ABSTRACT: BackgroundPrevious studies have shown that the risk of major cardiovascular events at 1 year is less than 1% in patients with normal
myocardial stress perfusion study results. However, the racial distribution of patients enrolled in these studies is not known.
Hence, the prognostic value of normal stress perfusion study results in black patients is not well established. Our objective
was to determine the incidence of major cardiovascular events in black patients with normal stress perfusion study results
over a 12-month period.
Methods and ResultsWe searched the nuclear cardiology database at our institution for all black patients who had normal stress perfusion study
results between January 1990 and December 1996. We excluded patients with a history of coronary revascularization, valvular
heart disease, cardiomyopathy, congenital heart disease, left bundle branch block, or pre-excitation syndrome. Patients were
followed up for at least 12 months from the time of inclusion. A total of 592 patients were enrolled and were followed up
for 18 ± 6 months (mean ± SD). Of these, 388 underwent treadmill exercise testing, 155 underwent dipyridamole stress testing,
and the remainder underwent dobutamine stress testing. Perfusion studies were performed in all patients with thallium 201
single photon emission computed tomography imaging. During the follow-up period, 11 cardiac deaths and 7 myocardial infarctions
(MIs) occurred. The incidence of cardiac deaths was 1.2% per year, and that of nonfatal MIs was 0.8% per year. The total incidence
of major cardiovascular events was 2% per year. In patients who underwent treadmill exercise testing, the incidence of major
cardiovascular events was 1% per year. Performance of a pharmacologic stress test and a prior MI were significantly associated
with death or nonfatal MI (P < .05).
ConclusionsThe overall incidence of major cardiovascular events in black patients after normal exercise perfusion study results were
obtained was low (1%). However, black patients who had normal perfusion study results but underwent pharmacologic stress testing
or had a history of MI were at intermediate risk. These patients require close surveillance for major cardiovascular events.
Journal of Nuclear Cardiology 04/2012; 8(5):541-547. · 2.67 Impact Factor
Journal of Nuclear Cardiology 01/2009; 16(1):164-164. · 2.67 Impact Factor
Journal of Nuclear Cardiology 12/2006; 13(6):e56-79. · 2.67 Impact Factor
ABSTRACT: Various algorithms have been developed to compute right ventricular (RV) and left ventricular (LV) end-diastolic volumes, end-systolic volumes, and ejection fractions (EF) from tomographic radionuclide ventriculography (TRV). The aims of this investigation were to establish sex-specific normal limits, to determine whether different algorithms produce the same normal values, and to compare TRV normal limits vs for magnetic resonance imaging values in the literature.
Fifty-one healthy volunteers (29 men, 22 women) were studied prospectively. All subjects had normal electrocardiograms and echocardiographic examinations, and underwent both planar radionuclide ventriculography and TRV. Four algorithms were used to process TRV data.
Normal limits for most functional parameters differed significantly from one algorithm to another. Volumes were greater in men, but no statistically significant differences were found between men and women for LV EF or RV EF values for any method. Normal LV and RV EF and volumes were largely consistent with the literature for cardiac magnetic resonance imaging.
Ventricular measurements differ significantly among TRV algorithms. Therefore, it is important to apply sex-specific normal limits that are specific to a given TRV algorithm in interpreting LV and RV EF and volume measurements for each patient.
Journal of Nuclear Cardiology 10/2006; 13(5):675-84. · 2.67 Impact Factor
Clinical Nuclear Medicine 07/2006; 31(6):333-4. · 3.67 Impact Factor
ABSTRACT: It is not clearly understood why concentric left ventricular hypertrophy (increased left ventricular mass and relative wall thickness) is associated with higher cardiovascular risk than eccentric hypertrophy (increased left ventricular mass but normal relative wall thickness). Possible reasons include lower myocardial efficiency or perfusion reserve in concentric than in eccentric hypertrophy. We compared myocardial perfusion reserve and efficiency in normotensive controls and in hypertensive patients with concentric and with eccentric hypertrophy.
Study subjects comprised 16 patients with hypertension-induced left ventricular hypertrophy and 10 normotensive controls. We measured myocardial perfusion reserve and oxygen consumption by positron emission tomography. We calculated myocardial efficiency by dividing left ventricular minute work by myocardial oxygen consumption.
There was no significant difference in myocardial perfusion reserve between patients with concentric (n = 9) as compared to eccentric (n = 7) hypertrophy. However, myocardial perfusion reserve in both patient groups were lower than in controls. Although myocardial efficiency in patients with eccentric hypertrophy and in controls were not different, both values were higher than measurements in patients with concentric hypertrophy (18% +/- 6% v 16% +/- 3% v 13% +/- 4%, eccentric hypertrophy versus controls versus concentric hypertrophy, respectively, P =.04 for both eccentric versus concentric hypertrophy and for controls versus concentric hypertrophy).
Myocardial efficiency but not perfusion reserve is lower in hearts with concentric compared with eccentric left ventricular hypertrophy. This might be an explanation for the higher cardiovascular morbidity and mortality associated with concentric left ventricular hypertrophy.
American Journal of Hypertension 06/2004; 17(5 Pt 1):433-8. · 3.18 Impact Factor
ABSTRACT: The aim of this study was to identify the best correlate of myocardial oxygen demand (MVO(2)) in patients with hypertension induced left ventricular hypertrophy (LVH), and to examine whether relationships between these surrogates and MVO(2) differed between patients with LVH and control subjects.
