Determinants and outcome of amiodarone-associated thyroid dysfunction.

OBJECTIVE: Amiodarone is frequently associated with thyroid dysfunction. Identifying predictors for amiodarone-associated thyroid dysfunction and assessing treatment outcome may aid clinicians in daily practice. METHODS: We included 303 consecutive patients with amiodarone therapy for cardiac arrhythmias (260 with atrial fibrillation and 43 with ventricular arrhythmias). Thyroid function tests were performed every 6 months. RESULTS: Mean age was 63 ± 12 years and 66% was male. After median follow-up of 3·3 (0·1-24) years, 23 (8%) patients developed amiodarone-associated thyrotoxicosis (incidence rate 1·9 per 100 person years) and 18 (6%) hypothyroidism (incidence rate 1·1 per 100 person years). The only predictor for amiodarone-associated thyrotoxicosis was age <62 years [HR = 2·4 (95% CI 1·0-5·7), P = 0·05]. Predictors for amiodarone-associated hypothyroidism were thyroid stimulating hormone >1·4 mU/l at baseline [HR = 5·1 (95% CI 1·1-22·4), P = 0·03], left ventricular ejection fraction <45% [HR = 3·8 (95% CI 1·1-13·3), P = 0·04] and diabetes mellitus at baseline [HR = 3·3 (95% CI 1·1-10·3), P = 0·04]. Gender was not a predictor for amiodarone-associated thyroid dysfunction. Five out of 12 (42%) patients with thyrotoxicosis exhibited spontaneous normalization of thyroid function on continuation of amiodarone therapy. Mean time to normalization in the total group was 6·2 ± 3·3 months, with no difference between continuing or discontinuing amiodarone (6·6 ± 3·8 vs 5·8 ± 2·8 months, P = 0·5). CONCLUSIONS: During median follow-up of 3·3 years, the incidence of amiodarone-associated thyrotoxicosis was higher compared to hypothyroidism. Only general predictors for amiodarone-associated thyroid dysfunction were observed. Discontinuation of amiodarone did not influence treatment outcome.

Effect of continuous versus episodic amiodarone treatment on quality of life in persistent atrial fibrillation.

AIMS: Amiodarone is associated with significant adverse effects. We hypothesized that episodic amiodarone treatment would be associated with better quality of life (QoL) compared with continuous treatment in the prevention of recurrent atrial fibrillation (AF). METHODS AND RESULTS: Quality of life was assessed in 158 patients from the Continuous vs. Episodic Prophylactic Treatment with Amiodarone for the Prevention of AF (CONVERT) study, using the Short Form (SF)-36 health survey and University of Toronto AF Severity Scale (AF severity scale) questionnaires at baseline and 1 year. The episodic group received amiodarone 1 month peri-cardioversion, the continuous group continued amiodarone. Patients were assessed for major adverse events and maintenance of sinus rhythm during follow-up (i.e. no AF recurrences at every follow-up visit). Quality of life (assessed by SF-36 and AF severity scale) was comparable between both treatment groups at baseline and 12 months, with similar incidence rates of major adverse events. Fewer patients in the episodic group had maintenance of sinus rhythm during follow-up [27 (36%) vs. 49 (59%), P = 0.004]. In the episodic group, maintenance of sinus rhythm was associated with a significant improvement on four SF-36 subscales and AF severity scale at 12 months. In contrast, in the continuous group no significant differences in QoL were seen between patients with continued maintenance of sinus rhythm compared with those with AF recurrence at the end of follow-up. CONCLUSION: Quality of life was comparable in the episodic and continuous treated group after 12 months of follow-up. Continued maintenance of sinus rhythm was associated with an improvement in QoL in the episodic but not the continuous treated group.

Feasibility and outcome of epicardial pulmonary vein isolation for lone atrial fibrillation using minimal invasive surgery and high intensity focused ultrasound.

