Electrocardiograms (ECG’s) hold a strong diagnostic value in medicine. They are of particular usefulness when that can be extended to the prognostic arena. In a few cases, it offers particularly important information in the short term. One such finding is the presence of T wave alternans.
A 56 year old female with past medical history of chronic hypertension presented to medical attention with altered mentation after an acute aneurysmal rupture resulting in large subarachnoid hemorrhage. Her illness required intubation, sedation, and placement of ventriculostomy. She exhibited frequent episodes of non sustained ventricular tachycardia starting on hospital day number 8 on background of a prolonging QT segment from her baseline of less than 400ms to a peak of over 600ms. Echocardiography obtained to evaluate symptoms of cardiac failure showed an ejection fraction of 15% with pattern of stress-induced cardiomyopathy. On hospital day 12, cardiac telemetry raised concern for new ST segment elevation and new T wave inversions that prompted a twelve-lead electrocardiogram. This confirmed new T wave inversions and showed an impressive case of macro-oscillating T wave alternans in setting of long QT, a rare finding in literature. Three hours later, patient entered a period of torsades de pointes.
Discussion:
The case teaches the T alternans electrocardiography pattern and the typical progression to hemodynamically unstable ventricular dysrhythmia. Moreover, it shows how easy the pattern may be overlooked, as it was in this case upon initial ECG review by an expert clinician. It reinforces the need for close observation of patients exhibiting such ECG findings as they require aggressive electrolyte repletion, close monitoring, and possible investigation into its occult causes, such as elevated intracranial pressure or occult long QT states. It also offers a review of typical causes of T alternans, namely intracranial hemorrhage and recent acute hyper-adrenergic states. While our patient exhibited an impressive example of T alternans, investigations are under way to explore the prognostic utility of its more subtle variations in the prediction of sudden cardiac death in congestive systolic heart failure patients.
Conclusions:
T wave alternans is a rarely seen and easily overlooked electrocardiographic pattern noted in hyperadrenergic states that may indicate imminent life-threatening cardiac dysrrhythmias. Its recognition may prompt the clinician to address and minimize any risk factors, such as electrolyte disturbances, or look for physiologic stressors that may have developed (eg. occult cerebrovascular accident in a sedated patient).