Seasonal variation in morbidity and mortality related to atrial fibrillation—Could thyroid function contribute?

Recurrent acute pulmonary embolism and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism

“…It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes [2] but it is sufficient to induce arrhythmias [1] including atrial fibrillation [3,4] and atrial flutter [5]. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state [6].…”

Hashitoxicosis with pericardial effusion

“…Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a TSH level suppressed below the normal range and usually undetectable [2]. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes [3] but it is sufficient to induce arrhythmias [2] including atrial fibrillation [4][5][6][7][8][9][10] and atrial flutter [11,12]. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state [5,13].…”

Intermittent changing axis deviation with intermittent left anterior hemiblock during atrial flutter with subclinical hyperthyroidism

“…It has been reported that subclinical hyperthyroidism is not associated with CHD or mortality from cardiovascular causes [2] but it is usually associated with a higher heart rate and a higher risk of supraventricular arrhythmias [3,4] including atrial fibrillation and atrial flutter. Intermittent changing axis deviation during atrial fibrillation has also rarely been reported [5,6].…”