Major Ventricular Arrhythmias Research Articles

Exertional hypotension and postexertional ventricular fibrillation in stress testing

Six men, clinically diagnosed as having coronary heart disease, had postexertional ventricular fibrillation after maximal exercise testing. The common featureof their treadmill performance was "exertional hypotension," that is, a decrease or a limited increase (10 mm Hg) in systolic blood pressure. All six men were successfully resuscitated with electircal defibrillation. The major indication for electrocardiographic monitoring is the detection of major ventricular arrhythmias and changes in QRS-ST-T of acute myocardial infarction or severe ischemia, all of which are urgent indications for stopping exertion. Close supervision both during and after exercise testing is essential, particularly in men with severe coronary artery disease; monitoring of changes in systolic pressure during and shortly after exercise testing is as important as searching for changes in the -S-T segment.

Bretylium in Acute Myocardial Infarction

To the Editor.— The implications of the abstract and title of Bretylium Tosylate: Adverse Effects in Acute Myocardial Infarction in theArchives(135:515-518, 1975), by Luomanmaki and associates, should not be allowed to stand without comment. Actually, the authors provided no evidence of any adverse effects of the drug in question; rather, they reported favorable effects. They found average peak levels of serum glutamic oxaloacetic transaminase and lactic dehydrogenase to be considerably lower in patients treated with bretylium than in patients treated with lidocaine, although their series was too small to give reliable statistical significance to the favorable effect of bretylium. They themselves say that their data suggest that bretylium has therapeutic value in the prevention of major ventricular arrhythmias in acute myocardial infarction. No patient in their series on bretylium died while receiving treatment. One died 48 hours after the discontinuation of bretylium administration. Perhaps the most serious defect in

Surgical treatment of refractory life-threatening ventricular tachycardia

Aortocoronary bypass, with or without myocardial resection, was used to treat eight patients with refractory life-threatening ventricular tachycardia. All patients had documented evidence of coronary artery disease without recent myocardial infarction and were totally disabled by recurrent ventricular tachycardia while receiving aggressive medical treatment. Angiographic studies showed abnormalities of left ventricular contractions in all patients, including aneurysms in four, localized hypokinetic areas in two and diffusely poor contractility in two. Operative treatment consisted of resection of the aneurysm or localized hypokinetic area in six patients and aortocoronary bypass grafting to at least one major coronary artery in all eight patients. Seven patients are alive an average of 17 months after operation and all are free of major ventricular arrhythmias. We conclude that surgical treatment should be considered in patients with coronary artery disease who have life-threatening ventricular arrhythmias that cannot be prevented or controlled with drug therapy. Aortocoronary bypass, with or without myocardial resection, was used to treat eight patients with refractory life-threatening ventricular tachycardia. All patients had documented evidence of coronary artery disease without recent myocardial infarction and were totally disabled by recurrent ventricular tachycardia while receiving aggressive medical treatment. Angiographic studies showed abnormalities of left ventricular contractions in all patients, including aneurysms in four, localized hypokinetic areas in two and diffusely poor contractility in two. Operative treatment consisted of resection of the aneurysm or localized hypokinetic area in six patients and aortocoronary bypass grafting to at least one major coronary artery in all eight patients. Seven patients are alive an average of 17 months after operation and all are free of major ventricular arrhythmias. We conclude that surgical treatment should be considered in patients with coronary artery disease who have life-threatening ventricular arrhythmias that cannot be prevented or controlled with drug therapy.

Arrhythmias Associated with Acute Respiratory Failure in Patients with Chronic Airway Obstruction

Electrocardiograms of 70 patients with chronic airway obstruction were examined from 148 consecutive admissions for acute respiratory failure. Forty-seven percent of the patients had major supraventricular or ventricular arrhythmias. These arrhythmias were documented on 36 percent of hospital admissions. Supraventricular arrhythmias were slightly more common than ventricular arrhythmias, the most frequent being atrial tachycardia and multifocal atrial tachycardia. Supraventricular arrhythmias tended to recur. Ventricular arrhythmias were often preceded by premature ventricular contractions, supraventicular arrhythmias, or other ventricular arrhythmias. Ventricular arrhythmias were associated with a poor prognosis; 70 percent of patients with ventricular arrhythmia died during the hospital admission and none survived to the end of the study period. These data suggest that continuous electrocardiographic monitoring of chronic airway obstruction patients with acute respiratory failure would be of value in predicting prognosis and identifying patients likely to develop serious arrhythmias; these findings may have therapeutic implications.

Myocardial irritability associated with lithium carbonate therapy.

CARDIAC symptoms have not been conspicuous in cases of human lithium carbonate intoxication,1 and the effect of therapeutic doses of lithium on the human myocardium has been described as "benign."2 , 3 In a recent report concerning a patient, taking thioridazine and lithium carbonate, who manifested major ventricular arrhythmias and was found to be hypokalemic, the authors attributed her arrhythmia to thioridazine and concluded, "We know of no evidence which would link lithium to the production of ventricular arrhythmias."4 In the following case symptomatic premature ventricular contractions were associated with ingestion of lithium carbonate, which produced an intracellular potassium depletion.Case Report . . .

