The technique of obtaining an epicardial electrocardiogram trace by connecting the guidewire during coronary angioplasty to an electrocardiogram lead has been used since 1985. The intracoronary electrocardiogram appears to be more sensitive than the surface electrocardiogram in detecting transient ischemia, particularly in the territory of the left anterior descending and left circumflex coronary arteries. Importantly, recent studies have shown the intracoronary electrocardiogram to be particularly useful in demonstrating pre- and postconditioning during interventional procedures, predicting periprocedural myocardial damage, and in the determination of regional viability in the catheterization laboratory. Barriers to the use of the intracoronary electrocardiogram in the clinical setting include the lack of standardized methods for acquiring and analyzing the intracoronary electrocardiogram, and the lack of commercially available continuous intracoronary monitoring systems to permit analysis while performing coronary interventions. Facilitating these relatively simple technical developments may permit optimal integration of the intracoronary electrocardiogram into the catheterization laboratory.