Efficacy and safety of antiarrhythmic therapy in dogs with naturally acquired tachyarrhythmias treated with amiodarone or sotalol: a retrospective analysis of 64 cases.

INTRODUCTION/OBJECTIVE: Studies on the use of amiodarone or sotalol are limited in dogs. Therefore, this study aimed to provide data on the efficacy and safety of these drugs in dogs with ventricular tachyarrhythmia (VT) and/or supraventricular tachyarrhythmia (SvT). ANIMALS, MATERIALS, AND METHODS: Dogs with VT and/or SvT treated with amiodarone or sotalol as a first-line therapy were retrospectively evaluated. Signalment, clinical, diagnostic, therapeutic, and outcome data were retrieved. For VT, efficacy was demonstrated through a decrease of the Lown-Wolf grade to less than five or a reduction of at least 85% in the number of ventricular premature complexes observed on Holter monitoring. For SvT, efficacy was represented by cardioversion or a reduction in the mean heart rate on Holter monitoring ≤140 beats/min. Treatment-related side effects (TRSEs) were classified as clinically relevant and irrelevant. Statistical analysis was performed to compare data before and after antiarrhythmic prescription. RESULTS: Sixty-four dogs were included. Amiodarone and sotalol were efficacious in treating both VT (85.7% and 90.0% of cases, respectively) and SvT (75% and 71.4% of cases, respectively). No significant differences were found when comparing their efficacy rates in dogs with VT and SvT (P=0.531 and 0.483, respectively). Clinically relevant TRSEs were rare with both amiodarone and sotalol (8.3% and 5% of cases, respectively), while clinically irrelevant TRSEs occurred more frequently with amiodarone (29.2%) than with sotalol (10%). DISCUSSION: In dogs with tachyarrhythmias, amiodarone and sotalol are generally efficacious and safe, as clinically relevant TRSEs seem rare. CONCLUSIONS: This study provides novel data on the effects of amiodarone and sotalol in dogs with tachyarrhythmias.

A randomized clinical trial of catheter ablation and antiarrhythmic drug therapy for suppression of ventricular tachycardia in ischemic cardiomyopathy: The VANISH2 trial.

BACKGROUND: Recurrent ventricular tachycardia (VT) in patients with prior myocardial infarction is associated with adverse quality of life and clinical outcomes, despite the presence of implanted defibrillators (ICDs). Suppression of recurrent VT can be accomplished with antiarrhythmic drug therapy or catheter ablation. The Ventricular Tachycardia Antiarrhythmics or Ablation In Structural Heart Disease 2 (VANISH2) trial is designed to determine whether ablation is superior to antiarrhythmic drug therapy as first line therapy for patients with ischemic cardiomyopathy and VT. METHODS: The VANISH2 trial enrolls patients with prior myocardial infarction and VT (with one of: ≥1 ICD shock; ≥3 episodes treated with antitachycardia pacing (ATP) and symptoms; ≥5 episodes treated with ATP regardless of symptoms; ≥3 episodes within 24 hours; or sustained VT treated with electrical cardioversion or pharmacologic conversion). Enrolled patients are classified as either sotalol-eligible, or amiodarone-eligible, and then are randomized to either catheter ablation or to that antiarrhythmic drug therapy, with randomization stratified by drug-eligibility group. Drug therapy, catheter ablation procedures and ICD programming are standardized. All patients will be followed until two years after randomization. The primary endpoint is a composite of mortality at any time, appropriate ICD shock after 14 days, VT storm after 14 days, and treated sustained VT below detection of the ICD after 14 days. The outcomes will be analyzed according to the intention-to-treat principle using survival analysis techniques RESULTS: The results of the VANISH2 trial are intended to provide data to support clinical decisions on how to suppress VT for patients with prior myocardial infarction. CLINICALTRIALS: gov registration NCT02830360.

Chapter 5: Guideline Recommendations: Which AAD and for Whom?

