Hypertrophic cardiomyopathy and evolution of tracings

ECG 2A: The electrocardiogram shows a sinus rhythm with no clear abnormalities; prominent amplitude of the S wave in V2 but no obvious signs of hypertrophy; cardiac ultrasound revealed no evidence of hypertrophy (septum 10 mm);

ECG 2B: Electrocardiogram performed in this same patient 3 years later (at the age of 21 years); increase in R wave voltage in V4, V5, V6; ultrasound revealed a septal thickness at the upper limit of 11 mm;

ECG 2C: Electrocardiogram performed in the same patient 3 years later (at the age of 24); very marked increase in R wave voltage in V4, V5, V6; the Sokolow index is very clearly positive; ultrasound revealed a septal thickness at the upper limit of 14 mm confirming the fact that this patient, like his brother and his father, does indeed have hypertrophic cardiomyopathy;

Comments: These tracings show the progression over time of the electrical signs in a patient with hypertrophic cardiomyopathy. The penetrance is variable, which explains why for a same family both clinical and ultrasound forms may be variable. Major abnormalities in the electrocardiogram and a septum thickness greater than 20 mm were found in the father and brother. No mutation could be identified. The search for a possible disease in family members is based on clinical picture, ECG and cardiac ultrasound or MRI. In the absence of an identified mutation, the electrocardiograms and work-ups should be repeated over time, since the signs of hypertrophy may be delayed.

In patients with hypertrophic cardiomyopathy, the evolution of the electrocardiographic pattern is variable and not necessarily in obvious relation with its clinical evolution. Most often, although not a rule, the electrocardiogram shows a progressive increase in the signs of hypertrophy and repolarization disorders. The q waves can also be widened with the surge in hypertrophy or are oppositely erased by the onset of an incomplete left bundle branch block.

Take-home message: In some patients, the onset of electrical signs suggestive of hypertrophic cardiomyopathy may be delayed, justifying repeating the recordings over time.