Comparative hemodynamic effects of amiodarone, sotalol, and d-sotalol

A Retrospective Cohort Evaluation of Left Ventricular Remodeling, Perioperative Complications and Outcome in Medium and Large Size Dogs with Patent Ductus Arteriosus after Percutaneous Closure

This retrospective cohort study included one hundred fifty-seven medium and large-size dogs with the aim of evaluating the effect of signalment and echocardiographic features on complications, outcomes and left ventricular modifications before and after patent ductus arteriosus (PDA) closure. The patients were divided in two groups based on the heart remodeling after closure: Group A included dogs that had a reduction in the end-systolic volume index (ESVI) after closure compared to the ESVI measured before; Group B included dogs without a reduction in ESVI after closure. Body weight, minimal ductal diameter (MDD) of PDA, end-diastolic volume index and presence of arrhythmias at presentation were significantly higher in Group B compared to Group A. The shortening fraction and ejection fraction after closure were reduced in both groups, but in Group B there was a major reduction, and the mean values indicated a possible systolic dysfunction. Complications during the procedure and death due to cardiac reasons were greater in Group B compared to Group A. In conclusion, a higher body weight, a larger MDD, a more severe heart enlargement or arrhythmias at presentation increased the risk of developing a worsening structural and functional condition after ductal closure, and this can be associated with perioperative complications and cardiac death.

Intravenous Amiodarone and Sotalol Impair Contractility and Cardiac Output, but Procainamide Does Not: A Langendorff Study

INTRODUCTION

Direct comparison of the effects of antiarrhythmic agents on myocardial performance may be useful in choosing between medications in critically ill patients. Studies directly comparing multiple antiarrhythmic medications are lacking. The use of an experimental heart preparation permits examination of myocardial performance under constant loading conditions.

METHODS

Hearts of Sprague Dawley rats (n = 35, 402-507 g) were explanted and cannulated in working heart model with fixed preload and afterload. Each heart was then exposed to a 3-hour infusion of procainamide (20 µg/kg/min), esmolol (100 or 200 µg/kg/min), amiodarone (10 or 20 mg/kg/d), sotalol (80 mg/m²/d), or placebo infusions (n = 5 per dose). Cardiac output, contractility (dP/dT_max), diastolic performance (dP/dT_min), and heart rate were compared between groups over time by linear mixed modeling.

RESULTS

Compared with placebo, sotalol decreased contractility by an average of 24% ( P < .001) over the infusion period, as did amiodarone (low dose by 13%, P = .029; high dose by 14%, P = .013). Compared with placebo, mean cardiac output was significantly lower in animals treated with sotalol (by 22%, P = .016) and esmolol 200 μg/kg/min (by 23%, P = .012). Over time, amiodarone decreased cardiac output (20 mg/kg/d, β = -89 [-144, -33] μL/min² decrease, P = .002) and also worsened diastolic function, decreasing dP/dT_min by ∼18% and 22% ( P = .032 and P = .011, low and high doses, respectively). Procainamide did not have a significant effect on any measures of systolic or diastolic performance.

CONCLUSIONS

In isolated hearts, amiodarone and sotalol depressed myocardial contractility, cardiac output, and diastolic function. However, procainamide did not negatively affect myocardial performance and represents a favorable agent in settings of therapeutic equivalence.

Atrial stunning: basics and clinical considerations

Conversion of atrial fibrillation and flutter to sinus rhythm results in a transient mechanical dysfunction of atrium and atrial appendage, termed atrial stunning. Atrial stunning has been reported with all modes of conversion of atrial fibrillation and flutter to sinus rhythm including both transthoracic and low energy internal electrical, pharmacological, and spontaneous cardioversion, and conversion by overdrive pacing and by radiofrequency ablation. Atrial stunning is a function of the underlying arrhythmia becoming apparent at the restoration of sinus rhythm, not the function of the mode of conversion, and does not develop after the unsuccessful attempts of cardioversion or the delivery of electric current to the heart during rhythms other than atrial fibrillation or flutter. Tachycardia-induced atrial cardiomyopathy, cytosolic calcium accumulation, and atrial hibernation are the suggested mechanisms of atrial stunning. Atrial stunning is at maximum immediately after cardioversion and improves progressively with a complete resolution within a few minutes to 4-6 weeks depending on the duration of the preceding atrial fibrillation, atrial size, and structural heart disease. Atrial stunning causes postcardioversion thromboembolism despite restoration of sinus rhythm. Duration of anticoagulation therapy after successful cardioversion should depend on the duration of atrial stunning. Lack of improvement in cardiac output and functional recovery of patients immediately after cardioversion is attributed to the atrial stunning. Verapamil, acetylstrophenathidine, isoproterenol, and dofetilide have been reported to protect from atrial stunning in animal and small human studies. Right atrium stunning is less marked and improves earlier than that of left atrium, resulting in a differential atrial stunning explaining the rare occurrence of pulmonary edema after cardioversion.

