Refractory Ventricular Arrhythmias Research Articles

Treatment of early postinfarction ventricular aneurysm by intra-aortic balloon pumping and surgery

In nine patients with medically refractory left ventricular failure and/or ventricular arrhythmias, secondary to acute formation of a ventricular aneurysm, intra-aortic balloon pumping (IABP) was instituted 24 to 36 hours before diagnostic angiographic studies. Ventricular irritability was reduced and heart failure was controlled in all patients. Eight patients underwent operation, four within 3 weeks of an acute myocardial infarction and four within 3 months. All had resection of the recent infarction and two had myocardial revascularization as well. Two of the eight patients died in the early postoperative period from intractable ventricular fibrillation. All six patients who survived the operation (mean follow-up 12 months) had excellent clinical results. Ventricular irritability was suppressed and only one patient had residual heart failure. However, there was one late death 7 months after operation. The results suggest that surgical therapy may be effective in the management of medically unresponsive arrhythmias and/or congestive heart failure in the acute or intermediate postinfarction phase. IABP assistance was helpful in supporting the circulation and reducing ventricular irritability during the preoperative and postoperative periods.

Control of Refractory Cardiac Arrhythmias With Amiodarone

Amiodarone hydrochloride was used to treat 19 patients with symptomatic arrhythmias refractory to quinidine sulfate, procainamide hydrochloride, disopyramide phosphate, antazoline hydrochloride, lidocaine hydrochloride, bretylium tosylate, propranolol hydrochloride, phenytoin sodium, and practotol acetanilide given to the limit of tolerance. In 17 patients, attacks were completely controlled. Arrhythmias treated successfully included recurrent supraventricular tachycardias, recurrent supraventricular tachycardias with Wolff-Parkinson-White syndrome, and refractory ventricular arrhythmias including recurrent ventricular tachycardia and ventricular fibrillation complicating acute coronary heart disease. Control was confirmed by continuous ECG monitoring both in the hospital and when ambulatory and was maintained for up to four years. Attacks of supraventricular tachycardia were reduced from 7.9/mo to one attack every 53.5 months on amiodarone. Hospital admissions for arrhythmias were reduced from 34 the year before treatment to none the year after. Therefore, amiodarone is an excellent drug for control of many refractory arrhythmias, but two patients with recurrent atrial fibrillation were refractory to this treatment.

Efficacy of a new oral agent (tocainide) in the acute treatment of refractory ventricular arrhythmias

To assess the efficacy of tocainide, a new oral analog of lidocaine, 30 patients with ventricular arrhythmias refractory to quinidine, procainamide and propranolol were treated with this agent. The dose of tocainide ranged from 400 to 800 mg every 8 hours. Peak tocainide blood levels 1 to 4 hours after administration ranged from 5.0 to 15.0 microgram/ml (mean 10.3). The suppression of ventricular premature beats by 75 percent or more was arbitrarily used as a measure of drug efficacy. In 13 patients who met this criterion, ventricular premature complexes, assessed with 24 hour ambulatory tape monitoring, decreased by an average of 88 percent. In 8 of 11 patients, repeated symptomatic bouts of ventricular tachycardia were completely suppressed. Considering both the response of ventricular premature complexes and the abolition of ventricular tachycardia, 18 patients (60 percent) responded to tocainide. Twenty-one patients (70 percent) had initial gastrointestinal and central nervous system side effects; most of these were transient or responded to a reduction in dose. In two patients disorientation and a skin rash required withdrawal of tocainide. These adverse effects did not appear to be due to the interaction of tocainide with other antiarrhythmic agents. It is concluded that tocainide is an effective oral agent for the therapy of potentially lethal ventricular arrhythmias refractory to other medication.

Results of coronary revascularization in patients with recent myocardial infarction

Thirty-five patients underwent revascularization within 30 days of myocardial infarction. Group I (10 patients) underwent revascularization within 24 hours of infarction; Group II (nine patients), 2 to 7 days following infarction; and Group III (16 patients), 8 to 30 days after infarction. Indications for operation were persistent or recurrent pain following infarction, refractory ventricular arrhythmias, or persistent or recurrent pain associated with objective signs of reduced cardiac output. (A patient was not considered a surgical candidate if pain-free following infarction or if mechanical circulatory assistance was required in the treatment of cardiogenic shock.) There was an almost equal incidence of transmural and subendocardial myocardial infarction among the patients. Although severity of coronary vascular disease was the same for each of the three groups, left ventricular dysfunction was significantly more prevalent in Group I and Group III. There were no operative or late deaths during a short follow-up period (mean 9.8 months). Low morbidity and mortality in this very unstable group of patients was attributed to precise prebypass monitoring of rate-pressure product, Lead V 5 precordial electrocardiographic (ECG) changes, pulmonary capillary wedge pressure, and cardiac output. Pharmacologic intervention in the critical prebypass period included frequent use of intravenous propranolol and trinitroglycerin. Complications in the postoperative period (necessitating inotropic agents or intra-aortic balloon pumping) correlated with the degree of left ventricular dysfunction at the time of catheterization, rather than the infarction-revascularization interval. Satisfactory over-all graft patency (84 percent), patency of grafts into the infarcted area (82 percent), improvement in left ventricular function, and relief of angina pectoris were noted at the time of re-evaluation.

