Ejection fraction image: a noninvasive index of regional left ventricular wall motion

Analysis of the effects of electroacupuncture at the pericardium 6 acupoint on heart function in patients with angina using equilibrium radionuclide angiocardiography quantity analysis technique

OBJECTIVE

To analyze changes in cardiac function indices after electroacupuncture (EA) at the pericardium 6 (PC-6) acupoint using the equilibrium radionuclide angiocardiography (ERNA) quantity analysis technique.

DESIGN

Analysis of clinical outcomes after EA at PC-6 measured by ERNA.

SETTING

The study was conducted in a hospital.

PARTICIPANTS

31 participants (17 patients with angina and 14 healthy volunteers).

INTERVENTION

The study used ERNA to study outcomes of EA at PC-6 on heart function.

OUTCOME MEASURE

ERNA images were taken before the treatment (T0), at the end of the treatment (T1), and 20 minutes after the treatment (T2) and then processed.

RESULTS

Regional left ventricular ejection fraction (REF) increased after EA in the angina and control groups. REF at T2 was significantly higher than at T1 in the angina group (p<.01). In the control group, REF was higher at T1 than at T0 (p<.01) but did not differ between T1 and T2 (p=.08). The REF deviation among ventricular regions in the angina group was significantly greater than that in the control group at T0 (p<.01) but was reduced to the level of that in control group after EA (p=.52). Peak filling rate was lower in the angina group than in controls at all three time points (all p<.01). After EA, peak filling rate increased markedly in the angina group but not in the control group. The cardiac cycle was shorter in the angina group than in the control group at T0 (p<.01) and increased after EA. The cardiac cycle of the control group did not change.

CONCLUSION

Effects of EA at PC-6 on heart function can be detected and quantified by ENRA.

Comparison of B-Type Natriuretic Peptides for Assessment of Cardiac Function and Prognosis in Stable Ischemic Heart Disease

In 1,049 patients with stable ischemic heart disease (IHD), brain natriuretic peptide (BNP) and amino terminal pro-brain natriuretic peptide (NTproBNP) correlated closely (r = 0.09, p < 0.001) and were similarly related to left ventricular ejection fraction (LVEF) (r = -0.50 and -0.46, respectively), age (0.44 and 0.47), and creatinine clearance (-0.51 and -0.51). Receiver-operating characteristic curves for detection of LVEF <30% were similar (area under the curves = 0.83 and 0.80, both p < 0.001), and both peptides had strong negative predictive value (95% and 94%). Both independently predicted all-cause mortality and/or heart failure with closely overlapping event-free survival curves; BNP and NTproBNP display strong, near-identical test performance in ruling about severely reduced LVEF and in prediction of all-cause mortality or heart failure in stable IHD.

OBJECTIVES

The aim of this work was to test B-type natriuretic peptides for assessment of function and prognosis in stable ischemic heart disease (IHD) and to compare brain natriuretic peptide (BNP) with amino terminal pro-brain natriuretic peptide (NTproBNP), including the relative effects of age and renal function on test performance.

BACKGROUND

Brain natriuretic peptide and NTproBNP are emerging diagnostic and prognostic markers in heart failure and acute coronary syndromes. Their performance in assessing function and prognosis in stable IHD is unknown. Whether one marker is superior and the relative effects of age and renal function on test performance are uncertain.

METHODS

In 1,049 patients with stable IHD, left ventricular ejection fraction (LVEF) was measured by radionuclide scanning and creatinine clearance estimated by the Cockroft-Gault equation. Age, gender, and body mass index were recorded. Twelve-month all-cause mortality or admission with heart failure was prospectively recorded; BNP and NTproBNP were measured by radioimmunoassay.

RESULTS

Brain natriuretic peptide and NTproBNP correlated closely (r = 0.90, p < 0.001) and had similar relationships to LVEF (r = -0.50 and -0.46, respectively, both p < 0.001), age (0.44 and 0.47, both p < 0.001), and creatinine clearance (-0.51 and -0.51, both p < 0.001). Areas under receiver-operating characteristic curves for detection of LVEF <30% were similar (0.83 and 0.80, both p < 0.001) with strong negative predictive values for both (95% and 94%). Both markers independently predicted the clinical end point with closely overlapping event-free survival curves.

CONCLUSIONS

In stable IHD, BNP and NTproBNP display strong and near-identical test performance in ruling out severely reduced LVEF and in prediction of all-cause mortality or heart failure despite significant effects of age, gender, and renal function on levels of both markers.

Effects of losartan and captopril on left ventricular volumes in elderly patients with heart failure: results of the ELITE ventricular function substudy

BACKGROUND

The mechanism by which angiotensin-converting enzyme inhibitors reduce mortality rates and disease progression in patients with heart failure is likely mediated in part through prevention of adverse ventricular remodeling. This study examined the effects of the angiotensin-converting enzyme inhibitor captopril and the angiotensin II type 1 receptor antagonist losartan on ventricular volumes and function in elderly patients with heart failure and reduced left ventricular ejection fraction (< or =40%).

METHODS

Patients underwent radionuclide ventriculograms (RVG) at baseline and were randomized to either captopril (n = 16) or losartan (n = 13). After 48 weeks, another RVG was obtained. Therapy was then withdrawn for at least 5 days, and the RVG was repeated while the patient was not receiving the drug.

RESULTS

At 48 weeks both captopril and losartan significantly reduced left ventricular (LV) end-diastolic volume index (135 +/- 26 to 128 +/- 23 mL/m(2) for losartan, P <.05 vs baseline; 142 +/- 25 to 131 +/- 20 mL/m(2) for captopril, P <.01; mean (SD). Captopril also reduced LV end-systolic volume index (98 +/- 24 to 89 +/- 21 mL/m(2), P <.01 vs. baseline), whereas a nonsignificant trend was observed for the losartan group (97 +/- 23 to 90 +/- 16 mL/m(2), P = not significant). The between-group differences in the changes in LV volumes were not statistically significant. After drug withdrawal, LV end-diastolic volume index remained significantly lower than baseline in the captopril group (P <.01).

CONCLUSIONS

Both captopril and losartan prevent LV dilation, representing adverse ventricular remodeling, previously seen with placebo treatment. Reverse remodeling was observed in the captopril group. On the basis of these results, the relative effects on LV remodeling do not provide a rationale for a survival benefit of losartan over captopril.

Non-invasive measurement of left ventricular volumes and function by gated positron emission tomography

To date cardiac positron emission tomography (PET) studies have focussed on the measurement of myocardial blood flow, metabolism and receptors while left ventricular (LV) function and dimensions have been derived from other modalities. The main drawback of this approach is the difficulty of data co-registration, which limits clinical interpretation. The aim of this study was to evaluate whether it is possible to measure absolute cardiac volumes, and consequently LV function parameters such as ejection fraction, and wall motion with gated PET. Nineteen patients underwent a PET scan and planar radionuclide ventriculography (MUGA) within 9+/-9 days. A 9-min scan (16 gates/cardiac cycle) was acquired after inhalation of 3 MBq/ml of oxygen-15 labelled carbon monoxide at the rate of 500 ml/min over 4 min using a multislice PET camera. Noise reduction was performed on the gated image to enhance the definition of the ventricles before reslicing to the short-axis view. A threshold value was used to detect the edge of the LV at each gate. LV volumes at each gate were estimated by summing the volume of voxels within the LV boundary. PET measurements of LV volumes were as follows: LV end-diastolic volume ranged from 72 to 233 ml and LV end-systolic volume ranged from 24 to 203 ml. Phantom experiments supported the validity of this approach for estimating volumes. LV ejection fraction measured with MUGA was 38.4%+/-16.3% (range 15%-71%) and that measured with PET was 39.6%+/-17.7% (range 9%-72%) (P=NS). The LV ejection fraction measurements were highly correlated (r2=0.824). These results indicate that: (1) absolute end-diastolic and end-systolic volumes can be quantified using gated PET and (2) LV ejection fraction can be accurately measured by gated PET simultaneously with the other physiological PET parameters.

