Trifascicular block

A 45 years old male came with history of dyspnoea on exertion NYHA class III since the past 1 month. There was no history of coronary artery diseases or acute coronary syndrome in the past. During evaluation  pulse rate was 110 beats per minute, blood pressure was 110/60 mmhg, Echocardiography was suggestive of severe global left ventricular dysfunction . Patient ECG is shown below.

ECG 1

Sinus rhythm at rate around 100 beats per minute, left axis deviation, PR interval  240 msec suggestive of 1 degree heart block, there are rS complex in lead II,III,avF with qR in lead avL, suggestive of left anterior hemiblock, QRS complexes showed right bundle branch morphology with qrs duration of 120 msec so the ecg of the patient is suggestive trifascicular block (1 degree heart block with left anterior hemiblock with right bundle branch block)

Another ECG of the same patient is showing trifascicular block

ECG 2 (Click on the image to enlarge it)

Let's discuss what is trifascicular block

Trifascicular block indicate conduction abnormality in all the three fascicle of cardiac conduction system (Right fascicle, left anterior fascicle and left posterior fascicle). It will manifest on the ecg in the form of RBBB with Left anterior hemiblock with prolonged PR interval or 1 degree AV block or RBBB with left posterior hemiblock with prolonged PR interval.

Patient angiogram was done showed normal coronary artery so the final diagnosis of the patient was idiopathic dilated cardiomyopathy with trifascicular block. Patient was started on standard heart failure medication and was discharged in stable condition.

Thank you

Praveen Gupta