Usefulness of sotalol for drug-refractory malignant ventricular arrhythmias

Does Sotalol Still Have a Role in the Management of Arrhythmias?

Despite proven effectiveness in treating tachyarrhythmias, sotalol is proarrhythmic and can cause torsades de pointes. Given the emergence of studies that show no benefit from rhythm control strategies in managing atrial fibrillation, as well as the introduction of nonpharmacological approaches to treating arrhythmias, we felt it necessary to ascertain if there was any role for sotalol given its side effects. Review of the literature regarding sotalol use in the prevention and treatment of supraventricular and ventricular tachyarrhythmias seems to show that more effective and safer agents and nonpharmacological alternatives are currently available. However, sotalol still seems to be useful in preventing supraventricular tachyarrhythmias postcardiac surgery and in reverting hemodynamically stable sustained ventricular tachycardias in the setting of coronary artery disease. Its role in the prevention of tachyarrhythmias in the setting of arrhythmogenic right ventricular cardiomyopathy requires further investigation.

Sotalol in treatment of pediatric cardiac arrhythmias

BACKGROUND

There is limited experience on sotalol use in the management of childhood arrhythmias. This study reviews the results of our experience with oral sotalol for treatment and prevention of tachyarrhythmias in children.

METHODS

The records of 62 patients (27 female, 35 male, mean age: 8.5+/-5.3 years) treated with sotalol for supraventricular or ventricular arrhythmias from 1994 to 1999 at our institution were reviewed. Demographic, clinical, echocardiographic, electrocardiographic (ECG), ambulatory ECG and electrophysiologic variables were collected.

RESULTS

Forty-two (63.6%) patients had re-entrant supraventricular tachycardia, eight patients (12.9%) had atrial tachycardia, one patient (1.6%) had junctional ectopic tachycardia, four patients (6.5%) had ventricular tachycardia, and seven patients (11.3%) had complex ventricular arrhythmias, as evidenced by surface or ambulatory ECG records; or revealed during the electrophysiological study. The mean sotalol dose was 3.9+/-1.2 mg/kg per day. In 15.5+/-13.9 months of sotalol use 50% (n=31) had complete relief of symptoms and/or arrhythmia and 29% (n=18) had partial relief. Sotalol was ineffective in 20% (n=13). Sotalol was more effective in re-entrant type supraventricular tachycardias (P=0.012). Sotalol was the first choice in 35.5% of patients. The sotalol therapy was initiated in inpatient settings in 40.3% (25 patients). Complications due to sotalol were seen in six patients (five patients developed bradycardia/pauses, and one patient had torsades de pointes) for which the sotalol dose was modified. In patients with sick sinus syndrome, a pacemaker was implanted and in another patient sotalol was stopped.

CONCLUSION

Sotalol, being an effective and safe drug particularly in children, is a good therapeutic alternative for the preventive treatment of childhood tachyarrhythmias.

Sinus node dysfunction and atrial tachycardia after the Fontan procedure: The scope of the problem

Similar to other atrial baffling procedures, the Fontan procedure exposes patients to ongoing morbidity and mortality. The development of the bradycardia-tachycardia syndrome can have adverse effects on already-marginal hemodynamics and ventricular function. Patients with Fontan physiology and sinus node dysfunction can be managed with antibradycardic pacemakers. Atrial arrhythmias after "completion Fontan" are difficult to treat and usually require either antiarrhythmic agents, antitachycardic pacemakers, or radiofrequency catheter ablation of the re-entrant circuit. Successful treatment of atrial flutter occurs in only 50% to 70% of patients. There is a high recurrence rate of atrial flutter with any of the accepted management strategies. Copyright 1998 by W.B. Saunders Company

Long-term reproducibility of electrophysiologically guided therapy with sotalol in patients with ventricular tachyarrhythmias

OBJECTIVES

Goal of this study was to assess the long-term reproducibility of electrophysiologic drug testing in patients with ventricular tachyarrhythmias (VT/VF).

BACKGROUND

Programmed ventricular stimulation (PVS) is still widely used to guide antiarrhythmic therapy in patients with sustained ventricular tachycardia/fibrillation (VT/VF). Sotalol is considered as one of the most effective drugs for VT/VF. Because there is no proof of long-term reproducibility of a successful drug test with sotalol, we investigated the long-term reproducibility of drug testing with sotalol.

METHODS

Thirty patients with VT/VF (age: 57+/-11 years, 20 patients with coronary heart disease, 7 patients with no structural heart disease, 3 with others) and reproducible induction of VT/VF (28 patients VT, two patients VF) in a baseline PVS, were suppressible with sotalol (mean dosage 395+/-137 mg) in a subsequent PVS. After a mean follow-up of 13+/-10 months a PVS was again performed in patients, who had no evidence of progressive cardiac disease, who did not experience any arrhythmia recurrences or who were drug compliant. Irrespective of the inducibility after long-term therapy with sotalol, all patients were kept on the initial sotalol regimen. All 30 patients had a stable cardiac condition, were free of VT/VF recurrences and were drug compliant.

RESULTS

Despite the clinical efficacy of sotalol, in 12 patients (40%) VT/VF could again be induced after 13+/-10.2 months. Inducibility was independent of age, heart disease, ejection fraction and follow-up time. During a further follow-up of 22.1+/-10.9 months, five patients experienced nonfatal VT recurrences independently of the prior inducibility.

CONCLUSIONS

This study shows a lacking long-term reproducibility of an initial effective PVS with sotalol. Despite an uneventful clinical follow-up, late electrophysiologic testing showed a VT/VF inducibility in a high portion of patients. Hence, electrophysiologic testing performed late after the initial drug test may no longer be predictive of outcome.

Suppression of sustained ventricular tachyarrhythmias: a comparison of d,l-sotalol with no antiarrhythmic drug treatment

OBJECTIVES

This study evaluates the clinical efficacy of d,l-sotalol in patients with sustained ventricular tachyarrhythmias.

BACKGROUND

D,l-sotalol is an important antiarrhythmic agent to prevent recurrences of sustained ventricular tachyarrhythmias (VT/VF). However, evidence is lacking that an antiarrhythmic agent like d,l-sotalol can reduce the incidence of sustained ventricular tachyarrhythmias in comparison to no antiarrhythmic drug treatment.

