Sebastian A. Cook

Prognosis of patients with left ventricular dysfunction, with and without viable myocardium after myocardial infarction. Relative efficacy of medical therapy and revascularization.

BackgroundThe uptake of F-18 deoxyglucose into dysfunction segments after myocardial infarction identifies metabolically active (FDG+) or inactive (FDG−) myocardium. Although patients with FDG+ segments have been found to be at risk for adverse events, the prognostic significance of viable myocardium in relation to other influences on postinfarction prognosis, including revascularization, remain ill defined. The purpose of this study was to investigate the relative prognostic significance of FDG+ tissue and to establish whether myocardial revascularization in patients with viable tissue attenuates the risk of adverse outcome. Methods and ResultsOne hundred thirty-seven patients with left ventricular dysfunction and resting perfusion defects after myocardial infarction underwent positron emission tomography with both dipyridamole stress Rb-82 perfusion imaging and FDG imaging. After the exclusion of 4 patients proceeding to transplantation, 2 with uninterpretable scans and 2 lost to follow-up, 129 patients were followed clinically for 17 ± 9 months. Four groups were defined: patients with FDG+ dysfunctional myocardium who were revascularized (n = 49) or treated medically (n = 21) and those with FDG− segments who were revascularized (n = 19) or treated medically (n = 40). The groups of patients with FDG+ or FDG− findings, with and without revascularization, did not differ with respect to known determinants of postinfarction prognosis: age, left ventricular ejection fraction, or the prevalence of multivessel disease. Nonfatal ischemic events occurred in 48% of medically treated FDG+ patients compared with 8% of revascularized patients with FDG+ tissue (P < .001) and 5% of patients with FDG- myocardium (P < .001). Thirteen patients died from cardiac causes; 11 (85%) had a left ventricular ejection fraction of < 30%, and these patients were evenly distributed between FDG+ and FDG− groups. Using Coxs proportional hazards model, only the presence of FDG+ myocardium (odds ratio, 12.9; P < .001) and the absence of revascularization (odds ratio, 5.8; P = .002) independently predicted ischemic events, while only age (P = .02) and ejection fraction (P < .001) but not the presence of viable myocardium were predictive of death. ConclusionsResidual viable myocardium after myocardial infarction may act as an unstable substrate for further events unless it is revascularized. Despite this association, age and left ventricular dysfunction remained the strongest predictors of cardiac death after myocardial infarction in these patients with a spectrum of left ventricular dysfunction.

Computed tomography of the thorax and abdomen; a preliminary report

The utility of computed tomography (CT) in the study of the anatomy, physiology, and pathology of the human body has been the subject of considerable interest since the introduction of CT scanning. The advent of a new prototype scanning device has made it possible to examine a variety of abnormalities in the abdomen and thorax in a manner not previously possible. This development permits a remarkable insight into the study of human disease in vivo.

Anomalous origin of the left coronary artery from the pulmonary artery (Bland-White-Garland syndrome) in adult patients: Long-term follow-up after surgery

Congenital anomalous origin of the left coronary artery arising from the pulmonary artery, or the Bland-White-Garland syndrome (BWGS), is an uncommon but frequently lethal lesion of both children and adults.’ Although approximately 80 % to 90% of patients develop congestive heart failure and die in infancy, some patients may present as adolescents or adults.*z3 Although often asymptomatic, many adults with BWGS demonstrate evidence of previous myocardial infarction and frequently exhibit ischemic patterns when evaluated with stress electrocardiography or stress thallium-201 myocardial imaging.4-6 Several reports of recurrent arrhythmias7 or sudden death2s8 in such patients have been published. Most clinicians recognize the need for surgical intervention. Surgical approaches have included reimplantation of the anomalous left coronary artery from the pulmonary artery to the aorta,g ligation of the anomalous left coronary artery from inside the pulmonary artery,‘O or ligation of the left coronary artery combined with saphenous vein grafting to the anterior descending coronary artery.” No data are currently available which demonstrate the superiority of one surgical approach over another in adult patients. This report describes the presentation, evaluation, and long-term follow-up in 10 adult patients with BWGS following various methods of surgical repair.

Successful Percutaneous Extraction of a Chronic Left Ventricular Pacing Lead

This report describes a patient with a chronic endocardial left ventricular pacing lead. To avoid the risk of future embolization, it was felt that the lead should be removed and right ventricular pacing established. The lead was carefully evaluated by transesophageal echocardiography to exclude adherent thrombus. Successful percutaneous lead extraction was accomplished without sequelae, thus avoiding the morbidity of a thoracotomy.

The incidence of scintigraphically viable and nonviable tissue by rubidium-82 and fluorine-18-fluorodeoxyglucose positron emission tomographic imaging in patients with prior infarction and left ventricular dysfunction

BackgroundAlthough reversible perfusion defects, perfusion-metabolism mismatch and match patterns are important for differentiating viable from nonviable myocardium, the frequency of these scintigraphic patterns has not been reported. The study objective was to establish the incidence of these scintigraphic patterns to estimate the clinical need for metabolic positron emission tomography for evaluating tissue viability in patients with prior myocardial infarction (MI).Methods and Results82Rb perfusion images were interpreted to identify reversible or irreversible defects, followed by determination of their 18F-fluorodeoxyglucose (18F-FDG) uptake pattern. In 155 patients with prior MI, analysis of 613 abnormal segments showed reversible perfusion defects in 13%. The 87% irreversible defects, 18% showed perfusion-metabolism mismatch, whereas 69% showed the match pattern. Reversible perfusion defects and perfusion-metabolism mismatches were noted in 20% (31/155) and 29% (45/155) of patients, respectively, whereas the match pattern was noted in 51% (79/155) of patients.ConclusionIrreversible perfusion defects were common in our patients with prior MI, and distinction between viable and nonviable tissue was not possible by perfusion imaging alone. The identification of hibernating myocardium was possible only with the additional 18F-FDG imaging in about one third of patients. This indicates a significant clinical demand for 18F-FDG imaging that identifies patients who will benefit from revascularization.