This chapter discusses the American College of Cardiology/American Heart Association/ Heart Rhythm Society (AHA/ACC/HRS) and European Society of Cardiology (ESC) guidelines for atrial fibrillation (AF) management with particular focus on antiarrhythmic drug (AAD) selection and the identification of individuals for whom AAD treatment is appropriate. Discussion includes AAD indications, when to start an AAD, choosing among AADs, how to minimize proarrhythmic risk, how to determine efficacy, and the use of adjuvant interventions. The indications for all AADs are based on safety; the current AHA/ACC/HRS and ESC guidelines state that the choice of AAD is based on the presence or absence of structural heart disease (SHD), coronary artery disease, or heart failure (HF), with further recommendations in the ESC guidelines based on HF type (e.g., HF with reduced ejection fraction [HFrEF] versus HF with preserved ejection fraction [HFpEF]). The chapter closes with a discussion of the lack of consistent use of guideline-directed care, with a review of supportive data from the recently reported AIM-AF survey-a multinational survey on AF management that involved both cardiologists and electrophysiologists. In AIM-AF, inappropriate drug selection in terms of suitable candidate selection and drug choice occurred with all types of drugs and in most patient groups. Most notable was the overuse of amiodarone in patients without SHD, and the widespread use of sotalol, including its use in patients with HFrEF. Chapter 5 is summarized as follows.

Mortality and ventricular arrhythmias in patients on d,l-sotalol for rhythm control of atrial fibrillation: A nationwide cohort study.

BACKGROUND: Use of d,l-sotalol for rhythm control in patients with atrial fibrillation (AF) has raised safety concerns. Previous randomized studies are few and not designed for mortality outcome. OBJECTIVE: The purpose of this study was to compare the incidences of mortality and ventricular arrhythmias in AF patients treated with d,l-sotalol for rhythm control vs matched control patients treated with cardioselective beta-blockers. METHODS: This population-based cohort study included AF patients from the Swedish National Patient Registry (2006-2017) who underwent rhythm control after a second cardioversion. Incidence rates (IRs) and adjusted hazard ratios (aHRs) for mortality and a composite endpoint of cardiac arrest/death and ventricular arrhythmias were calculated for the overall cohort and a 1:1 propensity score matched cohort of d,l-sotalol vs beta-blocker treatment. RESULTS: Among patient treated with d,l-sotalol (n = 4987) and beta-blocker (n = 27,078) (mean follow-up 458 days), all-cause mortality was lower in patients treated with d,l-sotalol: IR 1.21; 95% confidence interval 0.95-1.52 vs 2.42 (2.26-2.60) deaths per 100 patient-years; aHR 0.66 (0.52-0.83). The difference in mortality persisted in the propensity score matched comparison (n = 4953 in each group): aHR 0.63 (0.48-0.86). No differences were observed in the composite outcome: IR in propensity cohorts 2.13 (1.78-2.52) vs 2.07 (1.73-2.53) events per 100 years; aHR 1.01 (0.78-1.29). CONCLUSION: There was no excess mortality with d,l-sotalol compared with cardioselective beta-blockers in patients undergoing rhythm control treatment for AF after a second cardioversion. Our results indicate that the risk associated with d,l-sotalol treatment for AF can be mitigated by careful patient selection and strict adherence to follow-up protocols.

Association of sotalol versus atenolol therapy with survival in dogs with severe subaortic stenosis.

INTRODUCTION/OBJECTIVES: Dogs with severe subaortic stenosis (SAS) are at risk of dying suddenly from fatal arrhythmias. Survival is not improved when treated with pure beta-adrenergic receptor (ß)-blockers; however, the effect of other antiarrhythmic drugs on survival is unknown. Sotalol is both a ß-blocker and a class III antiarrhythmic drug; the combination of these differing mechanisms may provide benefit to dogs with severe SAS. The primary objective of this study was to compare survival in dogs with severe SAS that were treated with either sotalol or atenolol. The secondary objective was to evaluate the effect of pressure gradient (PG), age, breed, and aortic regurgitation on survival. ANIMALS: Forty-three client-owned dogs. MATERIALS AND METHODS: Retrospective cohort study. Medical records of dogs diagnosed with severe SAS (PG ≥ 80 mmHg) between 2003 and 2020 were reviewed. RESULTS: No statistical difference was identified in survival time between dogs treated with sotalol (n=14) and those treated with atenolol (n=29) when evaluating all-cause mortality (p=0.172) or cardiac-related mortality (p=0.157). Of the dogs that died suddenly, survival time was significantly shorter in dogs treated with sotalol compared to those treated with atenolol (p=0.046). Multivariable analysis showed that PG (p=0.002) and treatment with sotalol (p=0.050) negatively influenced survival in the dogs that died suddenly. CONCLUSIONS: Sotalol did not have a significant effect on survival overall but may increase the risk of sudden death in dogs with severe SAS compared to atenolol.