METHODS

A prospective study was performed in 146 consecutive patients with inducible sustained ventricular tachycardia or ventricular fibrillation. In 53 patients, oral d,l-sotalol prevented induction of VT/VF during electrophysiological testing and patients were discharged on oral d,l-sotalol (sotalol group). In 93 patients, VT/VF remained inducible and a defibrillator (ICD) was implanted. After implantation of the device patients were randomly assigned to oral treatment with d,l-sotalol (ICD/sotalol group, n=46) or no antiarrhythmic medication (n=47, ICD-only group).

RESULTS

During follow-up, 25 patients (53.2%) in the ICD-only group had a VT/VF recurrence in comparison to 15 patients (28.3%) in the sotalol group and 15 patients (32.6%) in the ICD/sotalol group (p=0.0013). Therapy with d,l-sotalol, amiodarone or metoprolol was instituted in 12 patients (25.5%) of the ICD-only group due to frequent VT/VF recurrences or symptomatic supraventricular tachyarrhythmias. In nine patients, 17% of the sotalol group, an ICD was implanted after VT/VF recurrence, three patients (5.7%) received amiodarone. Total mortality was not different between the three groups.

CONCLUSIONS

D,l-sotalol significantly reduces the incidence of recurrences of sustained ventricular tachyarrhythmias in comparison to no antiarrhythmic drug treatment.

General principles of antiarrhythmic therapy for ventricular tachyarrhythmias

Sudden cardiac death due to ventricular arrhythmias is a significant cause of mortality in patients with structural heart disease. Over the past several decades, the introduction of new pharmacologic and nonpharmacologic therapy has expanded the treatment options available. This article will focus on the use of antiarrhythmic medication for the treatment of ventricular arrhythmias and will review the following: (1) treatment goals for various clinical populations, (2) the mechanisms of antiarrhythmic and proarrhythmic actions of antiarrhythmic medications, and (3) empiric versus guided pharmacologic therapy.

Drugs versus devices in controlling ventricular tachycardia, ventricular fibrillation, and recurrent cardiac arrest

Patients with symptomatic ventricular tachycardia, ventricular fibrillation, or aborted sudden cardiac death remain at high risk for arrhythmia recurrence. In recent years, strategies to treat these patients have changed. Concerns about the proarrhythmia risk and uncertain efficacy of class I agents have resulted in a shift in interest to non-class I antiarrhythmic drugs such as sotalol and amiodarone. Both drugs have class III antiarrhythmic properties (i.e., both lengthen repolarization and refractoriness); however, each also has its own additional electrophysiologic effects. Prospectively designed, randomized studies have shown that both sotalol and amiodarone have more potent antiarrhythmic actions than class I agents. However, even as the advantages of sotalol and amiodarone have been recognized, enthusiasm for nonpharmacologic modes of treatment, particularly the implantable cardioverter-defibrillator (ICD), has also markedly increased. The ICD has been shown to decrease dramatically the incidence of sudden death, which may lead to the reduction of total mortality. Whether patients with life-threatening ventricular tachyarrhythmias should be treated first with antiarrhythmic agents or with an ICD is an important question. The results of recent studies suggest that treatment with an ICD is more effective than electrophysiologically guided treatment with class I agents. However, results of prospectively designed randomized studies comparing the efficacy of the ICD with that of sotalol and amiodarone must become available before definitive recommendations can be made concerning the use of the ICD as first-line therapy in patients with ventricular tachycardia/ventricular fibrillation or aborted sudden cardiac death. In addition, there may be a significant role for the use of antiarrhythmic drugs in conjunction with ICDs.

Sotalol Is More Powerful Than Propranolol in Suppressing Complex Ventricular Arrhythmias

BACKGROUND: Sotalol has combined type II and type III antiarrhythmic properties. Although the beta-blocking action of sotalol is thought to contribute to its antiarrhythmic actions, few data are available from direct comparative clinical trials with pure beta-blocking drugs. METHODS AND RESULTS: In this double-blind, randomized, multicenter, placebo-controlled, parallel study, we have compared the antiarrhythmic efficacy and safety of treatment with sotalol vs propranolol in 181 patients with organic heart disease and frequent (>30 ventricular premature complexes [VPCs]/h) repetitive ventricular premature complexes. Eighty-seven were randomized to receive sotalol and 94 received propranolol. The demographic and clinical characteristics of the two groups were identical, and the majority of patients had coronary artery disease or hypertensive heart disease. Most patients had a long-standing history (>5 years) of ventricular arrhythmias and, in a significant proportion, antiarrhythmic therapy with other drugs had failed in the past. After withdrawal of all antiarrhythmic drugs and 1 week of placebo, qualified patients were randomized to sotalol (320 mg/day) or propranolol (120 mg/day). patients not achieving adequate response were given higher doses of sotalol (640 mg/day) or propranolol (240 mg/day)At baseline, both groups had comparable frequency of total VPCs/hour (274/h and 255/h for sotalol and propranolol groups, respectively) which was reduced to 71 VPCs/h and 109/VPCs/h, respectively, at the end of phase 1. At final evaluation there was a significantly greater response to sotalol as demonstrated by 80% reduction in VPCs/hour with sotalol compared with only 50% reduction noted in the propranolol group. Adequate therapeutic response was also achieved in a significantly greater percentage of patients on sotalol compared with propranolol (56% vs 29%, P =.02). Sotalol was also superior to propranolol in suppressing the VT events/day during phase 1 (89% vs 78% reduction in VT events/day, P <.05). Sotalol was more effective than propranolol in all subgroups and in patients with heart rate <75 beats per minute. CONCLUSIONS: Sotalol is more powerful than propranolol in suppressing ventricular arrhythmias documented on Holter recordings. The superiority of sotalol appears to be related to its combined class II and class III antiarrhythmic actions.

Efficacy and safety of d,l-sotalol in patients with ventricular tachycardia and in survivors of cardiac arrest

OBJECTIVE

The aim of this study was to assess the antiarrhythmic efficacy and safety of d,l-sotalol in patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) and in survivors of cardiac arrest and to identify the factors that are associated with arrhythmia suppression and therefore might be helpful in predicting drug efficacy.

BACKGROUND

Despite increasing use of the class III antiarrhythmic agent d,l-sotalol, data on its short- and long-term efficacy in a large patient cohort are lacking. Information on its long-term tolerability and safety is limited.

METHODS

A total of 396 patients with inducible sustained VT or VF (VT/VF) underwent programmed stimulation before and after receiving oral d,l-sotalol (240 to 640 mg/day). Patients in whom VT/VF was rendered either noninducible or more difficult to induce (more extrastimuli or faster drive cycle length needed for VT/VF induction) were discharged on a regimen of oral d,l-sotalol.

