PROPRANOLOL (INDERAL) IN PERSISTENT VENTRICULAR FIBRILLATION

Esmolol in the management of pre-hospital refractory ventricular fibrillation: A systematic review and meta-analysis

BACKGROUND

Esmolol has been proposed as a viable adjunctive therapy for pre-hospital refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT).

OBJECTIVES

We performed a systematic review and meta-analysis to assess the effectiveness of esmolol on pre-hospital refractory VF/pVT, compared with standard of care.

METHODS

MEDLINE, Embase, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched for eligible studies. Two investigators independently extracted relevant data and assessed the methodological quality of each included study using the ROBINS-I tool. The quality of evidence for summary estimates was assessed according to GRADE guidelines. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) for each outcome of interest were calculated.

RESULTS

The search yielded 3253 unique records, of which two studies were found to be in accordance with the research purpose, totaling 66 patients, of whom 33.3% (n = 22) received esmolol. Additional evidence was provided in the paper but was not relevant to the analysis and was therefore not included. Esmolol was likely associated with an increased rate of survival to discharge (RR 2.82, 95% CI 1.01-7.93, p = 0.05) (GRADE: Very low) and survival with favorable neurological outcome (RR 3.44, 95% CI 1.11-10.67, p = 0.03) (GRADE: Very low). Similar results were found for return of spontaneous circulation (ROSC) (RR 2.63, 95% CI 1.37-5.07, p = 0.004) (GRADE: Very low) and survival to intensive care unit (ICU)/hospital admission (RR 2.63, 95% CI 1.37-5.07, p = 0.004) (GRADE: Very low).

CONCLUSION

The effectiveness of esmolol for refractory VF/pVT remains unclear. Trial sequential analysis (TSA) indicates that the evidence is inconclusive and that further trials are required in order to reach a conclusion. Therefore, it is imperative to continue to accumulate evidence in order to obtain a higher level of scientific evidence.

Use of beta-blockers for the treatment of cardiac arrest due to ventricular fibrillation/pulseless ventricular tachycardia: a systematic review

INTRODUCTION

Advanced Life Support guidelines recommend the use of epinephrine during Cardiopulmonary Resuscitation (CPR), as to increase coronary blood flow and perfusion pressure through its alpha-adrenergic peripheral vasoconstriction, allowing minimal rises in coronary perfusion pressure to make defibrillation possible. Contrasting to these alpha-adrenergic effects, epinephrine's beta-stimulation may have deleterious effects through an increase in myocardial oxygen consumption and a reduction of subendocardial perfusion, leading to postresuscitation cardiac dysfunction.

OBJECTIVE

The present paper consists of a systematic review of the literature regarding the use of beta-blockade in cardiac arrest due to ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT).

METHODS

Studies were identified through MEDLINE electronic databases research and were included those regarding the use of beta-blockade during CPR.

RESULTS

Beta-blockade has been extensively studied in animal models of CPR. These studies not only suggest that beta-blockade could reduce myocardial oxygen requirements and the number of shocks necessary for defibrillation, but also improve postresuscitation myocardial function, diminish arrhythmia recurrences and prolong survival. A few case reports described successful beta-blockade use in patients, along with two prospective human studies, suggesting that it could be safe and effectively used during cardiac arrest in humans.

CONCLUSION

Even though the existing literature points toward a beneficial effect of beta-blockade in patients presenting with cardiac arrest due to VF/pulseless VT, high quality human trials are still lacking to answer this question definitely.

β-Blockers for the treatment of cardiac arrest from ventricular fibrillation?