Clinical and economic outcomes associated with use of anti-arrhythmic drugs versus ablation in atrial fibrillation.

Aim: To evaluate the clinical and economic impact of antiarrhythmic drugs (AADs) compared with ablation both as individual treatments and as combination therapy without/with considering the order of treatment among patients with atrial fibrillation (AFib). Materials & methods: A budget impact model over a one-year time horizon was developed to assess the economic impact of AADs (amiodarone, dofetilide, dronedarone, flecainide, propafenone, sotalol, and as a group) versus ablation across three scenarios: direct comparisons of individual treatments, non-temporal combinations, and temporal combinations. The economic analysis was conducted in accordance with CHEERS guidance as per current model objectives. Results are reported as costs per patient per year (PPPY). The impact of individual parameters was evaluated using one-way sensitivity analysis (OWSA). Results: In direct comparisons, ablation had the highest annual medication/procedure cost ($29,432), followed by dofetilide ($7661), dronedarone ($6451), sotalol ($4552), propafenone ($3044), flecainide ($2563), and amiodarone ($2538). Flecainide had the highest costs for long-term clinical outcomes ($22,964), followed by dofetilide ($17,462), sotalol ($15,030), amiodarone ($12,450), dronedarone ($10,424), propafenone ($7678) and ablation ($9948). In the non-temporal scenario, total costs incurred for AADs (group) + ablation ($17,278) were lower compared with ablation alone ($39,380). In the temporal scenario, AADs (group) before ablation resulted in PPPY cost savings of ($22,858) compared with AADs (group) after ablation ($19,958). Key factors in OWSA were ablation costs, the proportion of patients having reablation, and withdrawal due to adverse events. Conclusion: Utilization of AADs as individual treatment or in combination with ablation demonstrated comparable clinical benefits along with costs savings in patients with AFib.

Risk for Bleeding-Related Hospitalizations During Use of Amiodarone With Apixaban or Rivaroxaban in Patients With Atrial Fibrillation : A Retrospective Cohort Study.

BACKGROUND: Amiodarone, the most effective antiarrhythmic drug in atrial fibrillation, inhibits apixaban and rivaroxaban elimination, thus possibly increasing anticoagulant-related risk for bleeding. OBJECTIVE: For patients receiving apixaban or rivaroxaban, to compare risk for bleeding-related hospitalizations during treatment with amiodarone versus flecainide or sotalol, antiarrhythmic drugs that do not inhibit these anticoagulants' elimination. DESIGN: Retrospective cohort study. SETTING: U.S. Medicare beneficiaries aged 65 years or older. PATIENTS: Patients with atrial fibrillation began anticoagulant use between 1 January 2012 and 30 November 2018 and subsequently initiated treatment with study antiarrhythmic drugs. MEASUREMENTS: Time to event for bleeding-related hospitalizations (primary outcome) and ischemic stroke, systemic embolism, and death with or without recent (past 30 days) evidence of bleeding (secondary outcomes), adjusted with propensity score overlap weighting. RESULTS: There were 91 590 patients (mean age, 76.3 years; 52.5% female) initiating use of study anticoagulants and antiarrhythmic drugs, 54 977 with amiodarone and 36 613 with flecainide or sotalol. Risk for bleeding-related hospitalizations increased with amiodarone use (rate difference [RD], 17.5 events [95% CI, 12.0 to 23.0 events] per 1000 person-years; hazard ratio [HR], 1.44 [CI, 1.27 to 1.63]). Incidence of ischemic stroke or systemic embolism did not increase (RD, -2.1 events [CI, -4.7 to 0.4 events] per 1000 person-years; HR, 0.80 [CI, 0.62 to 1.03]). The risk for death with recent evidence of bleeding (RD, 9.1 events [CI, 5.8 to 12.3 events] per 1000 person-years; HR, 1.66 [CI, 1.35 to 2.03]) was greater than that for other deaths (RD, 5.6 events [CI, 0.5 to 10.6 events] per 1000 person-years; HR, 1.15 [CI, 1.00 to 1.31]) (HR comparison: P = 0.003). The increased incidence of bleeding-related hospitalizations for rivaroxaban (RD, 28.0 events [CI, 18.4 to 37.6 events] per 1000 person-years) was greater than that for apixaban (RD, 9.1 events [CI, 2.8 to 15.3 events] per 1000 person-years) (P = 0.001). LIMITATION: Possible residual confounding. CONCLUSION: In this retrospective cohort study, patients aged 65 years or older with atrial fibrillation treated with amiodarone during apixaban or rivaroxaban use had greater risk for bleeding-related hospitalizations than those treated with flecainide or sotalol. PRIMARY FUNDING SOURCE: National Heart, Lung, and Blood Institute.

