Noninvasive method to assess cor pulmonale in patients with chronic obstructive pulmonary disease

In our study of 15 patients with chronic obstructive pulmonary disease, we performed myocardial perfusion single-photon-emission computerized tomography (SPECT) with thallium-201 to quantitatively assess right ventricular hypertrophy. On the SPECT images, we determined the ratio of activity in the right-to-left ventricular wall as the thallium score. Right ventricular ejection fraction (RVEF) was measured by multigated equilibrium radionuclide ventriculography with krypton-81m. Both the thallium scores and RVEF values correlated well with pulmonary arterial pressure (r = 0.65 and r = -0.86, respectively) and permitted the structural and functional assessment of cor pulmonale. When the patients were classified according to the thallium scores and RVEF values, those who had both a high thallium score and reduced RVEF had a significantly high pulmonary arterial pressure and vice versa. The combined evaluation of the thallium score and RVEF enabled accurate noninvasive assessment of cor pulmonale.     

Right ventricular function in patients with chronic obstructive pulmonary disease measured by krypton-81m

Right ventricular function was assessed at rest and during exercise in patients with chronic obstructive pulmonary disease (COPD). Right ventricular ejection fraction (RVEF) was measured by first-pass radionuclide angiography using ultrashort-lived radionuclide krypton-81m. The half-life of this nuclide is only 13 sec, and it is completely expired from the lungs. These properties allow measurement of RVEF without correcting for background activity. In 30 patients with cardiac or pulmonary disease, RVEF was first measured by krypton-81 m scintigraphy (Kr-RVEF), then by technetium-99m (Tc-RVEF), without changing the patients' positions. In eight of the 30 cases, right ventricular cineangiography (RVG) was performed within 72 hrs after the radionuclide study, and RVEF was measured according to the Chapman's rule (RVG-RVEF). Kr-RVEF correlated significantly with Tc-RVEF (r = 0.87), and also with RVG-RVEF (r = 0.80). In 10 patients with stable COPD, who had severe hypoxemia (PaO2 less than or equal to 60 mmHg) and pulmonary hypertension [mean pulmonary arterial pressure (mean PAP) greater than or equal to 20 mmHg], and in seven normal control subjects, radionuclide angiographic and hemodynamic monitoring were performed at rest and during supine ergometer exercise. Kr-RVEF at rest was 47.6 +/- 5.4% (mean +/- SD) in patients with COPD and was 54.1 +/- 4.8% in normal subjects. Kr-RVEF during exercise was 51.8 +/- 7.3% in the patients, and 62.3 +/- 3.2% in the normal subjects. Hemodynamically, mean PAP and pulmonary vascular resistance (PVR) increased significantly during exercise, but the RV end-diastolic volume index (RVEDVI) did not change. There was inverse correlation between Kr-RVEF and mean PAP (r = -0.51) or PVR (r = -0.47) as an index of RV afterload. However, there was no correlation between Kr-RVEF and RVEDVI as an expression of RV preload. These findings suggest that a poor response by RVEF during exercise in patients with COPD is associated with elevation of afterload. Thus, right ventricular imaging techniques using the ultrashort-lived nuclide krypton-81 m allow noninvasive, serial and accurate assessments of right ventricular function in patients with COPD.     

Changes in right ventricular function with unilateral pulmonary artery occlusion test for pre-operative evaluation prior to lung resection]

We measured the right ventricular ejection fraction (RVEF) before and during unilateral pulmonary artery occlusion test (UPAO) by thermodilution method. We also measured the right ventricular end-diastolic volume index (RVEDVI), right ventricular end-systolic volume index (RVESVI), and right ventricular stroke volume index (RVSVI). RVEF and RVSVI were significantly decreased by UPAO (p less than 0.05), but there were no obvious changes in RVEDVI and RVESVI. Some cases showed only a small decrease in RVEF by UPAO, even though their total pulmonary vascular resistance indices were over 700 dyne.sec.cm-5/m2 during UPAO. On the other hand, some cases had a decreased in RVEF of more than 10% by UPAO, even though their total pulmonary vascular resistance indices were under 400 dyne.sec.cm-5/m2 during UPAO. We consider that it is important to measure right ventricular functions such as RVEF together with pulmonary vascular hemodynamics in the pre-operative evaluation of cases of lung resection.     

