Relation between ventricular function and antiarrhythmic responses to sotalol

The Arrhythmogenicity of Sotalol and its Role in Heart Failure: A Literature Review

ABSTRACT

According to the American Heart Association, approximately 6 million adults have been afflicted with heart failure in the United States in 2020 and are more likely to have sudden cardiac death accounting for approximately 50% of the cause of mortality. Sotalol is a nonselective β-adrenergic receptor antagonist with class III antiarrhythmic properties that has been mostly used for atrial fibrillation treatment and suppressing recurrent ventricular tachyarrhythmias. The use of sotalol in patients with left ventricular dysfunction is not recommended by the American College of Cardiology or American Heart Association because studies are inconclusive with conflicting results regarding safety. This article aims to review the mechanism of action of sotalol, the β-blocking effects on heart failure, and provide an overview of clinical trials on sotalol use and its effects in patients with heart failure. Small- and large-scale clinical trials have been controversial and inconclusive about the use of sotalol in heart failure. Sotalol has been shown to reduce defibrillation energy requirements and reduce shocks from implantable cardioverter-defibrillators. Torsades de Pointes is the most life-threatening arrhythmia that has been documented with sotalol use and occurs more commonly in women and heart failure patients. Thus far, mortality benefits have not been demonstrated with sotalol use and larger multicenter studies are required going forward.

Acute echocardiographic effects of sotalol on ventricular systolic function in dogs with ventricular arrhythmias

Background

Sotalol is a commonly used antiarrhythmic drug that may alter ventricular function.

Objective

To determine the effect of sotalol on echocardiographic indices of ventricular systolic function in dogs with ventricular arrhythmias.

Animals

Thirty‐five client‐owned dogs with ventricular arrhythmias.

Methods

Dogs with ventricular arrhythmias (n = 27) had an echocardiogram and 5‐minute ECG performed at baseline and 2‐4 hours post‐sotalol (2‐2.5 mg/kg PO once). Eight additional dogs underwent the same protocol but did not receive sotalol (within‐day variability controls). Left ventricular (LV) internal dimension at end‐systole normalized to bodyweight (LVIDs_N), LV ejection fraction (LV EF), LV shortening area, LV fractional shortening, tricuspid annular plane systolic excursion (TAPSE), and right ventricular systolic myocardial velocity were evaluated as indices of systolic function.

Results

All indices except TAPSE had mild decreases in systolic function post‐sotalol (all P ≤ .0007) compared with baseline but only the percent change in LVIDs_N and LV EF were significantly (P ≤ .0079) different from the percent change of the same indices in control dogs. Sinus heart rate, ventricular premature complexes/5‐minutes, and arrhythmia grade also were decreased post‐sotalol (all P ≤ .01) compared with baseline when assessed by a 5‐minutes ECG. No dog experienced an adverse event post‐sotalol, including dogs with systolic dysfunction or atrial enlargement.

Conclusions and Clinical Importance

A single dose of sotalol may cause a mild decrease in LV systolic function in dogs with ventricular arrhythmias. Sotalol appears to be well tolerated, even in dogs with atrial enlargement or systolic dysfunction.

Suppression of frequent premature ventricular contractions and improvement of left ventricular function in patients with presumed idiopathic dilated cardiomyopathy

OBJECTIVE

To examine the hypothesis that suppression of frequent premature ventricular contractions may be associated with improvement in left ventricular function in patients with presumed idiopathic dilated cardiomyopathy.

DESIGN

We conducted a retrospective case study and statistical analysis of the effect of cardiac medical therapy on outcome.

MATERIAL AND METHODS

The study population consisted of 14 patients with more than 20,000 premature ventricular contractions in 24 hours recorded by Holter monitoring and associated left ventricular dysfunction (ejection fraction, 40% or less). Clinical characteristics, number of premature ventricular contractions per hour on 24-hour ambulatory Holter monitoring, and ejection fraction based on transthoracic echocardiography were compared before and after cardiac therapeutic intervention.