Coronary calcium as a reliable tool for differentiating ischemic from nonischemic cardiomyopathy

In conclusion, the presence or absence of coronary calcium as detected by this rapid technique represents a simple and reliable noninvasive sign for the differential diagnosis between ischemic and nonischemic DC.

Stress imaging. Current clinical options for the diagnosis, localization, and evaluation of coronary artery disease

As technology advances, new methods evolve. In this article, the methods of stress testing and related imaging in coronary disease are addressed, and dynamic and pharmacologic stress, direct and indirect methods, are defined and evaluated. The stress imaging methods related to the modalities of scintigraphy and ultrasound are reviewed and their advantages and disadvantages assessed in view of scientific and economic factors.

A consideration of current clinical options for stress imaging in the diagnosis and evaluation of coronary artery disease

The evolution of technology and our health care system, tinctured by advocacy groups for specific imaging modalities, has produced controversy, relating to the optimal stress imaging method for coronary disease evaluation. Stress perfusion scintigraphy and stress echocardiography advocates seem to make claims that each nullify the other. This extensive, in-depth review of the subject presents facts as well as opinion and experience in an effort to assess the full portrait of the issue for consideration by advocates as well as those many yet undecided. The issue is an evolving one, affected strongly by the reader's own experience. The presentation is not meant to be the final word. Rather, it seeks to present a basis for understanding and progress in both fields.

Effects of the angiotensin converting enzyme inhibitor enalapril on the long-term progression of left ventricular dilatation in patients with asymptomatic systolic dysfunction. SOLVD (Studies of Left Ventricular Dysfunction) Investigators

BACKGROUND

Patients with heart failure and reduced left ventricular (LV) ejection fraction (EF) manifest progressive LV dilatation, which is prevented by angiotensin converting enzyme (ACE) inhibitors. In patients with asymptomatic LV systolic dysfunction, in whom there is less activation of the renin-angiotensin system, ventricular remodeling might be less rapid and the benefit of ACE inhibitors less discernible.

METHODS AND RESULTS

One hundred eight patients enrolled in the Studies of Left Ventricular Dysfunction (SOLVD) Prevention Trial, with left ventricular ejection fraction < or = 0.35 but without clinical heart failure, underwent radionuclide ventriculograms, and 49 underwent left heart catheterizations. Measurements were made before and after double-blinded randomization to enalapril (2.5 to 20 mg/d) or placebo. Repeated-measures analysis of all time points showed significant differences for change in end-diastolic volume (EDV) between enalapril and placebo groups. Significant difference between the enalapril and placebo groups (P < .05) was present for change in EDV at 1 year within the catheterization study and at a mean of 25 months within the radionuclide study. Radionuclide EDV increased in placebo patients (119 +/- 28 to 124 +/- 33 mL/m2, mean +/- SD) and decreased in enalapril patients (120 +/- 25 to 113 +/- 25 mL/m2). Differences between the two groups were significantly less than previously described in patients with symptomatic heart failure (P < .02), with less increase in LV volumes in the placebo group and less decrease in volumes in the enalapril group.

CONCLUSIONS

Chronic ACE inhibitor treatment slows or reverses LV dilatation in patients with asymptomatic LV systolic dysfunction. Compared with symptomatic patients, asymptomatic patients manifest a slower rate of spontaneous LV dilatation and less reduction in LV volumes by enalapril.

Natural history of left ventricular function in patients with uncomplicated acute myocardial infarction

To investigate the serial changes of the infarcted and the noninfarcted areas, first-pass radionuclide angiocardiography was performed in 16 patients with uncomplicated anterior myocardial infarction (MI) at four weeks, one year, and two years after the onset of MI. Global ejection fraction (EF) and regional EF of the infarcted area improved significantly from four weeks to one year after MI (from 39 +/- 16 to 44 +/- 16 percent, 23 +/- 3 to 29 +/- 5 percent, both p < 0.01), but did not change from one year to two years after MI. Regional EF of the noninfarcted area and left ventricular end-diastolic and end-systolic volume did not change during the study period. There was a significant relation in the direction of the changes of global EF and regional EF of the infarcted area during the first year after MI, whereas no relation was observed between the changes of global EF and regional EF of the noninfarcted area. A greater improvement in regional EF of the infarcted area was observed in seven patients who had spontaneous recanalization compared with nine patients with totally occluded coronary arteries. Thus, a significant improvement in cardiac function, mainly due to the increase in regional EF of the infarcted area, was observed during the first year after MI, which was related to patency of coronary artery.

Effects of the angiotensin converting enzyme inhibitor enalapril on the long-term progression of left ventricular dysfunction in patients with heart failure. SOLVD Investigators

BACKGROUND

In patients with heart failure, activation of the renin-angiotensin system is common and has been postulated to provide a stimulus for further left ventricular (LV) structural and functional derangement. We tested the hypothesis that chronic administration of the angiotensin converting enzyme (ACE) inhibitor enalapril prevents or reverses LV dilatation and systolic dysfunction among patients with depressed ejection fraction (EF) and symptomatic heart failure.

METHODS AND RESULTS

We examined subsets of patients enrolled in the Treatment Trial of Studies of Left Ventricular Dysfunction (SOLVD). Fifty-six patients with mild to moderate heart failure underwent serial radionuclide ventriculograms, and 16 underwent serial left heart catheterizations, before and after randomization to enalapril (2.5-20 mg/day) or placebo. At 1 year, there were significant treatment differences in LV end-diastolic volume (EDV; p less than 0.01), end-systolic volume (ESV; p less than 0.005), and EF (p less than 0.05). These effects resulted from increases in EDV (mean +/- SD, 136 +/- 27 to 151 +/- 38 ml/m2) and ESV (103 +/- 24 to 116 +/- 24 ml/m2) in the placebo group and decreases in EDV (140 +/- 44 to 127 +/- 37 ml/m2) and ESV (106 +/- 42 to 93 +/- 37 ml/m2) in the enalapril group. Mean LVEF increased in enalapril patients from 0.25 +/- 0.07 to 0.29 +/- 0.08 (p less than 0.01). There was a significant treatment difference in LV end-diastolic pressure at 1 year (p less than 0.05), with changes paralleling those of EDV. The time constant of LV relaxation changed only in the placebo group (p less than 0.01 versus enalapril), increasing from 59.2 +/- 8.0 to 67.8 +/- 7.2 msec. Serial radionuclide studies over a period of 33 months showed increases in LV volumes only in the placebo group. Two weeks after withdrawal of enalapril, EDV and ESV increased to baseline levels but not to the higher levels observed with placebo.

CONCLUSIONS

In patients with heart failure and reduced LVEF, chronic ACE inhibition with enalapril prevents progressive LV dilatation and systolic dysfunction (increased ESV). These effects probably result from a combination of altered remodeling and sustained reduction in preload and afterload.

