Radiation effects on left ventricular function and myocardial perfusion in long term survivors of Hodgkin's disease

Abstract

We evaluated systolic and diastolic indices of left ventricular performance by radionuclide angiocardiography and myocardial perfusion with exercise/rest thallium scintigraphy in 16 patients previously irradiated for Hodgkin's disease. These commonly used indices of left ventricular (LV) performance included LV ejection fraction (LVEF) as a measure of systolic function, and LV peak filling rate (PFR) as a measure of diastolic function. The presence of coronary artery disease (CAD) was evaluated by ECG treadmill testing (13 patients) and by quantitative planar thallium scintigraphy (12 patients). Patients were 16–38 years old (mean 24.9 ± SD 6.2) at the time of irradiation, and were evaluated 2.5–21.5 years (mean 9.3 ± 6.3) after radiation therapy (RT). RT was delivered with beam energies of 2–18 MV, equally weighted AP-PA mantle fields with both fields treated daily for most patients (13 patients), and fraction sizes of 1.5–2.0 Gy. Six patients received radiation to the entire cardiac volume, most commonly via left-sided partial transmission lung blocks (PTLB). Patient data were analyzed according to the volume of heart treated. Individuals who had the entire cardiac volume irradiated were assigned to group I (N = 6), and those patients who had some portion of the heart shielded throughout treatment comprised group II (N = 10). In this series, no perfusion defects were evident in either group by quantitative planar thallium scintigraphy. Mean LVEF for all patients studied was 60% (normal LVEF ≥ 50%). Patients in group I had a lower mean LVEF than those in group II, 55 ± 4% versus 63 ± 6% ( p = 0.01). Mean PFR for all patients studied was normal at 3.5 EDV/sec (normal PFR ≥ 2.54 EDV/sec). Patients in group I had a lower mean PFR than those in group II, 3.0 ± 0.6 vs 3.8 ± 0.7 EDV/sec ( p = 0.04). Thus, patients irradiated to large cardiac and pulmonary volumes had lower LVEF and PFR within the normal range compared to patients who had some portion of the cardiac volume shielded. These differences are statistically significant in the relatively small groups studied but do not appear to be associated at the present time with clinically significant effects.