More than 160,000 people suffer sudden cardiac death each year in the US. It is estimated that ventricular fibrillation (VF) is the initial rhythm in approximately 30% of these cases. Ventricular fibrillation that does not respond to the first few defibrillation attempts is associated with mortality rates of up to 97%. Currently, no pharmacological intervention has been shown to increase long-term survival in patients with shock-refractory VF. The purpose of this review article is to evaluate whether beta-blocker administration during the resuscitation of cardiac arrest from VF or pulseless ventricular tachycardia (VT) improves outcome. We searched the MEDLINE and EMBASE databases for human clinical trials, animal experimental trials, review articles, case reports and abstracts published between 1966 and September 2006. No human prospective randomized controlled trial has studied the effects of beta-blocker administration during VF directly. Prospective trials of anti-arrhythmics with beta-blocking properties have been published, as well as several case reports/case series and experimental animal studies. The evidence thus far suggests that beta-blockade during resuscitation from VF may be associated with increasing rates of resuscitation, greater post-resuscitation survival, and improved post-resuscitation myocardial function. These positive effects on outcome may be mediated by a decrease in the oxygen requirements of the fibrillating heart, thus improving the overall balance between myocardial oxygen supply and demand during resuscitation. While no significant detrimental effects directly related to low dose beta-blockade during VF have been reported in the studies reviewed, concerns relating to possible loss of myocardial contractility and hypotension remain. To this day, high quality human trials are lacking. Preliminary human studies are needed to assess the effects of beta-blockers in the treatment of cardiac arrest from ventricular fibrillation or pulseless VT further.

Carbamazepine-induced eruption histologically mimicking mycosis fungoides

Carbamazepine is an important drug used in the management of seizures, trigeminal neuralgia, and chronic pain syndromes. It has been associated with a variety of adverse skin reactions including urticaria, lichenoid eruptions, erythroderma, erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis. A 39-year-old white male had been started on carbamazepine for intractable pain which resulted from a right foot crush injury. Approximately 3 months after the start of therapy, the patient had developed a generalized skin eruption following an entire day of sun exposure. Skin biopsies revealed an atypical lymphoid infiltrate in the dermis with collections of the atypical lymphocytes within spongiotic vesicles in the epidermis, suggestive of mycosis fungoides. The patient was treated with systemic prednisone. Subsequent biopsies failed to reveal atypical lymphocytes. Previous reports have described spongiotic eruptions with foci of atypical lymphocytes in contact dermatitis and in patients treated with phenytoin. To the best of our knowledge, this is the first reported case of a carbamazepine-induced eruption simulating mycosis fungoides histologically.

Ventricular antiarrhythmic effects of beta-adrenergic blocking drugs: a review of mechanism and clinical studies

Beta-adrenergic blocking drugs are now commonly used in patients with ventricular arrhythmias. This review examines the possible mechanisms of their ventricular antiarrhythmic effect. Actions on the myocardial cell, as well as actions on the central and autonomic nervous system, are reviewed. Many clinical studies have attempted to show the efficacy of beta blockers in controlling ventricular arrhythmia and decreasing the incidence of sudden death after acute myocardial infarction. Although some of these clinical trials tended to show an impact on sudden death, the size of these trials or their design problems do not allow firm conclusions to be made. The Beta Blocker Heart Attack Trial (BHAT) is a placebo-controlled, double-blind, randomized trial of propranolol currently under way in the United States. Important additions to the previous trials include the addition of drug levels to ensure beta-blocking dosage, long-term electrocardiographic monitoring, and a study population of 4200 patients followed for an average of three years. These important design features will be of value in addressing some of the unanswered questions presented in this review.

Comparative studies on the pharmacological actions of antiarrhythmic drugs in isolated rate papillary muscle

1. The effects of ajmaline, cocaine, phenytoin, lignocaine, procainamide, propranolol, quinidine and trimetazidine on the contractility and the refractory period of isolated rat papillary muscles were compared. 2. At the higher concentrations used, all drugs suppressed the contractile tension of the rat papillary muscles. 3. The effects of these drugs on the refractory period were compared at concentrations at which the contractile tension was suppressed by 30% of the control. At this point, lignocaine, procainamide, ajmaline and quinidine prolonged the refractory period more than two-fold while the effects of propranolol and phenytoin were slight, cocaine and trimetazidine had little or no effect.

Pindolol (Viscén) in persistent ventricular fibrillation. A case report

The beneficial effect of a beta-blocking agent (pindolol), given as an adjuvant to DC-shock and lidocaine therapy in a case of heart resuscitation is reported. A 65-year-old female patient was operated for an abdominal aortic aneurysm. At the conclusion of the operation, which was prolonged and difficult, the patient developed alternating ventricular tachycardia and fibrillation. Within a time interval of 50 min electrical defibrillation was performed 20 to 25 times, and as much as 1100 mg of lidocaine was administered. Simultaneously, combined internal/external cardiac massage was performed. The patient's arrhythmia continued to recur after defibrillation until pindolol in dosages of 0.2 mg had been given twice intravenously. A permanent sinus rhythm was then achieved.

