Stiff left atrial syndrome after low-dose radiotherapy for right breast cancer: The need for invasive hemodynamics at exercise

Stiff left atrial (LA) syndrome is a distinct phenotype of heart failure with preserved ejection fraction, characterized by predominant high LA pressure. We describe the case of a middle-aged woman who developed exertional breathlessness during low-dose radiotherapy for right breast cancer and who was eventually found to be affected by stiff LA syndrome. Invasive hemodynamics allowed the recognition of pathognomonic tall V waves in the wedge position during exercise, in spite of inconclusive noninvasive investigations.