Effect of low-dose amiodarone on atrial fibrillation or flutter in Japanese patients with heart failure

Heart failure and atrial flutter: a systematic review of current knowledge and practices

While the interplay between heart failure (HF) and atrial fibrillation (AF) has been extensively studied, little is known regarding HF and atrial flutter (AFL), which may be managed differently. We reviewed the incidence, prevalence, and predictors of HF in AFL and vice versa, and the outcomes of treatment of AFL in HF. A systematic literature review of PubMed/Medline and EMBASE yielded 65 studies for inclusion and qualitative synthesis. No study described the incidence or prevalence of AFL in unselected patients with HF. Most cohorts enrolled patients with AF/AFL as interchangeable diagnoses, or highly selected patients with tachycardia‐induced cardiomyopathy. The prevalence of HF in AFL ranged from 6% to 56%. However, the phenotype of HF was never defined by left ventricular ejection fraction (LVEF). No studies reported the predictors, phenotype, and prognostic implications of AFL in HF. There was significant variation in treatments studied, including the proportion that underwent ablation. When systolic dysfunction was tachycardia‐mediated, catheter ablation demonstrated LVEF normalization in up to 88%, as well as reduced cardiovascular mortality. In summary, AFL and HF often coexist but are understudied, with no randomized trial data to inform care. Further research is warranted to define the epidemiology and establish optimal management.

Low-dose Amiodarone Is Safe: A Systematic Review and Meta-analysis

Amiodarone is commonly used for a variety of arrhythmias and, in some parts of the world, is the only available antiarrhythmic drug (AAD). Yet, amiodarone is known to have a wide range of potential side effects, many of which are dose- and duration-dependent. We sought to study the incidence of side effects leading to the discontinuation of low-dose amiodarone, arbitrarily defined as 200 mg/day or less, and very-low-dose amiodarone, defined as 100 mg/day or less. In this study, literature databases were searched through June 2019. Studies that reported the incidence or prevalence of side effects of amiodarone were included. Effect estimates from individual studies were extracted and combined using the random-effects generic inverse variance method of DerSimonian and Laird. A total of 10 observational cohort studies involving 901 patients were included in the analysis. The pooled estimated incidence of overall side effects for low-dose amiodarone was 0.17 [95% confidence interval (CI): 0.12–0.22]. In addition, the pooled estimated incidence of side effects requiring medication discontinuation was 0.06 (95% CI: 0.03–0.11). As compared with 200 mg/day of amiodarone, the pooled estimated incidence of overall side effects was 0.11 (95% CI: 0.04–0.27), while the incidence of side effects requiring medication discontinuation was 0.02 (95% CI: 0.01–0.06) for the dose of 100 mg/day. In conclusion, very-low-dose amiodarone displays a low incidence of significant side effects requiring medication discontinuation.

Efficacy and Safety of Low-Dose Amiodarone Therapy for Tachyarrhythmia in Congenital Heart Disease

Amiodarone (AMD) is a class III anti-arrhythmic drug that is highly effective for tachyarrhythmia treatment. AMD is widely used in adults with congenital heart disease (CHD); however, higher doses of AMD (> 200 mg/day) can cause various non-cardiac side effects. The purpose of this study was to assess the efficacy, safety, and adverse events of low-dose AMD (≤ 200 mg/day) for tachyarrhythmia in patients with CHD. We retrospectively studied 80 patients with CHD and tachyarrhythmia who received oral low-dose AMD (≤ 200 mg/day) from January 2004 to March 2016. Low-dose AMD therapy was used to treat supraventricular tachycardia (SVT) in 51 patients and ventricular tachycardia (VT) in 29 patients. After a mean follow-up of 2.9 years for SVT and 3.2 years for VT, 36% and 65% of the patients with SVT and VT, respectively, were free from a first tachyarrhythmia recurrence for 3 years. The incidence of AMD-induced side effects was 23%, and all these cases consisted of thyroid dysfunction. Low-dose AMD was effective for the treatment of tachyarrhythmia in patients with CHD and had a relatively low incidence of side effects. These findings suggest that low-dose AMD is useful and effective for decreasing the frequency of tachyarrhythmia in patients with CHD and has a low incidence of side effects.

Patterns and predictors of discontinuation of rhythm-control drug therapy in patients with newly diagnosed atrial fibrillation

STUDY OBJECTIVE

To assess patterns and predictors of discontinuation of rhythm-control drug therapy in managed care patients with newly diagnosed atrial fibrillation and the direct medical costs of atrial fibrillation in these patients.

DESIGN

Retrospective cohort study.

DATA SOURCE

PharMetrics Patient-Centric Database.

PATIENTS

A total of 3549 adults with a new diagnosis of atrial fibrillation between April 1, 2002, and March 31, 2006, and who had at least one claim for rhythm-control drug therapy within 6 months of the initial diagnosis.

MEASUREMENTS AND MAIN RESULTS

Discontinuation (defined as a gap in rhythm-control drug therapy coverage [days' supply] > or = 30 days) was assessed after the initiation of rhythm-control therapy. Among the 3549 patients included in the analysis, 2688 (75.7%) discontinued initial rhythm-control therapy in the first 12 months, with a median time to discontinuation of 89 days. Significant predictors of rhythm-control therapy discontinuation included cardiac arrest (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.04-4.83), history of coronary artery bypass graft surgery (OR 2.03, 95% CI 1.02-4.05), valvular heart disease (OR 1.67, 95% CI 1.33-2.09), ischemic heart disease (OR 1.44, 95% CI 1.13-1.82), and severity of illness (Charlson Comorbidity Index score; OR 1.09, 95% CI 1.01-1.17). Over 12 months, 661 (18.6%) of the 3549 patients had a hospital stay and 285 (8.0%) had an emergency department visit that were related to atrial fibrillation. Total annual atrial fibrillation-related costs/patient were $6165: $3872 for inpatient costs, $1503 for outpatient costs, and $790 for pharmacy costs.