Acute circulatory actions of intravenous amiodarone loading in cardiac surgical patients

BACKGROUND

The duration, severity, and cause of hypotension after intravenous amiodarone has not been well characterized in anesthetized cardiac surgical patients. Because amiodarone is tolerated in patients with advanced cardiac disease, we hypothesized that left ventricular systolic performance is preserved despite hypotension during amiodarone loading.

METHODS

In a prospective double-blind trial, 30 patients undergoing coronary artery bypass graft (CABG) surgery were randomly assigned to receive intravenous amiodarone (n = 15) or placebo (n = 15). Cardiac output (CO), mixed venous oxygen saturation (SVO), arterial blood pressure (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP]), pulmonary artery pressure, and central venous pressure (CVP) were recorded. Transesophageal echocardiographic left ventricular end-diastolic area (EDA), end-systolic area (ESA), fractional area change (FAC), and end-systolic wall stress (ESWS) were measured every 5 minutes.

RESULTS

Mean arterial pressure, SBP, and DBP decreased over time after drug administration in both groups (p < 0.05). At 6 minutes, amiodarone decreased the MAP by 14 mm Hg (p = 0.004) and placebo decreased the MAP by 4 mm Hg. The change in MAP, SBP, and DBP between groups was statistically different for the first 15 minutes after drug administration. Hypotension requiring intervention occurred in 3 of 15 after amiodarone and 0 of 15 after placebo (p = 0.22). The mean heart rate was 11.5 beats per minute less after amiodarone (p < 0.02), but pulmonary artery pressure, CVP, SVO, and FAC were not different between groups.

CONCLUSIONS

Intravenous amiodarone decreased heart rate and caused a significant, but transient decrease in arterial pressure in the first 15 minutes after administration. Left ventricular performance was maintained suggesting that selective arterial vasodilation was the primary cause of drug-induced hypotension.

Transient atrial mechanical dysfunction (stunning) after cardioversion of atrial fibrillation and flutter

BACKGROUND

Conversion of atrial fibrillation (AFib) and flutter (AFlt) to sinus rhythm results in a transient mechanical dysfunction of atria (atrial stunning). Methods used as a means of assessing atrial stunning, atrial stunning after conversion of atrial fibrillation/flutter, and the cause, mechanisms, determinants of the extent, and drugs affecting atrial stunning were examined.

METHODS

Studies on the subject, identified through a comprehensive literature search, were thoroughly evaluated.

RESULTS AND CONCLUSIONS

Left atrial (LA) stunning has been reported with all modes of conversion of AFib/AFlt to sinus rhythm. The incidence of LA stunning is 38% to 80%. Spontaneous echocardiographic contrast, LA appendage (LAA) flow velocities and emptying fraction, transmitral inflow velocity of atrial wave (A-wave), time-velocity integral of A-wave, and atrial filling fraction have been used as means of assessing LA stunning. The data on right atrial (RA) stunning are limited, but parallel findings have been reported in the right atrium. Atrial stunning does not develop after the unsuccessful attempts of cardioversion or on delivery of electric current to the heart without AFib/AFlt, and it is a function of the underlying AFib/AFlt manifesting at the restoration of sinus rhythm. Tachycardia-induced atrial myopathy and chronic atrial hibernation are suggested mechanisms. Duration of preceding AFib/AFlt, atrial size, and underlying heart disease are determinants of the extent of atrial stunning. Verapamil, dofetilide, and acetylstrophenathidine have been shown to attenuate or protect from atrial stunning in animal or small human studies. A comprehensive knowledge of atrial stunning would be helpful in selecting the patients for, and the duration of, anticoagulation therapy after cardioversion.

