- ECG or Holter abnormalities that may be suggestive of underlying cardiac disease including: left atrial abnormality and/or left ventricular hypertrophy, frequent ectopic or multifocal atrial beats, frequent premature ventricular beats, significant conduction abnormalities such as widened QRS, left bundle branch block, significant axis deviation, atrial fibrillation or flutter, frequent premature ventricular contractions or ventricular tachycardia (including torsades de point), repolarization changes suggestive of myocardial ischemia (e.g., ST-T wave abnormalities suggestive of ischemia), evidence of a previous myocardial infarction, atrioventricular (AV) nodal reentrant tachycardia or tachycardias associated with preexcitation/accessory pathway syndromes and high grade AV block