Effectiveness of preload reserve as a determinant of clinical status in patients with left ventricular systolic dysfunction. The SOLVD Investigators

The hemodynamic determinants of clinical status in patients with left ventricular (LV) systolic dysfunction have not been established. In the present study, preload reserve--LV distension during exercise--was related to clinical status, and the effect of acute angiotensin-converting enzyme inhibition was examined in 97 patients with ejection fraction less than or equal to 0.35 enrolled in the trial, Studies of Left Ventricular Dysfunction (SOLVD). Sixty-one asymptomatic patients (group I) were compared with 36 patients with symptomatic heart failure (group II). Radionuclide LV volumes were measured at rest and during maximal cycle exercise. Group II patients had higher resting heart rates, end-diastolic and end-systolic volumes, and lower ejection fractions (all p less than 0.005). During exercise, only patients in group I had increased stroke volume (from 35 +/- 8 to 39 +/- 11 ml/m2 [mean +/- SD; p less than 0.0005]) due to an increase in end-diastolic volume (from 119 +/- 29 to 126 +/- 29 ml/m2 [p less than 0.0005]), contributing to a greater increase in LV minute output (p less than 0.0001, group I vs group II). After administration of intravenous enalapril (1.25 mg), LV end-diastolic volume response to exercise was augmented in group II (rest, 140 +/- 42; exercise, 148 +/- 43 ml/m2; p less than 0.0005) and LV output response increased slightly (p less than 0.05). Thus, in patients with asymptomatic systolic dysfunction, recruitment of preload during exercise is responsible for maintaining a stroke volume contribution to the cardiac output response.(ABSTRACT TRUNCATED AT 250 WORDS)

Augmentation of mortality risk discriminating power of left ventricular ejection fraction by measures of nonuniformity in systolic emptying on radionuclide ventriculography

Employing equilibrium-gated radionuclide ventriculography in the left anterior oblique view, six geometric models and five mathematic coefficients of nonuniformity in regional left ventricular emptying were tested for their relative mortality risk-stratifying power and capacity to augment the risk-discriminating potency of the continuous and dichotomized global ejection fraction. Radionuclide ventriculography was performed an average of 7.6 days after acute myocardial infarction. All geometric models significantly separated 20 normal subjects from 137 patients with recent infarction (p less than 0.001). Cumulative mortality data demonstrated that significant independent univariate dichotomizing potency and augmentation of the mortality risk-discriminating power of the global ejection fraction were provided by models of regional emptying that 1) conformed to coronary artery perfusion areas, 2) encompassed total ventricular counts, 3) expressed variability in regional relative to global ejection fraction, and 4) simulated a pattern of emptying directed toward the center of geometry of the left ventricle. The combination of a four quadrant geometric model with axes drawn 45 degrees above the horizontal and a coefficient of variation calculated as square root of sigma(GEF - REF)2/4 x 100/GEF (where GEF = global ejection fraction and REF = regional ejection fraction) proved to be optimal. This coefficient averaged 12.2% in normal subjects and 32.2% in patients with recent acute myocardial infarction (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitation of left ventricular asynchrony on radionuclide angiography phase images

Quantitation of left ventricular (LV) asynchrony is relevant in clinical cardiology, as well as in evaluating LV mechanical properties. Radionuclide angiography (RA) phase images are extensively used, and asynchrony is usually assessed by computing the standard deviation of phase angle distribution (SD). However, SD is dependent on count statistics and does not take into account the spatial distribution of asynchrony. In this study a new index to evaluate asynchrony on phase images is presented (differential uniformity parameter, DUP). DUP is based on the frequency analysis of phase images. Diagnostic accuracy and reproducibility of either SD or DUP were tested. Reproducibility was evaluated in 15 patients studied by RA twice within a few minutes. DUP showed a better reproducibility than SD. Diagnostic accuracy was estimated in 84 patients, divided into four subgroups on the basis of coronary arteriography and contrast ventriculography findings: (a) 25 control subjects, (b) 16 patients with coronary artery disease (CAD) and normal LV wall motion, (c) 23 patients with CAD and LV hypokinesia and (d) 20 patients with CAD and LV dyskinesia. Relative diagnostic ability was assessed by comparing the areas under receiver-operating characteristic curves. DUP's area was larger than SD's when group D was tested against all the other groups (DUP's area = 87% +/- 5%, SD's area = 76% +/- 7%; P less than 0.01). Thus, our study indicates that DUP is more reproducible and more accurate than SD in identifying patients with CAD and LV dyskinesia.

Determination of left ventricular wall motility injury by factor analysis in patients with advanced ischemic heart disease

Left ventricular phase and amplitude images (Fourier analysis, PAI) and factor analysis images (FAI) from gated radionuclide ventriculography were obtained in 235 patients after myocardial infarction (MI) and in 44 patients with well documented ischemic heart disease (IHD) in order to assess areas of regional left ventricular motility injury (LVMI). The sensitivity of FAI for LVMI detection was higher than with PAI (36.3% vs 22.7% in patients without MI; 76.6% vs 68% in those after anterior MI; and 53.2% vs 31.9% after posterior MI, respectively). In 2.9% of all patients PAI were unclear due to small time activity amplitudes and heart rate irregularity, whereas FAI could be easily assessed. Significantly decreased left ventricular ejection fraction was observed predominantly after anterior MI in connection with distinct signs of LVMI in a large area of anterior wall or in the anteroseptal and/or apical region. Areas of LVMI could be sharply delineated in FAI; however, in contrast to PAI, FAI is unable to distinguish between dyskinetic and akinetic regions. The use of both PAI and FAI is recommended for more detailed detection of regional LVMI in patients with IHD.

Protective effects of retrograde compared with antegrade cardioplegia on right ventricular systolic and diastolic function during coronary bypass surgery

The effect of retrograde cardioplegia delivered through the right atrium on right ventricular performance has not been critically examined in humans. We randomized 20 patients with right coronary artery lesions to receive cold blood cardioplegia solution either retrograde through the right atrium (group 1, n = 10) or antegradely (group 2, n = 10). The patients were similar in age, sex, severity of coronary artery disease, cross-clamp time, and completeness of revascularization. Before operation, right ventricular function was assessed by radionuclide ventriculography, and 18-24 hours after operation, right ventricular volumes and performance were assessed at a constant-paced heart rate by simultaneous hemodynamic-radionuclide measurements, before and after a fluid challenge. Intraoperative right ventricular temperatures were not different between the groups. Right ventricular volumes and ejection fractions were not different at baseline. After operation, at similar heart rates and loading conditions, there was a trend for the antegrade group to increase right ventricular end-systolic volume (p less than 0.1) whereas the retrograde group had no change in this parameter from the preoperative state. Postoperative ventricular function curves (p = NS, retrograde versus antegrade) suggest equivalent systolic performance in both groups. Right ventricular diastolic performance showed no significant differences between the two groups, suggesting no detriment to compliance due to right ventricular distension during operation. This suggests that retrograde cardioplegia adequately protects the right ventricular myocardium during bypass surgery and may be used as an alternative procedure in situations where ventricular cooling is inadequate with antegrade delivery due to severe coronary artery disease or aortic valvular disease.

