Aim: To evaluate the therapeutic effect of resynchronization in patients with chronic heart failure who are symptomatic despite adequate pharmacological medication.
Sample and methodology: 118 patients with chronic heart failure, mostly dilated cardiomyopathy and ischaemic heart disease, with depressed systolic function, decreased left ventricular ejection fraction (LVEF) and left bundle branch block wide QRS complex, underwent implantation of the biventricular system between the years 2000-2006. We assessed changes in the NYHA functional class, hemodynamic parameters acquired during right heart catheterization, the maximum oxygen consumption during stress spiroergometric examination, as well as echocardiographic parameters.
Results: A statistically significant improvement was found in the NYHA functional class (from 2.8 +/- 0.4 to 2.3 +/- 0.5 after 3 m, p < 0,001 and to 2.5 +/- 0.6 after 12 m, p < 0,01 respectively), as well as an increase in the maximum oxygen consumption during spiroergometric examination (VO2 max from 14.1 +/- 3.1 ml/kg/min to 15.3 +/- 3.1 ml/kg/ min, p < 0,001 and to 15.3 +/- 2.5 ml/kg/min, p = NS respectively). In regard to hemodynamic parameters, there were increases in cardiac output and cardiac index after three months. After 12 months the change was not statistically significant (CO from 3.9 +/- 1 l/min to 4.2 +/- 0.9 l/min, p < 0,05, and to 4.1 +/- 0.9 l/min, p = NS, CI from 2 +/- 0.5 l/kg/min to 2.2 +/- 0.4 l/kg/min, p < 0,05, and to 2.1 +/- 0.4 l/kg/min, p = NS). Mean pulmonary artery pressure, as well as pulmonary capillary wedge pressure was reduced after 3, as well as after 12 months to a statistically significant degree (MPA from 29.1 +/- 11.5 mm Hg to 23.9 +/- 10.3 mm Hg, p< 0,001, and to 24.9 +/- 11.8 mm Hg, p < 0,01 respectively, and PCWP from 19.9 +/- 9.5 mm Hg to 15.2 +/- 9.2 mm Hg, p < 0,01, and to 15.6 +/- 9 mm Hg, p < 0,01 respectively). In regard to echocardiographic parameters, there was an increase in LVEF, a reduction in the end-diastolic diameter of the left ventricle, as well as a statistically significant reduction in severity of mitral regurgitation after 3, as well as 12 months (LVEF from 20.5 +/- 5.3%, to 23 +/- 6.5%, p < 0,001, and to 24.5 +/- 8%, p < 0,001, LVEDD from 69 +/- 9 mm to 68 +/- 9 mm, p < 0.01 and to 65 +/- 12 mm, p< 0.01 respectively, mitral regurgitation from 2.2 +/- 0.8 to 1.9 +/- 0.8, p< 0.001, and to 2 +/- 0.8, p < 0.001.
Conclusions: In patients with chronic heart failure, resynchronization therapy leads to reduced symptoms, reduction in dyspnea and to improvements in cardiac performance due to increase in the systolic function of the left ventricle and hemodynamic changes.