RESULTS

d,l-Sotalol suppressed VT/VF in 151 patients (38.1%) and rendered the arrhythmia more difficult to induce in 76 patients (19.2%). The extent of drug-induced prolongation of right ventricular refractoriness and a shorter VT cycle length at baseline were independent predictors of immediate drug efficacy. Torsade de pointes developed in seven patients (1.8%). Two hundred ten patients (53%) continued to receive d,l-sotalol and were followed up for 34 +/- 18 months (mean +/- SD). The actuarial rates for the absence of arrhythmic recurrence (either VT/VF or sudden death) at 1 and 3 years were 89% and 77%, respectively. Actuarial rates for overall survival at 1 and 3 years were 94% and 86%, respectively. VT/VF suppression by d,l-sotalol was an independent discriminant variable that separated patients with and without arrhythmia recurrence. However, noninducibility of VT/VF did not predict freedom from sudden death.

CONCLUSION

Oral d,l-sotalol is effective and safe in patients with VT/VF. However, sudden cardiac death develops in a significant proportion of patients, and programmed stimulation seems to be of limited value for its prediction.

Efficacy and proarrhythmia with the use of d,l-sotalol for sustained ventricular tachyarrhythmias

This study prospectively evaluated the clinical efficacy, the incidence of torsades de pointes, and the presumable risk factors for torsades de pointes in patients treated with d,l-sotalol for sustained ventricular tachyarrhythmias. Eighty-one consecutive patients (54 with coronary artery disease, and 20 with dilated cardiomyopathy) with inducible sustained ventricular tachycardia or ventricular fibrillation received oral d,l-sotalol to prevent induction of the ventricular tachyarrhythmia. During oral loading with d,l-sotalol, continuous electrocardiographic (ECG) monitoring was performed. Those patients in whom d,l-sotalol prevented induction of ventricular tachycardia or ventricular fibrillation were discharged with the drug and followed up on an outpatient basis for 21 +/- 18 months. Induction of the ventricular tachyarrhythmia was prevented by oral d,l-sotalol in 35 (43%) patients; the ventricular tachyarrhythmia remained inducible in 40 (49%) patients; and two (2.5%) patients did not tolerate even 40 mg of d,l-sotalol once daily. Four (5%) patients had from torsades de pointes during the initial oral treatment with d,l-sotalol. Neither ECG [sinus-cycle length (SCL), QT or QTc interval, or U wave] nor clinical parameters identified patients at risk for torsades de pointes. However, the oral dose of d,l-sotalol was significantly lower in patients with torsades de pointes (200 +/- 46 vs. 328 +/- 53 mg/day; p = 0.0017). Risk factors associated with the development of torsades de pointes were the appearance of an U wave (p = 0.049), female gender (p = 0.015), and significant dose-corrected changes of SCL, QT interval, and QTc interval (p < 0.05). During follow-up, seven (20%) patients had a nonfatal ventricular tachycardia recurrence, and two (6%) patients died suddenly. One female patient with stable cardiac disease had recurrent torsades de pointes after 2 years of successful treatment with d,l-sotalol. Torsades de pointes occurred early during treatment even with low doses of oral d,l-sotalol. Pronounced changes in the surface ECG (cycle length, QT, and QTc) in relation to the dose of oral d,l-sotalol might identify a subgroup of patients with an increased risk for torsades de pointes. Other ECG parameters before the application of d,l-sotalol did not identify patients at increased risk for torsades de pointes. Recurrence rates of ventricular tachyarrhythmias are high despite complete suppression of the arrhythmia during programmed stimulation. Therefore programmed electrical stimulation in the case of d,l-sotalol seems to be of limited prognostic value.

Suppression of inducible ventricular arrhythmias by intravenous azimilide in dogs with previous myocardial infarction

The class III antiarrhythmics azimilide dihydrochloride and dl-sotalol were evaluated for ability to suppress induction of ventricular tachyarrhythmias (VT) in anesthetized, male mongrel dogs 4-6 days after surgical infarction of the left ventricle (LV) produced by ligation/reperfusion of the left anterior descending coronary artery. Postmortem infarcts averaged 28.2 +/- 3.3% and 27.5 +/- 3.9% of the LV for azimilide- and sotalol-treated dogs, respectively. Both agents (0.3-30 mg/kg i.v.) increased ventricular effective refractory period as a function of dose in LV normal and infarcted zones without increasing conduction time. Azimilide was well tolerated hemodynamically up to 30 mg/kg i.v., whereas sotalol produced a significant and dose-related decrease in both blood pressure and heart rate. Azimilide was effective in five (56%) of nine dogs in preventing induction of ventricular arrhythmias by programmed electrical stimulation (PES) at doses from 1 to 30 mg/kg. Efficacy was seen for nonsustained and sustained VT and for ventricular fibrillation. Although sotalol (0.3-10 mg/kg) was effective in all five VT dogs tested, one of two nonsustained ventricular tachyarrhythmia (NSVT) dogs and two of three sustained ventricular tachyarrhythmia (SVT) dogs were reinducible with the baseline arrhythmia at doses higher than the effective dose, and one dog died after 30 mg/kg of sotalol. Both agents increased the cycle length of VT. Thus azimilide simultaneously increased refractoriness and provided antiarrhythmic efficacy as suppression of PES-induced ventricular arrhythmias in infarcted dogs without the hemodynamic depression seen with sotalol.

Long-term results of electrophysiologically guided sotalol therapy for life-threatening ventricular arrhythmias

The efficacy and safety of sotalol therapy for ventricular arrhythmias was evaluated in 133 patients with drug-refractory ventricular arrhythmias. All patients had baseline electrophysiologic studies before and after oral sotalol therapy. Sixty-six patients were discharged home, treated with sotalol (52 patients without inducible ventricular tachycardia or fibrillation and 14 patients with hemodynamically stable inducible ventricular tachycardia). The mean follow-up period was 41 +/- 27 months for the 14 patients with hemodynamically stable ventricular tachycardia. Sotalol was effective in 8 of these 14 patients. Recurrent nonlethal ventricular tachycardia occurred in 3 patients; 2 patients had sudden death; and 1 patient had adverse side effects. The 52 patients without inducible ventricular tachycardia were followed up for a mean period of 36 +/- 30 months. Thirty-five of 52 patients were successfully treated. Two patients had recurrent ventricular tachycardia; both of these episodes of ventricular tachycardia occurred within the first year. Four patients had sudden cardiac death; three of these deaths occurred within the first month, and the last episode of sudden death occurred after 8 years of sotalol therapy. The actuarial incidence of sotalol efficacy was 76% at 1 year, 72% at 2 years, 64% at 4 years, and 52% at 5 years. Approximately 46% of patients receiving long-term sotalol treatment reported side effects. Side effects severe enough to warrant withdrawal of sotalol occurred in 7 (11%) patients. The results of our study suggest that sotalol is effective for selected patients with drug refractory ventricular arrhythmias. Although the incidence of side effects are high, patients appear to tolerate long-term sotalol therapy well.

