Effect of remote ischemic postconditioning on left ventricular mechanics.

Background: Remote ischemic postconditioning (RIPC) decreases infarct size and prevents left ventricular (LV) remodeling in patients with myocardial infarction. However, there is no study that evaluates the effect of RIPC on LV mechanics assessed by speckle tracking echocardiography. Therefore, we aimed to test the effects of RIPC on LV deformation parameters such as strain, strain rate, rotation, and twist in healthy subjects.

Methods: The study group consisted of 22 healthy subjects. To test the effects of RIPC, 3 cycles of reperfusion followed by ischemia (each lasting 10 or 30 seconds) were applied immediately after 20 minutes of nondominant arm ischemia. Transthoracic echocardiography (TTE) was obtained at baseline and repeated 30 minutes after the completion of these cycles. In TTE images, apical 4-3-2 chamber longitudinal strain (LS)/strain rate, basal and apical circumferential strain/strain rate, and rotational parameters, such as basal rotation, apical rotation, and LV twist, were recorded.

Results: Apical 4-3-2 chamber LS and apical circumferential strain/strain rate measurements were comparable before and after RIPC, whereas basal circumferential strain was significantly decreased after RIPC (-23 ± 3.4 vs. -18.9 ± 6.9, P = 0.017). After RIPC, apical rotation was significantly increased (11.6 ± 3.7 vs. 16.7 ± 4.0, P < 0.001) and basal rotation was significantly decreased (-6.1 ± 2.1 vs. -4.7 ± 2.4, P = 0.03).Consequently, net LV twist was significantly increased (17.4 ± 4.5 vs. 21.7 ± 4.7).

Conclusions: We proposed that RIPC affects the rotational mechanics of the heart rather than longitudinal mechanics. These results might give new insights into understanding the favorable effects of the post- conditioning.