Epicardial cardioverter-defibrillators do not cause postoperative arrhythmias. The CABG Patch Trial Investigators. Coronary Artery Bypass Graft

Device therapies in the post-myocardial infarction patient with left ventricular dysfunction

The post-myocardial infarction (MI) patient with left ventricular dysfunction (LVD) is at risk for ventricular arrhythmias resulting in sudden cardiac death. In high-risk post-MI patients with a depressed left ventricular ejection fraction, prophylactic implantable cardioverter defibrillators (ICDs) may significantly improve survival. These benefits are in addition to those of optimal pharmacologic therapy, and ICD therapy should be considered the standard of care in these patients. Recent device trials have demonstrated the benefits of prophylactic ICD placement in patients who have been selected based on post-MI left ventricular systolic dysfunction alone. In addition, cardiac resynchronization therapy can improve the quality of life beyond that achievable with drug therapy alone and should be considered in patients with symptomatic heart failure with QRS prolongation. Further risk stratification studies of post-MI LVD patients will allow ICD therapy to be applied in a more cost-effective manner.

Routine delivery of myoblasts during coronary artery bypass surgery: why not?

Skeletal myoblast transplantation has now entered the clinical arena as a potential means of restoring function to scarred myocardium. While the current experience derived from phase I trials suggests that cell implantation during coronary artery bypass operations is a straightforward and safe procedure, routine use of myoblast transplantation would certainly be premature. Two major issues have not yet been addressed: firstly, the risk-benefit ratio needs to be assessed, specifically whether the potential proarrhythmic risk associated with myoblast transplantation is supported by the results of an ongoing large, randomized study, and if so, whether this risk is offset by a benefit in terms of improvement of left ventricular function and patient outcome. Secondly, this putative benefit will then have to be weighed against the financial burden inherent to this type of procedure, to assess whether the cost-effectiveness ratio is favorably shifted and supports the expanded indication of myoblast transplantation during coronary artery revascularization in patients with severe ischemic heart failure.

[Predictors of sudden death in coronary artery disease]

Although advances in the management of acute myocardial infarction have resulted in a decline in long-term risk of sudden death, it continues to be high in certain subsets of patients. Thus, it is important to identify and treat these patients. Left ventricular ejection fraction less than 0.40, frequent premature ventricular ectopy on Holter monitoring, late potentials on signal-averaged electrocardiogram, impaired heart rate variability, abnormal baroreflex sensitivity and inducible sustained monomorphic ventricular tachycardia during electrophysiological study are predictors of sudden death and arrhythmic events. Although the negative predictive value of each factor is high, the positive predictive accuracy is low. Several tests can be combined to obtain higher positive predictive values. In fact, in some studies combined noninvasive tests have been used to select patients for ventricular stimulation study. Some preventive treatment can be applied in these patients. Available data do not justify prophylactic therapy with amiodarone in high-risk survivors of acute myocardial infarction. Sudden death and total mortality have been significantly reduced in postinfarction patients by long-term beta blockade. Hence, beta blockers should be given to all patients with acute myocardial infarction who do not have contraindications to their use. The MADIT study has shown the beneficial effect of implantable cardioverter defibrillator in reducing mortality in patients with prior myocardial infarction, an ejection fraction less than 0.36, asymptomatic nonsustained ventricular tachycardia, and inducible sustained ventricular tachycardia, unsuppressable by procainamide. Besides, several studies are under way to evaluate the prophylactic use of implantable defibrillator for improving survival in high-risk patients.