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.

Comparison of d,l-sotalol and implantable defibrillators for treatment of sustained ventricular tachycardia or fibrillation in patients with coronary artery disease

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) and d,l-sotalol are widely used to treat ventricular tachyarrhythmia and ventricular fibrillation (VT/VF). The purpose of this study was to compare the long-term efficacy of d,l-sotalol and ICDs in patients with coronary artery disease.

METHODS AND RESULTS

In a case-control study, 50 patients treated with oral d,l-sotalol were matched to 50 patients treated with ICDs. Both groups were matched for sex (82 men), age (58 +/- 10 years), ejection fraction (40 +/- 12%), extent of coronary artery disease, presenting arrhythmia, and year that treatment began. In all patients in the sotalol group, VT/VF was inducible in the drug-free electrophysiological study. Induction of sustained VT/VF was suppressed by d,l-sotalol (438 +/- 95 mg/d). In the ICD group, either VT/VF was not inducible (n = 5) or inducible sustained VT/VF was refractory to antiarrhythmic drug treatment (n = 45). Sotalol treatment led to a marked reduction in arrhythmic events. Whereas 83% of the patients in the sotalol group were free of sudden death and nonfatal VT at 3 years, only 33% of the ICD patients did not receive appropriate ICD therapies (P < .005). Actuarial rates for absence of sudden death at 3 years were 85% in the sotalol group and 100% in the ICD group (P < .005). Actuarial rates for overall survival at 3 years were 75% in the sotalol group and 85% in the ICD group (P = .02).

CONCLUSIONS

In this case-control study, ICD therapy was more effective tha electrophysiologically guided antiar-rhythmic treatment with d,l-sotalol in prevention of sudden death and reduction of total morality in patients with coronary artery disease. Prospective studies are needed to confirm these results.

Electrophysiologic Study versus Electrocardiographic Monitoring (ESVEM): a critical appraisal

This paper reviews the Electrophysiologic Study versus Holter Monitoring (ESVEM) trial, addressing several areas of concern including potential enrollment bias, an inadequate electrophysiologic testing protocol during drug therapy, and an unexpectedly high recurrence rate in patients deemed to be controlled by either method. The paper concludes that there are insufficient data to warrant extrapolation of the ESVEM results to survivors of cardiac arrest.

Positive and negative inotropic effects of DL-sotalol and D-sotalol in failing and nonfailing human myocardium under physiological experimental conditions

BACKGROUND

DL-Sotalol has class III antiarrhythmic activity through prolongation of the repolarization phase of the action potential as well as beta-adrenoceptor-blocking properties. Although the former effect was found to exert positive inotropic effects in animal experimental studies, the latter may be detrimental in heart failure due to negative inotropism. In contrast to DL-sotalol, D-sotalol is suggested to exert only positive inotropic effects, which were never tested in isolated human myocardium.

METHODS AND RESULTS

Therefore, we investigated the effects of racemic DL-sotalol and its enantiomer D-sotalol in human right atrial muscle strip preparations and in left ventricular muscle strip preparations from nonfailing and end-stage failing human hearts. DL-sotalol and D-sotalol significantly (P < .01) increased peak developed force in atrial preparations by 14.0 +/- 3.4% and 16.7 +/- 3.8%, respectively, but had no effect in ventricular myocardium. In nonfailing ventricular myocardium, both DL-sotalol and D-sotalol shifted the dose-response curve for isoproterenol to higher concentrations (P < .01); however, DL-sotalol was 100-fold more effective than D-sotalol. In non-failing myocardium, a positive force-frequency relation was found between 30 and 120 beats per minute, but isoproterenol was much more powerful in its inotropic effects. In failing myocardium, reduction in stimulation rate from 120 to 30 beats per minute increased peak developed force more pronounced than did the application of isoproterenol.

CONCLUSIONS

(1) D-Sotalol has no relevant beta-adrenoceptor-blocking activity compared with DL-sotalol. (2) Neither DL-sotalol nor D-sotalol exhibit positive inotropic effects in human left ventricular myocardium. (3) Heart rate reduction increases contractile force in end-stage failing human myocardium due to an inverse force-frequency relation and thereby counteracts the potential negative inotropic properties of beta-blockade.

Efficacy and proarrhythmia of oral sotalol in pediatric patients

OBJECTIVES

This study sought to assess the efficacy of oral sotalol for various arrhythmias in pediatric patients and to evaluate the incidence of proarrhythmia and systemic side effects.

BACKGROUND

Sotalol is a beta-adrenergic blocking agent with additional class III antiarrhythmic properties. Experience in pediatric patients is limited. Data concerning the incidence of proarrhythmia in children are lacking.

METHODS

Seventy-one pediatric patients (mean age 7.3 years) with various supraventricular and ventricular tachyarrhythmias were treated with oral sotalol. All the patients were admitted to the hospital for initiation of sotalol therapy. Antiarrhythmic and proarrhythmic effects of sotalol were assessed by daily surface electrocardiograms (ECGs) during the in-hospital phase and by serial Holter monitoring.

RESULTS

Sotalol was either completely (27 [66%] of 41 patients) or partially effective (11 [27%] of 41) in 38 (93%) of 41 patients with supraventricular reentrant tachycardias. In patients with atrial flutter predominantly after operation for congenital heart disease, sotalol was effective in 84% of patients (completely in 9 of 19 and partially in 7 of 19). Ventricular tachycardia was completely (3 of 11) or partially (4 of 11) controlled in 64% of children. Proarrhythmia occurred in seven patients (10%) and consisted of symptomatic bradycardia from sinoatrial block and high grade atrioventricular (AV) block, respectively, in two children; asymptomatic high grade AV block in one; torsade de pointes in one; and relevant increased ventricular ectopic activity in three. Proarrhythmia required drug discontinuation in four patients. Mean duration of treatment for all patients was 18 months (range 1 to 40).

CONCLUSIONS

Sotalol was an effective antiarrhythmic drug for a wide range of pediatric tachyarrhythmias. The considerable number of patients with proarrhythmic effects indicates the need for initiation of treatment on an inpatient basis and close monitoring by serial Holter electrocardiography.

