ABSTRACT
BACKGROUND: Two methods of computing left ventricular volumes and ejection fraction (EF) from 8-frame gated perfusion single photon emission computed tomography (SPECT) were compared with each other and with magnetic resonance (MR) imaging. METHODS AND RESULTS: Thirty-five subjects underwent 8-frame gated dual-isotope SPECT imaging and 12- to 16-frame gated MR imaging. Endocardial boundaries on short-axis MR images were hand traced by experts blinded to any SPECT results. Volumes and EF were computed with the use of Simpson's rule. SPECT images were analyzed for the same functional variables with the use of 2 automatic programs, Quantitative Gated SPECT (QGS) and the Emory Cardiac Toolbox (ECTb). The mean difference between MR and SPECT EF was 0.008 for ECTb and 0.08 for QGS. QGS showed a slight trend toward higher correlation for EF (r = 0.72, SE of the estimate = 0.08) than ECTb (r = 0.70, SE of the estimate = 0.09). For both SPECT methods, left ventricular volumes were similarly correlated with MR, although SPECT volumes were higher than MR values by approximately 30%. CONCLUSIONS: QGS and ECTb values of cardiac function computed from 8-frame gated perfusion SPECT correlate very well with each other and correlate well with MR. Averaged over all subjects, ECTb measurements of EF are not significantly different from MR values but QGS significantly underestimates the MR values.
Subject(s)
Cardiac Volume/physiology , Magnetic Resonance Imaging , Stroke Volume/physiology , Tomography, Emission-Computed, Single-Photon , Ventricular Dysfunction, Left/diagnostic imaging , Ventricular Dysfunction, Left/pathology , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/pathology , Coronary Artery Disease/physiopathology , Female , Gated Blood-Pool Imaging , Heart/diagnostic imaging , Heart/physiopathology , Humans , Image Processing, Computer-Assisted , Male , Middle Aged , Myocardium/pathology , Ventricular Dysfunction, Left/physiopathologySubject(s)
Cardiomyopathy, Dilated/complications , Adolescent , Adult , Cardiomyopathy, Dilated/drug therapy , Female , Follow-Up Studies , Humans , Male , Middle Aged , PrognosisSubject(s)
Anemia, Hemolytic/etiology , Endocardial Cushion Defects/surgery , Heart Septal Defects/surgery , Adolescent , Adult , Child , Child, Preschool , Female , Heart Septum/surgery , Heart Valve Prosthesis/adverse effects , Humans , Infant , Male , Mitral Valve/abnormalities , Mitral Valve/surgery , Postoperative Complications/etiologySubject(s)
Cardiac Output/drug effects , Catecholamines/administration & dosage , Dobutamine/administration & dosage , Adult , Dose-Response Relationship, Drug , Female , Heart Failure/drug therapy , Heart Failure/physiopathology , Humans , Infusions, Parenteral , Male , Middle Aged , Monitoring, Physiologic/methods , Plethysmography, Impedance , Stroke Volume/drug effectsSubject(s)
Cardiac Pacing, Artificial/methods , Sick Sinus Syndrome/diagnosis , Adolescent , Aged , Electrocardiography , Esophagus , Female , Humans , Male , Middle AgedSubject(s)
Arrhythmia, Sinus/diagnosis , Electric Stimulation/methods , Adult , Aged , Electrodes , Esophagus , Female , Heart Conduction System/physiopathology , Humans , Male , Middle AgedSubject(s)
Resuscitation , Coronary Care Units , History, 20th Century , Humans , Poland , Resuscitation/history , Resuscitation/standardsSubject(s)
Heart Valve Diseases/surgery , Heart Valve Prosthesis , Adult , Aortic Valve/surgery , Female , Follow-Up Studies , Humans , Male , Middle Aged , Mitral Valve/surgery , Time FactorsSubject(s)
Myocardial Infarction/mortality , Acute Disease , Adult , Age Factors , Aged , Coronary Care Units , Humans , Middle Aged , Time FactorsABSTRACT
The influence of retrograde conduction of the artificial pacemaker impulse from the right ventricle to the atria exerted upon the occurrence of rapid supraventricular rythms was investigated in patients with sick sinus syndrome. The bouts of tachycardia occurred in cases with fixed V-A retrograde block or coincided with temporary V-A block. The usually operating retrograde conduction from the pacemaker to the atria protects the patients from paroxysms of supraventricular tachycardia by means of the coordinated depolarization of the atria and junctional tissue.
