Vnitr Lek 2011, 57(3):243-247

Left ventricular end-systolic wall stress during antihypertensive treatment

J. Bulas^1,*, J. Murín¹, I. Janiga², K. Kozlíková³

¹ I. interná klinika Lekárskej fakulty UK a UN Bratislava, Slovenská republika, prednostka doc. MUDr. Soňa Kiňová, PhD.

² Slovenská technická univerzita Bratislava, Slovenská republika, dekan prof. Ing. Ľubomír Šóoš, PhD.

³ Ústav lekárskej fyziky, biofyziky, informatiky a telemedicíny Lekárskej fakulty UK Bratislava, Slovenská republika, prednostka prof. MUDr. Elena Kukurová, CSc.

Introduction:
The mechanical load of left the ventricular wall by blood pressure generated during systole causes a strain associated with the impedance to ventricular emptying. Among several indices, the circumferential systolic wall stress is used to describe this load. The calculated stress depends on systolic blood pressure, wall thickness and ventricular cavity dimension. Methods enabling noninvasive quantification of those indices are based on echocardiographic examinations and blood pressure measurements. Left ventricular hypertrophy in hypertension is considered as a compensatory mechanism allowing the heart to withstand the hemodynamic strain associated with increased arterial pressure.

Subjects and methods:
In the group of 25 female patients with treated arterial hypertension with suboptimal blood pressure levels in the initial evaluation, we realized echocardiographic examination and calculated left ventricular mean circumferential systolic wall stress. The re-evaluation was done after achieving the target blood pressure levels (below 140/90 mm Hg) in the time interval of 6 month to 2 years.

Results:
The statistically significant decrease of systolic wall stress was mainly due to lowering of blood pressure. The next favourable factor was diminishing of the left ventricular end-diastolic diameter, though the difference was not statically significant. By the multiple regression analysis we found that the final significant lowering of systolic wall stress was influenced also by favourable geometrical remodelling of the left ventricle by the tendency of diminishing of left ventricular diastolic diameter and the increase of relative wall thickness.

Conclusion:
We considered repeated echocardiographic examination and the systolic wall stress calculation (which integrates the ventricular geometry with the blood pressure values achieved) as an appropriate parameter for evaluation of the effect of antihypertensive therapy in the long-term management of hypertensive patients.

Keywords: systolic wall stress; arterial hypertension; echocardiography

Received: January 13, 2011; Published: March 1, 2011  Show citation