmental strain, SR E and SR A provide new insights into the LV cardio mechanics in hypertensive hearts.