Ventricular rate ≥ 40 beats per minute PR interval ≤ 200 ms Q waves < 30 ms (up to 50 ms permitted in lead III only) QRS interval to be ≥ 60 ms and ≤ 110 ms QTc interval < 450msec (QTcB or QTcF; machine or manual reading) based on a single ECG value, or an average from three ECGs obtained over a brief recording period