The spiked helmet sign (SHS) is a rare electrocardiographic marker associated
with an increased risk of lethal ventricular tachyarrhythmias and sudden cardiac
death. To our knowledge, this is the first study aimed at reviewing recent
research progress on this electrocardiogram (ECG) pattern to summarize its
electrophysiological mechanisms, epidemiological features, clinical
characteristics, and clinical significance. SHS formation is attributed to
sympathetic hyperactivity, which mediates increased dispersion of ventricular
repolarization, leading to marked QT prolongation and macroscopic T-wave
alternans. This pattern can be observed in critically ill patients with cardiac
or noncardiac conditions. In particular, immediate identification of this ECG
abnormality is crucial in recognizing and treating noncardiac conditions in older
male patients.