James Schumacher

Electrocardiographic changes during selective aortocoronary saphenous vein bypass graft angiography in man

Abstract Simultaneous leads I, II, and III of the electrocardiogram were recorded during selective aortocoronary saphenous vein bypass graft angiography in 20 patients. Arrhythmias associated with such graft opacification included sinus bradycardia, sinus arrest, atrial premature beats, ventricular premature beats, ventricular tachycardia and two episodes of ventricular fibrillation. Rhythm disturbances were unrelated to the anatomic location of the grafts. Patent right graft injection effected a mean rightward frontal plane QRS axis shift of 32.7 ° with leftward T wave axis deviation. A majority of subjects with patent aortic-left anterior descending coronary arterial grafts also manifested right axis shift (mean 22.6 °), possibly related to collateral circulation between the left and right coronary arterial systems. Those patients with stenosed and occluded grafts had minimal or no electrocardiographic changes during bypass angiography. It is concluded that electrocardiographic alteration during graft angiography is a physiologic demonstration of aortocoronary bypass efficacy.

Assessment of aortocoronary saphenous vein bypass function utilizing selective indicator dilution curves

Aortocoronary saphenous graft function was evaluated in 21 postoperative patients with the selective indocyanine green indicator dilution method. Selective indicator injections were made into the aortic root, diseased coronary artery, and saphenous bypass graft with constant sampling at the main pulmonary artery. There were no major electrocardiographic alterations associated with dye injection. Graft, aortic, and coronary dilution curves obtained from such testing were analyzed with respect to corrected appearance time (AT), build-up time (BT), peak amplitude (PA), peak amplitude build-up time ratio (PABT), clearance time (CT), and spread ratio (SR). When compared with aortic root indicator dilution curves, characteristic findings were: (1) patent grafts: shorter AT (P<0.001), higher PA (P<0.001), greater PABT (P<0.001), shorter CT (P<0.05), and greater SR (P<0.01), (2) occluded graft: no significant difference in any measurement. There were significant differences in BT (P<0.01), PA (P<0.01), PABT (P<0.001), and CT (P<0.05) when curves from injection of grafts with good and poor angiographic clearance were compared. Where graft flow appeared more satisfactory than bypassed coronary arterial flow there were significant differences between the majority of these measurements. It is concluded that the selective indicator dilution technique is safe and useful for the evaluation of aortocoronary graft function.