Sotalol: from "just another beta blocker" to "the prototype of class III antidysrhythmic compound"

Sotalol is a beta-blocking drug devoid of membrane stabilizing properties, as well as intrinsic sympathomimetic actions, or cardioselectivity. In addition, sotalol prolongs atrial and ventricular repolarization (Class III antiarrhythmic activity). It appears to have less myocardial depressant effect than other beta-blocking agents. Given orally, bioavailability of the drug reaches 100%. Sotalol's plasma half-life is 15 hours (range 7-18) and is dependent only on renal function. In clinical practice, it has been found effective in the suppression of nearly all supraventricular and ventricular dysrhythmias except those related to prolonged ventricular repolarization. Most common adverse effects are dyspnea, bradycardia, and fatigue, which results in drug termination in 16% of the cases. Torsades de pointes usually associated with bradycardia and drug induced QTc prolongation has been reported in 1.9%-3.5% of the patients receiving sotalol. This complication may be reduced by limiting the dose (< 640 mg/day) especially in patients with impaired renal function. In addition hypokalemia must be avoided. To sum up, the combination of Class II and Class III effects may carry additional benefits. However, further studies are required to test such hypotheses.

Electrophysiologic effects of sotalol and amiodarone in patients with sustained monomorphic ventricular tachycardia

No prospective studies have compared sotalol and amiodarone during electropharmacologic testing. The purpose of this prospective, randomized study was to compare the electrophysiologic effects of sotalol and amiodarone in patients with coronary artery disease and sustained monomorphic ventricular tachycardia (VT). Patients with coronary artery disease and sustained monomorphic VT inducible by programmed stimulation were randomly assigned to receive either sotalol (n = 17) or amiodarone (n = 17). The sotalol dose was titrated to 240 mg twice daily over 7 days. Amiodarone dosing consisted of 600 mg 3 times daily for 10 days. An electrophysiologic test was performed in the baseline state and at the end of the loading regimen. An adequate response was defined as the inability to induce VT or the ability to induce only relatively slow hemodynamically stable VT. During the follow-up electrophysiologic test, 24% of patients taking sotalol and 41% of those taking amiodarone had an adequate response to therapy (p = 0.30). Amiodarone lengthened the mean VT cycle length to a greater degree than sotalol (28% vs 12%, p < 0.01). There were no significant differences in the effects of sotalol and amiodarone on the ventricular effective refractory period. In patients with coronary artery disease, amiodarone and sotalol are similar in efficacy in the treatment of VT as assessed by electropharmacologic testing. The effects of the 2 drugs on ventricular refractoriness are similar, but amiodarone slows VT to a greater extent than sotalol.

Efficacy of sotalol guided by programmed electrical stimulation for sustained ventricular arrhythmias secondary to coronary artery disease

Sotalol is a class III antiarrhythmic drug with additional beta-blocker activity that has been shown to be effective in supraventricular and ventricular arrhythmias. Its long-term efficacy for ventricular arrhythmias is not as well described. Patients with documented sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) who had their clinical arrhythmia inducible at baseline electrophysiologic study received sotalol 320 to 640 mg/day. Repeat programmed stimulation was performed after a minimum of 72 hours while receiving the final dose. Of 28 patients (25 men and 3 women) whose arrhythmias were inducible at baseline, 15 had their arrhythmias suppressed with sotalol. Sotalol had greater success in suppressing arrhythmias in those with VF (8 of 9, 89%) than in those with VT (7 of 19, 37%, p < 0.01). In patients with a history of coronary artery disease but no history of myocardial infarction the arrhythmia was suppressed in 7 of 8 (88%) compared with 8 of 20 (40%, p < 0.05) patients with a history of myocardial infarction. All 15 patients in whom ventricular arrhythmias were suppressed continued to take long-term sotalol, and at a follow-up of 10.3 +/- 6.4 months none has had arrhythmia recurrence. Thus, sotalol is an effective drug for the suppression of ventricular arrhythmias as judged by programmed electrical stimulation. It appears to be more effective in patients in whom the clinical arrhythmia is VF rather than VT.

Empiric use of amiodarone and sotalol

Several studies have demonstrated that class I antiarrhythmic drugs do not reduce, and may increase, sudden cardiac death mortality and total cardiac mortality. Because of this, alternative drug choices for antiarrhythmic therapy are necessary. Amiodarone has been demonstrated to be an important and effective antiarrhythmic agent, as has sotalol. The purpose of this article is to review the various indications and possible benefits of the empiric use of these 2 antiarrhythmic agents.

Sotalol: a breakthrough antiarrhythmic?

OBJECTIVE

To review the pharmacology, pharmacokinetic, dosing, adverse effects, and therapeutic uses of sotalol.

DATA IDENTIFICATION

Articles were identified with an English-language literature computer search via Knowledge Finder, using the term sotalol, and with an extensive search of bibliographies of identified articles.

STUDY SELECTION

Relevant or representative animal studies, human trials, and case reports were selected for evaluation.

DATA EXTRACTION

The literature was assessed for quality, methodology, and outcome information.

DATA SYNTHESIS

Sotalol is a racemic compound with Class II (beta-blocking properties) and Class III (prolonged action potential) antiarrhythmic activity. It has been suggested that the plasma concentration associated with QTc prolongation (a measure of the Class III action) is much greater than that associated with beta-blockade. Therefore, sotalol is categorized as a Class III antiarrhythmic agent. The 1-isomer is responsible for the beta-blocking activity, whereas both isomers have Class III properties. After oral dosing in fasting patients with normal renal function, sotalol is > 90 percent absorbed, achieves peak serum concentrations in 2-4 h, is excreted unchanged 80-90 percent in the urine, has a volume of distribution of 1-2 L/kg, and has an elimination half-life of about 12 h. Sotalol is effective in patients with life-threatening ventricular arrhythmias that have been refractory to other conventional antiarrhythmic drugs. In general, sotalol appears to be well tolerated, with many of its adverse effects caused by beta-blocking activity. As with other antiarrhythmic agents, the possibility of proarrhythmia (frequently torsade de pointes) exists.

CONCLUSIONS

Racemic sotalol is an effective Class III antiarrhythmic agent approved by the Food and Drug Administration for the treatment of documented life-threatening ventricular arrhythmias. Investigations continue with racemic sotalol in the management of supraventricular arrhythmias. Trials with the d-isomer are also ongoing.

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.

