Response to Role of a 12‐Lead Electrocardiogram in the Diagnosis of Cardiac Tamponade as Diagnosed by Transthoracic Echocardiography in Patients With Malignant Pericardial Effusion

Argula RG et al. Clin Cardiol. 2015;38:139–144.

We read with great pleasure the recently published article by Arugla et al in Clinical Cardiology.1 The authors have commendably reviewed the role of 12‐lead electrocardiography in the diagnosis of cardiac tamponade resulting from malignant pericardial effusions.

However, we want to emphasize 2 additional important electrocardiographic markers, namely total electrical alternans and vector alternans, which are highly specific for the diagnosis of cardiac tamponade. Electrical alternans often affects the QRS segment alone; however, it may involve the other (or all of the rest) electrocardiographic segments. QRS‐amplitude alternans (ie, beat‐to‐beat variation of the QRS amplitude), a diagnostic electrocardiographic finding for tamponade, may however often be the result of other conditions, such as atrial arrhythmias, which may frequently accompany pericardial effusion or tamponade. In such situations, the electrocardiographic differentiation of these two conditions must be sought based on the alternate electrocardiographic parameters. The combination of QRS‐amplitude alternans and QRS‐vector alternans (namely, beat‐to‐beat variation of the QRS vector) on a 12‐lead electrocardiogram is very highly specific for cardiac tamponade.2 QRS‐vector alternans is most commonly appreciated in only 1 or 2 precordial leads. One must recognize that the sensitivity of vector alternans is low; however, when present, it is almost a give‐away to the diagnosis. Total electrical alternans is yet another highly specific finding for the diagnosis of tamponade, which involves electrical alternation of P wave, QRS complex, ST segment, and T wave. Again, this finding is present in only in about 5% to 10% of cardiac tamponade patients, but its presence is virtually quasispecific for the diagnosis.3, 4

One must be mindful of these important diagnostic electrocardiographic findings in cardiac tamponade, as these features may serve as invaluable diagnostic tools and facilitate in an early targeted therapeutic approach.

Nauman Khalid, MD
Department of Cardiovascular Medicine
Hartford Hospital
University of Connecticut Health Center
Hartford, Connecticut
Lovely Chhabra, MD
Hartford Hospital
University of Connecticut School of Medicine
Hartford, Connecticut
David H. Spodick, MD, DSc
Saint Vincent Hospital
University of Massachusetts Medical School
Worcester, Massachusetts