Abstract 2326: Impact of Persistent Cardiac Dyssynchrony on Functional Outcomes in Patients with Viable Myocardium Undergoing Surgical Myocardial Revascularization
Background. Dyssynchrony of cardiac contractions (DYS) is associated with deterioration of left ventricular (LV) contractile function. The aim of the present study was to investigate the relationship between DYS and LV functional recovery in patients with ischemic cardiomyopathy and large extent of viable myocardium undergoing surgical myocardial revascularization (CABG).
Methods: The study consisted of 88 consecutive patients with ischemic cardiomyopathy and large extent of viable myocardium (>5 dysfunctional but viable segments) (age 67 ± 8y; 84% males, LV ejection fraction 31±7%) undergoing CABG. DYS was calculated by tissue-Doppler imaging from measurements of regional electromechanical coupling times in basal segments of the left ventricle before and within 7 days after CABG. In healthy individuals, mean value of DYS is 10±8 ms. Based on the previous studies, significant DYS was defined as DYS >= 72 ms. LV ejection fraction was assessed by echocardiography (biapical Simpson method) before and 12 months after revascularization.
Results. Mean pre-CABG and post-CABG DYS were 67±46 ms and 46±38ms, respectively. Twenty-five (28%) patients showed significant post-CABG DYS (>=72 ms). At follow-up, marked (>=10% units) increase in LV ejection fraction was observed in 59 out of 63 (94%) patients without post-CABG DYS but only in 8 out of 25 (32%) patients with post-CABG DYS (p<0.0001). Extent of ejection fraction improvement significantly correlated with decrease in DYS between pre and post-CABG examination (r=−0.43, p< 0.0001). During follow-up, nine patients (36%) with persistent DYS had clinical endpoints (2 cardiac deaths and 7 hospitalizations), while only 2 hospitalizations (3%) occurred in 63 patients without post-CABG DYS (p< 0.0001).
Conclusions. Patients with persistence of post-CABG DYS are characterized by absence of functional LV recovery and high event-rate despite large extent of viable myocardium. Hence, implantation of biventricular pacemaker may be warranted in these patients.