Nili Zafrir

The incidence of atrial arrhythmias during inferior wall myocardial infarction with and without right ventricular involvement.

The atrial arrhythmia profile during inferior wall acute myocardial infarction (AMI) has not been systematically examined with respect to right ventricular (RV) involvement. To this end, 62 consecutive patients with first inferior wall AMI and no other conditions known to increase susceptibility for rhythm disturbances were studied by 24-hour Holter monitoring during the first and tenth day of infarction. Based on radionuclear ventriculography performed on day 2 of infarction, patients were allocated to two groups: group A--36 patients (58%) with right ventricular ejection fraction (RVEF) less than 40% (mean +/- SD, 31 +/- 6%) and group B--26 patients (42%) with normal (greater than 40%) RVEF (mean +/- SD, 47 +/- 5%). There were no significant differences between the two groups with respect to age, sex, or left ventricular (LV) function. In the group as a whole, ectopic activity in the different categories of atrial arrhythmias was significantly higher during the first day than on the tenth day of infarction. Comparing the two groups, 33 patients (92%) in group A had a mean hourly frequency of one or more atrial premature contractions (APCs) during the first day of infarction compared with 18 patients (69%) in group B (p less than 0.001). Atrial and supraventricular tachycardia were recorded more frequently in group A patients (16 of 36 [44%] versus 8 of 26 [31%]) as well as atrial fibrillation (AF) (7 of 36 [19%] versus 1 of 26 [4%]). Quantitative analysis showed a similar trend for a higher rate of ectopic events in group A patients. Ectopic activity was neither influenced by LVEF nor by age or sex.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolated mid-anterior myocardial infarction: a special electrocardiographic sub-type of acute myocardial infarction consisting of ST-elevation in non-consecutive leads and two different morphologic types of ST-depression

UNLABELLEDnWe describe eight patients with a distinct electrocardiographic pattern of anterior wall myocardial infarction characterized by three main features: (1) a pattern of transmural ischemia (ST-elevation with positive T-wave) in non-consecutive leads: a VL and V2, and two different types of ST-depression; (2) a pattern of true reciprocal changes (ST-depression and negative T-wave) in III and a VF; (3) a pattern of sub-endocardial ischemia (ST-depression with positive T-wave) in V4-5, while ST in V3 was either isoelectric or depressed. We characterize the electrocardiographic features and correlate them with the echocardiographic, radionuclide, and angiographic data. All patients admitted to the coronary care unit from January 1990 to April 1992 with evolving acute myocardial infarction were evaluated prospectively. Patients whose admission electrocardiogram met the description above were included. The electrocardiographic evolution, echocardiographic, Technetium MIBI tomography, and coronary angiography are described. Of 471 patients with acute anterior wall myocardial infarction, admitted to the coronary care unit during the study period, eight patients met the inclusion criteria (1.7% of acute anterior wall myocardial infarction). Echocardiographic studies revealed mid-anterior hypokinesis in two patients, anterior and apical hypokinesis in one, and no wall motion abnormality in four patients. Technetium MIBI tomography, done in five patients, was consistent with mid-anterior or midanterolateral infarction without involvement of the septum or apex. Coronary angiography, performed in seven patients, demonstrated significant obstruction of the first diagonal branch in all of the patients. In four patients, the diagonal occlusion was the only significant coronary lesion in the left coronary artery.nnnCONCLUSIONnMost of the anterior myocardial infarctions also involve the septal and apical regions. Anterior wall myocardial infarctions limited to the mid-anterior or mid-anterolateral wall, without apical or septal wall involvement are relatively rare. This study describes a special electrocardiographic form of anterior wall acute myocardial infarction. This distinct electrocardiographic pattern represents true mid-anterior wall myocardial infarction, caused by occlusion of a first diagonal branch of the left anterior descending coronary artery. The septal and apical regions are not involved because the blood supply via the left anterior descending artery is not interrupted.