RESULTS

Of the 14 patients, 10 had presumed idiopathic dilated cardiomyopathy, and 4 had ischemic heart disease. Of the overall study group, seven had received additional cardiac medical therapy after the index evaluation, including four patients who had amiodarone therapy. A significant reduction (75% or more from baseline) in premature ventricular contractions after medical therapeutic intervention was observed in five patients at the first follow-up examination. The mean interval to the first follow-up examination was 6 +/- 3 months. Of the five patients, four had significant improvement in clinical functional status and the ejection fraction. The mean ejection fraction of these five patients increased from 27 +/- 10% at baseline to 49 +/- 17% after medical therapy (P = 0.04).

CONCLUSION

The suppression of frequent premature ventricular contractions may be associated with improvement of left ventricular function in patients with presumed idiopathic dilated cardiomyopathy.

Evolving role of sotalol in the management of ventricular tachyarrhythmias

Sotalol is a unique compound with several potential antiarrhythmic mechanisms, including beta blockade (class II activity), action potential duration prolongation (class III activity), and possibly reduction of QT dispersion. In recent years, trials such as the Cardiac Arrhythmia Suppression Trial (CAST) and the Electrophysiologic Study versus Electrocardiographic Monitoring (ESVEM) trial reported disappointing results with the use of class I agents in the management of ventricular arrhythmias in patients with coronary artery disease. These results have led to increased interest in class III antiarrhythmic agents, including sotalol. Sotalol is effective in suppressing ventricular premature complexes as well as nonsustained and sustained ventricular tachyarrhythmias. The interaction between sotalol and implantable cardioverter-defibrillators (ICDs) is generally favorable. As is the case with other antiarrhythmic drugs, there is no placebo-controlled trial assessing the effect of sotalol on mortality. It is not known if sotalol is more effective than placebo, conventional beta blockade, amiodarone, or ICDs in reducing mortality from life-threatening ventricular arrhythmias. In addition, the optimal method of selecting patients for sotalol therapy has yet to be determined. The safety profile of sotalol has been well established in > 3,000 patients worldwide. Proarrhythmia occurs in approximately 4% of patients, and torsades de pointes occurs in approximately 2.5%. The majority of episodes of torsades de pointes occurs within 3 days of commencing sotalol therapy, and the risk of torsades de pointes increases sharply at dosages > 320 mg daily. It is recommended that initiation of sotalol therapy or dosage increases be performed in a monitored setting. Overall, only 1% of patients enrolled in clinical trials of sotalol discontinued therapy as a result of drug-related congestive heart failure. However, these trials have excluded patients with poor left ventricular systolic function and/or overt heart failure. The optimal management of these patients, who are at greatest risk of sudden cardiac death, and of patients with substrates other than coronary artery disease remains to be elucidated.

Hemodynamic effects and safety of sotalol in the prevention of supraventricular arrhythmias after coronary artery bypass surgery

Sotalol is a beta-adrenergic blocking drug with the additional property of lengthening the cardiac action potential. These electrophysiologic properties render the drug attractive for use in the prevention of postoperative supraventricular arrhythmias (SVA), and previous studies have suggested that it was indeed effective. The hemodynamic response to sotalol and its safety early after coronary artery bypass graft (CABG) surgery were therefore studied. Forty-two patients undergoing CABG were randomly assigned either to receive sotalol to prevent postoperative SVA (25 patients) or to serve as controls (17 patients). Sotalol was started 6 hours after surgery if patients had a cardiac index > 2.8 L/min/m2 with a pulmonary capillary wedge pressure < 15 mmHg, and if they had no contraindications to the use of beta-blockers. The drug was given as a loading infusion of 1 mg/kg over 2 hours, followed by a maintenance infusion of 0.15 mg/kg/h for 24 hours. Three hours later, patients received the first oral dose of 80 mg to be repeated every 8 or 12 hours. Adverse effects necessitating discontinuation of the drug (bradycardia < 50 beats/min, systolic blood pressure < 90 mmHg, or cardiac index < 2.2 L/min/m2) occurred in six patients (24%) and were mainly related to the loading infusion. The hemodynamic data for patients who completed the study were characterized by a significant fall of the cardiac index caused by a lower heart rate without significant change of the stroke volume index. The incidence of supraventricular arrhythmias was not significantly different in the two groups (3/19 in the sotalol group, 5/17 in the control group).(ABSTRACT TRUNCATED AT 250 WORDS)