We measured MVO(2) by positron emission tomography using carbon-11 acetate in 20 patients and 10 normotensive control subjects, and compared the relationships between commonly used surrogates and MVO(2).
With the exception of diastolic blood pressure, the same variables correlated with resting MVO(2) in the patients and control subjects.
The best correlate of resting MVO(2) in the patients with hypertension induced LVH was the stress-mass-heart rate product.
American Journal of Hypertension 04/2003; 16(3):240-3. · 3.18 Impact Factor
ABSTRACT: This study examines the relationship between functional capacity, left ventricular diastolic function, and myocardial perfusion reserve (MPR) in patients with left ventricular hypertrophy (LVH).
We studied 16 patients with LVH and 10 controls. Functional capacity was assessed by cardiopulmonary exercise, MPR by positron emission tomography, and left ventricular diastolic function by echo-Doppler.
Functional capacity and MPR were significantly lower in the patients. Functional capacity correlated positively with MPR and left ventricular diastolic function.
Diminished functional capacity in patients with hypertension-induced LVH is related to the impairment in MPR and left ventricular diastolic function.
American Journal of Hypertension 11/2002; 15(10 Pt 1):907-10. · 3.18 Impact Factor
ABSTRACT: The goal of this study was to compare myocardial perfusion reserve (MPR) before and after long-term treatment with lisinopril and losartan in patients with hypertension and left ventricular hypertrophy (LVH).
Studies have suggested that treatment with angiotensin-converting enzyme inhibitors (ACEIs) improves MPR in patients with hypertension by potentiating endogenous bradykinins. Because angiotensin receptor blockers (ARBs) lack a direct effect on bradykinins, we hypothesized that they may not improve MPR.
We measured pre- and post-treatment myocardial blood flow (MBF) by positron emission tomography in 17 patients (lisinopril: 9 patients, losartan: 8 patients) with hypertension and LVH at baseline and after coronary vasodilation with intravenous dipyridamole. In addition, we measured rest and hyperemic blood flow in eight normotensive controls.
Post-treatment maximal coronary blood flow and MPR in the lisinopril group increased significantly compared with pretreatment values (3.5 +/- 1.2 vs. 2.6 +/- 1.1 ml/min/g, p = 0.02; 3.7 +/- 1.1 vs. 2.4 +/- 1 ml/min/g, respectively, p = 0.002, respectively). Post-treatment hyperemic flow in the patients treated with lisinopril was not significantly different from corresponding measurements in controls (3.5 +/- 1.2 vs. 3.9 +/- 1 ml/min/g, respectively, p = NS). In the patients treated with losartan, there was no difference between pre- and post-treatment MBF values and MPR.
Myocardial perfusion reserve and maximal coronary flow improved in asymptomatic patients with hypertension-induced LVH after long-term treatment with lisinopril but not with losartan. Thus, ACEIs, but not ARBs, might be effective in repairing the coronary microangiopathy associated with hypertension-induced LVH.
Journal of the American College of Cardiology 09/2002; 40(4):703-9. · 14.16 Impact Factor
Journal of Nuclear Cardiology 12(1):3-4. · 2.67 Impact Factor
Journal of Nuclear Cardiology 14(6):e39-60. · 2.67 Impact Factor
ABSTRACT: Calculation differences between various gated blood pool (GBP) single photon emission computed tomography (SPECT) (GBPS) algorithms may arise as a result of different modeling assumptions. Little information has been available thus far regarding differences for right ventricular (RV) function calculations, for which GBPS may be uniquely well suited.
Measurements of QBS (Cedars-Sinai Medical Center, Los Angeles, Calif) and BP-SPECT (Columbia University, New York, NY) algorithms were evaluated. QBS and BP-SPECT left ventricular (LV) ejection fraction (EF) correlated strongly with conventional planar-GBP LVEF for 422 patients (r = 0.81 vs r = 0.83). QBS correlated significantly more strongly with BP-SPECT for LVEF than for RVEF (r = 0.80 vs r = 0.41). Both algorithms demonstrated significant gender differences for 31 normal subjects. BP-SPECT normal LVEF (67% +/- 9%) was significantly closer to values in the magnetic resonance imaging (MRI) literature (68% +/- 5%) than QBS (58% +/- 9%), but both algorithms underestimated normal RVEF (52% +/- 7% and 50% +/- 9%) compared with the MRI literature (64% +/- 9%). For 21 patients, QBS correlated similarly to MRI as BP-SPECT for LVEF (r = 0.80 vs r = 0.85) but RVEF correlation was significantly weaker (r = 0.47 vs r = 0.81). For 16 dynamic phantom simulations, QBS LVEF correlated similarly to BP-SPECT (r = 0.81 vs r = 0.91) but QBS RVEF correlation was significantly weaker (r = 0.62 vs r = 0.82). Volumes were lower by QBS than BP-SPECT for all data types.
Both algorithms produced LV parameters that correlated strongly with all forms of image data, but all QBS RV relationships were significantly different from BP-SPECT RV relationships. Differences between the two algorithms were attributed to differences in their underlying ventricular modeling assumptions.
Journal of Nuclear Cardiology 11(3):282-92. · 2.67 Impact Factor