Left ventricular inotropic effect of atrial pacing after coronary artery bypass grafting

The effect of atrial pacing on left ventricular (LV) performance was studied in 19 patients, 24 hours after coronary artery bypass grafting (CABG). LV volumes were calculated from simultaneous radionuclide-thermodilution measurements at rest (heart rate 82 +/- 12 beats/min), 10 minutes after the start of atrial pacing (100 beats/min), and with atrial pacing plus volume loading to return preload toward baseline. Atrial pacing reduced preload as reflected by LV end-diastolic volume index (69 +/- 14 vs 60 +/- 14 ml/m2, mean +/- standard deviation) (p less than 0.0001), but returned to baseline with volume loading. Afterload, as reflected by arterial end-systolic pressure, did not change with atrial pacing (63 +/- 9 at baseline vs 64 +/- 8 mm Hg with pacing, difference not significant). Afterload increased with volume loading (68 +/- 10 mm Hg, p less than 0.025 vs baseline and pacing). LV stroke volume decreased with atrial pacing due to reduced preload, but returned to baseline with volume loading. Cardiac index increased with atrial pacing and increased further with volume loading. Compared with baseline, LV end-systolic volume index was reduced during atrial pacing both before and after volume loading, despite unchanged or augmented afterload. The combination of atrial pacing and volume loading resulted in augmentation of LV stroke work, despite no increase in preload compared with baseline. Thus, after CABG, increased (paced) heart rate augments inotropic state, as indicated by reduced LV end-systolic volume under conditions of unchanged or increased afterload, and elevated LV stroke work without an increase in preload or a decrease in afterload.

Doxorubicin cardiotoxicity: response of left ventricular ejection fraction to exercise and incidence of regional wall motion abnormalities

Gated radionuclide ventriculograms were performed to evaluate cardiac function in 53 patients who received doxorubicin treatment for various malignancies (mean dose: 449 +/- 128 mg/m2 BSA). In fourteen patients (Group I) function was evaluated before and after treatment; there was a significant decrease of resting left ventricular ejection fraction after therapy (p less than 0.001). Twenty-two patients (Group II) had serial studies during treatment which also showed a significant fall of resting left ventricular ejection fraction (p less than 0.001). Eighteen patients in Groups I and II had supine exercise studies. A normal exercise response was maintained in the majority of patients. Exercise testing added little to the diagnostic performance when compared to serial resting studies. We found regional wall motion abnormalities (mild apical hypokinesis) at rest by visual inspection in 33 of 36 Group I and Group II patients who had received doxorubicin. In the baseline or initial study, only 4 of these patients demonstrated WMA. In 18 Group I and II patients who were exercised, 3 had wall motion abnormalities during the initial study. All of these patients demonstrated wall motion abnormalities at rest after the second study, however only 7 of 18 demonstrated abnormalities during the exercise study. The results indicate that resting left ventricular ejection fraction declines after doxorubicin treatment. Exercise radionuclide angiography may not increase diagnostic accuracy for the detection of doxorubicin related cardiotoxicity. Regional wall motion abnormalities occur with a relatively high incidence following doxorubicin therapy, more readily detectable at rest. However, the exercise study can distinguish doxorubicin related wall motion abnormalities from those due to coronary artery disease.

Usefulness of dipyridamole-thallium-201 perfusion scanning for distinguishing ischemic from nonischemic cardiomyopathy

To determine noninvasively the etiology of left ventricular (LV) dysfunction, 22 patients with a diagnosis of cardiomyopathy determined via cardiac catheterization and 5 normal control subjects underwent radionuclide ventriculography and intravenous dipyridamole-thallium-201 perfusion scanning. Both ischemically and nonischemically induced LV dysfunction had comparable global LV ejection fractions (24 +/- 6 vs 23 +/- 8%, respectively) and extent of segmental wall motion abnormalities. Right ventricular ejection fraction was significantly better in the group with an ischemic etiology of LV dysfunction (41 +/- 26 vs 13 +/- 10%, p less than 0.005) but significant group overlap was present. However, computer-assisted analysis of dipyridamole-thallium-201 myocardial perfusion scanning demonstrated more homogeneous myocardial perfusion in idiopathic cardiomyopathy (mean perfusion defect 25 +/- 11 vs 6 +/- 6%, p less than 0.001) and successfully predicted the correct etiology of LV dysfunction in 20 of 22 (91%) patients.

Efficacy of retrograde coronary sinus cardioplegia in patients undergoing myocardial revascularization: a prospective randomized trial

The efficacy of retrograde coronary sinus cardioplegia (RCSC) administered through the right atrium compared with aortic root cardioplegia (ARC) has not been examined critically in patients undergoing coronary artery bypass grafting (CABG). Twenty patients having elective CABG were randomized prospectively to receive cold blood ARC (Group I, 10 patients) or cold blood RCSC (Group II, 10 patients). Patient demographics were similar in both groups. Ventricular function was assessed preoperatively by radionuclide ventriculography and postoperatively by simultaneous hemodynamic and radionuclide ventriculographic studies with volume loading. There was no change in ejection fraction (EF) (preoperative versus postoperative value) in Group I (50 +/- 6% versus 53 +/- 6%) but in group II, at similar peak systolic pressure and similar left ventricular end-diastolic volume index (LVEDVI), LVEF improved significantly (49 +/- 6% versus 60 +/- 12%, p less than 0.05). Postoperative ventricular function (stroke work index versus EDVI) for the left ventricle and right ventricle were similar in both groups. Evaluation of postoperative LV systolic function (end-systolic blood pressure versus end-systolic volume index) and diastolic function (pulmonary capillary wedge pressure versus EDVI) were also similar in both groups. Retrograde coronary sinus cardioplegia is as effective as ARC for intraoperative myocardial protection, and provides excellent postoperative function in patients undergoing elective CABG.

A new method of three dimensional analysis of left ventricular wall motion

The three dimensional (3D) shape of left ventricles (LV) was reconstructed from gated blood pool emission computed tomography (GECT) to assess regional LV wall motion. The 3D LV shape was created using LV boundaries detected by a threshold method. Based on the length from each LV boundary to the end diastolic LV center of mass, regional percent shortening and phase of the first harmonic by Fourier analysis were calculated to create 3D functional images. These images clearly demonstrated the 3D extent of wall motion abnormality. In addition, the same 3D analysis was applied to biplane X-ray left ventriculography (LVG) by assuming that LV short axis sections were elliptic. Results of planar imaging, 3D analysis of GECT, 3D analysis of LVG and conventional LVG findings correlated well with each other. The 3D analysis of GECT is useful for non invasive quantitative analysis of LV wall motion.

Measurement of global and regional left ventricular performance with isotope technique in coronary heart disease

In order to evaluate the left ventricular function in coronary artery disease, radionuclide measurements of global and regional ejection fraction (EF), regional wall motion and phase analyses of the left ventricular contraction were performed by equilibrium technique. One group of patients with angina pectoris and one group with myocardial infarction were compared with a control group. All the above-mentioned parameters significantly separated the infarction group from the reference group both at rest and during work, while the group of patients with angina pectoris showed disturbances mainly during work, such as impaired ability to increase global and regional ejection fraction and regional wall motion. Adding regional analysis and phase analysis to the global EF determination increases the possibility of studying the left ventricular function. However, this addition has a limited value in detecting impaired left ventricular function compared to the determination of just global EF in patients with angina pectoris and in patients with myocardial infarction.

