technetium-tc-99m-tetrofosmin and Ventricular-Fibrillation

Topics: 3-Iodobenzylguanidine; Electrophysiologic Techniques, Cardiac; Female; Humans; Male; Organophosphorus Compounds; Organotechnetium Compounds; Tachycardia, Ventricular; Tomography, Emission-Computed, Single-Photon; Ventricular Fibrillation

The purpose of this study is to assess mIBG uptake in scar border zone and its relation with ventricular arrhythmia (VA) inducibility on electrophysiology (EP) testing using I-123 mIBG SPECT and resting Tc-99m SPECT myocardial perfusion imaging (MPI).. Forty-seven patients from a previous clinical trial were retrospectively analyzed. These patients underwent I-123 mIBG and resting Tc-99m tetrofosmin SPECT, and EP testing. Twenty-eight patients were positive (EP+) and 19 patients were negative (EP-) for inducibility of sustained (>30 seconds) VA on EP testing. MPI scar extent, border zone extent, and mIBG uptake in border zone were used to predict VA inducibility on EP testing, respectively.. There was no significant difference in scar extent between the EP+ and EP- groups. The EP+ group had significantly larger border zone and lower mIBG uptake ratio in the border zone than the EP- group. Receiver operating characteristic (ROC) curve analysis showed that the prediction accuracy for border zone extent (area under ROC = 0.75) was better than scar extent (area under ROC = 0.66). The prediction accuracy was further improved (area under ROC = 0.78), when assessing mIBG uptake in the border zone.. A new tool has been developed to measure scar and border zone and to assess mIBG uptake in scar and border zone from combined I-123 MIBG SPECT and resting Tc-99m SPECT MPI. The mIBG uptake in the border zone predicted VA inducibility on EP testing with a promising accuracy.

Topics: 3-Iodobenzylguanidine; Aged; Electrophysiologic Techniques, Cardiac; Female; Humans; Male; Organophosphorus Compounds; Organotechnetium Compounds; Prognosis; Radiopharmaceuticals; Reproducibility of Results; Retrospective Studies; Sensitivity and Specificity; Tachycardia, Ventricular; Tomography, Emission-Computed, Single-Photon; Ventricular Fibrillation

Ventricular arrhythmias have been shown to originate in the myocardial peri-infarct region due to irregular heterotopic conduction. Hypoperfused but viable myocardium is often localised in those areas and may be involved in the pathogenesis of arrhythmias. We tested the hypothesis that these myocardial perfusion/metabolism mismatches (MM) are significantly associated with ventricular arrhythmias in the chronic post infarction state.. 47 post infarction patients were included in the study. 33 suffered from ventricular arrhythmia whereas 14 did not. All patients underwent (99m)Tc tetrofosmin SPECT and (18)F-FDG PET. A region-of-interest(ROI)-analysis was used to assess viable myocardium based on predefined MM-criteria. Univariate analyses as well as a logistic regression model for the multivariate analysis were carried out.. 94% of the arrhythmic patients displayed at least one MM-segment as compared to 64% of the non-arrhythmic patients. MM-segments and arrhythmia showed a statistically significant relation (p = 0.018). The logistic regression model predicted the occurrence or absence of arrhythmia in 85% of all cases. Multivariate analysis gave consistent results, after adjusting for symptomatic chronic heart failure (CHF), aneurysms and age.. Our results support the hypothesis that hypoperfused but viable myocardium represents an arrhythmogenic substrate and is a relevant risk factor for developing ventricular arrhythmias following myocardial infarction. Therefore, the detection of MM-segments allows the identification of patients with a higher risk for future cardiac events.

Topics: Coronary Disease; Female; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Myocardial Infarction; Myocardial Reperfusion; Myocardium; Organophosphorus Compounds; Organotechnetium Compounds; Positron-Emission Tomography; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon; Ventricular Dysfunction, Left; Ventricular Fibrillation

Idiopathic ventricular fibrillation (VF) is diagnosed in up to nearly 10% of survivors of out-of-hospital cardiac arrest. The arrhythmogenic substrate is unknown. This study examined the role of cardiac innervation as a possible contributor to this arrhythmia. Eight patients with idiopathic VF were compared with eight normal subjects (controls) by [123] I metaiodobenzylguanidine SPECT (MIBG), measuring peak uptake, late uptake, and clearance of the nuclear tracer. The left ventricle was divided in 13 segments in the bull's-eye target plot. Peak and late MIBG uptake was increased in the anterolateral segments (2,3,7,8) compared to the inferoposterior and septal segments, in controls and in patients. No difference was observed between controls and patients in the inferoposterior and septal segments. In contrast, a significantly higher MIBG uptake was observed in patients compared to controls in the anterolateral segments (94 +/- 4% vs 81 +/- 11%, P < 0.03 for peak uptake; 94 +/- 5% vs 79 +/- 12%, P < 0.01 for late uptake). No difference was observed in MIBG clearance in any segment in either study group. Cardiac sympathetic innervation is highly heterogeneous, though predominant in anterolateral segments in normal subjects. Patients with idiopathic VF exhibit the same distribution, though have a significantly greater density of sympathetic terminals in the anterolateral segments than controls, which may promote ventricular arrhythmias.

Topics: 3-Iodobenzylguanidine; Adult; Electrocardiography; Female; Heart; Heart Arrest; Heart Ventricles; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Sympathetic Nervous System; Tomography, Emission-Computed, Single-Photon; Ventricular Fibrillation