Article

Abnormal sympathetic innervation of viable myocardium and the substrate of ventricular tachycardia after myocardial infarction.

Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Journal of the American College of Cardiology (Impact Factor: 14.09). 07/2008; 51(23):2266-75. DOI: 10.1016/j.jacc.2008.02.062
Source: PubMed

ABSTRACT The aim of this study was to characterize the relationship between impaired sympathetic innervation and arrhythmia with noninvasive biologic imaging in an animal model of post-infarct ventricular tachycardia (VT).
Innervation might be abnormal in the normally perfused borderzone of myocardial infarction, contributing to myocardial catecholamine overexposure and arrhythmogenic risk.
Myocardial infarction was induced by mid-left anterior descending coronary artery balloon occlusion in 11 pigs. Positron emission tomography (PET) of tissue perfusion and catecholamine uptake and storage was performed with [13N]-ammonia and [11C]-epinephrine 4 to 12 weeks later. Magnetic resonance imaging and invasive electrophysiology (electroanatomic mapping, basket catheter, VT inducibility) were performed within 1 week of PET.
When compared with a normal database of 9 healthy animals, reduced perfusion was observed in 37 +/- 7% of the left ventricle (LV). Epinephrine retention was reduced in 44 +/- 7% of LV, resulting in a perfusion/innervation mismatch of 7 +/- 4% LV. Sustained monomorphic VT was inducible in 7 of 11 animals. These animals showed a larger perfusion/innervation mismatch (10 +/- 4% vs. 4 +/- 2% LV for animals without VT; p = 0.02). Regionally, the degree of perfusion/innervation mismatch did not correlate with wall thickness or thickening but showed a significant correlation with reduced myocardial voltage (r = 0.93; p = 0.001) and with the site of earliest VT activation (chi-square 13.1; p < 0.001).
Noninvasive mapping of cardiac sympathetic nerve terminals reveals regionally impaired catecholamine uptake and storage in the normally perfused borderzone after experimental myocardial infarction. These areas might be useful to characterize the individual risk for ventricular arrhythmia.

0 Bookmarks
 · 
63 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Evaluation of the molecular processes responsible for disease pathogenesis and progression represents the new frontier of clinical radiology. Multi-modality imaging lies at the cutting edge; combining the power of magnetic resonance imaging for tissue characterisation, microstructural appraisal and functional assessment; together with new positron emission tomography tracers designed to target specific metabolic processes.The recent commercial availability of an integrated clinical whole-body Positron Emission Tomography-Magnetic Resonance Imaging (PET-MRI) provides a hybrid platform for exploring and exploiting the synergies of multi-modal imaging. First experiences on the clinical and research application of hybrid PET-MRI are emerging. This article reviews the rapidly evolving field and speculates on potential future direction.
    The British journal of radiology 11/2013; · 2.11 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Intramyocardial bone marrow cell injection has been associated with improvements in myocardial perfusion and left ventricular function. The current substudy of a randomized, placebo-controlled, double-blinded study, investigated the effect of intramyocardial bone marrow cell injection on myocardial sympathetic innervation in patients with chronic myocardial ischemia. In a total of 16 patients (64 ± 8 years, 13 men), early and late iodine-123 metaiodobenzylguanidine (MIBG) imaging was performed before and 3 months after intramyocardial bone marrow cell injection. No improvements were observed in global early H/M ratio (P = 0.40), late H/M ratio (P = 0.43) and cardiac washout rate (P = 0.98). However, late 123-I MIBG SPECT defect score showed a trend to improvement in the bone marrow cell group (from 31.0 ± 7.1 to 28.1 ± 14.9) as compared to the placebo group (from 33.6 ± 8.5 to 34.5 ± 9.8, P = 0.055 between groups). This trend was mainly driven by a substantial improvement in three bone marrow cell-treated patients, which all had diabetes and severe MIBG defects. In these patients, the extent and severity of MIBG defects improved substantially independent of myocardial perfusion and cell injection sites. The present study does not demonstrate improvements in global cardiac sympathetic nerve innervation after intramyocardial bone marrow cell injection in patients with chronic myocardial ischemia. However, regional analysis of sympathetic nerve innervation reveals improvements in three diabetic patients independent of myocardial perfusion, suggestive of a therapeutic effect on diabetic cardiac sympathetic dysinnervation.
    The international journal of cardiovascular imaging 01/2014; · 2.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cardiac sympathetic nerve sprouting and the dysregulation of β-adrenergic receptor (β-AR) play a critical role in the deterioration of cardiac function after myocardial infarction (MI). Growing evidence indicates that exercise provides protection against MI. The aims of this study were to investigate whether aerobic exercise following MI could inhibit sympathetic nerve sprouting and restore the balance of β3-AR/β1-AR.
    PLoS ONE 01/2014; 9(5):e97810. · 3.53 Impact Factor

Full-text (2 Sources)

View
23 Downloads
Available from
May 21, 2014