Differential effects of milrinone and dobutamine on right ventricular preload, afterload and systolic performance in congestive heart failure secondary to ischemic or idiopathic dilated cardiomyopathy

To compare the effects of intravenous dobutamine and milrinone on right ventricular (RV) systolic function, 14 patients with severe congestive heart failure underwent simultaneous radionuclide-hemodynamic study. Patients were randomized to receive intravenous milrinone (50 micrograms/kg bolus then 0.5 microgram/kg/min) or dobutamine (2.5 to 15 micrograms/kg/min) to achieve equal increases in cardiac output. Both drugs significantly improved cardiac performance, with identical 24% increases in mean cardiac index (p less than 0.05 vs baseline; difference not significant for milrinone vs dobutamine) and no change in heart rate. Neither drug substantially altered RV preload, as reflected by mean right atrial pressure and RV end-diastolic volume. Both drugs caused similar increases in RV ejection fraction (mean +/- standard deviation; dobutamine: 0.32 +/- 0.09 to 0.40 +/- 0.11; p less than 0.05; milrinone: 0.35 +/- 0.19 to 0.43 +/- 0.21; p less than 0.05) resulting from reductions in RV end-systolic volume. RV afterload reduction contributed substantially to drug effect on RV systolic performance in patients treated with milrinone but not those treated with dobutamine. With doses effecting equal increases in cardiac index and RV systolic performance, pulmonary artery end-systolic pressure was significantly reduced by milrinone (40 +/- 12 to 33 +/- 12 mm Hg; p less than 0.05), but not by dobutamine. Thus, in patients with congestive heart failure milrinone's effect on RV systolic function is explainable, at least in part, by RV afterload reduction, whereas RV inotropic augmentation contributed more strongly to dobutamine's effect.

Augmented preexcitation assessed by scintigraphic phase analysis during atrial pacing

We sought to characterize the effect of augmented preexcitation on the phase image pattern associated with scintigraphic acquisition during conduction via accessory arteriovenous connections. For this reason we assessed phase image scintigraphy, acquired in sinus rhythm and during rapid atrial pacing in 12 patients with documented right (five patients) or left (seven patients) lateral accessory pathways. Augmented preexcitation during atrial pacing was documented at electrophysiologic study in all patients during atrial pacing at similar rates. Phase analysis was abnormal in only 8 patients during sinus rhythm but in all 12 patients during atrial pacing. Atrial pacing brought a significant delay in both mean left and right ventricular phase angles, LV phi and RV phi, respectively. With atrial pacing, the site of earliest phase angle, interpreted to indicate the site of earliest excitation, shifted to the site of the accessory pathway. There was increased relative "prematurity" of the mean phase angle of the ipsilateral ventricle and an absolute increase in the difference between mean and earliest left and right ventricular phase angles, delta phi (LV-RV) and delta phi 0 (LV-RV), respectively. In patients with right-sided pathways, delta phi (LV-RV) increased from 9.5 +/- 12.6 degrees to 47.9 +/- 22.8 degrees, whereas delta phi 0 (LV-RV) increased from 28.1 +/- 18.0 degrees to 67.6 +/- 25.0 degrees (both p less than 0.05). Patients with left-sided pathways demonstrated similar changes in which delta phi (LV-RV) decreased from 2.9 +/- 10.8 degrees to -26.5 +/- 9.0 degrees and delta phi 0 (LV-RV) decreased from 3.4 +/- 14.2 degrees to -27.4 +/- 17.9 degrees (both p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of nifedipine and isosorbide dinitrate when added to maximal propranolol therapy in stable angina pectoris

A study was performed to compare isosorbide dinitrate and nifedipine as adjunctive therapy in 14 patients with coronary artery disease and stable angina pectoris taking maximal beta-blocking drugs. Drug titration phases ensured maximal therapy of propranolol, isosorbide or nifedipine. The combination of nifedipine and propranolol was more effective than the combination of isosorbide and propranolol in reducing angina and increasing exercise capacity (323 vs 416 seconds, p less than 0.005) during exercise treadmill testing. Nifedipine produced a greater reduction in systolic blood pressure at submaximal exercise than isosorbide. Global and regional ejection fraction at rest and exercise was assessed with radionuclide ventriculography. The substitution of nifedipine for isosorbide depressed the global ejection fraction at rest (0.61 to 0.56 p less than 0.05) and produced a slight improvement in exercise ejection fraction (0.47 to 0.51, difference not significant). The decrease in ejection fraction from rest to exercise was 0.14 to 0.04 with nifedipine (p less than 0.005). The benefit of nifedipine compared with isosorbide occurred in regions with marked exercise-induced ischemia. In patients treated with maximal beta-blocking therapy, nifedipine is an effective alternative to isosorbide as a combination agent with propranolol. The salutary effects of nifedipine included afterload reduction with exercise and possible improvements in coronary blood supply.

Early and late global and regional left ventricular function after experimental transmural myocardial infarction: relationships of regional wall motion, wall thickening, and global performance

Experimental myocardial infarction of the posterolateral wall of the left ventricle was produced in dogs by injecting 80 micron microspheres into the left circumflex coronary artery to determine changes in regional myocardial function after infarction, to examine how the changes in regional myocardial function relate to the changes in global left ventricular function, and to examine the relationship between regional wall motion and wall thickening after myocardial infarction. Serial measurements of global ventricular and regional myocardial function were made in six dogs before and during 20 days after infarction, with the use of M-mode echocardiography and chronic Swan-Ganz catheter implantation. One hour after infarction, stroke volume index had decreased 49% from baseline, percent fractional shortening had decreased 52%, lateral wall motion had decreased 80%, and lateral wall thickening had decreased 100%. By 6 days after infarction, stroke volume index had increased 41% from its low point, percent fractional shortening had increased 34%, and lateral wall motion had increased 100% toward but not to baseline. Lateral wall thickening did not return following infarction. Peak and end-systolic circumferential wall stresses and systemic arterial blood pressure remained stable. End-systolic diameter increased acutely (36%) after infarction and did not change during the 20-day time period, while end-diastolic diameter gradually increased, resulting in the increase in percent fractional shortening. In conclusion, after posterolateral wall infarction, wall motion can return without an improvement in regional myocardial function, presumably because the infarcted region stiffens, allowing it to be pulled inward.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic correlates of left ventricular versus right ventricular radionuclide volumetric responses to vasodilator therapy in congestive heart failure secondary to ischemic or dilated cardiomyopathy

Previous studies have failed to demonstrate the clinical relevance of radionuclide functional measurements during treatment of congestive heart failure (CHF). In the present study, data derived before and during nitroprusside infusion were analyzed in 16 patients with CHF to compare correlations of changes in left (LV) and right ventricular (RV) radionuclide measurements with simultaneous changes in 8 hemodynamic variables. Nitroprusside infusion decreased systemic artery pressure, pulmonary arterial wedge pressure, pulmonary artery pressure, right atrial pressure, and pulmonary and systemic vascular resistance, and increased cardiac output. Nitroprusside decreased LV and RV end-diastolic and end-systolic volumes and increased LV and RV ejection fraction and stroke volume. Changes in RV volumes exceeded changes in LV volumes. LV radionuclide measurements did not correlate significantly with any hemodynamic measurement except for a weak correlation between changes in LV end-systolic volume and right atrial pressure (r = 0.51). In contrast, the combination of changes in RV end-systolic volume and stroke volume predicted changes in pulmonary artery peak systolic (r = 0.90) and mean (r = 0.89) pressures. Changes in pulmonary arterial wedge pressure correlated with changes in RV end-diastolic (r = 0.78) and end-systolic (r = 0.71) volumes. In conclusion, LV radionuclide measurements are of limited value in predicting hemodynamic responses to vasodilator therapy in CHF, whereas RV volumes are strongly influenced by load changes. Their responses to nitroprusside correlate well with changes in pulmonary artery and pulmonary arterial wedge pressures.

