Coronary artery diameters in the heart with complete transposition of the great vessels.

The use of echocardiography established values for dimensions of normal coronary arteries in the setting of the heart with complete transposition (concordant atrioventricular and discordant ventriculoarterial connections) was evaluated. The diameters of the proximal coronary arteries measured at autopsy in 20 patients with complete transposition who had or had not undergone surgery were directly comparable with values determined in normal hearts by two-dimensional echocardiography. The values showed a linear increase with age, weight and length of the patients despite different branching patterns of the coronary arteries. Although there was right ventricular hypertrophy in all cases, the orifices of the right and left coronary arteries did not show any significant difference in diameter. Histologic examination and measurement of the arteries also revealed findings comparable with those in normal hearts. These findings suggest a relatively constant developmental pattern of the proximal coronary arteries despite different hemodynamics between the concordantly connected heart and the heart with complete transposition. In contrast, the functional significance of the stiff and slitlike orifices of the coronary arteries and their comparatively small diameters in relation to the ventricular wall thickness in four hearts studied after the arterial switch procedure for transposition merit further investigation.