Mitral-Valve Prolapse Syndrome and Recurrent Ventricular Tachyarrhythmias

Of 60 patients referred for management of drug-refractory ventricular tachyarrhythmias, 10 (17%) had mitral-valve prolapse. These 10 patients ranged in age from 19 to 70 years (mean, 47 years); seven were women. All 10 had recurrent ventricular tachycardia, while four had a history of ventricular fibrillation. Nine patients were refractory to propranolol in combination with one or more of the standard antiarrhythmic agents. All showed improvement with aprindine therapy. The results show that refractory malignant ventricular prolapse syndrome; patients with mitral-valve prolapse account for a rather high percentage of those patients referred with recurrent drug-refractory ventricular tachyarrhythmias; in patients with unexplained ventricular arrhythmias, mitral-valve prolapse should be considered; and aprindine may be effective for ventricular tachyarrhythmias associated with mitral-valve prolapse.

Refractory ventricular arrhythmias in a patient with mitral valve prolapse. Successful control with mitral valve replacement

A 35-year-old woman with proven mitral valve prolapse developed life threatening ventricular arrhythmias which were refractory to medical therapy. She had one episode of "cardiac arrest" presumably due to ventricular tachycardia or possibly ventricular fibrillation, and was successfully resuscitated with closed chest compression. Mitral valve replacement resulted in dramatic control of the ventricular arrhythmias. Over a period of three years following the operation, she has been able to resume an active life with occasional ventricular premature beats and no further episodes of ventricular tachyarrhythmias.

Long-term results of surgical therapy for refractory ventricular arrhythmias

Long-term results of surgical therapy for refractory ventricular arrhythmias

Chronic overdrive pacing in the control of refractory ventricular arrhythmias.

Eleven patients with recurrent ventricular tachycardia or ventricular fibrillation that was refractory to antiarrhythmic drugs were treated with long-term, overdrive atrial or ventricular pacing. Pacing rates ranged from 70 to 110 impulses per minute. In eight patients chronic pacing was successful and prevented recurrent ventricular tachycardia or ventricular fibrillation for periods of 6 to 46 months. In the other three patients chronic pacing was unsuccessful; they died within 5 weeks—two of recurrent ventricular tachycardia and one suddenly of unknown cause. Overdrive suppression was successful in all four patients with prepacing heart rates of 40 to 60 and in four of the seven patients with prepacing heart rates of 70 to 95. Long-term overdrive suppression of refractory ventricular arrhythmias is frequently successful, especially where prevailing heart rates are slow. It is also successful in a substantial number of patients with normal heart rates.

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.

Transvenous Atrial and Ventricular Pacing from the Coronary Sinus Complicated by Perforation and Cardiac Tamponade

The use of transvenous atrial pacing from a coronary sinus site in a patient with a refractory ventricular arrhythmia is reported. The advantages of this site for atrial pacing are stability of the electrode catheter position and low threshold for stimulation. The complication of perforation of the coronary sinus with a subsequent infusion-induced cardiac tamponade is noted, and measures to prevent this complication are discussed. It is suggested that pacing from the coronary sinus, with proper safety precautions, may be useful in clinical situations where atrial pacing is to be preferred to ventricular pacing.

Bretylium tosylate in treatment of refractory ventricular arrhythmias complicating myocardial infarction.

Bretylium tosylate in treatment of refractory ventricular arrhythmias complicating myocardial infarction.

Long-term pervenous atrial pacing.

Long-term pervenous right atrial pacing has been used in five patients with intact atrioventricular (A-V) conduction for the treatment of refractory ventricular arrhythmias in two subjects and marked sinus bradycardia in three, two of whom also had paroxysmal supraventricular arrhythmias. The pervenous method was used to avoid a thoracotomy, and atrial pacing was chosen over ventricular pacing to preserve the normal A-V contraction sequence. Reliable atrial pacing was established in four cases, but one patient required ultimate conversion to a ventricular system because of irregular atrial capture. The most constant pacing was achieved by using a curved electrode with the tip positioned in the right atrial appendage.

Treatment of refractory ventricular tachysystole with hyperbaric oxygenation

A case of acute myocardial infarction in a 37 year old man resulting in severe ventricular tachyarrhythmias is reported. The patient's course was altered for the better after two exposures to hyperbaric oxygenation, each lasting seven hours. Hyperbaric oxygenation appeared to be successful in reducing the ventricular rate and in abolishing the requirement for vasopressors; during the first period of exposure, when the patient was critically ill, the number of ventricular ectopic beats was reduced during hyperbaric oxygenation. This experience indicates the need for further experimental trials of hyperbaric oxygenation in the control of refractory ventricular arrhythmias due to myocardial infarction.