Left Ventricular Perfusion Deficit in Patients with Cystic Fibrosis

Left ventricular failure is not considered an important feature in cystic fibrosis (CF), but abnormalities of left ventricular function have been reported. Except for a few cases of heart failure in neonates with CF, there is no evidence of a primary disorder of the myocardium in patients with CF. Since left ventricular perfusion disturbances can cause left ventricular dysfunction, we decided to investigate left ventricular perfusion during exercise using sestamibi-Tc-99m-labeled macroaggregates. Eighteen CF patients with varying degrees of disease severity participated in the study. They underwent a thorough clinical evaluation, lung perfusion scan, pulmonary function testing, echocardiography, transcutaneous measurement of oxygen saturation at rest and during exercise, and an exercise test with injection of sestamibi-Tc-99m-labeled macroaggregates at peak exercise. Six patients (33%) showed abnormalities of the myocardial distribution of sestamibi-Tc-99m-labeled macroaggregates during exercise. Scanning abnormalities correlated with the clinical score, mean maximum expiratory flow at 50% of vital capacity (MEF50), and arterial oxygen desaturation during exercise. We conclude that deficits in left ventricular uptake of sestamibi-Tc-99m-labeled macroaggregates during exercise seem common in patients with severe CF lung disease. The cause of these deficits is not fully understood, but the occurrence seems to be associated with a poor prognosis.