Comparative evaluation of thermodilution and gated blood pool method for determination of right ventricular ejection fraction at rest and during exercise

BACKGROUND: Since the development of a Swan-Ganz thermodilution ejection fraction catheter several studies have been published which compare this technique for obtaining right ventricular ejection fraction (RVEF(TD)) with alternative methods. However, the reliability of RVEF(TD) measurements under exercise conditions remains undetermined. Therefore, the aim of the present study was a comparative evaluation of RVEF(TD) with the established gated blood pool method (RVEF(GBP)) under exercise conditions. METHODS AND RESULTS: Twenty-two patients with different cardiac diseases underwent right heart catheterization, including RVEF(TD) and simultaneous RVEF(GBP) determination at rest and during supine bicycle exercise. Linear regression analysis showed a significant correlation between RVEF(TD) and RVEF(GBP) at rest (r = 0.73, p < or = 0.0005) and during exercise (r = 0.74, p < or = 0.0005). A Wilcoxon analysis showed a high probability of agreement of RVEF(TD) and RVEF(GBP) at rest and exercise (level of significance for error of the 0 hypothesis of 95.9/73.3%). CONCLUSION: The thermodilution ejection fraction catheter provides a useful device for reliable, repetitive and safe RVEF measurements, not only at rest but also under exercise conditions. This seems to be clinically important, because by it means RVEF, as a sensitive parameter of primary or secondary right ventricular dysfunction, can be determined in the course of standard right heart catheterization.     

Right ventricular ejection fraction from equilibrium krypton-81m blood pool scans: a noninvasive predictor of pulmonary arterial hypertension

Based on the relation between the impedance to right ventricularejection and ejection fraction of the right ventricle (RVEF)we tested the hypothesis that radionuclide RVEF correlates inverselywith pulmonary artery pressure and allows the noninvasive predictionof pulmonary hypertension. A recently developed improved equilibriumright ventricular blood pool imaging technique using ultrashort-livedkrypton-81m and simultaneous right heart catheterization werecombined for assessment of right ventricular systolic performancein relation to right ventricular loading in a heterogeneousgroup of cardiopulmonary disorders. The study group included9 patients with pulmonary artery hypertension secondary to leftventricular dysfunction, 5 with primary pulmonary hypertension,5 with corrected tetralogy of Fallot, and 10 normal subjects.Linear regression analysis between radionuclide RVEF and simultaneouslyrecorded hemodynamic measurements of right ventricular loadingrevealed a significant inverse correlation with mean PA pressure(r= –0.87; P<0.001), with total pulmonary resistanceindex (r= –0.81; P<0.001) and with pulmonary vascularresistance index (r= –0.78, P<0.01). The sensitivityand specificity of a resting RVEF less than 40% to indicatepulmonary hypertension (mean PA pressure >20mmHg) were 71%and 100%, respectively; positive and negative predictive valueswere 100% and 80%, respectively. Thus, radionuclide RVEF asa parameter of right ventricular systolic performance is predominantlydependent on right ventricular afterload and has the potentialfor the noninvasive prediction of pulmonary hypertension ina heterogeneous group of cardiopulmonary disorders.     

Prediction of pulmonary arterial pressure in chronic obstructive pulmonary disease by radionuclide ventriculography

Pulmonary arterial hypertension represents an important parameter for the assessment of the severity of chronic bronchitis. The measurement of the pulmonary arterial pressure, however, requires invasive techniques of limited routine use because of costs and associated risks. The aim of this study is to evaluate whether the 81mKr right ventricular ejection fraction and parameters derived from equilibrium 99mTc red blood cells' right ventricular curve allow a better estimation of PAP than the 99mTc RVEF. In 41 patients with severe chronic bronchitis, the linear correlation between PAP and 99mTc RVEF was -0.61 (p less than 0.001). None of the parameters derived from the right ventricular curve was better correlated to PAP than the 99mTc RVEF. In 16 other chronic bronchitis patients, the 81mKr RVEF correlated moderately to PAP. In conclusion, the alternative isotopic methods proposed in this work do not provide a reliable estimation of pulmonary arterial pressure in patients with chronic bronchitis.     

