Surgical revascularization in the treatment of ventricular tachycardia and fibrillation exposed by exercise-induced ischaemia

Abstract

The role of myocardial revascularization in the treatment of malignant ventricular arrhythmias is not well defined. Our hypothesis was that in patients with ventricular tachycardia or fibrillation exposed by exercise-induced ischaemia, the acute transient ischaemia plays a principal causal role, and that in these patients surgical myocardial revascularization alone might be an effective treatment. Among 1100 consecutive patients undergoing isolated coronary artery bypass surgery (CABG) 30 patients (2.7%) characterized by ventricular tachycardia or fibrillation at the symptom-limited exercise tests prior to revascularization were studied prospectively. All patients had exercise-induced angina pectoris or ischaemic ST-segment depression preceding at least one of the arrhythmic events. In addition, eight of these 30 patients had experienced syncope during out-of-hospital exertional activities. After surgical revascularization, the 28 patients surviving to hospital discharge were followed for 1.6 to 86 months (mean 29 +/- 29 months) as outpatients and underwent between one to eight exercise tests (mean 2.6 +/- 1.9). One of these patients died suddenly of unknown causes at 14 months, another from cancer at 53 months. Twenty-six patients experienced a total of 34 episodes of ventricular tachycardia before revascularization. Two of these patients, both having residual ischaemia, had arrhythmia recurrences during follow-up; odds ratio (OR) 84.5, 95% confidence interval (CI) 18.7-381.9; P = < 0.010. Exercise-induced ventricular fibrillation occurred in eight patients pre-operatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Secondary Prevention After Coronary Artery Bypass Graft Surgery

“…260 Among these patients, CABG can suppress malignant arrhythmias and reduce subsequent episodes of cardiac arrest, 261,262 especially if the arrhythmias are related to ischemia. 263 On the other hand, CABG may not mitigate all the conditions predisposing to ventricular arrhythmias, as in the case of patients with sustained monomorphic ventricular tachycardia and prior MI, and concomitant ICD insertion after CABG may be warranted in such patients.…”

2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery

“…In survivors of cardiac arrest who have severe but operable CAD, CABG can suppress the appearance of arrhythmias, reduce subsequent episodes of cardiac arrest, and result in a good long-term outcome (271)(272)(273). It is particularly effective when an ischemic cause of the arrhythmia can be documented (for instance, when it occurs with exercise) (275). Still, because CABG may not alleviate all the factors that predispose to ventricular arrhythmias, concomitant insertion of an implantable cardioverter-defibrillator is often warranted (276).…”

Effect of Elapsed Time From Coronary Revascularization to Implantation of a Cardioverter Defibrillator on Long-Term Survival in the MADIT-II Trial

“…CR can potentially alter all these mechanisms 1 and reduce the risk for ventricular arrhythmias during the first years after the procedure. Several studies have suggested that CR is associated with ventricular arrhythmia risk‐reduction 14,15 . Most recently, we have shown in post‐MI patients with left ventricular dysfunction enrolled in MADIT‐CRT that the risk of life threatening ventricular arrhythmias, the probability of antitachycardia pacing, and appropriate ICD shocks increase as a function of time elapsed since the revascularization procedure 3 .…”

“…Several studies have suggested that CR is associated with ventricular arrhythmia risk-reduction. 14,15 Most recently, we have shown in post-MI patients with left ventricular dysfunction enrolled in MADIT-CRT that the risk of life threatening ventricular arrhythmias, the probability of antitachycardia pacing, and appropriate ICD shocks increase as a function of time elapsed since the revascularization procedure. 3 Although the response by physicians for appropriate ICD therapy is commonly a sense of relief that a ventricular arrhythmia was treated and possibly sudden death was averted, there are several studies 4,5 that showed that in highrisk cardiac patients, the reduction in arrhythmic mortality with an ICD may translate into a subsequent increase in the risk for heart failure and nonsudden cardiac mortality.…”