Short-term amiodarone treatment for atrial fibrillation after catheter ablation induces a transient thyroid dysfunction: Results from the placebo-controlled, randomized AMIO-CAT trial.

BACKGROUND: Amiodarone is known to affect the thyroid, but little is known about thyroid recovery after short-term amiodarone treatment. OBJECTIVES: We aimed to evaluate the impact of 8weeks of amiodarone treatment on thyroid function in patients with atrial fibrillation (AF) undergoing catheter ablation in a randomised, double-blind clinical trial. METHODS: 212 patients referred for AF ablation at two centres were randomized to 8weeks of oral amiodarone or placebo. Thyroid function tests (TSH, thyroid stimulating hormone; T4, thyroxine; T3, triiodothyronine; fT4, free T4; fT3, free T3) were performed at baseline and 1, 3 and 6months. RESULTS: Study drug was discontinued due to mild thyroid dysfunction in 1 patient in the placebo vs. 3 in the amiodarone group (p=0.6). In linear mixed models there were significant effects of amiodarone on thyroid function tests, modified by follow-up visit (p<10(-9) for both TSH, T4, T3, fT4 and fT3). The amiodarone group had higher TSH, fT4 and T4 after 1 and 3months compared to placebo, whereas T3 and fT3 were lower. In all cases, the amiodarone-induced thyroid dysfunction was largest at 1month, declining at 3months, and with no differences at 6months, compared to baseline. CONCLUSION: We found amiodarone to have a significant impact on thyroid function after only 1month, but with a fast recovery of thyroid function after amiodarone discontinuation. Our study indicates that short-term amiodarone can be considered safe in patients without prior thyroid dysfunction.

Autonomic dysfunction and new-onset atrial fibrillation in patients with left ventricular systolic dysfunction after acute myocardial infarction: a CARISMA substudy.

BACKGROUND: Atrial fibrillation (AF) increases morbidity and mortality in patients with previous myocardial infarction and left ventricular systolic dysfunction. The purpose of this study was to identify patients with a high risk for new-onset AF in this population using invasive and noninvasive electrophysiological tests. METHODS: The study included 271 patients from the Cardiac Arrhythmias and RIsk Stratification after Myocardial InfArction (CARISMA) study with an acute myocardial infarction (AMI) and left ventricular ejection fraction ≤40% without previous AF at enrollment. Within 21 days after the AMI, an implantable loop recorder was inserted and used to diagnose AF over the 2-year study duration. The following tests were performed: heart rate variability (HRV) and turbulence (HRT) analyses from repeated 24-hour Holter recordings, 2-dimensional (2D)-echocardiograms, exercise test, and programmed electrophysiologic stimulation. RESULTS: A total of 101 patients (37%) developed AF during the study. Predictive measures included several indexes of HRV including reduced low-frequency (LF) power from spectral HRV analysis (adjusted HR = 1.6, P = 0.034), HRT slope ≤2.5 (HR = 1.6, P = 0.032) and Detrended Fluctuation Analysis (DFA1) from HRV analysis (HR = 1.8, P = 0.011); all are measures of cardiac autonomic nervous system dysfunction. Combined with age >60 years, low values for LF, HRT slope, and DFA1 provided a powerful risk score for prediction of new-onset AF (1-2 points: HR = 4.3, P = 0.001, 3-4 points: HR = 7.0, P < 0.001). CONCLUSION: Abnormal HRV and HRT parameters, which are associated with disturbances in the cardiac autonomic regulation, are associated with increased risk of new-onset AF independently of conventional clinical risk variables.

Diastolic dysfunction predicts new-onset atrial fibrillation and cardiovascular events in patients with acute myocardial infarction and depressed left ventricular systolic function: a CARISMA substudy.

AIMS: The aim of this study was to investigate the association between diastolic dysfunction and long-term occurrence of new-onset atrial fibrillation (AF) and cardiac events in patients with acute myocardial infarction (AMI) and left ventricular (LV) systolic dysfunction. METHODS AND RESULTS: The study was performed as a substudy on the CARISMA study population. The CARISMA study enrolled 312 patients with an AMI and LV ejection fraction

[General practitioner views on drug-assisted rehabilitation and the Norwegian substance abuse reform]. / Fastlegers syn på legemiddelassistert rehabilitering og rusreformen.

BACKGROUND: Due to increased use of injected heroin in Norway the official policy has shifted from an ideal drug-free position to a more realistic harm reduction, where one element is substitution therapy. This implies controlled distribution of opiates, methadone and buprenorfine to selected individuals, combined with close follow-up and social rehabilitation. After the "substance abuse reform" was implemented in 2004, a number of treatment facilities have been included in the ordinary specialist health care system, and the clients who can document their right to <> have obtained ordinary patient rights according to the Patients Rights Act. General practitioners are supposed to follow up these patients, by prescribing opiates to those eligible for substitution therapy, and by participating in local <>. We wanted to investigate how general practitioners' perceive their involvement in substitution therapy, and to see whether this view had changed from 2000 to 2006. MATERIAL AND METHODS: Postal questionnaires were sent to 1606 doctors in 2000 and to 1400 of the same doctors in 2006. Of the 1318 (82 %) who responded in 2000, 227 were general practitioners and 78 were municipal medical officers; of the 966 (69 %) who responded in 2006, 227 were regular general practitioners. 208 of these had also responded in 2000. In 2006 we also asked the doctors about the recent substance abuse reform. RESULTS: 53 % of the general practitioners were in favour of substitution therapy with methadone or buprenorfine; 50 % said they might prescribe the drugs themselves and 77 % were positive towards participating in "responsibility groups". Two thirds felt that transferral of responsibility for patients with substance abuse problems to the specialist health care service, was a necessary and useful reform. The fraction of doctors with a positive attitude towards substitution therapy increased slightly from 2000 to 2006, but individual viewpoints varied largely. INTERPRETATION: Political and cultural rather than medical arguments seem to dominate doctors' views on these issues.