Takotsubo cardiomyopathy mimics acute myocardial infarction but is a separate clinical entity characterized by distinct wall motion abnormalities in the absence of obstructive coronary lesions. The prevalence of this condition is relatively uncommon yet has gained increasing recognition in recent years. It has rarely been associated with the use of dobutamine infusion during cardiac stress testing. We present in detail two cases of dobutamine-induced Takotsubo cardiomyopathy from our case series, one from 2002 and the other from 2008. While both cases display the typical features of Takotsubo cardiomyopathy, the former was initially diagnosed as dobutamine-induced vasospasm. These cases may provide insight into the pathophysiological mechanism of the condition and suggest that the increasing recognition of Takotsubo cardiomyopathy results from increasing familiarity of the condition.
There are several markers of poor prognosis in heart failure (HF). The most established markers of poor prognosis in HF include neurohormonal (NH) imbalance, low ejection fraction (EF), ventricular arrhythmias, intraventricular conduction delays, low functional capacity, low SBP, and renal failure. The relative importance of these factors is unknown, as they have never been studied together. We present a 74-year-old female with nonischemic cardiomyopathy and an EF<20% who over 24 years since diagnosis, never developed clinical or hemodynamic congestion, was never hospitalized for HF, and never required a loop diuretic. She had all of the clinical indicators of poor prognosis in HF except for severe NH imbalance and renal failure, illustrating their importance in HF prognosis. While NH activation in HF is initially an adaptive mechanism, an imbalance of NH effectors causes congestion leading to a vicious cycle of congestion, renal dysfunction, and worsening of HF. The combination of NH activation and renal failure in HF is a vasomotor nephropathy known as the cardiorenal syndrome (CRS) and portends a poor prognosis. Pharmacological disruption of NH pathways early in HF may prevent CRS and, therefore, improve outcomes.
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