Chemotherapy-Induced Cardiomyopathy Unmasking Partial Anomalous Pulmonary Venous Return
A 64-year-old woman with a medical history of B-cell non-Hodgkin lymphoma was found to have left ventricular (LV) dysfunction with an ejection fraction (EF) of 20% by echocardiography 1 year after completing treatment with mediastinal radiation and 8 cycles of doxorubicin, rituximab, and cytoxan. Evaluation at that time included a left heart catheterization that revealed no coronary artery disease. She had no documented hypoxia. A follow-up echocardiogram 8 years later showed improvement in LVEF to 45-50%. The patient was well-compensated for several more years but now presented with 2 months of progressive exertional dyspnea. Vitals were notable for a blood pressure of 99/59 mmHg with a heart rate of 66 bpm and an oxygen saturation of 98% on room air. Physical exam revealed a 2/6 systolic murmur at the upper right and left sternal borders and trace lower extremity edema. A chest x-ray showed a mildly enlarged cardiac silhouette. The electrocardiogram showed left axis deviation. A transthoracic echocardiogram showed a moderately dilated LV with severe global hypokinesis and EF of 15-20%. Right ventricular (RV) size and function were normal, with an estimated RV systolic pressure of 61 mmHg. A right heart catheterization at an outside institution demonstrated a right atrial pressure of 9 mmHg, RV pressure of 42/14 mmHg, mean pulmonary artery pressure of 27 mmHg, and pulmonary capillary wedge pressure of 21 mmHg. A repeat right heart catheterization after diuresis and medical optimization showed improved filling pressures but importantly demonstrated a step up in oxygen saturation in the left brachiocephalic vein (Tables 1-2).
Table 1: Venous and Right Heart Saturation Run With Step-Up in Oxygen Saturation in the Left Brachiocephalic Vein
Table 2: Invasive Intra-Cardiac Pressure Measurements
The findings above prompted cardiac magnetic resonance imaging (MRI) for further evaluation of the cardiomyopathy and identification of the etiology of the left-to-right shunt. Cardiac MRI showed severe LV dysfunction (calculated EF of 21%) and a mildly dilated RV with normal systolic function (Figure 1). There was no delayed hyperenhancement to suggest scar or infiltrative cardiomyopathy (Figure 2). A vertical vein was identified connecting the left upper pulmonary vein to the left brachiocephalic vein (Figure 3). Velocity flow mapping with cardiac MRI resulted in a Qp:Qs of 2.7. Repeat catheterization with angiography confirmed the diagnosis of a partial anomalous pulmonary venous connection (Figure 4) with a Qp:Qs of 2.64.
Figure 1: Cardiac MRI Showing LV Quantification
Figure 2: Four-Chamber Cardiac MRI Shows No Evidence of Late Gadolinium Enhancement
Figure 3: Three-Dimensional Volume Rendered Magnetic Resonance Angiography Depicting the Communication Between Left Upper Pulmonary Vein and Left Brachiocephalic Vein via a Vertical Vein
Figure 4: Conventional Subtraction Angiography Depicting the Communication Between Left Upper Pulmonary Vein and Left Brachiocephalic Vein via a Vertical Vein
What is the most likely etiology of this patient's dyspnea?