Safety and efficacy of oral sotalol for sustained ventricular tachyarrhythmias refractory to other antiarrhythmic agents

The safety and efficacy of oral sotalol were evaluated in 481 patients with drug-refractory sustained ventricular tachyarrhythmias (VT) in an open-label multicenter study. After drug-free baseline evaluations, therapy was initiated at 80 mg every 12 hours, with upward dose titrations of 160 mg/day being allowed at intervals of 72 hours to a maximum dose of 480 mg every 12 hours. Efficacy determinations were made by either programmed electrical stimulation (PES) or Holter monitoring responses. Of the 481 patients enrolled, 473 underwent acute-phase titration. Of the 269 patients assessable by PES, 94 (34.9%) exhibited complete response (suppression of inducible VT), with an additional 67 patients (24.9%) exhibiting partial response. Of the 109 patients assessable by Holter monitoring, 43 (39.4%) exhibited a complete response. There were no significant differences between responders and nonresponders with regard to left ventricular ejection fraction. Although response rates tended to improve as the sotalol dose was increased to 640 mg/day, efficacy was most commonly achieved at a sotalol dose of 320 mg/day. Sotalol was discontinued because of adverse effects in 42 (8.9%) of the acute-phase patients. The most common adverse effect was proarrhythmia, which was observed in 23 patients (4.9%). Proarrhythmia took the form of torsades de pointes in 12 patients and an increase in VT episodes in 11. In 3 acute-phase patients (0.6%), sotalol was discontinued because of the emergence of congestive heart failure. A total of 286 patients entered the long-term phase. Life-table estimates of the proportion of patients who remained free of recurrence of arrhythmia at 12, 18, and 27 months were 0.76, 0.72, and 0.66, respectively. There were no significant differences in time to recurrence of arrhythmia as related to PES response, Holter monitor response, baseline left ventricular ejection fraction, or history of congestive heart failure. Among the 70 patients (24.5%) in whom there was recurrence of arrhythmia, sudden death occurred in 17 and sustained VT in 41. Sotalol was discontinued owing to presumed adverse effects in 21 (7.3%) of the long-term patients, including 8 with proarrhythmia; proarrhythmia consisted of torsades de pointes in 3 patients and increased episodes of VT in 5. These findings suggest that sotalol is an effective drug for the long-term treatment of patients with drug-refractory sustained VT. Proarrhythmia was observed in only 6.4% of the study population and tended to occur during the acute titration phase. The need to discontinue therapy because of congestive heart failure was uncommon.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of oral sotalol on systemic hemodynamics and programmed electrical stimulation in patients with ventricular arrhythmias and structural heart disease

We explored the central hemodynamic responses to oral sotalol during dose titration in patients with ventricular arrhythmias who underwent programmed ventricular stimulation. Twelve patients were included in the study, 9 with a history of sustained ventricular tachyarrhythmias (6 postmyocardial infarction and 3 with cardiomyopathy) and 3 with a history of nonsustained ventricular tachycardia postmyocardial infarction. Left ventricular ejection fractions were < 45% in 10 patients, and < 35% in 5; the mean ejection fraction was 37% (range 20-51%). Sotalol prevented the induction of ventricular tachycardia in each of 3 patients with nonsustained ventricular tachycardia and in 6 of 9 with sustained ventricular tachycardia at baseline study. At peak action (2 hours) after sotalol loading (mean dose, 167 mg orally twice daily), the hemodynamic effects included bradycardia, decreased cardiac index, increased left ventricular filling pressure and systemic vascular resistance, and no change in stroke volume or stroke work index. One patient was not continued on sotalol, owing to an excessive increase in the pulmonary capillary wedge pressure, despite the lack of symptomatic heart failure. Congestive heart failure in association with marked bradycardia developed in another patient, who had suppression of inducible ventricular tachycardia after sotalol loading; this patient was managed with a reduction in the dose of sotalol and a regimen of digoxin and furosemide, and has been well compensated and without a recurrence of sustained ventricular tachycardia for more than 4 years. Ventricular tachycardia has been controlled with sotalol, without hemodynamic deterioration, in 6 of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of sotalol for life-threatening ventricular arrhythmias

Two trial designs have been used in evaluating sotalol in patients with sustained tachyarrhythmias: open-label dose escalation and randomized comparison with reference agents. At least 7 open-label studies (n = 16-65) have been reported from single centers in patients in whom trials of numerous other antiarrhythmic agents were unsuccessful. At the doses used, usually 320-640 mg/day, plasma concentrations were in the range associated with both beta blockade and class III antiarrhythmic activity (2-3 micrograms/mL). These concentrations produced electrophysiologic changes that were consistent across studies: 10-16% increase in right ventricular effective refractory period (ERP), 4-8% increase in corrected QT interval (QTc), and 17-30% increase in sinus cycle length (corresponding to a 15-23% decrease in heart rate). In these open-label trials, sotalol suppressed inducible ventricular tachyarrhythmias in 20-72% of patients; the higher degrees of efficacy were reported when induction protocols were confined to double extrastimuli. Side effects leading to discontinuation of sotalol in patients with sustained ventricular tachycardia or fibrillation include fatigue (4.0%), marked bradycardia (3.0%), torsades de pointes (3.0%), and heart failure or pulmonary edema (1.0%). A multicenter randomized trial compared intravenous sotalol with intravenous procainamide in a double-blind prospective fashion. Sotalol suppressed ventricular tachyarrhythmias inducible with triple extrastimuli in 15 (30%) of 50 patients, whereas procainamide was effective in 10 (20%) of 50. In this and other series, responsiveness to sotalol was prospectively identified by a particularly fast tachycardia at baseline (e.g., cycle length of < 270 msec), but not by the extent of changes in global indices of repolarization (QTc, ERP).(ABSTRACT TRUNCATED AT 250 WORDS)

Practical considerations in the use of sotalol for ventricular tachycardia and ventricular fibrillation

Sotalol is a unique antiarrhythmic drug that combines beta-blocking effects with actions to prolong action potential duration. The net effect is a drug that is efficacious in the management of ventricular tachyarrhythmias. Although sotalol has effects on both heart rate and QT interval, these effects do not help predict the antiarrhythmic efficacy of the agent. Changes in QT dispersion may, however, prove to be relevant to both the antiarrhythmic effects and the arrhythmogenic effects of sotalol. Thus, although sotalol may occasionally cause torsades de pointes, this complication may be predictable and clinically controllable. Sotalol is well tolerated, and it may be used, with caution, in some patients with impaired myocardial contractile performance, despite its beta-blocking action. Sotalol has an important indication for the management of ventricular tachyarrhythmias.

