EUROMEDICA  Hanover 23-24  Mai 2011	Advanced methods of diagnosis, treatment and prophylactics
	European Academy of Natural Sciences, Hanover European Scientific Society, Hanover

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A relatively new method of treatment of chronic heart failure is cardiac resynchronization therapy (CRT). One important issue is the selection of CRT patients with good prognosis response to intervention. Several studies have shown that 20-30% of patients do not respond adequately to therapy. Is of interest to attempt to use antiorthostatic stress test (AOT) for predicting the effectiveness of CRT.

The aim of the study was to explore the possibility of antiorthostatic load test to assess the contractile reserve of the free wall of the left ventricle in patients with congestive heart failure.

Materials and methods. The study included 24 people in the age of 54 ± 10,2 years. All patients had heart failure functional class III NYHA; 11 person group included dilated cardiomyopathy (DCMP), 13 people - a group of ischemic cardiomyopathy (ICMP). All patients should have coronary angiography for verification of ischemic heart disease. The results of the effectiveness of CRT were evaluated after 5-7 days and 12 months after implantation of biventricular stimulator. As a test, with a passive load volume using a modified version of AOT (lifting the legs to 45 ° for 5 minutes). Local contractile reserve was studied by assessing the dynamics of systolic myocardial velocity (SMV) by pulsed-wave tissue Doppler. In the initial state and at the peak of the study also estimated all of the standard echocardiographic indices. Before and after biventricular stimulation was determined by exercise tolerance with the use of standard test with a 6-minute walk.

Results:

Initially the group ICMP and DCMP significantly differed anterior-posterior size of the right ventricle to the rest of the studied echocardiographic parameters significant differences were found. During AOT patients DCMP end-diastolic left ventricular volume (EDV) were not significantly altered in patients ICMP EDV tended to increase, rates of contractile and pump function of left ventricle (LV) was not significantly changed; SMV free wall of LV tended to increase in both groups, there was a statistically significant increase in LV contractile state in the form of higher index of contractility. We divided the patients with DCMP and ICMP into 2 subgroups: with positive - Group A and a negative inotropic response - group B. The main criterion for separating patients on inotropic response been a significant increase of LV contractility index, the increase in SMV free wall of LV during a test with a passive load capacity. In group B had higher value end-diastolic pressure of LV (p = 0,004), lowest SMV of free wall. This group is characterized by a low contractility index 1, 4 ± 0,5, while in group A, 1,8 ± 0,6, respectively. Groups A and B differed significantly in systolic velocity of the tricuspid valve annulus (SRV). There was a high correlation between SMV free wall LV and SRV r = 0,7 (p = 0.01). In patients of group A was observed most marked improvement in hemodynamic parameters after CRT, the ejection fraction EF increased by 42%, end systolic volume of LV (ESV ) decreased by 25%, SMV free wall increased by 40%, a distance of 6minute walk increased from 240 ± 110 to 328 ± 105 m in group B against CRT EF increased by 17%, ESV has decreased only by 9%, SMV free wall increased by 18%, a distance of 6-minute walk increased from 225 ± 110 to 265 ± 105m. The effect of CRT was significantly proved for patients with dilated cardiomyopathy, and for patients with ischemic myocardial damage (p <0.05). However, the group ICMP noted less pronounced increase in LVEF in the background of the CRT. It should be noted the significance rate of LV contractility index, which can be independent if a dynamic study of left ventricular function.

Conclusions:

1. Passive load capacity during the AOT is gentle and quiteinformative method for assessing the functional reserves of the left ventricle in patients with DCMP and the ICMP.
2. The positive inotropic response to a passive load volume up to CRT in the form of increased SMV LV free wall and increase the contractility index LV, can be an indicator of relatively rapid improvement in hemodynamic parameters after CRT.
3. Reducing SRV less than 9 cm /s may serve as indirect signs of exhaustion contractile reserve of left ventricular free wall.