The Feasibility and Safety of Flecainide Use Among Patients With Varying Degrees of Coronary Disease.

BACKGROUND: Class IC antiarrhythmic agents are effective for treating atrial tachyarrhythmias, but their use is restricted in patients with coronary artery disease (CAD). Data on the safety of the use of IC agents in patients with CAD in the absence of recent acute coronary syndromes are lacking. OBJECTIVES: This study sought to evaluate the safety and feasibility of treatment with IC agents in patients with varying degrees of CAD in a large serial, real-world cohort. METHODS: We retrospectively identified all patients at our institution from January 2005 to February 2021 on a IC agent (n = 3,445) and those on sotalol or dofetilide (n = 2,216) as controls, excluding those with a prior history of ventricular tachycardia, implantable cardioverter-defibrillator placement, or nonrevascularized myocardial infarction. Baseline clinical characteristics included degree of CAD (categorized as none, nonobstructive, or obstructive), other comorbid illness, and medication use. Clinical outcomes, including survival, were ascertained. We performed Cox regression analysis to evaluate the effect of IC use on event-free survival across varying degrees of CAD. RESULTS: After adjustment for baseline characteristics, there was an independent association between IC use and improved mortality. However, there was an interaction between IC use and degree of CAD (compared to sotalol) demonstrating poorer event-free survival among those with obstructive coronary disease (HR: 3.80; 95% CI: 1.67-8.67; P = 0.002). CONCLUSIONS: Among select patients with nonobstructive CAD and without a history of ventricular tachycardia, IC agents are not associated with increased mortality. Therefore, these agents may be an option for some patients in whom they are frequently restricted. Further prospective studies are warranted.

A value-based budget impact model for dronedarone compared with other rhythm control strategies.

Aim: The budgetary consequences of increasing dronedarone utilization for treatment of atrial fibrillation were evaluated from a US payer perspective. Materials & methods: A budget impact model over a 5-year time horizon was developed, including drug-related costs and risks for long-term clinical outcomes (LTCOs). Treatments included antiarrhythmic drugs (AADs; dronedarone, amiodarone, sotalol, propafenone, dofetilide, flecainide), rate control medications, and ablation. Direct comparisons and temporal and non-temporal combination scenarios investigating treatment order were analyzed as costs per patient per month (PPPM). Results: By projected year 5, costs PPPM for dronedarone versus other AADs decreased by $37.69 due to fewer LTCOs, treatment with dronedarone versus ablation or rate control medications + ablation resulted in cost savings ($359.94 and $370.54, respectively), and AADs placed before ablation decreased PPPM costs by $242 compared with ablation before AADs. Conclusion Increased dronedarone utilization demonstrated incremental cost reductions over time.

Transplacental Therapeutic Drug Monitoring in Pregnant Women with Fetal Tachyarrhythmia Using HPLC-MS/MS.

