Novel pharmacological therapies for atrial fibrillation

Dofetilide: Electrophysiologic Effect, Efficacy, and Safety in Patients with Cardiac Arrhythmias

Dofetilide is a class III antiarrhythmic agent with a selective blockade of rapid component of delayed rectifier potassium current (IKr). Dofetilide was found to be safe in patients after myocardial infarction and those with congestive heart failure and left ventricular systolic dysfunction (ejection fraction of less than 35%). An important adverse effect of dofetilide is its potential proarrhythmic risk of ventricular tachyarrhythmias, mostly torsades de pointes. Because dofetilide has about an 80% renal excretion, dose adjustment is required in patients with impaired renal function. Dofetilide should not be given or discontinued if the QTc is greater than 500 ms.

Dilated left atrium and pulmonary veins in patients with calcified coronary artery: a potential contributor to the genesis of atrial fibrillation

INTRODUCTION

Coronary artery disease (CAD) is an important etiology of atrial fibrillation (AF). Coronary artery calcification is a marker of coronary atherosclerosis and coronary events. The purpose of this study was to investigate whether larger left atrium (LA) and pulmonary veins (PVs) were seen by multidetector computed tomography (MDCT) scans in those patients with higher coronary calcium scores.

METHODS AND RESULTS

A total of 166 patients undergoing MDCT for general check-up (n = 128, 77%) or suspected CAD (n = 38, 23%) were enrolled and divided into a control (calcium score = 0, n = 60), medium calcium score (calcium score = 100 approximately 400, n = 47), and high calcium score (calcium score >400, n = 59) groups. Diameters and areas of the LA, left atrial appendage (LAA), and PVs were measured by MDCT. The high calcium score group had significantly larger PVs diameters, LAA orifice area (1.9 +/- 1.4 cm(2), 0.9 +/- 0.5 cm(2), 0.8 +/- 0.4 cm(2), P < 0.005), LA anterior-posterior distance (32.2 +/- 6.8 mm, 30.4 +/- 6.5 mm, 27.3 +/- 6.0 mm, P < 0.05), and transverse distance (52.6 +/- 7.3 mm, 50.2 +/- 9 mm, 49.5 +/- 4.6 mm, P < 0.05) than the medium calcium score and control groups. Six (3.6%) patients with paroxysmal AF had higher calcium scores and larger diameters of LA, LAA, and PVs than those (96.4%) without paroxysmal AF. Two patients in the high calcium score group had calcified PVs localized to the right upper and left upper PVs. The incidence of calcified PVs was 1.2% for the total patients and 3.3% for the high calcium score patients.

CONCLUSION

In the presence of high calcium scores in this patient population, the LA, LAA, and PVs were enlarged.