The morphological ECG changes most frequently encountered in a subject with SAH are U waves, T-wave abnormalities, R-wave abnormalities and non-specific ST-T changes. The predominant rhythm abnormalities seem to be relatively benign sinus tachycardias and bradycardias. However, the possibility of development of supraventricular arrhythmias, sinoatrial blocks and arrests, and life-threatening ventricular arrhythmias warrants a close monitoring of the ECG in these patients.