Robert M. Mentzer

Unanticipated Postoperative Ventricular Tachyarrhythmias

Eighteen (1.4%) of 1,251 patients who underwent cardiac operations during a three-year period had new sustained ventricular tachycardia (12 patients) or ventricular fibrillation (6 patients) not caused by but resulting in hemodynamic compromise. In 13 patients, the initial arrhythmia occurred in the first 48 hours postoperatively. Lidocaine was being administered to 10 of these patients for suppression of previously noted ventricular ectopy, but it did not prevent the occurrence of the arrhythmia. The initial episode was fatal for 5 patients. Two of these deaths were directly related to the adverse effects of the antiarrhythmic agents used to suppress ventricular tachycardia or fibrillation. Five of 10 survivors underwent electrophysiological studies after initial resuscitation. In all 5, programmed ventricular stimulation reproduced the clinical arrhythmia. There have been 2 late sudden deaths in patients who either did not undergo or remained uncontrolled at electrophysiological study during serial drug trials. Our experience suggests that a cardiac operation may unmask or induce potentially lethal arrhythmias that previously had not been apparent. Pharmacological suppression of ventricular ectopy does not necessarily prevent ventricular tachycardia or ventricular fibrillation in the early postoperative period. Electrophysiological study may be helpful in determining the appropriate prophylactic therapy in such patients.

Influence of magnesium ion on human ventricular defibrillation after aortocoronary bypass surgery

The administration of magnesium ion (Mg++) has been reported to defibrillate the ventricles and to decrease the incidence of arrhythmias after cardiopulmonary bypass. In a prospective study of 76 randomly selected patients undergoing coronary artery bypass grafting, patients received either no Mg++, 0.25 mEq/kg of Mg++ during cardiopulmonary bypass with the aorta clamped, or 0.375 mEq/kg of Mg++ before cardiopulmonary bypass. Spontaneous resumption of a cardiac rhythm or spontaneous defibrillation during reperfusion was not significantly affected by Mg++ administration. However, the number of shocks to initial and to sustained defibrillation and the energy required for the last direct-current shock was greatest in patients who received Mg++ before bypass and in those whose plasma Mg++ was greater than 2.26 mg/dl. Thus, the administration of Mg++ may have adverse effects on the heart if intraoperative plasma Mg++ exceeds 2.26 mg/dl.

Carotid endarterectomy after a completed stroke: Reduction in long-term neurologic deterioration

The merit of carotid endarterectomy for patients who previously have sustained a completed stroke remains controversial. Between January 1976 and December 1983, 118 stroke patients with mild to severe permanent neurologic deficits were evaluated. Fifty-nine patients were managed nonoperatively and 59 operatively. Both cohorts were similar in age and sex distribution, incidence of hypertension (69%), diabetes mellitus (25%), and cardiac disease (39%). In the long-term follow-up (medical cohort average was 44.1 +/- 5.0 months; surgical cohort average, 41.8 +/- 3.7 months) the overall survival rate was comparable, that is, there were nine medical deaths and eight surgical deaths. However, there was a significant difference in the development of new neurologic deficits. Twelve of the 59 unoperated patients had new neurologic deficits and three patients died at 12, 36, and 48 months as a result of a recurrent stroke. New neurologic deficits developed in only two of the 59 surgical patients and there were no stroke-related deaths. When the cumulative probability of remaining free from recurrent deficits was examined in the surviving patients at 6 years, all of the patients in the operated group remained free from recurrent deficits, whereas only 58% of the patients in the unoperated group were free of new neurologic deficits (p = 0.02). These data suggest that stroke patients with fixed mild to moderate neurologic deficits and with carotid lesions may be protected from recurrent neurologic complications by carotid endarterectomy.

Baffle Obstruction Following the Mustard Operation: Cause and Treatment

Baffle obstruction developed in 11 patients after they had undergone the Mustard procedure. Eight of them required operative revision. The cause of the baffle obstruction seemed to be related to patient age (less than 1 year) and to the use of Dacron for the baffle but not to the shape of the baffle. A technique of revision that involves widely opening the previously placed baffle and enlarging it and the atriotomy with polytetrafluoroethylene was employed for the last 6 patients. All 5 survivors of this operation had good long-term results without recurrence.

Lidocaine enhances intraoperative ventricular defibrillation.

The efficacy of lidocaine during myocardial reperfusion in coronary artery bypass surgery was evaluated in 20 patients randomly assigned to a control group (n = 10) or to receive lidocaine, 1 mg/kg intravenously 5 min before aortic unclamping and cardiac reperfusion, followed by infusion at 40 μg·kg−1 ·min−1 (n = 10). We recorded ECG leads II and V5 continuously, and number, energy, and current of direct current (DC) shocks starting at 1 joule. The number of low energy DC shocks to sustained defibrillation (5.5 ± 2.0 vs 3.5 ± 2.0, mean ± SD, P < 0.05) decreased significantly with lidocaine infusion. The energy (11.0 ± 6.3 vs 5.6 ± 3.9 joules, P < 0.05) and current (12.7 ± 4.2 vs 8.9 ± 4.7 amperes, not significant) likewise decreased with lidocaine infusion. Energy and current for the first successful shock, although lower in the lidocaine group, were not statistically significantly lower than in the control group. Initial reperfusion rhythm was not influenced by lidocaine. Plasma electrolyte levels, arterial blood gas tensions, myocardial temperature, and surgical technique—factors known to influence defibrillation—were similar in all patients. Administration of lidocaine during myocardial reperfusion allows defibrillation with fewer DC shocks of lower energy and current.

Acute coronary occlusion with exercise testing after initially successful coronary angioplasty for acute myocardial infarction.

Abstract Exercise testing is frequently performed within several days after percutaneous transluminal coronary angioplasty (PTCA) to assess the functional result of the procedure. 1,2 Early stress testing is considered safe, and few complications have been described. Dash 3 reported a case of acute coronary occlusion after early treadmill stress testing necessitating emergency bypass surgery. Herein we describe a patient in whom acute occlusion of the left anterior descending coronary artery (LAD) developed during symptom-limited exercise testing 5 days after angiographically successful PTCA.

Bilateral renal artery embolism: A diagnostic and therapeutic problem

A case of bilateral renal artery embolism in a patient occurring after coronary artery bypass operation is reported, describing the diagnostic techniques and therapeutic aspects of management of this unusual disease. The diagnosis should be suspected in patients with underlying cardiovascular disease who have acute renal failure.

Celiac Artery Compression Syndrome: Report of a Case and Review of Current Opinion

The celiac artery compression syndrome (or median arcuate ligament syn drome) is characterized by postprandial abdominal pain, an epigastric bruit, and arteriographic evidence of significant extrinsic compression of the celiac artery. Although the concept of extrinsic compression of vessels is well estab lished in vascular surgery, the existence of the celiac artery compression syn drome has been a matter of controversy. A patient relieved of celiac artery compression and postprandial pain is presented. A review of the controversy and an approach to evaluating patients suspected of having this type of com pression is outlined.

Abdominal Aortic Aneurysm and Horseshoe Kidney: Evaluation and Surgical Management— A Case Report

This report describes the successful repair of a ruptured abdominal aortic aneurysm (AAA) associated with a horseshoe kidney (HK). The operative man agement of this problem is discussed. The preoperative evaluation of patients in whom an AAA and HK are known to coexist, the indications for elective aneu rysm resection, and the operative management of this problem are examined.