Effect of coronary occlusion on intracardiac electrogram morphology.

Aims: The effect of coronary occlusion on the morphology of intracardiac electrograms (IKG) may be of diagnostic value in recipients of cardiac implantable electronic device (CIED) and in other patients at risk of ischaemic heart disease (IHD), but remains grossly uncharacterized. The aim of the current study was to examine the effect of total occlusions in the major coronary artery distributions on the IKG.

Methods And Results: Domestic crossbred pigs (n= 11, 20-30 kg) were implanted with dual-coil right ventricular defibrillators, and bipolar right atrial and left ventricular leads. Through the femoral approach, percutaneous balloon total occlusion of the major coronary arteries was performed in random order in the left anterior descending, left circumflex, and right coronary arteries. Each occlusion was maintained for 3-5 min with 30 min periods of reperfusion in between. Simultaneous 15-vector IKG and 12-lead surface electrocardiograms (ECG) were recorded and analysed at baseline and during coronary occlusions. With coronary occlusions, significant ST-segment disturbances are consistently seen on both surface ECG leads and IKG tracings compared with baseline recordings and are reproducible over time. Given the multiple intracardiac recording vectors, each occluded vessel has a specific signature, allowing coronary localization from the IKG.

Conclusions: Total coronary occlusion induces consistent IKG changes with injury patterns that allow the detection and localization of the culprit coronary artery. If duplicated in patients with IHD, these changes are likely to improve the time to diagnosis of acute coronary syndromes and thus favourably impact clinical outcomes.