Asymmetric distribution of left ventricular asynergy in coronary artery disease and its relation to coronary stenoses

In 100 patients with coronary artery disease (CAD), the prevalence and severity of asynergy was determined for 9 left ventricular (LV) segments by both radionuclide and contrast angiography. The anterior, septal and lateral LV walls had significantly more prevalent and more severe asynergy in the medial segments than in the basal segments. In contrast, the inferior LV wall exhibited equally severe asynergy in both the medial and basal segments. In general, asynergy was most severe in the apical, medial septal, medial inferior and basal inferior LV segments. This asymmetric distribution of LV asynergy could not be explained by the distribution of occlusions or significant stenoses in the arterial tree, which were relatively uniformly distributed among the left anterior descending (32%), left circumflex (29%) and right (26%) coronary arteries. It is postulated instead that the asymmetric distribution of LV asynergy results from asymmetry of the coronary arterial tree supplying the left ventricle and that the prevalence of asynergy in an LV segment is directly related to its vascular distance from the coronary ostia. Unlike the relatively direct supply of the left anterior descending and circumflex arteries to the basal segments of the anterior, septal and lateral LV walls, the arterial supply to the basal inferior wall begins only after the right or dominant circumflex artery has traversed the length of the atrioventricular groove, significantly increasing its susceptibility to the pressure attenuation and occlusive jeopardy of more proximal stenoses.

Functional imaging of the heart

The generation of functional images from the time-activity curves of individual pixels in the gated blood-pool study has become a routine part of most nuclear medicine computer systems. These images have the advantage of extracting useful functional information from the entire study and presenting it in an easily interpretable format. One can rapidly examine them, especially the phase and amplitude images, to seek out potential abnormalities of contraction and conduction. These are not designed to be "stand alone" images and correlation with the remainder of the study, including the cine display, is required. In addition to their use in assessing abnormalities of either ventricular chamber, they also have been shown to be useful in delineating atrioventricular borders in both the left and right sides of the heart. This facilitates definition of regions of interest for the calculation of ejection fractions. These images are produced at no increased expense or inconvenience to the patient and therefore should always be evaluated.

Contribution of reduced mitral regurgitant volume to vasodilator effect in severe left ventricular failure secondary to coronary artery disease or idiopathic dilated cardiomyopathy

Although vasodilators improve cardiac output in severe left ventricular (LV) failure, the degree to which reduction in mitral regurgitation (MR) contributes to this response is unknown. In the present study, nitroprusside-induced changes in forward cardiac output were compared with simultaneous radionuclide LV output in 14 patients with severe LV systolic dysfunction in the absence of known primary valvular disease. Regurgitant output was estimated as LV output minus forward output and regurgitant fraction was calculated as regurgitant output/LV output. At rest, LV ejection fraction averaged 0.16 +/- 0.04 (mean +/- standard deviation). Patients were classified into 2 groups based on regurgitant fraction at rest. Group I (n = 5) had little or no detectable valvular regurgitation, with regurgitant fraction less than 0.10; group II (n = 9) had evidence of MR with regurgitant fraction greater than 0.30. Nitroprusside increased forward cardiac output in all patients in both groups, but this effect was significantly greater in group II (64 +/- 34%) than in group I (31 +/- 17%) (p less than 0.01). Nitroprusside decreased regurgitant fraction in all group II patients, with mean regurgitant fraction decreasing from 0.44 +/- 0.12 to 0.26 +/- 0.15 (p less than 0.005). Thus, a large percentage of patients with severe LV systolic dysfunction have clinically relevant MR, defined as a regurgitant fraction greater than 0.30. Nitroprusside has a greater effect on forward cardiac output in patients with LV failure and MR than in patients with comparable ventricular dysfunction in the absence of detectable MR.(ABSTRACT TRUNCATED AT 250 WORDS)

The scintigraphic evaluation of myocardial infarction and regional ventricular performance using technetium-99m hexakis (t-butylisonitrile) technetium (I) (TBI): a new myocardial imaging agent

Technetium-99m hexakis (t-butylisonitrile) technetium (I) (99mTc-TBI) is a new myocardial perfusion imaging agent. To determine its potential in the evaluation of myocardial infarction, 15 patients with suspected or confirmed acute infarction were studied by bedside imaging in the coronary care unit. Good-quality planar scintigrams in multiple projections were obtained in 13 patients. Gated perfusion studies were performed in 14 patients, and for comparison 13 of these were restudied 24-72 h later by standard gated equilibrium blood pool radionuclide ventriculography. Conventional and planar scintigraphic criteria for myocardial infarction (acute or old) agreed in 12 (92%) patients (k = 0.81, p less than 0.05). All the infarctions detected by scintigraphy were associated with electrocardiographic Q-waves. Localization of infarction by the electrocardiogram and scintigraphy exhibited moderate agreement (k = 0.49, p less than 0.1). Regional wall motion analysis by standard radionuclide ventriculography and gated 99mTc-TBI scintigraphy were in complete agreement for 25 (64%) of 39 left ventricular segments (k = 0.35, p less than 0.05). However, in 7 other segments, associated with areas of infarction, regional wall motion abnormalities were noted only on gated 99mTc-TBI scintigraphy. Therefore, 99mTc-TBI scintigraphy can readily provide data on regional myocardial perfusion and wall motion, permitting detection and localization of areas of myocardial infarction. The superior imaging properties, ready availability and low cost of 99mTc point to the considerable potential value of 99mTc-TBI in assessing patients with suspected or confirmed myocardial infarction.

Left ventricular diastolic filling and its association with age

Thirty normal subjects, aged 22 to 80 years, were studied by radionuclide ventriculography to determine the age dependence of cardiac ventricular diastolic function and to evaluate the association of other factors with ventricular diastolic performance. A strong negative correlation was found between peak diastolic filling rate and age (r = -0.82, p less than 0.0001). Partial correlation analysis was used to factor out the strong age dependence and yielded additional significant correlations of peak filling rate with heart rate (r = 0.48, p less than 0.01) and time to peak filling rate (r = -0.48, p less than 0.01). Time to peak filling rate is also correlated with heart rate but not definitely with age. Analysis by multiple linear regression yields an equation predicting peak filling rate from age and heart rate. Thus, the rate of rapid diastolic filling declines markedly with age in normal subjects. The association of peak filling rate with age and with other factors indicates the need for careful consideration of these factors in the interpretation of scintigraphic findings in patients with heart disease.

Effect of amrinone on right ventricular function: predominance of afterload reduction

Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the left ventricle, the effect of this drug on right ventricular contractility in the clinical setting is unknown. We studied the effect of short-term intravenous administration of amrinone on right ventricular systolic function in nine patients with severe congestive heart failure and, using radionuclide ventriculography, examined the right ventricular end-systolic pressure-volume relationship to determine whether reduced right ventricular afterload or increased contractility predominantly accounted for the observed improvement in right ventricular systolic function. In each patient the right ventricular end-systolic pressure-volume relationship was derived with use of varying doses of nitroprusside. After nitroprusside was stopped, intravenous amrinone (3 mg/kg) caused decreases from baseline in pulmonary arterial end-systolic pressure in eight of nine patients (23 +/- 11% [overall mean +/- SE], p less than .05), and in pulmonary vascular resistance in all patients (38 +/- 6%, p less than .001). Right ventricular end-systolic volume decreased (23 +/- 8%, p less than .01) and right ventricular ejection fraction increased (31 +/- 10%, p = .01). The amrinone-induced decrease in right ventricular end-systolic volume was compared with that predicted for right ventricular afterload reduction alone based on the effect of amrinone on pulmonary arterial end-systolic pressure and the pressure-volume relationship observed during infusion of nitroprusside.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of angiotensin II infusion on a prostaglandin I2-metabolite and on left ventricular function

