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

Early experience with intravenous sotalol in children with and without congenital heart disease

BACKGROUND

Arrhythmias are common in the pediatric population. In patients unable to take oral medications or in need of acute therapy, options of intravenous (IV) antiarrhythmic medications are limited. Recently IV sotalol has become readily available, but experience in children is limited.

OBJECTIVE

The purpose of this study was to describe our initial experience with the use of IV sotalol in the pediatric population.

METHODS

A retrospective study of all pediatric patients receiving IV sotalol was performed. Patient demographic characteristics, presence of congenital heart disease, arrhythmia type, efficacy of IV sotalol use, and adverse effects were evaluated.

RESULTS

A total of 47 patients (26 (55%) male and 24 (51%) with congenital heart disease) received IV sotalol at a median age of 2.05 years (interquartile range 0.07-10.03 years) and a median weight of 12.8 kg (interquartile range 3.8-34.2 kg), and 13 (28%) received IV sotalol in the acute postoperative setting. Supraventricular arrhythmias occurred in 40 patients (85%) and ventricular tachycardia in 7 (15%). Among 24 patients receiving IV sotalol for an active arrhythmia, acute termination was achieved in 21 (88%). Twenty-three patients received IV sotalol as maintenance therapy for recurrent arrhythmias owing to inability to take oral antiarrhythmic medications; 19 (83%) were controlled with sotalol monotherapy. No patient required discontinuation of IV sotalol secondary to adverse effects, proarrhythmia, or QT prolongation.

CONCLUSION

IV sotalol is an effective antiarrhythmic option for pediatric patients and may be an excellent agent for acute termination of active arrhythmias. It was well tolerated, with no patient requiring discontinuation secondary to adverse effects.

Cardiac and hemodynamic effects of intravenous dofetilide in patients with heart failure

This study assesses the effects of dofetilide, a new selective Ikr blocker with class III properties, on left ventricular function and hemodynamics of heart failure and compares these effects with those of placebo and amiodarone. Because available antiarrhythmic drugs may depress myocardial performance, an invasive hemodynamic study was performed to assess the safety of this agent. Hemodynamic and angiographic data were obtained at baseline and after 30 minutes of double-blind infusion of dofetilide (8 microg/kg; n = 12), placebo (n = 12), or amiodarone (5 mg/kg; n = 6) in heart failure patients (New York Heart Association class II or III, ejection fraction <35%). Intravenous dofetilide preserved the inotropic indexes and the end-systolic volume index despite a slight but significant decrease in heart rate, whereas intravenous amiodarone increased end-diastolic and end-systolic volume indexes. Amiodarone induced a negative inotropic effect illustrated by a rightward shift of the pressure-volume loop and a reduction in pressure-derived indexes of contractility. Intravenous dofetilide acutely prolonged QT interval more than intravenous amiodarone; however, dofetilide did not slow the overall relaxation rate and reduced QT dispersion. In an acute setting, compared with intravenous amiodarone, intravenous dofetilide preserves cardiac function offering a hemodynamic advantage to treat arrhythmias in patients with impaired left ventricular function.

Oral d,l sotalol reduces the incidence of postoperative atrial fibrillation in coronary artery bypass surgery patients: a randomized, double-blind, placebo-controlled study

OBJECTIVES

The purpose of this prospective, randomized, double-blind, placebo-controlled study was to assess the efficacy of preoperatively and postoperatively administered oral d,l sotalol in preventing the occurrence of postoperative atrial fibrillation (AF).

BACKGROUND

Atrial fibrillation is the most common arrhythmia following coronary artery bypass surgery (CABG). Its etiology, prevention and treatment remain highly controversial. Furthermore, its associated morbidity results in a prolongation of the length of hospital stay post-CABG.

METHODS

A total of 85 patients, of which 73 were to undergo CABG and 12 CABG plus valvular surgery (ejection fraction > or = 28% and absence of clinical heart failure), were randomized to receive either sotalol (40 patients; mean dose = 190 +/- 43 mg/day) started 24 to 48 h before open heart surgery and continued for four days postoperatively, or placebo (45 patients, mean dose = 176 +/- 32 mg/day).

RESULTS

Atrial fibrillation occurred in a total of 22/85 (26%) patients. The incidence of postoperative AF was significantly (p = 0.008) lower in patients on sotalol (12.5%) as compared with placebo (38%). Significant bradycardia/hypotension, necessitating drug withdrawal, occurred in 2 of 40 (5%) patients on sotalol and none in the placebo group (p = 0.2). None of the patients on sotalol developed Torsade de pointes or sustained ventricular arrhythmias. Postoperative mortality was not significantly different in sotalol versus placebo (0% vs. 2%, p = 1.0). Patients in the sotalol group had a nonsignificantly shorter length of hospital stay as compared with placebo (7 +/- 2 days vs. 8 +/- 4 days; p = 0.24).

CONCLUSIONS

The administration of sotalol, in dosages ranging from 80 to 120 mg, was associated with a significant decrease (67%) in postoperative AF in patients undergoing CABG without appreciable side effects. Sotalol should be considered for the prevention of postoperative AF in patients undergoing CABG in the absence of heart failure and significant left ventricular dysfunction.