Left and right ventricular function in inferior acute myocardial infarction and significance of advanced atrioventricular block.

Of 139 consecutive patients with a first inferior acute myocardial infarction, 26 (19%) had advanced atrioventricular (AV) block and 113 (81%) did not. All were evaluated by 2-dimensional echocardiography (2-D echo) and radionuclide angiography. Patients with advanced AV block had lower radionuclide left ventricular (LV) ejection fraction (51 +/- 10 vs 58 +/- 11%, p less than 0.01), higher LV wall motion score on 2-D echo (5.6 +/- 2.6 vs 3.1 +/- 2.7, p less than 0.001), lower radionuclide right ventricular (RV) ejection fraction (32 +/- 15 vs 39 +/- 16%, p less than 0.001) and higher RV wall motion score on 2-D echo (3.4 +/- 1.7 vs 1.5 +/- 2, p less than 0.002) than did patients without AV block. The incidence rate of RV dysfunction was higher in patients with advanced AV block (78 vs 40%, p less than 0.02), and the mortality rate was also higher (although not significantly) in patients with advanced AV block (15 vs 6%). In conclusion, patients with inferior acute myocardial infarction and advanced AV block have larger infarct sizes (as seen on radionuclide angiography and 2-D echo) and lower RV and LV function than patients without AV block. This finding may explain the higher mortality rate observed in this group.

Use of noninvasive tools in primary pulmonary hypertension to assess the correlation of right ventricular function with functional capacity and to predict outcome

Abstractxa0Most patients with Primary Pulmonary Hypertension (PPH) have severe exertional limitation which ultimately leads to right heart failure and death. The purpose of the study was to assess the correlation between right ventricular (RV) systolic and diastolic noninvasive variables and exercise tolerance, as well as the predictors of adverse outcome in treated patients.MethodsWe prospectively studied 29 patients, 17 with PPH and 12 with PPH due to collagen disease. RV parameters were assessed by echocardiography and Radionuclide ventriculography. Pulmonary function and clinical profile were assessed by 6xa0min walk test and NYHA class. The patients were followed-up during 2xa0years for cardiac death and cardiac deterioration.ResultsMean age was 51xa0±xa015xa0years, 22 (78%) women. NYHA class1 in 2 pts, class 2 in 17, class 3 in 8 and class 4 in 2xa0pts. Pulmonary function (DLCO) was low in 25 (86%) pts, mean 22xa0±xa048%. Six minutes walk distance was 358xa0±xa0132xa0m, RVEF was 34xa0±xa011% (range 16–51%). Among RV variables, RVEF, RA area and TR were independently correlated to 6xa0min walk. Within follow up of 2xa0years, there were 10 patients with adverse outcome (4 deaths and 6 deteriorated to NYHA class 3 and 4). Among all clinical and noninvasive variables, RVEF only was correlated to adverse outcome.ConclusionThe noninvasive tests of RVEF, RA size and TR were closely correlated to exercise tolerance. However, among the various clinical, functional and RV variables, RVEF was the only variable correlated with adverse outcome in pts with PPH.

Prognostic value of left ventricular dyssynchrony by myocardial perfusion-gated SPECT in patients with normal and abnormal left ventricular functions

BackgroundLeft ventricular (LV) dyssynchrony by phase analysis has been studied by myocardial perfusion imaging (MPI)-gated SPECT in patients with LV dysfunction in various clinical settings. We aimed to investigate the routine use of phase analysis with gated SPECT for predicting cardiac outcome.MethodsPatients referred to a tertiary medical center in 2010-2011 prospectively underwent a gated SPECT and phase analysis, and follow-up for cardiac events. The values of clinical variables, MPI, LV function, and LV dyssynchrony in predicting cardiac events were tested by univariate and multivariate analyses.ResultsThe study group included 787 patients (66.5xa0±xa011xa0years, 81% men) followed for a mean duration of 18.3xa0±xa06.2xa0months. There were 45 (6%) cardiac events defined as composite endpoint; cardiac death occurred in 26 patients, and the rest had new-onset or worsening heart failure and life-threatening arrhythmias. In multivariate analysis, it was shown that NYHA class, diabetes mellitus, and LVEF <50% were the independent predictors for composite endpoint. However, the independent predictors for cardiac mortality were NYHA class (for each increment in class) and phase standard deviation (SD) (for each 10° increment).ConclusionGated SPECT with phase analysis for the assessment of LV dyssynchrony can successfully predict cardiac death together with NYHA class, in patients with LV dysfunction.