Sotalol and type IA drugs in combination prevent recurrence of sustained ventricular tachycardia

OBJECTIVES

This study assessed the efficacy of the combination of sotalol and either quinidine or procainamide in preventing sustained ventricular tachycardia inducibility and recurrence and prospectively evaluated the ability of the drug combination to prevent ventricular tachycardia recurrence when the arrhythmia remained inducible but was modified.

BACKGROUND

Individual antiarrhythmic drugs are often ineffective in preventing the induction and recurrence of sustained ventricular tachycardia. Beta-adrenergic blockade and prolongation of refractoriness may be important components of successful antiarrhythmic therapy in patients with ventricular tachycardia. We reasoned that the combination of sotalol, which has beta-adrenergic blocking properties and prolonged ventricular refractoriness, and quinidine or procainamide, two agents that slow conduction and prolong refractory periods, would be effective therapy in such patients.

METHODS

We administered low dose sotalol (205 +/- 84 mg/day) plus quinidine sulfate (1,278 +/- 479 mg/day) or procainamide (2,393 +/- 1,423 mg/day) to 50 patients with spontaneous sustained ventricular tachycardia or fibrillation and inducible ventricular tachycardia.

RESULTS

In 21 (46%) of 46 patients, ventricular tachycardia was rendered noninducible at electrophysiologic study (group I), and in 17 patients (37%), inducible tachycardia was modified according to prospectively identified criteria (group II), for a combined 83% response rate. Ventricular refractory periods increased from 252 +/- 24 to 316 +/- 28 ms and from 265 +/- 33 to 316 +/- 24 ms in groups I and II, respectively (p < 0.001), but from 234 +/- 19 to only 286 +/- 13 ms in the group of patients with unmodified ventricular tachycardia inducibility (n = 8, group III, p < 0.001). Cycle length of induced ventricular tachycardia slowed from 324 +/- 62 to 432 +/- 70 ms in group II patients (p < 0.001), whereas it slowed less in group III patients (279 +/- 73 to 314 +/- 63 ms, p = NS). Forty-two of the 50 patients (including all patients in groups I and II) were discharged on treatment with the drug combination. After 25 +/- 19 months of follow-up, the actuarial recurrence rate of ventricular tachycardia was 6%, 6% and 11% at 1, 2 and 3 years, respectively. Among patients in whom this drug combination was unsuccessful at electrophysiologic study (group III) and in those who received alternative therapy after combination therapy was discontinued because of side effects, actuarial recurrence rates were 9%, 14% and 32% at 1, 2 and 3 years, respectively.

CONCLUSIONS

The combination of sotalol plus quinidine or procainamide markedly prolongs ventricular refractoriness and slows induced ventricular tachycardia in a high proportion of patients. Patients with modified or noninducible tachycardia have a low rate of arrhythmia recurrence in follow-up. This drug combination deserves further evaluation.

Sotalol: a novel beta-blocker with class III anti-arrhythmic activity

Initially synthesized in 1960, sotalol is a novel beta-adrenoreceptor blocking agent that also possesses class III anti-arrhythmic properties. The drug's ability to lengthen repolarization and prolong effective refractory periods in all cardiac tissues in addition to its beta-blocking effects make sotalol an attractive agent for use in a variety of supraventricular and ventricular arrhythmias.

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.

Effects of sotalol on the signal-averaged electrocardiogram in patients with sustained ventricular tachycardia: relation to suppression of inducibility and changes in tachycardia cycle length

OBJECTIVES

This study examines the effects of sotalol on the signal-averaged electrocardiogram (ECG) in patients with spontaneous and inducible sustained ventricular tachycardia and correlates these findings with the effect of sotalol on tachycardia inducibility and tachycardia rate.

BACKGROUND

Standard electrocardiography generally does not detect any change in the duration of the QRS complex resulting from sotalol therapy. However, the signal-averaged ECG is more sensitive than the standard ECG for detecting changes in QRS duration induced by antiarrhythmic drugs and can also detect changes in late potential duration.

METHODS

Signal-averaged electrocardiography was performed before therapy in 30 patients with spontaneous and inducible ventricular tachycardia, and both electrophysiologic study and a signal-averaged ECG were repeated during therapy with d,l-sotalol.

RESULTS

During sotalol therapy the signal-averaged QRS duration decreased by 2.6 +/- 6.6 ms in the 11 patients with no inducible tachycardia during therapy, whereas it increased by 3.8 +/- 5.8 ms (p = 0.01) in the 19 patients with inducible tachycardia during therapy. In the latter group there was a significant positive correlation between prolongation of tachycardia cycle length and prolongation of late potential duration by sotalol (r = 0.56, p = 0.01).

CONCLUSIONS

Sotalol can alter QRS and late potential duration as measured by the signal-averaged ECG. Prolongation of QRS duration or late potential duration may reflect a slowing of conduction by sotalol that may interfere with this agent's antiarrhythmic efficacy and slow ventricular tachycardia.

Effectiveness of oral sotalol for treatment of pediatric arrhythmias

Sotalol is a beta blocker with class III activity. Few investigators have reported its use in pediatric patients. From August 1985 to May 1990, 66 patients (mean age 8.7 years; range 9 days to 24 years), including 14 infants aged less than 3 months, were treated with oral sotalol alone (n = 46) or in association with digoxin (n = 20). Supraventricular reentrant tachycardia was present in 38 patients (20 with documented preexcitation), atrial flutter in 10 and atrial ectopic tachycardia in 7. Three patients had other types of supraventricular tachycardia. Tachycardia was of ventricular origin in 6 patients and both of supraventricular and ventricular origin in the remaining 2. Mean dose of oral sotalol was 135 mg/m2/day given in 2 doses. Congenital heart disease was present in 28 patients, 14 with previous cardiac surgery, mostly at the atrial level. Prior treatment with 1 or more antiarrhythmic agent had been unsuccessful in 83% of patients. Mean duration of treatment was 13.3 months (range 2 months to 5 years). Overall, treatment was successful in 79% of cases. Highest rate of success was observed in patients with supraventricular reentrant tachycardia with or without preexcitation (89%) and in those with atrial ectopic tachycardia (85.5%). Atrial flutter could be controlled in 60% of cases. Sotalol seemed less effective in ventricular tachycardia with a complete control of the arrhythmia being achieved in only 17%; however, it decreased the number of runs of ventricular tachycardia and the number of ventricular premature complexes in 50% of patients. There were no adverse effects in 89% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy and electrophysiologic effects of oral sotalol in patients with sustained ventricular tachycardia caused by coronary artery disease

