Trifascicular block with sinus bradycardia

 A70 years old female came with a history of giddiness since one week. She had a history of two episode of syncope with transient loss of consciousness over last one week. During the evaluation in the emergency, patient pulse was 40 beats per minute. Patient ECG is shown below.

ECG 1(Click on the image to enlarge it)

ECG is showing sinus bradycardia @ 48 beats per minute,  left axis deviation (LAD), rS complex in lead II, III, avF suggestive of left anterior hemiblock(LAHB), PR interval is 280 msec, suggestive of first degree AV block, QT interval is 560 msec, corrected QT interval is 501 msec, QRS complex of RBBB morphology, QRS duration120 msec, no other ST- T wave changes.  ECG is suggestive of trifasicular block. 

ECG 2 (Click on the image to enlarge it)

ECG is showing sinus bradycardia with a heart rate of 45 beats per minute, there is LAD, LAHB, RBBB. 

Diagnosis is Trifasicular block. Patient was put on single-chamber ventricular pacemaker (VVI)  in view of high-grade AV block and later discharged in stable condition.

Let's discuss Trifasicular block

Trifascicular block indicates conduction abnormality in all the three fascicles 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.

Thank you

Praveen Gupta