- Myocardial infarction, heart failure (NYHA class III or IV), gross cardiac enlargement (cardiothoracic ratio > 0.5), significant heart block or cardiac arrhythmias within 3 months; history of uncontrolled complex ventricular arrhythmias, uncontrolled atrial fibrillation/flutter or uncontrolled supraventricular tachycardia, pacemaker or implantable cardiac device were not eligible for this study.