Photo Credit: Grandeduc

Researchers identified ECG patterns to help clinicians distinguish apical HCM from Wellens’ syndrome, Takotsubo cardiomyopathy, and intracranial processes.

Diagnosing apical hypertrophic cardiomyopathy (ApHCM), also known as Yamaguchi syndrome, is difficult. This rare type of HCM currently has no diagnosing guidelines.

In a recent paper for Current Problems in Cardiology, Adrian Baranchuk, MD, and coinvestigators evaluated the extent to which electrocardiograms (ECGs) help with diagnosis. While the researchers noted that ECG is a good starting point, they also wrote that ECG patterns for ApHCM can look like patterns for other conditions, suggesting that additional imaging is required to diagnose.

In an interview with Physician’s Weekly, Dr. Baranchuk explains, “The diagnosis of apical HCM starts with observing an abnormal ECG; however, more complex imaging is crucial.”

Evaluating ApHCM Patterns

The authors reviewed previous research on ECG patterns in ApHCM and related conditions. Researchers selected 14 papers from 2010 to the present, including three case reports, three systematic reviews, two guideline papers, two case studies, two retrospective studies, one cohort study, and one book chapter.

Based on previous studies, the researchers observed that deep T-wave inversions, particularly in leads V1-V4, distinguish ApHCM. Displays included deep T-wave inversions, ST-segment depression, negative Uwaves, and prolonged QTc intervals.

Distinguishing ApHCM From Other Conditions

The reviewed papers established clear ECG patterns for ApHCM, but the researchers noted the patterns were similar for Wellens’ syndrome, Takotsubo cardiomyopathy, and intracranial processes.

Wellens’ syndrome can cause an ischemic state due to a temporary obstruction in the left anterior descending coronary artery, resulting in an ECG pattern like ApHCM’s. Both Wellens’ and ApHCM ECG patterns presented an inverted T-wave, though Wellens’ ECG patterns can have periods of angina with normalized T-waves, making diagnosis tricky.

While similar, some key differences exist between the ECG T-waves of these two conditions: ApHCM waves exceed 10 mm, while Wellens’ patterns measure 6 mm or less in men and 3 mm or less in women.

Takotsubo cardiomyopathy presents ECG patterns featuring a QTc interval prolongation, T-wave inversion, or ST-segment elevation. The first two can be like ApHCM, but the latter is where the conditions differ. ApHCM presents ST-segment depression instead of elevation. ApHCM also tends to have longer negative T-waves than Takotsubo cardiomyopathy.

Symmetrical inverted T-waves can result from acute intracranial hemorrhage, a manifestation of serious trauma to the central nervous system. When intracranial processes are detected in ECG patterns, the results look like ApHCM. However, the researchers noted that intracranial processes have a more pronounced prolongation of QT intervals. Additionally, ST-segment can be depressed or elevated for intracranial processes (as opposed to always depressed for ApHCM).

When using ECG, Dr. Baranchuk says that “knowing these patterns will resolve 99% of cases.”

ECGs Play Supporting, Not Primary, Role in Diagnosis

While clinicians may be able to differentiate ApHCM’s ECG patterns from similar conditions, this is not always the case. As a result, the researchers recommended using ECG patterns alongside other diagnostic processes. For any of these conditions, ECG patterns should play a supporting diagnostic role, not a primary one.

“The most important issue is that ECG can trigger more complex (and expensive) diagnostic tests, which should follow a specific algorithm to detect the cause producing the ECG abnormality,” Dr. Baranchuk says.