Sotalol: An important new antiarrhythmic

Sotalol, the most recently approved oral antiarrhythmic drug, has a unique pharmacologic profile. Its electrophysiology is explained by nonselective beta-blocking action as well as class III antiarrhythmic activity (including fast-activating cardiac membrane-delayed rectifier current blockade), which leads to increases in action potential duration and refractory period throughout the heart and in QT interval on the surface electrocardiogram. Its better hemodynamic tolerance than other beta-blockers may be a result of enhanced inotropy associated with class III activity. Sotalol's ability to suppress ventricular ectopy is similar to that of class I agents and better than that of standard beta-blockers. Unlike class I agents, its use in a postinfarction trial was not associated with increased mortality rate. Therapeutically, it has shown superior efficacy for prevention of recurrent ventricular tachycardia and ventricular fibrillation, which was the basis for its approval. In a randomized study, the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial, sotalol was associated with an increased in-hospital efficacy prediction rate (by Holter monitor or electrophysiologic study), reduced long-term arrhythmic recurrence rate with superior tolerance, and lower mortality rate than class I ("standard") antiarrhythmic drugs. Sotalol was 1 of 2 drugs selected for comparison with implantable defibrillators in the recent National Institutes of Health Antiarrhythmics versus Implantable Defibrillator (AVID) study. Sotalol appears to be a preferred drug for use with implantable defibrillators; unlike some other agents (eg, amiodarone) it does not elevate and, indeed, may lower defibrillation threshold. Although unapproved for this use, sotalol is active against atrial arrhythmias. It has shown efficacy equivalent to propafenone and quinidine in preventing atrial fibrillation recurrence, but it is better tolerated than quinidine and provides excellent rate control during recurrence. Sotalol's major side effects are related to beta-blockade and the risk of torsades de pointes (acceptably small if appropriate precautions are taken). Unlike several other antiarrhythmics (eg, amiodarone), it has no pharmacokinetic drug-drug interactions, is not metabolized, and is entirely renally excreted. Initial dose is 80 mg twice daily, with gradual titration to 240 to 360 mg/day as needed. The daily dose must be reduced in renal failure. On the basis of favorable clinical trials and practice experience, sotalol has shown a steadily growing impact on the treatment of arrhythmias during its 5 years of market availability, a trend that is likely to continue.

Acute hemodynamic effects of intravenous ibutilide in patients with or without reduced left ventricular function

Many antiarrhythmic agents have adverse hemodynamic effects which limit their use in patients with impaired ventricular function or during tachyarrhythmias. Ibutilide is an intravenous, selective class III antiarrhythmic agent that is effective for conversion of atrial fibrillation or flutter. This multicenter, randomized, placebo-controlled, dose-ranging study evaluated the effects of intravenous ibutilide on hemodynamic parameters during invasive monitoring in 47 patients with or without reduced left ventricular ejection fraction (LVEF) > 35% or < or = 35%. Patients received either placebo or ibutilide as a 10-minute loading and a 30-minute maintenance infusion using 1 of the following dosing regimens: placebo then placebo (n = 12); 0.01 then 0.002 mg/kg (n = 12); 0.02 then 0.004 mg/kg (n = 12); or 0.03 then 0.006 mg/kg (n = 11). Ibutilide significantly increased QT and QTc intervals in a dose-related manner with mean increases ranging from 51 to 99 ms, but did not alter the PR interval or QRS duration. During ibutilide infusion, a few small but statistically significant changes from baseline in several hemodynamic variables were present. However, the changes in cardiac output, pulmonary artery or capillary wedge pressures, blood pressure, or heart rate in patients receiving ibutilide were not significantly different from the changes in patients receiving placebo. Thus, ibutilide did not cause clinically important adverse hemodynamic effects, even in patients with depressed ventricular function. One patient developed 2 episodes of nonsustained torsades de pointes during ibutilide. These results demonstrate that with careful monitoring for proarrhythmia, ibutilide can be used safely from a hemodynamic standpoint in the acute treatment of arrhythmias, even in patients with reduced ventricular function.

Hemodynamic effects of intravenous sematilide in patients with congestive heart failure: a class III antiarrhythmic agent without cardiodepressant effects

OBJECTIVES

This study sought to evaluate the hemodynamic effects of intravenous sematilide hydrochloride, a selective class III antiarrhythmic agent, in patients with heart failure and left ventricular systolic dysfunction.

BACKGROUND

Class I antiarrhythmic agents, which primarily slow conduction, can depress ventricular function, particularly in patients with heart failure. In contrast, pure class III agents, which selectively prolong repolarization, do not adversely affect hemodynamic variables in animal models, but there are no data evaluating their hemodynamic effects in humans.

METHODS

In 39 patients with congestive heart failure and a left ventricular ejection fraction < 40%, hemodynamic and electrocardiographic measurements were obtained at baseline, after a loading dose and during a maintenance infusion of intravenous sematilide using either a low (0.75 then 0.3 mg/min) or high dose (1.5 then 0.6 mg/min) regimen. The study had an 80% power to detect clinically meaningful differences in hemodynamic variables.

RESULTS

Both low (n = 20) and high (n = 19) dose sematilide infusions produced dose-dependent increases in QT interval (5 +/- 8% [mean +/- SD] and 18 +/- 10%, respectively) and corrected QT interval (4 +/- 8% and 14 +/- 10%), and high dose sematilide decreased heart rate by 7 +/- 10% (all p < 0.025 vs. baseline). Neither dose regimen had a statistically significant effect on any other hemodynamic variable, including mean arterial, right atrial, pulmonary artery and pulmonary capillary wedge pressures; cardiac index, stroke volume, systemic and pulmonary vascular resistances; and left ventricular stroke work index. Sematilide showed no adverse hemodynamic effects in patients with left ventricular ejection fraction < or = 25% or > 25% and in patients with cardiac index < 2 or > or = 2 liters/min per m2. Sustained polymorphic ventricular tachycardia (n = 1) and excessive QT prolongation (n = 4) were seen during the high dose.

CONCLUSIONS

Sematilide, in the doses administered, prolonged repolarization but did not alter hemodynamic variables in patients with heart failure. These data suggest that class III antiarrhythmic agents, which selectively prolong repolarization, are not cardiodepressant but may be proarrhythmic in humans, especially at high doses.