A 67-year-old woman presented with palpitations. Her ECG showed a narrow-QRS tachycardia at a rate of 160 beats per minute. P waves were visible and preceded the QRS complexes, with negative P waves in leads II, III, aVF, and V3-V6. The PR interval was 140 milliseconds. Based on these characteristics, the patient was diagnosed with atrial tachycardia. Additional analysis found a normal QRS axis and duration, no ventricular hypertrophy, no signs of infarction, and normal T waves.

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.

7. 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.