Fetal arrhythmia develops in 0.1-5% of pregnancies and may cause fetal heart failure and fetal hydrops, thus increasing fetal, neonatal, and infant mortality. The timely initiation of transplacental antiarrhythmic therapy (ART) promotes the conversion of fetal tachycardia to sinus rhythm and the regression of the concomitant non-immune fetal hydrops. The optimal treatment regimen search for the fetus with tachyarrhythmia is still of high value. Polymorphisms of these genes determines the individual features of the drug pharmacokinetics. The aim of this study was to study the pharmacokinetics of transplacental anti-arrhythmic drugs in the fetal therapy of arrhythmias using HPLC-MS/MS, as well as to assess the effect of the multidrug-resistance gene ABCB1 3435C > T polymorphism on the efficacy and maternal/fetal complications of digoxin treatment. The predisposition to a decrease in the bioavailability of the digoxin in patients with a homozygous variant of the CC polymorphism showed a probable association with the development of ART side effects. A pronounced decrease in heart rate in women with the 3435TT allele of the ABCB1 gene was found. The homozygous TT variant in the fetus showed a probable association with an earlier response to ART and rhythm disruptions on the digoxin dosage reduction. high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) methods for digoxin and sotalol therapeutic drug monitoring in blood plasma, amniotic fluid, and urine were developed. The digoxin and sotalol concentrations were determined in the plasma blood, urine, and amniotic fluid of 30 pregnant women at four time points (from the beginning of the transplacental antiarrhythmic therapy to delivery) and the plasma cord blood of 30 newborns. A high degree of correlation between the level of digoxin and sotalol in maternal and cord blood was found. The ratio of digoxin and sotalol in cord blood to maternal blood was 0.35 (0.27 and 0.46) and 1.0 (0.97 and 1.07), accordingly. The digoxin concentration in the blood of the fetus at the moment of the first rhythm recovery episode, 0.58 (0.46, 0.8) ng/mL, was below the therapeutic interval. This confirms the almost complete transplacental transfer of sotalol and the significant limitation in the case of digoxin. Previously, ABCB1/P-glycoprotein had been shown to limit fetal exposure to drugs. Further studies (including multicenter ones) to clarify the genetic features of the transplacental pharmacokinetics of antiarrhythmic drugs are needed.

The Future of Antiarrhythmic Drug Therapy: Will Drugs Be Entirely Replaced by Procedures?

Antiarrhythmic drug therapy has traditionally been centered in modulating the generation or propagation of the cardiac action potential by drugs acting on membrane ion channels. The history of this approach has been disappointing, marked by catastrophic failures such as those of sodium channel blockers or sotalol to treat ventricular arrhythmias in the setting of structural cardiomyopathies, which led to increased mortality, and by modest clinical efficacy in paroxysmal atrial fibrillation. As catheter ablation has become an established effective therapy for most tachyarrhythmias, membrane-acting drugs have been relegated to symptomatic control of benign arrhythmias in normal hearts or to adjunctive treatments of ventricular tachycardia (combined with catheter ablation and cardiac defibrillators) in the setting of cardiomyopathies. Novel targets of biological modulation of arrhythmia substrates beyond the membrane potential appear promising and could represent future opportunities for arrhythmia pharmacotherapy.

Evaluation of a program for outpatient sotalol loading with physician and pharmacist monitoring.

