 - Exclusion Criteria for 24-Hour Screening Holter: Any symptomatic arrhythmia except isolated extra systoles, Sustained cardiac arrhythmias such as atrial fibrillation or flutter, supraventricular tachycardia 10 consecutive beats, complete heart block. Non-sustained or sustained ventricular tachycardia defined as 3 consecutive ventricular ectopic beats. Any conduction abnormality including but not specific to left or right incomplete or complete bundle branch block, atrioventricular AV block 2nd degree or higher, Wolff-Parkinson-White WPW syndrome etc.. Sinus Pauses 3 seconds. 300 or more supraventricular ectopic beats in 24 hours. 250 or more ventricular ectopic beats in 24 hours. 