Lambda-like waveform: A new risk predictor of impending malignant arrhythmias in patients with coronary artery disease

Author(s): Xuexun L, Guangqiang Wang, Shu Zhong, Huiyuan Sun

Background: The association between the appearance of a lambda-like waveform and occurrence of malignant arrhythmias during acute myocardial ischemia is unclear in patients with Coronary Artery Disease (CAD).

Hypothesis: Lambda-like waveform is a new risk predictor of impending malignant arrhythmias in patients with CAD.

Methods: We evaluated electrocardiograms (ECGs) from 8 patients with transient ischemia. The lambda-like pattern was defined as a distinctively notched, giant J wave with a descending ST-segment elevation followed by an alternately negative T wave. The typical pattern was followed by ventricular tachyarrhythmias and/or severe bradyarrhythmias in the CAD group.

Results: Lambda-wave patientshad a higher incidence of syncope, CAD, arrhythmia, cardiopulmonary resuscitation, obvious coronary artery stenosis, slower heart rate, and longer PR and QT intervals than the control patients. In addition, more lambda-wave patients took medicine for coronary artery dilatation and had recurrent malignant arrhythmias than the control patients. A difference with respect to the distribution and morphology of ischemic ECG waveforms between the 2 groups was observed. Furthermore, the incidence of severe bradyarrhythmias and/or ventricular tachyarrhythmias was significantly higher in the CAD group than that in the control group.

Conclusion: An inferior and lateral lambda-like pattern may predict malignant arrhythmias in patients with CAD. A notched giant J wave may also be a risk factor for impending arrhythmias in inferior and lateral leads. The relevance of this pattern to acute ischemia may be important; however, no risk stratification or management strategies for this pattern have been established.