Risk stratification of patients with prior myocardial infarction and advanced left ventricular dysfunction by gated myocardial perfusion SPECT imaging.
ABSTRACT The Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II) has shown that the prophylactic implantable cardiac defibrillator improves the survival rate of patients with prior myocardial infarction and advanced left ventricular (LV) dysfunction. However, a more accurate noninvasive predictor should be found to identify subgroups at high risk, one that would allow implantable cardiac defibrillator therapy to be directed specifically to the patients who would benefit most.
To elucidate whether technetium 99m tetrofosmin electrocardiogram-gated single photon emission computed tomography (SPECT) imaging at rest can determine the risk of arrhythmic death, 106 patients who met the MADIT-II criteria (LV ejection fraction <or=0.3, myocardial infarction >1 month earlier, and no sustained ventricular tachyarrhythmia) were recruited from a pool of 4628 consecutive patients who had undergone resting Tc-99m tetrofosmin SPECT imaging. By use of the endpoints of lethal arrhythmic events, which included documentation of sustained ventricular tachycardia, ventricular fibrillation, or diagnosis of sudden cardiac death, we performed follow-up for a mean of 30 months. Lethal arrhythmic events occurred in 14 patients. Patients with lethal arrhythmic events had a lower LV ejection fraction, greater LV end-systolic and end-diastolic volume indices, and a greater perfusion defect volume than the remaining patients. By receiver operating characteristic curve analysis, myocardial defect volume was the strongest predictor for the development of lethal arrhythmic events.
Our results confirm that perfusion defect volume by Tc-99m tetrofosmin scintigraphy is the most pivotal predictor of the future occurrence of lethal arrhythmic events and of sudden cardiac death. Tc-99m tetrofosmin SPECT images may assist in identifying subsets of patients with a greater likelihood of arrhythmic death among patients with LV dysfunction.
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ABSTRACT: BACKGROUND: Although several predictors of an electrical storm (ES) are indicated in patients with idiopathic dilated cardiomyopathy (IDCM), whether the severity of the myocardial tissue damage (SMTD) evaluated by myocardial perfusion SPECT (MPS) has an association with an ES remains unclear. The purpose of this study was to elucidate the clinical significance of SMTD for the prediction of ES in IDCM patients with an ICD. METHODS: Thirty-seven (27 men, mean age 58 ± 15 years) IDCM patients receiving ICD implantations for secondary prevention with preoperative MPS were enrolled in this study. The medical history, physical and laboratory findings, electrocardiograms, echocardiograms and MPS findings were evaluated. The SMTD was assessed by the summed scores of 17 segments using a 4-point system (0, normal ~3, severe defect). RESULTS: During a mean follow-up of 43.9 ± 30.7 months, an ES developed in 12/37 (32.4 %) patients. The SMTD score predicted an ES with a 92 % sensitivity and 56 % specificity, at a cut-off score of 10. In addition, a multivariate analysis showed that the SMTD score remained an independent predictor of an ES (HR 1.09/score 1 increase, 95 % CI 1.01-1.19, p = 0.02). The SMTD score was significantly associated with three indices of late potentials on the signal-averaged electrocardiograms, and was significantly higher in patients with positive late potentials (p = 0.0006). CONCLUSION: SMTD score assessed by MPS has a strong correlation to the late potentials and higher SMTD score may increase the risk of ES among patients with IDCM and an ICD.Annals of Nuclear Medicine 02/2013; · 1.41 Impact Factor
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ABSTRACT: Left ventricular ejection fraction (LVEF) is a useful tool for stratifying risk for heart failure progression and life-threatening arrhythmic events. Yet, the clinical course of heart failure patients with severely reduced LVEF is variable, and the majority of patients who die suddenly do not have an LVEF ≤35%. A recently completed large multicenter trial, ADMIRE-HF, confirms that cardiac neuronal imaging with I-123 metaiodobenzylguanidine is an important independent predictor of heart failure progression and sudden cardiac death. Data from that study indicate that heart failure patients with severe impairment of cardiac sympathetic innervation are at highest risk for heart failure progression, heart failure patients with moderate impairment of sympathetic innervation are at highest risk for life-threatening arrhythmic events, and heart failure patients with preserved sympathetic innervation are at low risk for either death due to heart failure progression or sudden cardiac death. KeywordsNuclear cardiology-Neuronal imaging-I-123 metaiodobenzylguanidine-C-11 hydroxyephedrine-Heart failure-Implantable cardioverter-defibrillator-Sympathetic nervous systemCurrent Cardiovascular Imaging Reports 06/2010; 3(3):119-126.
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ABSTRACT: OBJECTIVE: To identify the predictive factors of myocardial stunning as assessed by the drop in post-stress Left Ventricular Ejection Fraction (LVEF) in patients with a recent history of myocardial infarction (MI). METHODS: We prospectively included 215 consecutive patients admitted for acute MI who underwent percutaneous coronary intervention with a greater than or equal to grade-3 TIMI flow in the culprit vessel. Six months after discharge, a post-stress/rest (99m)Tc-sestamibi gated SPECT was performed. The perfusion score was evaluated visually using a 17-segment model. The LVEF drop was considered significant if the post-stress LVEF was ≥5 % below the rest LVEF (QGS(®) software). RESULTS: A post-stress LVEF drop was observed in 51 (24 %) patients. Patients with an LVEF drop were more likely than patients with a stable post-stress LVEF to have diabetes (22 % vs. 10 %, p = 0.048), significant ischemia (SDS > 2) (51 % vs. 28 % p = 0.003) and higher rest LVEF [62 % (56-69) vs. 56 % (49-63) p < 0.001]. In contrast, summed rest score, related to infarct size, did not differ between the groups. Multivariate logistic regression analysis identified SDS > 2 (OR 3.78, 95 % CI 1.8-7.92, p < 0.001), diabetes (OR 3.35, 95 % CI 1.33-8.49; p = 0.011) and rest LVEF (OR 1.08, 95 % CI 1.04-1.12, p < 0.001) as independent explanatory variables of an LVEF drop. CONCLUSION: In patients with recent MI and post-procedural grade-3 TIMI flow, ischemia and diabetes were independent predictive factors of myocardial stunning. The higher incidence of reversible perfusion abnormalities validates the model of myocardial stunning in the post-MI period, and excludes the potential involvement of myocardial necrosis.Annals of Nuclear Medicine 10/2012; · 1.41 Impact Factor