BACKGROUND: Dose-dependent QT prolongation with class III antiarrhythmics mandates close monitoring often in an inpatient setting. Outpatient sotalol loading monitor provides an alternative to patients that is cost effective and allows preservation of hospital resources. OBJECTIVES: The objectives for this study include assessing adverse events, assessing patient adherence to monitoring and follow-up, comparing hospital cost and resource utilization, and evaluating patient satisfaction with outpatient sotalol loading program. PRACTICE DESCRIPTION: One pharmacist in the antiarrhythmic clinic at OhioHealth Riverside Methodist Hospital completed 3-day outpatient sotalol loads under a collaborative practice agreement. Clinic services included pharmacotherapy management, medication counseling, and device education. PRACTICE INNOVATION: This service allows pharmacists to provide direct patient monitoring to provide increased patient access. EVALUATION METHODS: All data were collected via the electronic medical record, patient journal documentation, and a patient satisfaction survey. RESULTS: A total of 12 patients completed outpatient sotalol loading; 10 patients started in normal sinus rhythm, and 1 patient was cardioverted during the load. No patients experienced any adverse events during the loading phase. One patient completed a successful dose increase during the loading phase. All 12 patients attended the first visit, completed baseline laboratory tests, and uploaded electrocardiograms for all 3 days. A total of 11 patients were evaluated as a cost comparison for inpatient sotalol loading. On average, outpatient loading cost was $886.30, in comparison with $7571.76 for inpatient loading (P < 0.001). A total of 10 patients completed the satisfaction survey, and all of the patients preferred to complete this in the outpatient setting. CONCLUSION: In this study, 12 patients safely completed outpatient sotalol loading, with an overall decrease in the cost of their care in comparison with inpatient loading. This study showed that pharmacists can serve as physician extenders to continue to provide high-quality and safe care to patients in the antiarrhythmic space.

Echocardiographic and electrocardiographic effects of atenolol versus sotalol in dogs with severe subaortic stenosis.

BACKGROUND: Subaortic stenosis (SAS) is a commonly diagnosed canine congenital cardiac defect, with severe forms of carrying a poor long-term prognosis. To date, an effective treatment strategy has not been developed in veterinary medicine. This study sought to determine if sotalol, a class III antiarrhythmic, may have salient echocardiographic and antiarrhythmic benefits for medical management for dogs affected with severe SAS. METHODS: Ten dogs diagnosed with severe SAS were enrolled in this prospective, double-blinded, crossover study. Dogs underwent physical exam, non-invasive blood pressure measurement, electrocardiography, echocardiography, and 24-h Holter monitoring. Diagnostics were repeated 12-16 days following randomization to oral atenolol (0.5-1 mg/kg) or sotalol (1-2 mg/kg) twice daily. After a medication taper and four-day washout, dogs were crossed-over to the alternate study medication, and the diagnostics were repeated in 12-16 days. Linear and multinomial mixed models were developed to evaluate the effects of treatments on echocardiographic and electrocardiographic variables. RESULTS: Indices of left ventricular systolic function were reduced based on the volumetric assessment when dogs received sotalol compared to atenolol. No difference was noted between groups in left ventricular systolic function based on the linear assessment. No difference was observed in the reduction in left ventricular outflow tract velocity. No significant differences were observed between treatment groups for any variable on 24-h Holter monitor. CONCLUSIONS: Sotalol may be a viable therapy to consider for dogs with severe SAS based on this pilot study. A larger, prospective study is necessary to investigate further.

Management of acute atrial fibrillation in the intensive care unit: An international survey.

BACKGROUND: Atrial fibrillation (AF) is common in intensive care unit (ICU) patients and is associated with poor outcomes. Different management strategies exist, but the evidence is limited and derived from non-ICU patients. This international survey of ICU doctors evaluated the preferred management of acute AF in ICU patients. METHOD: We conducted an international online survey of ICU doctors with 27 questions about the preferred management of acute AF in the ICU, including antiarrhythmic therapy in hemodynamically stable and unstable patients and use of anticoagulant therapy. RESULTS: A total of 910 respondents from 70 ICUs in 14 countries participated in the survey with 24%-100% of doctors from sites responding. Most ICUs (80%) did not have a local guideline for the management of acute AF. The preferred first-line strategy for the management of hemodynamically stable patients with acute AF was observation (95% of respondents), rhythm control (3%), or rate control (2%). For hemodynamically unstable patients, the preferred strategy was observation (48%), rhythm control (48%), or rate control (4%). Overall, preferred antiarrhythmic interventions included amiodarone, direct current cardioversion, beta-blockers other than sotalol, and magnesium in that order. A total of 67% preferred using anticoagulant therapy in ICU patients with AF, among whom 61% preferred therapeutic dose anticoagulants and 39% prophylactic dose anticoagulants. CONCLUSION: This international survey indicated considerable practice variation among ICU doctors in the clinical management of acute AF, including the overall management strategies and the use of antiarrhythmic interventions and anticoagulants.