Unilateral Hyperlucent Lung. Non-Invasive Diagnosis of Pulmonary Artery Agenesis

Presented in part before the Western Regional Scientific Conference of the American College of Angiology and International College of Angiology, February, 1980. From the Departments of Pulmonary Disease (J.R.Y., J.F.T.), Respiratory Therapy (E.M.C.), Internal Medicine (C.M.G.), and Nuclear Radiology (S.A.C.), The Cleveland Clinic Foundation, Cleveland, Ohio. Congenital absence of a pulmonary artery is a rare condition. The patient who survives to adulthood usually presents with an abnormal chest roentgenogram, few symptoms, and a variety of diagnostic possibilities. 1

Prediction of improvement in left ventricular function after ventricular aneurysmectomy using fourier phase and amplitude analysis of radionuclide cardiac blood pool scans

Postoperative improvement in left ventricular (LV) function is a common objective of LV aneurysmectomy, but is difficult to predict. The first Fourier component of time-activity curves of pre- and postoperative gated radionuclide angiographic studies was evaluated for this purpose in 20 patients who had undergone aneurysmectomy. LV aneurysms had portions that characteristically exhibited marked phase delay with varying degrees of amplitude. Total aneurysmal amplitude was obtained preoperatively by summing the amplitude component of all pixels that exhibited phase delay, suggesting paradoxical motion. LV ejection fraction (EF) before and after aneurysmectomy and the absolute postoperative increase in LVEF were calculated. Nine of 20 patients had an absolute increase of EF less than 10% despite resection of large aneurysms. A strong correlation was found between the absolute increase in EF after aneurysmectomy and the total amplitude within paradoxically moving areas (r = 0.93, p less than 0.0001). Thus, preoperative measurement of the total paradoxical amplitude predicts absolute change in EF and may be important in selecting patients for aneurysmectomy. The data also suggest that the total aneurysmal amplitude reflects the stroke volume ejected into an aneurysm in systole and that paradoxical expansion of an aneurysm contributes to LV dysfunction in some of these patients.

Parametric phase display for biventricular function from gated cardiac blood pool single-photon emission tomography

Complete assessment of biventricular function from planar ECG-gated cardiac blood pool studies has been limited because of the overlap of adjacent activity-containing structures. Theoretically, single-photon emission tomography (SPET) can be used to comprehensively evaluate both ventricles by isolating them from surrounding anatomy. However, an enormous amount of parametric data is generated from gated SPET studies, and much of it is diagnostically irrelevant for ventricular wall motion analysis. To compress this information to a more easily interpretable format, a two-dimensional parametric display has been developed. Fourier analysis of short-axis tomograms from a gated cardiac blood pool SPET study generates three-dimensional, first-harmonic phase data. Circumferential profile data from the parametric tomograms of the right and left ventricle are mapped onto a two-dimensional polar display. This method is demonstrated in a normal patient and in three patients with abnormal ventricular contraction patterns and appears to have potential application for the analysis and characterization of biventricular wall motion.

Verification of Fourier phase and amplitude values from simulated heart motion using a hydrodynamic cardiac model

Using pusher-plate-type artificial hearts, changes in the degree of synchrony and stroke volume were compared to phase and amplitude calculations from the first Fourier component of individual-pixel time-activity curves generated from gated radionuclide images (RNA) of these hearts. In addition, the ability of Fourier analysis to quantify paradoxical volume shifts was tested using a ventricular aneurysm model by which the Fourier amplitude was correlated to known increments of paradoxical volume. Predetermined phase-angle differences (incremental increases in asynchrony) and the mean phase-angle difference calculated from RNAs showed an agreement of -7°±4.4° (mean ±SD). A strong correlation was noted between stroke volume and Fourier amplitude (r=0.98; P<0.0001) as well as between the paradoxical volume accepted by the ‘aneurysm’ and the Fourier amplitude (r=0.97; P<0.0001). The degree of asynchrony and changes in stroke volume were accurately reflected by the Fourier phase and amplitude values, respectively. In the specific case of ventricular aneurysms, the data demonstrate that using this method, the paradoxically moving areas may be localized, and the expansile volume within these regions can be quantified.

Automatic Roi Selection for First Transit Nuclear Cardiology

A fully automated chest parsing algorithm has been developed to delineate eight major regions of the upper body after a bolus injection of radiopharmaceutical. The algorithm uses the time-to-max functional image and depends on only one size parameter. Regions are selected by a 4-connected region growing procedure which is table driven from values extablished by an analysis of moments of the time-to-max image and region separation by iterative cluster optimization with a Fishers linear discriminant. On a set of 88 scans (59 cardiac outputs with 11 in heart failure and 29 pediatric shunt analyses), the chest parsings algorithm gave a satisfactory choice for the lungs, 89%; the right heart, 93%; and the left heart, 76%.