Reversal of severe pulmonary hypertension with beta blockade in a patient with end stage left ventricular failure

A 52 year old man with severe chronic left ventricular failure (New York He art Association class IV) was considered unsuitable for cardiac transplanta tion because of high and irreversible pulmonary vascular resistance (PVR). In an attempt to produce symptomatic improvement, metoprolol was cautiously introduced, initially at 6.25 mg twice daily. This was slowly increased to 50 mg twice daily over a two month period and continued thereafter. After four months of treatment the patient's symptoms had improved dramatically. His exercise tolerance had increased and diuretic requirements reduced to f usemide 160 mg/day only. Assessment of right heart pressures was repeated a nd, other than a drop in resting heart rate, there was little change in his pulmonary artery pressure or PVR. His right heart pressures were reassesse d showing a pronounced reduction in pulmonary artery pressure and a signifi cant reduction in PVR, which fell further with inhaled oxygen and sublingua l nitrates. He was then accepted onto the active waiting list for cardiac t ransplantation. A possible mechanism of action was investigated by assessin g responses to beta agonists during treatment. Not only was there pronounce d improvement in PVR but it was also demonstrated that beta receptor subtyp e cross-regulation may have contributed to the mechanism of benefit.