Alterations in regional myocardial metabolism, perfusion, and wall motion in Duchenne muscular dystrophy studied by radionuclide imaging.

Abstract

Studies at necropsy have shown that the cardiomyopathy of Duchenne muscular dystrophy selects the posterobasal and contiguous lateral left ventricular (LV) walls as initial and primary sites of myocardial dystrophy in the absence of small-vessel coronary artery disease in these areas. The present investigation was designed chiefly to determine whether a myocardial metabolic abnormality could be identified in these same areas during a patient's life. Positron emission computed tomography was used to study regional LV metabolism with '8F 2-fluorodeoxyglucose, and metabolism and/or perfusion was studied with '3NH3. In addition, all subjects had the following performed: thallium-201 scans, technetium-99m multiple-gated equilibrium blood pool imaging, electrocardiograms, vectorcardiograms, and M mode and two-dimensional echocardiograms. '8F 2-fluorodeoxyglucose activity was selectively increased in the posterobasal and posterolateral walls of the left ventricle in 1 1 of 12 patients with technically adequate images, indicating accelerated regional exogenous glucose utilization.13NH3 activity was selectively decreased in the same areas in 13 of 15 patients, indicating either a regional metabolic alteration in uptake and trapping, a reduction in regional blood flow, or both. These data identify a myocardial metabolic abnormality concentrated in specific segments of the LV free wall in living patients with Duchenne dystrophy. Circulation 69, No. 1, [33][34][35][36][37][38][39][40][41][42] 1984 grams (ECGs) are found even in early childhood.56 Tall right precordial R waves and increased R/S amplitude ratios together with deep Q waves in leads 1, aVL, and V5-6 are characteristic of the classic rapidly progressive pseudohypertrophic X-linked dystrophy of Duchenne (figure 1).3-12 A reduction in or loss of electromotive forces caused by myocardial dystrophy in the posterobasal left ventricle (anterior shift of the QRS) and contiguous lateral wall (deep Q waves in leads I, aVL, and V5 6) is believed to be the mechanism responsible for the characteristic ECG.7-9, II Studies at necropsy showed that the above regions are the initial and most extensive sites of myocardial fibrosis,8 10. 11 which is preceded by ultrastructural (subcellular) abnormalities." The primary posterobasal abnormality spreads to the epicardial third of the contiguous lateral left ventricular (LV) free wall with progressive transmural fibrous replacement.", 1 ' There is relative sparing of the ventricular septum and comparatively minimal involvement of right ventricular and atrial

Occult Cardiac Contractile Dysfunction in Dystrophin-Deficient Children Revealed by Cardiac Magnetic Resonance Strain Imaging

“…Three of 4 regions manifested significantly decreased circumferential strain, as did the basal and midventricular segments by repeated-measures ANOVA. In contrast to the present findings, previous investigations with standard echocardiography and radionuclide imaging have reported the primary defects of cardiac involvement in DMD to reside within the inferior 20,21 or posterolateral walls. 22 The reason for this difference most probably reflects the enhanced sensitivity of CMR for detecting widespread but subtle changes of intramural contractile function, which are interpretable only at regional or global levels with the use of alternative technologies.…”

Thallium-201 Single Photon Emission Computed Tomography (SPECT) in Patients With Duchenne's Progressive Muscular Dystrophy

“…Yamamoto et al reported that hypoperfusion or perfusion defects are frequently observed in the posterior and apical walls, 18 and Perloff et al reported that 201 Tl-SPECT and 18 F-fluorodeoxyglucose positron emission tomography can reveal hypoperfusion or perfusion defects in the posterolateral wall. 19 Our results agree with these previous reports. We also found that, in areas with hypoperfusion or perfusion defects, the degree of myocardial fibrosis and fatty infiltration was more severe and extended transmurally.…”

“…It has been reported that 201 Tl-SPECT perfusion defects are frequently seen in the posterolateral wall of the left ventricle in patients with DMD, [18][19][20] and we have also observed the redistribution phenomenon on delayed resting 201 Tl-SPECT images in some patients with DMD. Although the redistribution phenomenon is seen in patients with coronary artery disease, 21 no previous reports have described such a phenomenon or its pathophysiologic correlation in patients with DMD.…”

Proposed Diagnostic Criteria for the Brugada Syndrome

“…Right or left bundle branch block, left ventricular hypertrophy 28 Acute myocardial ischemia or infarction 29 Acute myocarditis 30 Right ventricular ischemia or infarction 31 Dissecting aortic aneurysm 32 Acute pulmonary thromboemboli 33 Various central and autonomic nervous system abnormalities 34,35 Heterocyclic antidepressant overdose 36 Duchenne muscular dystrophy 37 Friedreich's ataxia 38 Thiamine deficiency 39,40 Hypercalcemia 41 Hyperkalemia 42 Cocaine intoxication 43,44 Mediastinal tumor compressing RVOT 45 Arrhythmogenic right ventricular dysplasia/cardiomyopathy 24,25 Long-QT syndrome, type 3 11,12 Other conditions that can lead to ST-segment elevation in the right precordial leads…”