Sotalol versus amiodarone for postoperative junctional tachycardia after congenital heart surgery.

BACKGROUND: Junctional ectopic tachycardia (JET) is a common arrhythmia after congenital heart disease surgery. There is variability in the choice of antiarrhythmic therapy, with amiodarone used commonly. Intravenous (IV) sotalol is a newly available agent that may be useful for JET. OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of IV sotalol for postoperative JET and compare outcomes with IV amiodarone. METHODS: This is a retrospective single-center study of all patients who received IV sotalol or IV amiodarone for postoperative JET at Texas Children's Hospital from December 15, 2015, to December 15, 2020. Data included antiarrhythmic efficacy, hemodynamics, and adverse effects. Successful JET control was defined as a decrease in JET rate to <170 beats/min (or decrease by >20%), or conversion to sinus rhythm, with persistent control over 24 hours without requiring alternative antiarrhythmics or mechanical support. RESULTS: A total of 32 patients (median age 71 days; interquartile range 17-221 days) received IV amiodarone (n = 20 [62%]) or IV sotalol (n = 12 [38%]) for postoperative JET. Amiodarone was successful in treating JET in 75% of cases; sotalol was successful in 83%. The JET rate decreased faster over the first 90 minutes after a sotalol bolus (25 beats/min per hour) than after an amiodarone bolus (8 beats/min per hour) (P < .01); no heart rate difference was seen after 24 hours. Amiodarone infusion was discontinued early because of hypotension/bradycardia in 2 patients; this was not required in any patients receiving sotalol. CONCLUSION: For children with postoperative JET, both IV sotalol and amiodarone are safe and efficacious. IV sotalol may lead to a faster improvement in heart rate.

COMBINED PHARMACOLOGICAL THERAPY INCLUDING SEVERAL ANTIARRHYTHMIC AGENTS FOR TREATMENT OF DIFFERENT DISORDERS OF CARDIAC RHYTHM.

Combined therapy using several antiarrhythmic agents can be useful for treatment of different disorders of cardiac rhythm, including their hazardous and stable forms. It is especially required in case of insufficient efficacy after using one antiarrhythmic agent. As a combined therapy one can use the administration of several preparations e.g. 1) preparations of IA subclass and ß-blocker adrenergic agents; 2) antiarrhythmic agents of I class and calcium channel blocker agents (verapamil and dilthiazem); 3) III class (amiodarone or sotalol) together with ß-blocker drugs; 4) antiarrhythmic agents of III class and calcium antagonists; 5) antiarrhythmic agents of I and III classes. The latter combination has especially strong effect for treatment of arrhythmias caused by re-entry mechanism with or without a short excitability period. Antiarrhythmic agents of II class (ß-blocker drugs) and III classes (amiodarone or sotalol) cause reduction of development risk of arrhythmias with trigger mechanism, including bidirectional spindle-shaped ventricular (torsade de pointes) tachycardia. Thus, combinations including preparations of II class together with III class and simultaneous using of antiarrhythmic agents of I and III classes should be administered to prevent hazardous potentially lethal arrhythmias. The authors of this article have developed a new method of combined therapy of paroxysmal supraventricular tachyarrhythmias in patients with ischemic heart disease, including the use of allapinin and cardiac glycosides. The author's certificate of invention was obtained for this method. The efficacy of this combined therapy for suppression of supraventricular paroxysmal tachyarrhythmias was analyzed compared to treatment with allapinin alone. It was proved that combined therapy has bigger effectiveness in comparison with therapy with help allapinin only. It is forbidden to use of such combinations of antiarrhythmic agents: ß-adrenergic blocker agent + verapamil; ß-adrenergic blocker agent + dilthizem; propafenone + verapamil; propafenone + dilthizem; propafenone + ß-adrenergic blocker agent. After administration of such combined therapy, it is possible the occurrence medicinal (toxic) disfunction of sinus node. The administration of propafenone together with ß-adrenergic blocker agent is impossible because propafenone has properties of ß-blocker preparation. It is connected with similar chemical structure of propafenone and non-selective ß-blocker agent propranolol.