Here we describe a 26-year-old woman who developed peripartum cardiomyopathy characterized by fatigue, poor exercise tolerance, and palpitations. Initial echocardiography showed global left ventricular dysfunction with an ejection fraction of 40%. Subsequently, the patient developed a resting tachycardia associated with symptomatic postural tachycardia. A diagnosis of Inappropriate Sinus Tachycardia was made based on Holter monitoring studies with an average heart rate of 121 beat per minute (bpm). Standard autonomic evaluation confirmed the diagnosis of Postural Tachycardia Syndrome. The cardiomyopathy subsequently resolved (ejection fraction 60%, normal left ventricular function). However, both the postural tachycardia and sinus tachycardia persisted.