Feasibility of myocardial perfusion imaging with half the radiation dose using ordered-subset expectation maximization with resolution recovery software

ObjectiveThis study sought to assess the feasibility of performing myocardial perfusion imaging (MPI) with half the technetium activity using ordered-subset expectation maximization with resolution recovery (OSEM-RR), an iterative reconstruction software developed to improve count statistics and acquisition time.MethodsTwo hundred eighteen patients referred for MPI were randomly allocated to undergo stress-rest or rest-stress protocols with standard full-dose (FD) injections of technetium (Tc)-99m sestamibi or half-dose (HD) injections and OSEM-RR processing. Dose activities were adjusted individually by weight. The groups were compared for image quality and clinical results.ResultsThe groups were similar for mean patient age, weight, and body mass index, sex distribution, pre-test probability of CAD and CAD prevalence. Mean Tc-99m activities for the low-dose and high-dose stages were as follows: FD group: 429xa0±xa085xa0MBq and 1132xa0±xa0200xa0MBq; HD group: 263xa0±xa0129xa0MBq and 629xa0±xa085xa0MBq (Pxa0<xa0.0001 for both). Mean effective dose per study was 13.6xa0±xa01.4xa0mSv in the FD group and 7.7xa0±xa01.0xa0mSv in the HD group (Pxa0<xa0.001). Over all image quality was good-to-excellent in 98% and 95% of the groups, respectively. However, when we analyzed the low-dose stage separately, image quality was slightly worse in the HD than the FD, though still within the good-to excellent range.ConclusionsMPI with nearly half the radiation dose is feasible with good image quality.

Dipyridamole first-pass radionuclide ventriculography: Prediction of future cardiac events

Dipyridamole thallium myocardial perfusion imaging is a useful alternative to stress testing in the diagnostic and prognostic assessment of patients with coronary artery disease. The diagnostic use of dipyridamole radionuclide ventriculography is much more controversial, but no long-term prognostic studies have been reported. Imaging results of 159 consecutive patients who were referred for dipyridamole first-pass radionuclide ventriculography were correlated with subsequent cardiac events over a mean follow-up period of 11 months. An abnormal response to dipyridamole infusion (any reduction in wall motion or absolute decrease in global left ventricular ejection fraction of > or = 5 ejection fraction units) was associated with an increased incidence of nonfatal myocardial infarction (4.5% vs 0%, p < 0.05) and cardiac-related death (9% vs 1%, p < 0.001). The sensitivity, specificity, and negative predictive value of dipyridamole first-pass radionuclide ventriculography in predicting future cardiac events were 86%, 71%, and 98%, respectively, with a relative risk of 15 (confidence interval 12.06 to 18.1). In conclusion, dipyridamole first-pass radionuclide ventriculography demonstrated significant prognostic value in a large unselected patient population. This technique may provide a widely applicable and useful alternative to dipyridamole thallium perfusion imaging in the assessment of cardiac risk in patients with coronary artery disease.

Feasibility of myocardial perfusion imaging with half the radiation dose in obese patients using ordered-subset expectation maximization with resolution recovery software.

