What Medical Condition Does this Patient Have?
By Ken Grauer, MD, Professor Emeritus in Family Medicine, College of Medicine,
University of Florida
Dr. Grauer is the sole proprietor of KG-EKG Press, and publisher of an ECG pocket brain book.
Scenario: Interpret the 12-lead ECG in the Figure. What medical condition is this patient likely to have?
Interpretation: Although there is no long lead II rhythm strip, we are still able to interpret the rhythm from surveillance of all 12 leads on this tracing. The QRS complex is narrow. The overall rhythm is irregularly irregular. However, despite this irregularity, the rhythm is not atrial fibrillation. Instead, there is definite atrial activity in each of the inferior leads (II, III, aVF). This is especially true in lead II, where several different P wave morphologies are seen. The rhythm is therefore multifocal atrial tachycardia (MAT).
Continuing with our systematic interpretation — intervals (PR, QRS, QT) are within normal. The mean QRS axis is also within the normal range, although it is relatively vertical (approximately +80 degrees) because the R wave in lead I is no more than barely positive. There are no q waves (other than perhaps a small q in lead aVL); R wave progression/transition is delayed (the R wave does not become taller than the S wave is deep until between leads V5-to-V6); and there are nonspecific ST-T wave abnormalities, but no acute changes.
Assessment for ECG signs of chamber enlargement is interesting. Right atrial abnormality (RAA) is suggested by the finding that several of the differently shaped P waves in lead II appear to be tall and peaked. In addition, we strongly suspect this patient has significant pulmonary disease, and probable right ventricular hypertrophy (RVH).
The ECG diagnosis of RVH is indirect and based on a combination of findings occurring in the right clinical setting. ECG signs suggesting RVH in this case are: 1) relatively low voltage (common in patients with pulmonary disease); 2) the relatively vertical axis (common in patients with emphysema); 3) RAA (most patients with RAA also have RVH); 4) persistent S waves throughout the precordial leads; 5) the very low amplitude of the QRS complex in association with ST-T wave flattening in lead I (known as Schamroth's sign, and suggestive of severe pulmonary disease); and 6) the rhythm, which is MAT. Taken together, it is highly likely that the patient in this case has longstanding and severe pulmonary disease.