Intravenous amiodarone suppression of electrical storm refractory to chronic oral amiodarone

We report the case of an electrical storm in a cardiac arrest survivor with an ICD, in whom chronic oral amiodarone failed to suppress ventricular arrhythmias, and in whom intravenous amiodarone resulted in stability for 6 weeks prior to successful cardiac transplantation. Intravenous amiodarone can be successful in suppressing life-threatening ventricular arrhythmias, even when chronic oral amiodarone is unsuccessful.

Hemodynamic effects of the class III antiarrhythmic drug, d-sotalol, in patients with congestive heart failure

In contrast to Vaughan Williams class I drugs, class III drugs, such as d-sotalol, may not be negative inotropic. These drugs block potassium ion channels and prolong repolarization, theoretically leading to improved contractility. We investigated the hemodynamic actions of acute intravenous administration of 1.5 mg/kg of d-sotalol in 28 patients with congestive heart failure randomized to receive placebo (n = 10) or active drug (n = 18) in a double-blind study. A Swan-Ganz catheter was placed in all patients > or = 16 hours before drug administration. All hemodynamic variables were assessed at baseline and 30 minutes and 1, 2, 4, 8, and 12 hours after administration of the drug. Electrocardiograms were obtained before and 1, 2, 4, and 12 hours after drug administration. The QT interval increased from 370 +/- 9 to 426 +/- 14 ms at 1 hour, whereas the QTc increased from 433 +/- 5 to 470 +/- 12 ms (both p < 0.001). The increase was still statistically significant at 12 hours. There was no change in the placebo group. Although heart rate decreased in the d-sotalol group (84 +/- 2 to 76 +/- 2 at 1 hour, p < 0.001), there were no changes in blood pressure or right atrial pressure. Cardiac index decreased slightly (2.0 +/- 0.2 to 1.9 +/- 0.1 mm Hg), consistent with the lower heart rate. Pulmonary capillary wedge pressure decreased from 18.9 +/- 2.4 to 17.9 +/- 1.9 mm Hg at 1 hour despite reduced cardiac index. We conclude that in contrast to class I, II, and IV antiarrhythmic drugs, d-sotalol exerts no clinically important acute hemodynamic actions at doses that produce electrophysiologic effects.

Aggravation of postcardioversion atrial dysfunction by sotalol

OBJECTIVES

This study determined the effect of sotalol on atrial function after electrical cardioversion of atrial fibrillation.

BACKGROUND

After electrical cardioversion of atrial fibrillation, the Doppler mitral A wave is often diminished, representing impaired atrial contractile function. Sotalol is an effective atrial antiarrhythmic drug with class III and beta-adrenergic blocking properties. Although the negative inotropic effect of sotalol on the ventricle is minimal in patients with normal ventricular function, it may manifest negative inotropy when ventricular function is impaired. We postulated that after cardioversion, when intrinsic atrial function is impaired, sotalol may have an adverse effect on the atrium.

METHODS

Thirty-seven patients enrolled in a randomized, double-blind study of sotalol for maintenance of sinus rhythm were studied by quantitative Doppler echocardiography within 24 h of electrical cardioversion and, for those still in sinus rhythm, again at 1 month. Doppler variables (E and A wave velocities and integrals) in patients receiving sotalol were compared with those in patients receiving placebo.

RESULTS

After electrical cardioversion, peak A wave velocity and A wave time-velocity integral in the 20 patients receiving placebo were reduced compared with normal values. In the 17 patients receiving sotalol (median dose 320 mg twice daily) these variables were further reduced (mean [+/- SD] peak A wave velocity 19.4 +/- 5.5 vs. 38.4 +/- 14.7 cm/s, p < 0.001 and mean A wave time-velocity integral 1.7 +/- 0.6 vs. 3.4 +/- 1.4 cm, p < 0.001, in sotalol- vs. placebo-treated patients, respectively). Early diastolic filling (E wave variables) did not differ between sotalol- and placebo-treated groups. At 1 month, five sotalol- and six placebo-treated patients remained in sinus rhythm, and A wave variables had increased for the whole group, with a greater increase in sotalol-treated patients.

CONCLUSIONS

After electrical cardioversion, when atrial stunning is prominent, sotalol has a negative atrial inotropic effect. This effect may be temporary, as suggested by resolution at 1 month. Negative inotropic effects of antiarrhythmic drugs on the atrium should be considered in assessing Doppler variables of left ventricular filling.

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.