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Electrophysiologic studies before and after myocardial revascularization in patients with life-threatening
Insights
Coronary artery bypass graft surgery can improve abnormal heart rhythms in some patients with severe coronary artery disease. However, results are unpredictable, and electrophysiologic studies are recommended before and after surgery.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Cardiac Surgery
Background:
- Patients with severe coronary artery disease and a history of cardiac arrest or ventricular tachycardia (VT) often have abnormal electrophysiologic findings.
- These patients typically undergo coronary artery bypass graft (CABG) surgery.
Purpose of the Study:
- To evaluate the impact of CABG surgery on electrophysiologic abnormalities in patients with severe coronary artery disease and a history of cardiac arrest or VT.
- To assess the efficacy of antiarrhythmic drugs in managing inducible arrhythmias before and after surgery.
Main Methods:
- Electrophysiologic studies with programmed cardiac stimulation were performed in 17 patients before and after CABG surgery.
- Antiarrhythmic drug therapy was assessed in patients with inducible VT or ventricular fibrillation (VF).
Main Results:
- Before surgery, VT or VF was inducible in all 17 patients.
- Postoperatively, 10 patients had no inducible arrhythmias without antiarrhythmic drugs, while 6 still had inducible VT.
- Antiarrhythmic drugs suppressed inducible arrhythmias in 7 of 13 patients preoperatively and were effective in 4 patients postoperatively.
- After a mean follow-up of 23 months, all but one patient were free of arrhythmias.
Conclusions:
- Myocardial revascularization via CABG surgery can improve abnormal electrophysiologic findings in select patients.
- The effect of CABG on arrhythmias is unpredictable.
- Pre- and postoperative electrophysiologic studies are recommended for evaluating these high-risk patients.
Abstract:
Electrophysiologic studies with programmed cardiac stimulation were performed in a selected group of 17 patients with severe proximal coronary artery disease involving at least 2 major vessels and left ventricular ejection fractions greater than 30% who were undergoing coronary artery bypass graft surgery after prehospital cardiac arrest or ventricular tachycardia (VT) unassociated with acute myocardial infarction. Before surgery and without antiarrhythmic drug therapy, programmed cardiac stimulation induced ventricular fibrillation (VF) in 4 patients, and VT (greater than or equal to 5 beats) in 11 patients. Inducible VT or VF was suppressed by antiarrhythmic drugs in 7 of 13 patients in whom they were tried. Patients underwent coronary artery bypass graft surgery unassociated with perioperative myocardial infarction. When studied again an average of 19 days after surgery, 10 patients had no inducible VT or VF without antiarrhythmic drug therapy; 6 had induced VT. One patient had spontaneous VT. An effective antiarrhythmic regimen that suppressed inducible or spontaneous VT, or both, was defined by serial electrophysiologic studies in 4 patients, whereas 3 patients continued to manifest electrically inducible VT with all antiarrhythmic regimens tested. All but 1 patient, in whom postoperative VT could not be suppressed, are free of arrhythmias after a mean follow-up period of 23 months (range 6 to 53). It is concluded that myocardial revascularization alone may improve the abnormal electrophysiologic findings in certain patients; however, this effect of coronary artery bypass graft surgery is unpredictable, and pre- and postoperative electrophysiologic studies are recommended as part of the evaluation of these patients.