Outcome of patients with high-risk Duke treadmill score and normal myocardial perfusion imaging on spect.

BACKGROUND: Annual mortality rate can range from <1% for patients with normal myocardial perfusion by SPECT to >5% based on a high-risk Duke treadmill score (DTS). Information on the prognosis of patients with the combination of HRDTS and normal SPECT is limited and is the purpose of this study. METHODS: Data from a large nuclear cardiology registry (n = 17,972 patients) were reviewed. A total of 340 had HRDTS (score ≤ -11) while undergoing SPECT. Combined cardiovascular mortality and non-fatal myocardial infarction (MI) and cardiovascular mortality alone were available in 310 patients at a mean follow-up of 4.01 ± 1.5 years. RESULTS: The majority of the patients had abnormal SPECT (n = 270, 71%). The abnormal SPECT patients compared to the normal were older (65.6 vs 62.8 years of age; P = .025), more likely to have abnormal left ventricular ejection fraction (26.1% vs 0%; P < .0001), known coronary artery disease (CAD, 35.9% vs 7.8%; P < .0001) and lower DTS (-14.5 vs -13.2; P = .0006), Kaplan-Meier survival analysis demonstrated a significantly lower cardiovascular mortality (5.4% vs 0%, P = .02) and combined outcome of MI and cardiovascular mortality (15% vs 4.4%, P = .009) in patients with normal versus abnormal SPECT. CONCLUSIONS: High-risk DTS is associated with abnormal perfusion SPECT in most patients, but nearly one-third of the patients had normal perfusion. Patients with a normal SPECT had a lower cardiovascular event rates.

Takotsubo or stress cardiomyopathy: role of nuclear cardiology using (123)I-MIBG.

Takotsubo cardiomyopathy, also known as broken heart syndrome or stress cardiomyopathy, is a very interesting syndrome of acute transient left ventricular dysfunction, usually following significant emotional stress. It was first described in Japan nearly two decades ago and many aspects of its pathogenesis still remain poorly understood. The incidence of out-of-hospital sudden death related to Takotsubo is currently unknown. Excess catecholamines following stress seem to trigger Takotsubo and play an important role. The clinical presentation resembles acute myocardial infarction, including chest tightness and/or dyspnea, ECG changes and elevated cardiac enzymes. However, in contrast to a typical acute myocardial infarction, no significant coronary lesions or thrombi are found on coronary angiography. Differentiating Takotsubo from acute myocardial infarction is important to avoid the unnecessary risks of thrombolytic therapy. Typically, left ventriculography shows marked abnormalities with akinesia in the mid-distal anterior wall and apex (occasionally involving other heart regions), giving a balloon shape to the left ventricle. The name Takotsubo originates from the shape of the left ventricle, which resembles a Japanese octopus-trapping pot. Hospital mortality is low but death can be caused by severe acute heart failure and/or ventricular arrhythmias. Typically, a stressful life event is reported preceding the acute symptoms. Takotsubo is most common in menopausal women although young individuals, including men, can also be affected. The autonomic nervous system has a defined role in the process. In this article, we will review the role of imaging the heart using (123)I-meta-iodobenzylguanidine, a radioactive marker allowing mapping of the autonomic nervous system of the heart, in cases of suspected Takotsubo.