Gerald D. Buckberg

Ventricular arrhythmias after LV remodelling: surgical ventricular restoration or ICD?

Ventricular arrhythmias cause ~50% of deaths in remodeled ventricles after myocardial infarction, and the Multicenter Automatic Defibrillator Implantation Trial (MADIT II) showed that the Implantable Cardioverter Defibrillator (ICD) saved lives in high risk coronary patients with advanced left ventricular dysfunction. We studied 382 patients with remodeled hearts by preoperative Ventricular stimulation (PVS) to evaluate surgical ventricular restoration (SVR) that excludes scar and lower ventricular volume alters the early and late arrhythmia process without ICD utilization.Methods: Clinical and hemodynamic results before and after SVR in post-infarction patients, are compared to contrast spontaneous and/or inducible ventricular tachycardia to patients without arrhythmias. Study arrhythmia groups included: Spontaneous in 87 patients with clinical documented ventricular arrhythmias and inducible or not inducible ventricular tachycardia: Inducible in 105 patients without clinical ventricular arrhythmias but PVS inducible ventricular tachycardia; and No arrhythmias in 190 patients without spontaneous or PVS inducible ventricular tachycardia.Results: Preoperative LV end systolic volume index helped define preoperative arrythmia potential: Spontaneous > 120/m2, inducible > 100 ml/m2, and none < 100ml/m2. Overall operative mortality rate was 7.6% (29/382). Sudden cardiac death rate was 2.5% causing 18.7% of all deaths. Surgical management reduced inducible ventricular tachycardia, from 41% preoperatively (144/352) to 8% (26/307) at early study, and 8% (14/177) one year later. Cardiac mortality was low at 5-years and not different between groups, despite use of only one late ICD device.Conclusions: Favorable electrical success rate and low mortality always included volume reduction to interrupt functional re-entry circuits, but also added endocardiectomy, cryoablation, CABG and mitral repair when needed. Overall SVR findings show volume and shape alteration limits ventricular arrhythmias that impair prognosis, and suggests ICD devices are not needed.

Mechanical Synchrony: Role of Surgical Ventricular Restoration in Correcting LV Dyssynchrony During Chamber Rebuilding

Cardiac failure is frequently complicated by intra and or interventricular conduction delay that results in dyssynchronized cardiac contraction and relaxation. In contrast to an electrical intervention by biventricular pacing, this study tests the capacity of geometric rebuilding by surgical ventricular restoration (SVR) to restore a more synchronous contractile pattern through mechanical reconstruction without exogenous pacing input.Thirty patients (58 ± 8 years) undergoing SVR at the Cardiothoracic Center of Monaco were prospectively evaluated with a protocol which uses simultaneous measurements of ventricular volumes and pressure to construct pressure/volume (P/V) and pressure/length (P/L) loops. Mean QRS duration was within normal limits (100± 17 ms) preoperatively. Preoperative LV contraction was highly asynchronous. Endocardial time motion was either early or delayed at the end-systolic phase, yielding P/L loops with abnormal in size, shape, and orientation. Postoperatively, SVR resulted in leftward shifting of P/V loops and increased area; endocardial time motion and P/L loops almost normalized. The hemodynamic consequences of SVR included improved ejection fraction; reduced end-diastolic and end-systolic volume index; more rapid peak filling rate; peak ejection rate and mechanical efficiency resulting in mechanical intraventricular resynchronization that improves LV performance.