A previously unreported case of small-vessel myocardial vasculitis presenting as restrictive cardiomyopathy and congestive heart failure is described. The hemodynamic study, showing severely increased and equalized diastolic pressures in atrial and ventricular chambers, and cardiac MRI, showing normal pericardium and ventricular endomyocardial biopsy, not including myocardial vascular component, were insufficient to make a diagnosis. This made a thoracotomy and surgical cardiac biopsy necessary. Steroids and cyclophosphamide, introduced after histologic evidence of necrotizing vasculitis, unassociated with a systemic disease, became available and improved the clinical profile and the diastolic dysfunction at two-dimensional echocardiographic Doppler analysis.