Sotalol

Sotalol is a novel antiarrhythmic agent combining beta-adrenergic-antagonist actions with the ability to increase cardiac repolarization and refractoriness. The drug's electrophysiologic and clinical profile is different from that of conventional beta-receptor antagonists. As compared with other antiarrhythmic agents, sotalol prevents recurrences of arrhythmia in a higher proportion of patients, particularly among those presenting with ventricular tachycardia and aborted sudden cardiac death. The net hemodynamic effect of sotalol is the result of a balance between the depressant effects due to beta-receptor blockade and an action that tends to increase contractility. Although initially marketed in the United States for treatment of life-threatening ventricular arrhythmias, sotalol also has demonstrated efficacy in many patients with supraventricular arrhythmias. As with all drugs that prolong the QT interval, the syndrome of torsade de pointes is a serious potential adverse effect.

Hemodynamic effects of oral sotalol during both sinus rhythm and atrial fibrillation

OBJECTIVES

This study investigated the hemodynamic effects of oral sotalol during both sinus rhythm and paroxysmal atrial fibrillation.

BACKGROUND

The hemodynamic effects of most antiarrhythmic drugs have been characterized in subjects during sinus rhythm. However, there are no data concerning these effects on the paroxysmal tachyarrhythmias.

METHODS

In 17 patients with paroxysmal atrial fibrillation and without heart failure (aged 62 +/- 11 years, ejection fraction 51 +/- 4%), an electrophysiologic-hemodynamic study was performed twice. In the first study, hemodynamic variables were evaluated both during sinus rhythm and after the induction of atrial fibrillation. Sotalol (160 or 240 mg/day) was administered for 6 to 7 days and the study was then repeated with the same methods.

RESULTS

The drug significantly diminished heart rate during both sinus rhythm and atrial fibrillation. During sinus rhythm, sotalol did not change systemic pressures and significantly increased left and right ventricular end-diastolic, left and right atrial and pulmonary pressures. Cardiac index decreased, whereas stroke volume was unchanged after the drug. Ejection fraction and left ventricular end-diastolic and end-systolic volumes evaluated by echocardiography were unchanged after sotalol. During atrial fibrillation, the drug had less evident effects on cardiac function. Left ventricular end-diastolic, left atrial and pulmonary pressures did not increase significantly.

CONCLUSIONS

The hemodynamic changes induced by oral sotalol appear to be mainly related to an involvement of ventricular distensibility; this effect is less evident during atrial fibrillation than during sinus rhythm. In patients with paroxysmal atrial fibrillation without heart failure treated with oral sotalol, a recurrence of the tachyarrhythmia is hemodynamically well tolerated.

Sotalol. An updated review of its pharmacological properties and therapeutic use in cardiac arrhythmias

Sotalol is a nonselective beta-adrenoceptor antagonist which prolongs cardiac repolarisation independently of its antiadrenergic action (class III antiarrhythmic properties). The antiarrhythmic action of sotalol appears to arise predominantly from its class III properties, and the drug exhibits a broader antiarrhythmic profile than the conventional beta-blockers. Sotalol is effective in controlling paroxysmal supraventricular tachycardias and the ventricular response to atrial fibrillation/flutter in Wolff-Parkinson-White syndrome, in maintaining sinus rhythm after cardioversion of atrial fibrillation/flutter, and in preventing initiation of supraventricular tachyarrhythmias following coronary artery bypass surgery. Sotalol shows promise in the control of nonmalignant and life-threatening ventricular arrhythmias, particularly those associated with ischaemic heart disease. It is effective in suppressing complex forms of ventricular ectopy, displaying superior antiectopic activity to propranolol and metoprolol. The acute efficacy of sotalol in preventing reinduction of sustained ventricular tachyarrhythmias and suppressing spontaneous episodes of these arrhythmias on Holter monitoring is translated into long term prophylactic efficacy against arrhythmia recurrence in approximately 55 to 85% of patients with refractory life-threatening ventricular arrhythmias. In addition, sotalol offers the advantage over the class I agents of reducing cardiac and all-cause mortality in the high risk population with life-threatening ventricular arrhythmias. The adverse effects of sotalol are primarily related to its beta-blocking activity and its class III property of prolonging cardiac repolarisation. Sotalol is devoid of overt cardiodepressant activity in patients with mild or moderate left ventricular dysfunction. The overall arrhythmogenic potential is moderately low, but torsade de pointes may develop in conjunction with excessive prolongation of the QT interval due to bradycardia, hypokalaemia or high plasma concentrations of the drug. In summary, sotalol displays a broad spectrum of antiarrhythmic activity, is haemodynamically well tolerated, and confers a relatively low proarrhythmic risk. It is likely to prove particularly appropriate in the treatment and prophylaxis of life-threatening ventricular tachyarrhythmias.

