75-year old patient presenting with acute dyspnoea, productive cough and wheeze. Describe the ECG.
Describe and interpret this ECG
ECG ANSWER and INTERPRETATION
- Irregularly irregular narrow-complex tachycardia at ~ 110 bpm
- At least 3 different P wave morphologies seen in the lead II rhythm strip, indicating multiple foci of activity within the atria
- No flutter or fibrillatory waves — rules out AF or flutter with variable block
- Evidence of right ventricular hypertrophy — RAD, dominant R wave in V1, deep S wave in V6
The combination of…
- Irregular narrow-complex tachycardia (> 100 bpm)
- Multifocal atrial activity (3 or more distinct P wave morphologies)
- No evidence of flutter / AF
… is diagnostic of multifocal atrial tachycardia (MAT).
MAT typically occurs in patients with severe COPD, as the final common pathway of multiple arrhythmogenic mechanisms:
- Right atrial dilatation (from cor pulmonale)
- Increased sympathetic drive — due to hypoxia / hypercarbia
- Bronchodilators — beta-agonist, theophylline
- Electrolyte abnormalities; hypokalaemia and hypomagnesaemia (e.g. secondary to diuretics / beta-agonists)
MAT typically resolves with treatment of the underlying COPD exacerbation and correction of any electrolyte abnormalities, although it may evolve into AF or flutter.