A 67-year-old woman presented with palpitations. An ECG showed a narrow-QRS tachycardia at a rate of 160 beats per minute, with visible P waves preceding each QRS complex. The P waves were negative in leads II, III, aVF and V3-V6, with a PR interval of 140 msec. The diagnosis was determined to be atrial tachycardia based on the ECG findings.

1. Stepwise interpretation of ECG ID 123 – Atrial tachycardia

2. ID 123 – 67 year old woman complaining of palpitation

3. ID 123 – 67 year old woman complaining of palpitation The patient has a narrow-QRS tachycardia (160/min) – Can your see P waves?

4. ID 123 – 67 year old woman complaining of palpitation If your answer was yes , go to the next slide, if it was no , look again and then go ahead

5. ID 123 – Atrial tachycardia, 160/min P waves precede the QRS complexes. They are negative in II, III, aVF and V3-V6. The PR interval is 140 msec. The arrhythmia is Atrial Tachycardia.

6. ID 123 – Final diagnosis: Atrial tachycardia, 160/min The QRS axis is normal. The QRS duration is 80 msec. There is no ventricular hypertrophy. No signs of infarction. T waves are seen in I, aVL and V4-V6 and appear normal.