Prehospital Precursors of Ventricular Arrhythmias in Acute Myocardial Infarction

During the past 28 months, 60 patients with suspected acute myocardial infarction (AMI) were admitted to a prehospital satellite industrial coronary care unit (SICCU). During patient stabilization, clinical data, blood studies and continuous electrocardiographic tape recordings were obtained. Thirty-three of the 60 patients had AMI, and the median SICCU arrival time was 45 minutes. Seventy-seven percent of the patients had one or more ventricular premature beats (VPBs) on the 78 ± 11 minute ECG tape recording, and 36% of the AMI patients developed major ventricular arrhythmias within 24 hours of the initial observation. Closely coupled VPBs and elevated cortisol levels were reliable prehospital precursors of serious ventricular arrhythmias. Early prehospital arrival, atrial bradycardia, frequent VPBs, hypertension, elevations of growth hormone or nonesterified fatty acid (NEFA), and decreased insulin levels lacked significance as indicators of subsequent ventricular arrhythmias.

Effectiveness of Bretylium Tosylate against Refractory Ventricular Arrhythmias

Thirty patients with ventricular tachyarrhythmias, which had not responded to intensive therapy with up to five antiarrhythmic drugs, were treated with bretylium tosylate. All patients had recurrent ventricular tachycardia, and 12 had repeated episodes of ventricular fibrillation. In 17 patients the arrhythmias followed acute myocardial infarction. Bretylium was administered intramuscularly or intravenously, and most patients received 4-5 mg/kg every 6 hours. Eighteen patients responded satisfactorily to bretylium and suffered no further ventricular tachyarrhythmias while receiving the drug. Bretylium partially suppressed ventricular arrhythmic activity in five patients and had no beneficial effects in seven patients. Administration of bretylium soon after the development of arrhythmias and withholding of other antiarrhythmic drugs during bretylium therapy favored a good antiarrhythmic response. Hypotension followed bretylium administration in 19 patients but exceeded 20 mm Hg in only one patient. Transient initial increases in blood pressure and ventricular arrhythmic activity occurred in five and four patients, respectively. Six patients were discharged from the hospital on oral bretylium 600 mg every 6 hours, and all have remained free from major ventricular arrhythmias for up to 15 months. In these patients postural hypotension was a transient and parotid pain a persistent side effect.

Mechanically-induced arrhythmias in digitalized hearts

Summary The arrhythmogenic effects of mechanical stimulation of isolated heart were investigated in the absence and presence of acetylstrophanthidin (AS). Brief mechanical shocks were applied to the anterior ventricular surface of Langendorff perfused rabbit hearts at known times in the cardiac cycle. Single premature ventricular contractions were consistently produced except when the mechanical stimuli were applied in the refractory period. In the absence of AS a refractory period was seen, but vulnerability to mechanical stimuli was not observed. During perfusion with AS (0.5 mg/L), mechanical stimuli applied in a vulnerable period induced countershock-reversible ventricular fibrillation in ten of fifteen hearts at a total mean AS dose of 0.4 mg. The other five hearts displayed major ventricular arrhythmias at a comparable AS dose. Control hearts, without mechanical stimuli, developed irreversible ventricular fibrillation at a total mean AS dose of 2.8 mg. Periods of refractoriness and vulnerability to mechanical stimuli were comparable to those for electrical stimuli, both in the absence and presence of AS. Some factors influencing mechanical stimulation are considered and some suggestions are advanced concerning avoidance of mechanically induced arrhythmias in humans.

Thiazide-induced hypokalemia with associated major ventricular arrhythmias. Report of a case and comment on therapeutic use of bretylium

Thiazide-induced hypokalemia with associated major ventricular arrhythmias. Report of a case and comment on therapeutic use of bretylium

Thiazide-Induced Hypokalemia With Associated Major Ventricular Arrhythmias

A 48-year-old woman survived multiple episodes of ventricular tachycardia, flutter, and fibrillation which were associated with a profound thiazide-induced hypokalemia. The significant features of the case are (1) the dosage of hydrochlorothiazide was quite modest, (2) the patient had no known underlying heart disease and was not receiving digitalis, and (3) the arrhythmias were remarkably refractory to the usual therapeutic measures. When recurring ventricular tachyarrhythmias could not be controlled with quinidine sulfate, procainamide hydrochloride diphenylhydantoin sodium, and lidocaine hydrochloride, treatment with bretylium tosylate was instituted. No further episodes occurred thereafter, and it was possible to discontinue this agent without ventricular automatism after potassium repletion had been accomplished. Bretylium appears to be a new and effective agent for the control of major ventricular arrhythmias.