Angiotensin II's influence on circulating levels of prostaglandin I2 metabolite 6-keto-PGF1-alpha were determined during a pharmacological stress test of left ventricular function in 10 control subjects and 5 patients with coronary artery disease. Angiotensin II infusion (1.5 +/- 0.34 micrograms/min) led to a significant increase of mean arterial blood pressure in both study groups (p less than 0.001). Heart rate decreased in control subjects (p less than 0.01) whereas in patients with coronary artery disease no significant change occurred. Global left ventricular ejection fraction determined by gated blood pool scanning decreased significantly in both study groups (p less than 0.05). The lack of reflex bradycardia in patients with coronary artery disease may be due to a compensatory increased sympathetic tone, prohibiting a more pronounced decline in ejection fraction. 6-keto-PGF1-alpha levels could be measured only in 6 of 15 persons. In the others they were below the limit of detection of the assay (70 pg/ml). During angiotensin II infusion 6-keto-PGF1-alpha increased significantly and could be determined in all persons. Patients with coronary artery disease reached slightly higher 6-keto-PGF1-alpha levels than controls (119 +/- 19 pg/ml versus 91.5 +/- 7 pg/ml; n.s.). Thus although angiotensin II infusion leads to vasoconstriction and increases peripheral resistance it also stimulates the production of vasodilating prostaglandins which may play a role in preserving microcirculation.

Prevalence and severity of circumflex coronary artery disease in electrocardiographic posterior myocardial infarction

To determine the coronary anatomy responsible for electrocardiographic posterior myocardial infarction, the prevalence and severity of disease in the right coronary and left circumflex coronary arteries were compared in 21 patients with electrocardiographic posterior infarction (17 of whom had associated inferior infarction) and 23 patients with isolated electrocardiographic inferior infarction. Significant circumflex coronary artery disease (greater than or equal to 75% stenosis) was more prevalent in patients with posterior or inferoposterior infarction (17 of 21) than in those with isolated inferior infarction (11 of 23) (p less than 0.02). Significant right coronary artery disease was less prevalent in patients with posterior or inferoposterior infarction (16 of 21) than in those with isolated inferior infarction (23 of 23) (p less than 0.05). Among the 21 patients with posterior or inferoposterior infarction, disease was more severe in the circumflex coronary artery in 10 and the right coronary artery in 5 and was of equal severity in 6. Among the 23 patients with isolated inferior infarction, the more diseased artery was the right coronary artery in 21 and the circumflex artery in 2 (p less than 0.001 by chi-square analysis). Variant patterns of coronary artery dominance accounted for only 4 of the 17 patients with inferoposterior infarction. These data suggest that the likely substratum for electrocardiographic posterior or inferoposterior infarction is severe circumflex coronary artery disease, usually in association with significant right coronary artery disease. The pattern of tall, wide R waves in leads V1 or V2 (RV1,2) in patients with inferior infarction is highly predictive of at least two vessel coronary artery disease.

Effect of beta blockade on silent regional left ventricular wall motion abnormalities

The effect of beta-adrenergic blockade on regional left ventricular wall motion abnormalities was studied in 11 patients with coronary artery disease and silent myocardial ischemia during exercise testing. Four patients were asymptomatic; 7 were asymptomatic after a myocardial infarction. Left ventricular wall motion abnormalities were characterized by reduced regional ejection fraction (EF) during exercise determined by gated left anterior oblique images of the cardiac blood pool. In the 11 patients, 10 anteroseptal and 8 inferoposterior regions were subserved by stenotic coronary arteries. Before beta blockade, regional EF decreased in 15 of 18 regions. After beta blockade, this occurred in only 6 of 18 regions (p less than 0.05); the other 12 regions showed no change or an actual increase in regional EF. Thus, beta-adrenergic blockade effectively improved the reduction in exercise regional EF usually seen in patients with coronary artery disease with silent myocardial ischemia. One probable mechanism of action is a reduction in myocardial oxygen requirement at peak exercise.

Relative contribution of inotropic and vasodilator effects to amrinone-induced hemodynamic improvement in congestive heart failure

The relative contribution of inotropic and vasodilator effect to amrinone-induced hemodynamic improvement in congestive heart failure (CHF) is unknown. In 9 patients with CHF, the effects of amrinone and nitroprusside on hemodynamic and radionuclide measurements were compared to determine whether reduced afterload accounts for the amrinone-induced decrease in left ventricular end-systolic volume. In each patient, the end-systolic pressure-volume relation was derived using nitroprusside. After terminating nitroprusside treatment, intravenous amrinone (3 mg/kg) caused end-systolic volume to decrease from 148 +/- 32 ml/m2 (mean +/- standard deviation) to 133 +/- 32 ml/m2 (p less than 0.05), causing an increase in cardiac index from 1.9 +/- 0.8 to 2.7 +/- 0.8 liters/min/m2 (p less than 0.001). Arterial end-systolic pressure decreased in all patients during amrinone administration, from 96 +/- 22 to 84 +/- 19 mm Hg (p less than 0.005), as did systemic vascular resistance. Nitroprusside doses needed to match the decrease in LV end-systolic volume induced by amrinone caused significantly greater decreases in arterial end-systolic pressure than did amrinone (p less than 0.01). The amrinone-induced decrease in end-systolic volume exceeded that predicted for a pure vasodilator based on arterial end-systolic pressure and the nitroprusside-derived pressure-volume relation in 6 patients. In 3 patients, the decrease in end-systolic volume did not exceed that expected for a pure vasodilator. In conclusion, after amrinone treatment, afterload reduction occurs in all patients with severe CHF and is the sole effect in some.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between coronary anatomy and serial changes in left ventricular function on exercise: a study using first pass radionuclide angiography with gold-195m

Serial changes in left ventricular function on exercise were assessed by first pass radionuclide angiography with gold-195m (half life 30.5 s) in 25 men with known coronary anatomy. In the seven patients with three vessel disease, abnormalities of global left ventricular function and regional wall motion occurred earlier during exercise, were of greater extent at peak exercise, and persisted longer after exercise than in the 11 patients with one and two vessel disease or the seven with normal coronary arteries. Although there were significant differences between the groups in absolute change in ejection fraction and the rate of change in ejection fraction related to exercise duration and heart rate, a considerable overlap of values between groups precluded the accurate prediction of coronary anatomy in individuals. These data suggest that the amount of myocardium at risk from ischaemia in some patients with one and two vessel disease may resemble that in patients with three vessel disease. This study shows that an anatomical classification based solely on the number of diseased vessels will not predict the extent of the impairment of left ventricular function on exercise.

Radionuclide assessment of regional left ventricular function in acute myocardial infarction

To determine changes in global and regional left ventricular function following acute myocardial function, 17 patients underwent radionuclide angiography at 3 and 10 days post infarction. Five patients had nontransmural myocardial infarction and 12 had transmural infarction (six anterior and six inferior). There were no previous infarctions in 16 (94%) patients. Regional ejection fractions were calculated by dividing the left ventricle into four quadrants using the geometric center of the left ventricle on the end-diastolic frame as a reference point. At 3 days post infarction, 8 of 17 (47%) patients had an abnormality of global left ventricular ejection fraction (LVEF), whereas 16 of 17 (94%) patients had abnormalities of one or more regional ejection fractions (p less than 0.01). Between 3 and 10 days, global LVEF did not change (51% to 49%, p = NS). However, there were significant changes in 23 of 68 (34%) regional LVEFs. These changes did not relate to type, ECG location, creatine kinase (CK) size of infarction, or initial global LVEF. These data suggest that regional LVEF is a sensitive technique for identifying segmental dysfunction associated with myocardial infarction. In addition, significant changes occur in regional LV function during acute myocardial infarction despite stable serial global LV performance.