BackgroundWe previously described the feasibility of myocardial perfusion imaging (MPI) with nearly half the radiation dose using ordered-subset expectation maximization with resolution recovery (OSEM-RR) processing. This study sought to determine if the findings can be expanded to obese patients.MethodsFifty obese patients (>100xa0kg) referred for MPI underwent stress-rest or rest-stress studies with a half dose of Tc-99m sestamibi in a 1-day protocol using OSEM-RR processing. Image quality and clinical results were compared with matched patients (by age, sex, weight, presence/probability of coronary artery disease) evaluated with standard “full-dose” Tc-99m sestamibi, mostly in a 2-day protocol. Dose activities were adjusted individually by weight.ResultsMean Tc-99m activity was 33.4xa0±xa013.9xa0mCi in the half-dose group and 60xa0±xa010xa0mCi in the full-dose group (Pxa0<xa0.0001). Respective mean effective doses per study were 10xa0±xa04 and 18xa0±xa03xa0mSv (Pxa0<xa0.0001). Overall image quality was good-to-excellent in 94% of the half-dose group and 80% of the full-dose group (Pxa0<xa0.045). There was no between-group difference in rate or size of ischemia or infarction, except for stress left ventricular ejection fraction.ConclusionsMPI with half the radiation dose is feasible in obese patients. Image quality is better than for full-dose MPI, and the procedure can be performed in 1xa0day.

Prognosis of stress-only SPECT myocardial perfusion imaging with prone imaging

BackgroundStress-only single-photon emission computed tomography myocardial perfusion imaging (SO SPECT MPI) is associated with similarly benign prognosis as stress-rest SPECT MPI. However, previous studies have used attenuation correction rather than prone imaging to increase the rate of SO studies.ObjectivesTo assess the prognosis of SO SPECT MPI performed with prone imaging.MethodsWe performed a retrospective cohort analysis of all patients who underwent a Tc-99m gated SPECT MPI over a 58-month period.ResultsTwo thousand four hundred and sixty five patients were followed up. Of them, 1114 (45.2%) patients had a SO supine test, 388 (15.7%) underwent a SO supine and prone test, and the remaining 963 (39.1%) patients underwent a full stress-rest SPECT MPI. There was a similar annual mortality rate between the SO supine/prone group (1.3%), the SO supine (1.5%), and the stress-rest (1.5%) group (Pxa0=xa00.47). Patients in the stress-rest group were significantly more likely to suffer from myocardial infarction (MI) as compared to the other two groups with an annual rate of 0.7% as compared to 0.4% (Pxa0=xa00.049).ConclusionsNormal supine-prone SO SPECT MPI is associated with a similarly benign prognosis as stress-rest SPECT MPI. The adjunction of prone imaging to the stress supine significantly increases the rate of SO SPECT MPI

Feasibility of myocardial perfusion SPECT with prone and half-time imaging.

BackgroundMyocardial perfusion imaging with single-photon emission tomography (SPECT) is associated with reduced specificity due to tissue attenuation. This can be corrected by prone imaging while necessitating additional imaging time. Image processing with iterative reconstruction allows for a half-time (HT) acquisition. ObjectiveTo assess the feasibility of myocardial perfusion with SPECT using prone imaging with HT acquisition. MethodsNinety-one patients referred for SPECT myocardial perfusion imaging and weighing up to 90 kg were enrolled for HT supine and prone SPECT protocol. Patients with known myocardial infarction were excluded. HT prone imaging was performed when supine imaging was visually equivocal or abnormal. Image quality was compared for each patient between supine and prone imaging. ResultsAcquisition time was 17.9±2.9 min in the HT group compared with 31.8±5.8 min in patients imaged with full-time acquisition. Image quality was good or excellent in 85.7% of studies in a supine position and in 81.3% of studies in the prone position (P=0.25). No study was considered as nondiagnostic. Prone imaging reduced the rate of equivocal scans from 40.7 to 15.4% and of ischemic studies from 34.1 to 7.7%. In the study population, 80% of inferior and septal defects were corrected by the prone position. ConclusionIn a selected population, HT prone and supine imaging is feasible and is associated with a good image quality in most studies whereas acquisition time is reduced almost by half.