The effects of practolol on the dysrhythmias complicating acute ischemic heart disease

The cardioselective beta-adrenoceptor blocking agent practolol was used in the management of ventricular and supraventricular dysrhythmias associated with acute myocardial infarction in 134 patients, and in the management of these dysrhythmias in 19 atients with acute myocardial ischemia. Practolol was frequently effective in controlling ventricular dysrhythmias which occurred within the first 24 hours after the onset of symptoms of acute myocardial infarction. It was also effective in controlling the ventricular dysrhythmias which occurred after resuscitation from ventricular fibrillation. It was of particular value when therapeutic doses of lidocaine had been ineffective. Practolol was much less effective in controlling ventricular dysrhythmias which occurred more than 24 hours after acute infarction. Atrial fibrillation and atrial flutter were infrequently abolished by practolol in undigitalized patients after acute myocardial infarction. There was no correlation between the effectiveness of practolol and the blood concentration of the drug. One adverse effect of practolol was the occurence of sinus bradycardia with or without an increase in the frequency of ventricular ectopic beats. Bradycardia was sometimes accompanied by hypotension. Severe hypotension occasionally occurred in the absence of bradycardia.

Psychopharmacologic management of anxiety in the cardiac patient

Of 253 patients who had suffered acute myocardial infarction ( MI), 88 percent received daytime sedation while hospitalized. Sixty percent of all prescriptions were for phenobarbital, 30 percent for chlordiazepoxide, and 6 percent for meprobamate. In addition, 79 percent of patients received night time hypnotic medication. Sixty-six percent of such prescriptions were for short-acting barbiturates, 21 percent for chloral hydrate, and 7 percent for diphenhydramine. Multiple drug use was common.

The barbiturates, while inexpensive sedative agents, are of questionable efficacy in reducing anxiety and probably produce only general CNS depression. A narrow margin of safety, liability to produce habituation, and antagonism of warfarin-type anticoagulants are other disadvantages. The benzodiazepine tranquilizers, whose antianxiety efficacy is more clearly established, do not produce general CNS depression, have a wide margin of safety, and do not interact with oral anticoagulants.

Antidepressant agents, phenothiazine tranquilizers, and propranolol were used infrequently or not at all. The risks associated with the use of these agents in patients with acute myocardial infarction are considerable and should be weighed carefully before they are administered.

Haemodynamic effects of dextro-propranolol in acute myocardial infarction

Intravenous injections of 20-25 mg. d-propranolol did not change the heart rate or systemic pressure in 13 patients with cardiac infarction. Cardiac output was depressed in 10, but there was no clinical deterioration. d-Propranolol was better tolerated than dl-propranolol under these conditions and justifies further investigation as an anti-dysrhythmic agent. The major depressant effects of dl-propranolol following cardiac infarction appear to be due to beta-adrenergic blockade and not to a direct depressant action on cardiac muscle.

Use of isoprenaline as an antiarrhythmic agent after valve replacement surgery

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Trial of propranolol in acute myocardial infarction

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Effects of propranolol on the transmembrane potentials of ventricular muscle and Purkinje fibers of the dog

Papillary muscle-false tendon tissue preparations isolated from dog hearts were perfused with Tyrode's solution containing propranolol in concentrations ranging from 0.1 to 20.0 mg/liter. Transmembrane action potentials of both ventricular muscle fibers and Purkinje fibers were recorded. With sufficient concentration of drug, the velocity of the upstroke and the overshoot of both fiber types decreased. The curve relating upstroke velocity to level of membrane potential for Purkinje fibers was displaced to the right and down. The ability of both ventricular muscle fibers and Purkinje fibers to respond to rapid frequencies of stimulation was decreased. Repolarization of Purkinje fibers was accelerated by propranolol, but repolarization of ventricular muscle fibers was unaffected. Duration of the effective refractory period of Purkinje fibers decreased; that of ventricular muscle fibers was unchanged. Graded responses and decremental impulse conduction in Purkinje fibers were abolished in the presence of propranolol. Low doses of propranolol which caused no change in the transmembrane potential completely blocked the increase in Purkinje diastolic depolarization normally induced by epinephrine. The possible mechanisms by which propranolol might exert its antiarrhythmic actions on ventricular arrhythmias were discussed.