AIMS: Transvenous pulmonary vein isolation (PVI) is the cornerstone of non-pharmacological rhythm control therapy in symptomatic atrial fibrillation (AF). Success and complications rates are, however, still not optimal. New techniques and energy sources are therefore being developed. METHODS AND RESULTS: Fifteen patients with lone AF refractory for antiarrhythmic drugs (AADs) underwent PVI by minimal invasive epicardial off-pump monolateral right-sided video-assisted thoracic surgery (VATS) using the UltraCinch with high-intensity focused ultrasound (HIFU). Primary endpoint was successful ablation defined as absence of AF or atrial flutter/tachycardia after 6 months assessed by complaints, 12 lead electrocardiogram, and 96 h Holter monitoring. Secondary endpoints were ablation success at the end of follow-up irrespective of AADs use or re-ablation and complications related to the procedure. Mean age was 47 +/- 10 years and 14 (93%) were male. Eleven (73%) had paroxysmal, and 4 (27%) patients had persistent AF. Median AF history was 5 (1-12) years. At 6 months, six (40%) patients had sinus rhythm after one epicardial PVI (four on AADs). After 1.3 +/- 0.6 years, four (27%) patients had sinus rhythm after one epicardial PVI (two on AADs) and in six (40%) patients endocardial radiofrequency re-ablation was performed, which was successful in three patients (20%). Two patients (13%) were planned for re-ablation. Three others (20%) refused re-ablation. Two major complications occurred (one late tamponade and one bleeding during surgery, necessitating sternotomy). CONCLUSION: Epicardial PVI using monolateral right-sided VATS with the UltraCinch delivering HIFU is feasible, but is associated with substantial complications. Furthermore, the success rate was low. More research is therefore warranted to assess optimal ablation techniques and energy sources to perform PVI.

Continuous vs episodic prophylactic treatment with amiodarone for the prevention of atrial fibrillation: a randomized trial.

CONTEXT: Amiodarone effectively suppresses atrial fibrillation but causes many adverse events. OBJECTIVE: To compare major events in patients randomized to receive episodic amiodarone treatment with those who received continuous amiodarone treatment while still aiming to prevent atrial fibrillation. DESIGN, SETTING, AND PARTICIPANTS: A randomized trial of 209 ambulatory patients with recurrent symptomatic persistent atrial fibrillation, conducted from December 2002 through March 2007 at 7 Dutch medical centers. INTERVENTION: Patients were randomly assigned to receive either episodic or continuous amiodarone treatment after electrical cardioversion following amiodarone loading. Episodic amiodarone treatment was discontinued after a month of sinus rhythm and reinitiated if atrial fibrillation relapsed (1 month peri-electrical cardioversion). In the continuous treatment group amiodarone was maintained throughout. MAIN OUTCOME MEASURES: The primary end point was a composite of amiodarone and underlying heart disease-related major events. The secondary end points were all-cause mortality and cardiovascular hospitalizations. RESULTS: After a median follow-up of 2.1 years (range, 0.4-2.5 years), 51 (48%) of those receiving episodic treatment vs 64 (62%) receiving continuous treatment had sinus rhythm (P = .05). There were 85 atrial fibrillation recurrences (80%) among the episodic treatment group vs 56 (54%) in the continuous treatment group (P < .001). No significant difference existed in the incidence of the primary composite end point between each group (37 [35%] episodic vs 34 [33%] continuous; incidence rate difference, 0.2; 95% confidence interval [CI], -10.2 to 10.6). However, there were nonstatistically significant differences in the incidence of amiodarone-related major events (20 [19%] episodic vs 25 [24%] continuous; incidence rate difference, -2.0; 95% CI, -8.7 to 4.6) and underlying heart disease-related major events (17 [16%] episodic vs 9 [9%] continuous; incidence rate difference, 3.6; 95% CI, -1.6 to 8.7). All-cause mortality and cardiovascular hospitalizations were higher among those receiving episodic treatment (56 [53%] vs 35 [34%], P = .02). CONCLUSIONS: In this study population, there was no difference in the composite of amiodarone and cardiac major adverse events between groups. However, patients receiving episodic treatment had a significantly increased rate of atrial fibrillation recurrence and a significantly higher rate of all-cause mortality and cardiovascular hospitalizations. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00392431.