Cardiac tamponade or normal respiratory variation? An illustrative case of septal ablation for obstructive hypertrophic cardiomyopathy.

Cardiac tamponade can be a lethal complication in the cardiac catheterization laboratory. Patients with obstructive hypertrophic cardiomyopathy are particularly vulnerable to the hemodynamic effects of tamponade because of their heightened sensitivity to ventricular load in the generation of forward stroke volume. Cardiac tamponade should be distinguished from the normal effects of respiration on dynamic outflow tract obstruction in these patients. This recognition not only ensures an accurate hemodynamic diagnosis, but it also will expedite timely therapy for patients in need.