Sotalol

Sotalol causes noncardioselective beta-adrenergic antagonism and prolongation of repolarization of cardiac tissues (Class III electrophysiologic action). This dual pharmacologic profile confers unprecedented antiarrhythmic properties to the drug. Sotalol is highly bioavailable when administered orally in the fasting state and is mostly cleared unchanged in the urine with an apparent half-life of elimination of 15 to 17 hours. It has been found effective in the suppression of nearly all cardiac arrhythmias, with the exception of those precipitated by prolongation of ventricular repolarization. Its safety and efficacy relative to other antiarrhythmic drugs need to be examined more fully in randomized controlled trials of unselected patients. The adverse effects potentially associated with the use of sotalol are those commonly observed with beta-adrenergic blockade, as well as those resulting from excessive prolongation of the QT interval. The occurrence of torsade de pointes during treatment with sotalol may be minimized by limiting doses to no more than 640 mg/day and by strictly avoiding the development of hypokalemia.

Efficacy and safety of sotalol in patients with complex ventricular arrhythmias

Sotalol is a unique beta-blocker that prolongs repolarization. Its use in 626 patients with complex ventricular ectopic activity, as reported in the literature, resulted in suppression of arrhythmia in 50 to 60% of treatment attempts. Detailed analysis of data on arrhythmias in 356 patients that were entered prospectively into a database revealed a median reduction in ventricular premature beats of 76%, compared to a median suppression of repetitive ventricular ectopic activity of 91% and of episodes of nonsustained ventricular tachycardia of 97% (p = 0.002 vs reduction of ventricular premature beats). This marked antiarrhythmic potency of sotalol in repetitive ventricular arrhythmias is thought to be due to its class III activity. Drug efficacy was independent of age, sex, the presence or absence of organic heart disease and the degree of sotalol-induced prolongation of corrected QT interval. Evaluation of left ventricular function in 215 patients treated with the drug demonstrated that depression of left ventricular ejection fraction occurred far less frequently than expected with conventional beta-blockers. Even patients with severely depressed pump function tolerated sotalol surprisingly well. There is a propensity of the drug to aggravate arrhythmia, which resulted in serious proarrhythmic events in 30 (3.5%) of 853 patients. These often consisted of torsades de pointes (9 of 30 patients). Proarrhythmia occurred primarily within the first 3 days of dosing, and exhibited a dose-dependence. In conclusion, sotalol is an effective and well-tolerated antiarrhythmic drug in patients with complex ventricular ectopic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Short- and long-term antiarrhythmic and hemodynamic effects of d,l-sotalol in patients with symptomatic ventricular arrhythmias

The antiarrhythmic and hemodynamic effects of sotalol (160 to 480 mg/day), a beta-blocking agent that prolongs ventricular repolarization, were examined in 38 patients with complex symptomatic ventricular ectopic activity. During ambulatory monitoring, 24 patients (63%) exhibited a reduction of greater than 75% in single ventricular premature beats (VPBs) and greater than 90% reduction in repetitive arrhythmia. In contrast to the effects of other agents, left ventricular ejection fraction as determined by radionuclide angiography was not impaired, increasing slightly from 45 +/- 14% to 47 +/- 14% during therapy (p less than 0.05). Antiarrhythmic drug efficacy did not correlate with baseline ejection fraction or sotalol-induced changes in ventricular function. Late follow-up studies disclosed that antiarrhythmic efficacy and tolerance were maintained in the majority of patients. Repeat radionuclide angiography at 6 months revealed no late drug-induced depression of left ventricular function. Sotalol appears to be an effective and well tolerated agent for treatment of complex ventricular ectopic activity, even in the setting of compromised cardiac function.