Clinical Trial: Pathogenesis of Stress-Induced Cardiomyopathy by I-123 MIBG

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: The Evaluation of the Pathogenesis of Stress-Induced Cardiomyopathy by I-123 MIBG Imaging

Brief Summary:

Objective: The objective of this pilot study is to characterize the cardiac uptake patterns of I-123 mIBG in stress-induced (Takotsubo's) cardiomyopathy.

Hypothesis: Perturbations in sympathetic innervation are the underlying pathogenesis of stress induced cardiomyopathy and will result in abnormalities in I-123 mIBG cardiac imaging. Thus, planar and SPECT I-123 MIBG imaging will provide insight into the pathogenesis of stress-induced cardiomyopathy, and may lead to the development of more specific diagnostic criteria.

Study design: This proposal is for a prospective pilot study to characterize perturbations in cardiac sympathetic innervation in patients with stress induced cardiomyopathy by performing planar and SPECT I-123 MIBG imaging during the acute presentation and after recovery of LV function.


Detailed Summary:

Background: Since the initial Japanese description of Takotsubo's cardiomyopathy in 1991 as a transient systolic dysfunction of the apical or mid left ventricular segments in the absence of obstructive coronary artery disease, stress induced cardiomyopathy has been increasingly recognized in the Unites States. Takotsubo's cardiomyopathy accounts for 1.2 to 2.2 percent of all cases of acute coronary syndrome. The current American Heart Association Statistical Update estimates that approximately 1.2 million Americans will experience an acute coronary event in 2010. Based on this estimate, between 15 and 26 thousand Americans will have stress induced cardiomyopathy annually. Takotsubo's cardiomyopathy has also been described in stroke and critically ill patients. Post menopausal women are disproportionally affected, accounting for 80 to 100 percent of the patient population. These patients classically present with signs of acute heart failure or acute coronary syndrome after a severe emotional stress. The presentation may include chest pain, shortness of breath, elevated troponin enzymes, ST segment elevations, deep T-wave inversions, ventricular arrhythmias, pulmonary edema or elevated biomarkers. Cardiac catheterization reveals angiographically normal coronary arteries while the ventriculogram and the echocardiogram shows apical ballooning with basal hyperkinesis. While the majority of patients recover complete function within few days to two weeks, up to eight percent of the patients will die from the acute heart failure.

The etiology of stress-induced cardiomyopathy remains speculative. Catecholamine excess leading to microvascular dysfunction or direct cardiomyocyte toxicity is hypothesized as the most likely etiology. This hypothesis is supported by the fact that most patients with Takotsubo's cardiomyopathy experience an intense physical or emotional stress. Furthermo
Sponsor: University of Pittsburgh

Current Primary Outcome: Number of Participants Who Had an Abnormal Regional Uptake of I-123 mIBG at Baseline (Acute Phase) and the Number of Participants Who Had an Abnormal I-123 mIBG Uptake on Follow up (Recovery Phase) [ Time Frame: During the acute phase (2-5 days with an expected mean 3 days) and after recovery of cardiac function (6 weeks) ]

Number of participants who had an abnormal regional uptake of I-123 mIBG at baseline (acute phase) and the number of participants who had an abnormal I-123 mIBG uptake on follow up (recovery phase)


Original Primary Outcome:

  • Change from baseline Heart to Mediastinal Ratio at 6 weeks. [ Time Frame: During the acute phase (2-5 days with an expected mean 3 days) and after recovery of cardiac function (6 weeks) ]
    Heart to Mediastinal ratio of early and delayed I123-MIBG uptake during the acute presentation and after ejection fraction recovery H/M ratio = (mean pixel count of cardiac ROI/mean pixel count of mediastinal ROI) H/M=Heart to Mediastinal ratio, ROI= Region of interest, WR%= Global washout rate
  • Change from baseline Global Washout Rate at 6 weeks [ Time Frame: During the acute phase (2-5 days with an expected mean 3 days) and after recovery of cardiac function (6 weeks) ]
    Global washout rate of I123-MIBG from the acute presentation and after ejection fraction recovery WR%= [(mean cardiac pixel count(early)-mean cardiac pixel count(delayed))/(mean cardiac pixel count (early))] x 100
  • Change from baseline Ejection Fraction at 6 weeks [ Time Frame: During the acute phase (2-5 days with an expected mean 3 days) and after recovery of cardiac function (6 weeks) ]
    Using the Simpson's method, all left ventricular ejection fractions will be calculated during the acute phase and after functional recovery.


Current Secondary Outcome:

Original Secondary Outcome:

Information By: University of Pittsburgh

Dates:
Date Received: September 7, 2011
Date Started: September 2011
Date Completion:
Last Updated: March 21, 2016
Last Verified: March 2016