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 population studies 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 cardiomechanics in
hypertensive hearts.