A study by Minnesota-based researchers showed that although electrocardiogram (ECG) which is widely used in in most of the hypertrophic cardiomyopathy (HCM) patients is abnormal, normal ECG does not definitively signify the absence of HCM.
A small, but significant proportion of patients with HCM, told senior investigator Dr. Steve R. Ommen, can have an entirely normal ECG. While these patients tended to have fewer major consequences of HCM, many still needed advanced therapies to minimize symptoms.
The findings were from the study done by Dr. Ommen and colleagues at the Mayo Clinic, Rochester on 135 HCM patients who had a normal ECG and 2350 who had had abnormal findings.
Patients with an abnormal ECG had worse symptoms and higher gradients.
Patients with a normal ECG had an overall survival of 92% at 5 years and 81% at 10 years . These proportions did not differ from those of matched controls from the general population. In addition, there were no cardiac deaths in the normal ECG group during follow-up period.
The investigators conclude that almost 6% of patients presenting with demonstrable echocardiographic evidence of HCM had a normal ECG at the time of diagnosis.
Thus, concluded Dr. Ommen, mass screening programs based on the ECG could inappropriately reassure a participant that they were free from disease.