We describe a case of malignant catatonia manifested by catatonic symptoms, fever, hemodynamic instability, and acute neurologic decline that was associated with electrocardiographic and echocardiographic abnormalities similar to those noted in patients with other central nervous system processes. The patient's electrocardiographic and echocardiographic abnormalities resolved after successful electroconvulsive therapy for the underlying neuropsychiatric disorder. The theoretic, physiologic, and clinical significances of this case are discussed.