The efficacy of oral sotalol in preventing sustained ventricular tachycardia induction by invasive electrophysiological testing was assessed in 22 patients (60 +/- 9 years) with prior myocardial infarction. Programmed stimulation consisted of two basic drives followed by up to three extrastimuli at two right ventricular sites. At baseline, sustained monomorphic ventricular tachycardia was inducible in all patients. With sotalol (360 +/- 172 mg/day), it was no longer inducible in 10 patients; in 12 others, it remained inducible and its cycle length was only minimally prolonged (322 +/- 42 to 345 +/- 44 msec, p less than 0.05). Sotalol markedly prolonged sinus cycle length, uncorrected QT interval, and right ventricular effective and functional refractory periods, but had little effect on ventricular conduction time either in sinus rhythm or with right ventricular pacing. There was no significant difference in drug dose or in electrophysiologic effect of drug that related to efficacy, nor was there any correlation between drug-induced prolongation of ventricular tachycardia cycle length and its effects. Six patients received oral sotalol over the long term without spontaneous recurrence of ventricular tachycardia (follow-up: 23 +/- 18 months). These results demonstrate that sotalol is effective (45%) against sustained ventricular tachycardia induction at moderate doses and is well tolerated over a long term in the setting of remote myocardial infarction. However, its electrophysiologic effects as measured at invasive testing are not predictive of efficacy against ventricular tachycardia induction.

Usefulness of d, I sotalol for suppression of chronic ventricular arrhythmias

Sotalol is a unique beta-blocking drug, possessing significant class III antiarrhythmic activity. The efficacy and safety of 2 doses of sotalol (320 and 640 mg/day, divided in 2 doses) were compared to placebo in a 6-week randomized, double-blind, multicenter study of 114 patients with chronic ventricular premature complexes (VPCs) at frequencies of greater than or equal to 30/hour. Sotalol significantly reduced VPCs in patients receiving both low (n = 38) and high (n = 39) doses, compared with patients (n = 37) receiving placebo (by 75 and 88%, respectively, vs 10%; p less than 0.001, sotalol vs placebo; p less than 0.05, high vs low dose). The individual efficacy criterion (greater than or equal to 75% VPC reduction) was achieved in 34% of low-dose and 71% of high-dose sotalol versus 6% of placebo-treated patients (p less than 0.003, sotalol vs placebo; p = 0.007, high vs low dose). Repetitive beats were suppressed 25% by placebo (difference not significant), 80% by low-dose (p less than 0.003) and 78% by high-dose sotalol (p less than 0.005). Sotalol decreased heart rate (by 24 to 25%, p less than 0.001) and increased PR (by 4 to 6%, p less than 0.001) and corrected JT intervals (by 12 to 13%, p less than 0.001), but did not change ejection fraction. Proarrhythmia (nonfatal) occurred in 3 sotalol and in 2 placebo patients. Nine discontinued therapy because of adverse effects (1 low dose and 8 high dose, p less than 0.02). In summary, sotalol is an efficacious antiarrhythmic drug for VPC suppression; in lower doses, it is somewhat less effective but better tolerated.

Effects of N-acetylprocainamide and sotalol on ion currents in isolated guinea-pig ventricular myocytes

The effects of N-acetylprocainamide (NAPA) and sotalol on membrane current systems of guinea-pig ventricular myocytes were examined and compared with those of quinidine using patch-clamp techniques. All of the drugs prolonged the action potential duration (i.e. Class III effect) in isolated guinea-pig papillary muscles. In isolated ventricular cells. NAPA (300 microM) and sotalol (100 microM) produced a decrease in the delayed outward potassium current (IK) concomitantly with a slight decrease in the calcium current (ICa), which was similar to quinidine (10 microM). NAPA also slightly depressed the inward rectifier potassium current (IKrect). Thus, NAPA and sotalol both inhibited IK, and this action appears to be mainly responsible for their Class III effect.

Sotalol versus class I and II antiarrhythmic agents

In two separate, double-blind, multicenter antiarrhythmic studies, sotalol was compared with propranolol or quinidine using placebo for baseline and/or washout periods. The comparison with quinidine was a crossover study. To be enrolled in these studies, patients were required to have a premature ventricular contraction (PVC) rate of at least 30/hr on a baseline 24-hour ambulatory ECG. At doses calculated to produce equivalent degrees of beta blockade, sotalol was more effective than propranolol in reducing the frequency of PVCs, and the two drugs produced similar reductions in ventricular tachycardia (VT) events. The side effects for sotalol and propranolol were mainly due to beta blockade, and the incidence of side effects with the two drugs was similar. Sotalol was comparable with quinidine in reducing PVCs and VT events. The side effects on sotalol were primarily related to beta-adrenergic blockade, while those on quinidine were predominantly gastrointestinal or neurologic in nature.

Safety and efficacy of sotalol in patients with drug-refractory sustained ventricular tachyarrhythmias

The safety and efficacy of oral sotalol, an investigational beta-adrenergic blocker with class III antiarrhythmic drug properties, were examined in a multicenter study in 236 patients with sustained ventricular tachyarrhythmias. In 104 patients, the index arrhythmia was a cardiac arrest, and all patients had undergone at least 3 previous unsuccessful antiarrhythmic trials (mean = 5 per patient). In the 106 patients assessed by programmed electrical stimulation, sotalol completely suppressed induction of ventricular tachycardia (VT) in 33 (31%) and rendered VT slower (greater than 100 ms prolongation of cycle length) or more difficult to induce in 29 (27%). Using continuous 24-hour ambulatory monitoring methods, sotalol complete- and partial-response rates were 51 and 12%, respectively. Of the 236 acute-phase patients, 151 were discharged receiving long-term sotalol therapy. The median sotalol dose was 480 mg/day. At a mean follow-up of 346 +/- 92 days, 27 patients (18%) had recurrence of sustained arrhythmia; 9, sudden death; 11, sustained VT; 5, automatic defibrillator discharge; and 2, syncope. Adverse effects forced discontinuation of therapy in 10 patients (7%): 6 secondary to symptomatic bradyarrhythmia, 2 due to refractory heart failure, 1 due to torsades de pointes, and 1 from bronchospasm. Life-table analysis of sotalol's overall long-term efficacy at 6, 12 and 18 months were 80, 76 and 72%, respectively. Although mean follow-up was short (less than 1 year), neither acute-phase programmed stimulation nor 24-hour ambulatory monitoring responses were significantly predictive of subsequent arrhythmic outcome. Proarrhythmia was documented in 18 patients (7%), 17 during the acute phase and 1 during long-term follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)