CONCLUSION

Initial rhythm-control drug therapy is associated with a high rate of discontinuation, especially early in therapy. Such rates of discontinuation will likely have an impact on the effectiveness of disease management and the quality of care in patients with atrial fibrillation.

Incidence and Predictors of Pulmonary Toxicity in Japanese Patients Receiving Low-Dose Amiodarone

BACKGROUND

Amiodarone-induced pulmonary toxicity (APT) is the most serious side-effect of amiodarone, and its detection and prevention are extremely important. This study was designed to evaluate the incidence and clinical risk factors of APT, and the utility of a pulmonary function test or serum KL-6 assay to predict pulmonary toxicity in Japanese patients receiving low-dose amiodarone.

METHODS AND RESULTS

Five hundred consecutive patients receiving amiodarone were retrospectively evaluated. Mean follow-up period was 48 months and mean maintenance dose was 141 mg daily. Cumulative incidence of APT was 4.2%, 7.8%, and 10.6% at 1, 3, and 5 years, respectively. On multivariate analysis, age at the start (hazard ratio (HR) =1.48, 95% confidence interval (CI) 1.13 to 1.93) was a significant pretreatment risk factor. Age (HR =1.64, 95% CI 1.29 to 2.09), maintenance dose (HR =1.90, 95% CI 1.45 to 2.49) and plasma monodesethylamiodarone concentration (HR =1.30, 95%CI 1.08 to 1.58) were risk factors. Sensitivity and specificity in screening with measurement of percent predicted diffusion capacity of carbon monoxide, > or =15% individual decrease, were 68% and 69%, and for > or =20% individual decrease, were 59% and 74%, whereas those in screening with serum KL-6 assay, > or =500 U/ml, were 25% and 91%, respectively.

CONCLUSIONS

Even at low dose, amiodarone shows substantial pulmonary toxicity. Higher age and higher maintenance dose are risk factors. Further decreasing the maintenance dose of amiodarone should be considered in order to reduce the incidence of pulmonary toxicity, at least in Japanese patients.

Prognostic Predictors of Sinus Rhythm Control by Amiodarone and Electrical Cardioversion in Patients Undergoing Percutaneous Transluminal Mitral Valvuloplasty for Rheumatic Atrial Fibrillation

BACKGROUND

Conversion to sinus rhythm (SR) is rarely attempted in patients with rheumatic atrial fibrillation (AF) because the length of AF duration and the dilation of left atrium (LA) make maintenance of SR difficult. In this study, predictors of the successful maintenance of SR with amiodarone and electrical cardioversion in rheumatic AF patients receiving percutaneous transluminal mitral valvuloplasty (PTMV) were identified.

METHODS AND RESULTS

This study included 23 consecutive patients undergoing PTMV for rheumatic AF (6 men, 53+/-11 years; AF duration 25 +/-24 months; LA diameter 44+/-6 mm; mitral valve area (MV) 1.1+/-0.2 cm(2)). Electrical cardioversion was required for the successful conversion to SR in all patients regardless of whether they had received amiodarone (400 mg/day) 2 months before PTMV (n=8) or 2 months after (n=15). After cardioversion, all patients received amiodarone 200 mg/day. With a follow-up period of 35+/-8 months, 14 patients (61%) remained in SR. A greater reduction in LA size (-4+/-3 mm vs 1+/-1 mm; p=0.004) and an greater increase in MV area (0.8+/-0.4 cm(2) vs 0.5+/-0.2 cm(2); p=0.01) by PTMV, not AF duration, were found to be the independent predictors for patients with successful maintenance of SR as compared with patients with recurrence of AF.

CONCLUSION

In rheumatic AF patients receiving PTMV, the successful maintenance of SR with amiodarone and electrical cardioversion can be predicted by the degree to which LA size is reduced and MV area is increased.

Detection of Amiodarone-Induced Pulmonary Toxicity in Supine and Prone Positions-High-Resolution Computed Tomography Study-

BACKGROUND

The aim of the present study was to describe the effectiveness and feasibility of high-resolution computed tomography (HRCT) in patients in supine and prone positions to detect amiodarone-induced pulmonary toxicity (APT). With regard to the possible differential diagnosis, our second goal was to emphasize the clinical value of HRCT with the patients in supine and prone positions compared with other paraclinical tests.

METHODS AND RESULTS

Thoracic HRCT taken in both positions for 23 patients who were administrated amiodarone were prospectively evaluated in the current study. High-resolution computed tomography scans obtained with the patient in a prone position were helpful in differentiating dependent opacity from lung disease in 11 out of 23 patients. In another 4 patients, HRCT scans obtained with the patient in a prone position were useful in confirming the presence of subtle ground-glass opacities, considered as APT. Combination of HRCT in supine and prone positions provided a more reproducible method for evaluating the global extent of APT than other paraclinical tests.

CONCLUSIONS

High-resolution computed tomography used in prone positions as well as a supine position could be an effective technique for reducing false-positive results in detection of APT and preventing the clinically serious pulmonary adverse effects by amiodanone.