Short-term outcome of early electrical cardioversion for atrial fibrillation in hyperthyroid versus euthyroid patients*

Background: Atrial fibrillation (AF) is the most common cardiac complication of hyperthyroidism. The influence of the time of cardioversion on hyperthyroidism-induced AF remains unclear. The aim of this study was to compare short-term outcomes of early electrical cardioversion for AF in hyperthyroid and euthyroid patients. Methods and Results: Sixty-seven subjects with persistent AF (duration, 10 days–12 months) were divided into two groups according to thyroid function: Euthyroid (Group 1, n = 36, female/male: 23/13, mean age: 61.77 ± 10.45 years) and hyperthyroid (Group 2, n = 31, female/male: 10/21, mean age: 65.43 ± 6.40 years). Two patients were excluded for unsuccessful cardioversion (one in each group). In Group 2, 19 patients had clinical and 11 had subclinical hyperthyroidism. Following transthoracic and transesophageal echocardiography, cardioversion was performed until the highest energy was reached (270 J) or until sinus rhythm was achieved. AF recurrence was detected in 13 of 35 patients (37.1%) in Group 1 and in 11 of 30 patients (36.9%) in Group 2 (p = 0.96) at one month. Recurrence rate was higher in the clinical hyperthyroid patients than in the subclinical hyperthyroid patients (52.6% vs 9.1%, p = 0.021), but neither the clinical nor the subclinical hyperthyroid subgroups were significantly different from Group 1 in terms of recurrence rate (p = 0.27 and p = 0.13, respectively). Conclusions: Electrical cardioversion should be performed for patients with persistent AF and hyperthyroidism as soon as possible. (Cardiol J 2012; 19, 1: 53–60

Fragmented QRS complexes are associated with left ventricular systolic and diastolic dysfunctions in patients with metabolic syndrome

Background: Metabolic syndrome (MetS) is found to be associated with deterioration of the left ventricular (LV) systolic and diastolic functions. One of the factors for this impairment is myocardial fibrosis. Fragmented QRS (fQRS) complexes are found to be associated with myocardial fibrosis. The aim of the study was to evaluate if the presence of fQRS on electrocardiogram (ECG) can detect pronounced impairment in the LV systolic and diastolic functions in MetS patients. Methods: The study included 111 (mean age 47 ± 9, 49.5% male) MetS patients and 96 (mean age 45 ± 9, 58.3% male) control subjects without MetS. ECG was evaluated for the presence of fQRS. Each patient underwent conventional echocardiography and tissue Doppler imaging. Results: Fragmented QRS was more common among MetS patients (26.1% vs. 14.6%, p = 0.041). MetS was associated with subclinical LV systolic and LV diastolic dysfunctions. In subgroup analyses of MetS patients, the presence of fQRS on ECG had a higher E/E’ ratio and lower E’ velocity, indicating pronounced diastolic dysfunction, as well as lower isovolumic acceleration (IVA), indicating profound subclinical LV systolic dysfunction. E/E’ ratio and IVA were independent predictors of fQRS presence in patients with MetS. Conclusions: Fragmented QRS is more common among MetS patients compared to non-MetS patients. The presence of fQRS is associated with pronounced subclinical LV systolic and diastolic dysfunctions in MetS patients