Left ventricular dysfunction after non-cardiac surgical procedures in patients with ischemic heart disease

In order to demonstrate the presence of postischemic ventricular dysfunction after non-cardiac surgical procedures, myocardial perfusion scintigraphy with thallium 201 and radionuclide ventriculography were performed before and 24 h after intervention in 20 patients suffering from angina pectoris. A long-term ECG recording was used in all patients to detect peroperative myocardial ischemia. In 14 of the 20 patients studied, both ventriculography and thallium scintigraphy were unchanged at the postoperative study. Comparison of pre- and postoperative radionuclide data revealed an increased deficit in one patient, both increased deficit and decreased ejection fraction in four others and a decreased ejection fraction in one other. In these five last patients, continuous ECG recording demonstrated the occurrence of peroperative ST segment depression. These results underline the part played by prolonged peroperative episodes of myocardial ischemia in the occurrence of postoperative left ventricular dysfunction.

Ejection fraction and heart rate correlate with diastolic peak filling rate at rest and during exercise

We investigated the independent variables correlating with the multigated radionuclide peak filling rate (PFR) at rest and during supine bicycle exercise in 20 normal individuals. Independent variables were systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), ejection fraction (LVEF), time to PFR (TPFR), peak ejection rate (PER) and time to PER (TPER). Fifteen subjects completed at least five stages of exercise at 25 watts each. Correlating independent variables were selected by a forward-backward stepwise multiple linear regression (BMDP2R). A partial correlation statistical program was also used to allow control of critical independent variables. The final regression equations were: a) resting state, PFR = -2.5 + 0.03HR + 0.05LVEF + 0.02SBP-0.02DBP, and b) exercise state, PFR = -3.8 + 0.04HR + 0.08LVEF. All independent variables mentioned above correlated with PFR (simple correlations designated as zero partials). However, when LVEF and HR were held constant (second order partials), the correlation of PFR with any of the other independent variables disappeared. In summary, the radionuclide global LV PFR is predominantly correlated to LVEF and HR at rest and during exercise. These correlations should be considered when assessing exercise effects of disease states on PFR.

Comparison of left and right ventricular end-systolic pressure-volume relations in congestive heart failure

A hemodynamic-radionuclide study was performed to compare the relations between end-systolic pressure and volume in the left and right ventricles in 10 patients with biventricular failure, and to correlate the end-systolic pressure-volume slope with baseline variables of systolic function. During nitroprusside or nitroglycerin infusion, or a combination of both, linear relations were found between end-systolic pressure and volume for both ventricles. In 9 of 10 patients, the end-systolic pressure-volume slope was greater for the left ventricle (mean +/- SD 1.12 +/- 0.36 mm Hg X m2/ml) than for the right ventricle (0.46 +/- 0.27 mm Hg X m2/ml) (p less than 0.001). In all 10 patients, the volume-axis intercept of the pressure-volume relation was greater for the left ventricle (82 +/- 66 ml/m2) than for the right ventricle (2 +/- 30 ml/m2) (p less than 0.005). Right ventricular pressure-volume slope correlated weakly with baseline right ventricular ejection fraction (r = 0.69, p less than 0.05), strongly with the baseline right ventricular end-systolic pressure-volume ratio (r = 0.89) and inversely with baseline right ventricular end-systolic volume (r = -0.86). In conclusion, 1) in patients with severe biventricular failure, changes in systolic pressure influence end-systolic volume more strongly in the right than in the left ventricle. 2) For the right ventricle, the slope of the end-systolic pressure-volume relation is directly related to rest indexes of systolic function. 3) The greater the end-systolic volume at rest, the greater the predicted improvement in right ventricular emptying for any vasodilator-induced reduction in pulmonary artery end-systolic pressure.

Beneficial effects of high-dose diltiazem in patients with persistent effort angina on beta-blockers and nitrates: a randomized, double-blind, placebo-controlled cross-over study

The effects of orally administered diltiazem combined with maximally tolerated doses of beta-blockers and nitrates were assessed in 12 patients, who during stress testing exhibited persistent effort angina and continued objective evidence for inducible myocardial ischemia. Patients performed multistage semisupine exercise on a bicycle ergometer during equilibrium-gated radionuclide angiography after consecutive 2 week treatment periods of placebo or diltiazem 90 mg qid (mean dose 340 mg/day) combined with maximally tolerated propranolol (mean dose 178 mg/day) and isosorbide dinitrate (mean dose 137 mg/day). All medications (including diltiazem or placebo) were administered four times daily for the duration of the study. Diltiazem or placebo was administered according to a double-blind design, with randomized cross-over at the end of each 2 week treatment period. The average number of angina attacks decreased during the double-blind cross-over phase of the trial (7 +/- 7 episodes/week at baseline vs 4 +/- 3 on placebo vs 2 +/- 2 on diltiazem; p = .08). Angina pectoris was abolished during peak exercise in eight of 12 patients on diltiazem (p less than .05 vs placebo). Diltiazem increased total exercise duration from 276 +/- 92 to 310 +/- 78 sec (p less than .005 vs baseline). Diltiazem likewise increased the time to onset of angina from 231 +/- 84 sec at baseline to 305 +/- 77 sec (p less than .005), as well as the time to the onset of 1 mm ischemic ST segment depression (p = .01). Diltiazem decreased heart rate at rest, during submaximal workload, and at peak exercise (p less than .05), and decreased systolic blood pressure at peak exercise only (p less than .05). A significant decline in rate-pressure product at submaximal and peak exercise was noted (p less than .05). At any given workload there was significantly less ST segment depression during submaximal (p = .05) and peak exercise (p less than .025).(ABSTRACT TRUNCATED AT 250 WORDS)

Digital processing in cardiac imaging

In recent years, imaging modalities have realized the potential for digitizing images of the heart. These modalities include nuclear cardiology, echocardiography, digital subtraction angiography, computed tomography, positron emission tomography, and magnetic resonance imaging. Once the cardiac images have been digitized by the computer and formatted in a pixel array of data, the computer can perform mathematical operations on the input (original) images for the purpose of providing improved output (processed) images. The computer can also analyze the original (or processed) images for the purpose of extracting global, regional, or temporal measurements of cardiac perfusion and function. These processes include the restoration, enhancement, analysis, manipulation, and coding of images. These basic processes are implemented by a combination of image processing operations. These operations include pixel point processing, pixel group processing, frame processing, geometric processing, and information extraction. This article describes how these operations are used to perform processes, and how these processes are applied to cardiac imaging, currently and in the future.

Sectoranalysis of left ventricular function by fully automated equilibrium radionuclide ventriculography

We describe a fully automated method for quantification of left ventricular performance by equilibrium radionuclide ventriculographic studies, based on subdivision of the left ventricular region into 9 equiangular sectors. The precise identification of the left ventricular contours is achieved by the use of morphological and functional criteria in a sequential edge detection algorithm with a success rate of 96%. In addition to left ventricular global and sectorial ejection fraction the first harmonic of the corresponding Fourier spectrum is approximated to each sectorial time-activity curve and to the global one. Sectorial phase is calculated as the difference between the phase of the sectorial and global first Fourier component. Computerized comparison between the sectorial parameters at rest and during peak exercise localizes and classifies the degree of global and regional impairment in response to exercise. The processing time of 60 sec makes this method suitable for routine use. The validity of our procedure has been tested in 34 patients before and after successful transluminal coronary angioplasty. In these patients, 73% of the stenosed vessels before dilatation were localized by sectorial ejection fraction, 77% by sectorial phases, and 88% by the combination of both.