Changes in right ventricular structure and function assessed using cardiac magnetic resonance imaging in bosentan-treated patients with pulmonary arterial hypertension

Patients with pulmonary arterial hypertension (PAH) usually show improvements in symptoms, exercise capacity, and hemodynamics after treatment with approved medical therapies. This study sought to determine whether improvement in right-sided cardiac function measured using cardiac magnetic resonance imaging would also be seen and whether these changes would correlate with improvement in exercise capacity. Sixteen patients with PAH underwent evaluation at baseline and after 12 months of treatment with bosentan. After treatment, cardiac index, pulmonary vascular resistance, and 6-minute walk distance improved, and there was a trend toward improvement in right ventricular (RV) stroke volume (70 +/- 27 to 81 +/- 30 ml; p = 0.08), but no change in RV ejection fraction (RVEF) or RV end-diastolic volume. Six-minute walk distance improved by 59 m (p <0.05) in the overall cohort and improved more in patients in whom RVEF increased compared with those with stable or decreased RVEF (+98 vs -37 m, respectively; p = 0.01). Three patients died during follow-up, and these patients had significantly lower RVEF and left ventricular end-diastolic volume indexes than surviving patients. In conclusion, these results suggest that cardiac magnetic resonance imaging may have value in determining response to therapy and prognosis in patients with PAH.     

超声心动图对先天性心脏病右心室功能的评价

目的以右心室造影为对照,使用超声心动图常规的四腔心切面和全新的右心室全显示切面定量评价右心室射血分数（right ventricular ejection fraction,RVEF）,探讨右心室全显示切面在右心功能评价中的应用价值。方法2011年4月至2011年11月通过临床和超声心动图检查选择伴有右心室形态或血流动力学改变的先天性心脏病患者22例（男13例,女9例,年龄16～67岁）为研究对象。除对人选患者行常规的超声心动图检查外,还使用四腔心切面和右心室全显示切面测量RVEF。在心导管实验室使用右心室造影测量RVEF。将四腔心和右心室全显示切面RVEF与右心室造影RVEF行随机区组设计方差分析及Pearson相关性分析,右心室全显示切面RVEF与其余右心功能指标行Pearson相关分析,并采用Bland—Ahman法评价右心室全显示切面与右心室造影的一致性。结果3种方法测得的RVEF分别为右心室全显示切面48．O％±11．3％、四腔心切面49．5％±13．1％、右心室造影48．7％±12．1％。3种方法测量结果比较,差异无统计学意义（F=0．327,P=0．723）。右心室全显示切面RVEF与右心室造影RVEF呈高度相关（r=0．908,P〈0．001）,四腔心切面RVEF与右心室造影RVEF呈中度相关（r=0．659,P=0．001）。右心室全显示切面RVEF与肺动脉收缩压及主肺动脉宽度负相关（P〈0．05）,与右心室每搏输出量正相关（P〈0．05）,与其他右心功能评价指标则无明显相关性。结论与常规的四腔心测量方法相比。超声心动图右心室全显示切面测量的RVEF与右心室造影的相关性更好,可能是一种准确和可靠的评价右心室收缩功能的方法。     

Right ventricular function in patients with chronic right ventricular infarction

To assess right ventricular function in patients with chronic right ventricular infarction, Tc-99m angiocardiography was performed in 64 patients one to three months after the onset of myocardial infarction. These patients were categorized into four groups according to their hemodynamic data in the acute stage using the Forrester classification: 39 patients in group I, 15 in group II, eight in group III and two in group IV. Mean right atrial pressure was nearly equal to or greater than diastolic pulmonary arterial pressure in all patients in group III. We calculated right ventricular ejection fraction (RVEF) and the right ventricular end-diastolic volume index (RVEDVI) as the parameter of right ventricular function, and assessed right ventricular wall motion using the right ventricular regional ejection fraction images (RVREFI). 1. RVEF in group III (25 +/- 3%) was significantly lower than those in groups I, II and IV (44 +/- 6%, 45 +/- 7% and 37 +/- 4%, respectively), and RVEF of all patients in group III was less than 30%. 2. RVEDVI in group III (150 +/- 25 ml/m2) was significantly greater than those in groups I, II and IV (74 +/- 20 ml/m2, 59 +/- 14 ml/m2 and 91 +/- 36 ml/m2, respectively). 3. RVREFI in group III decreased at the inferior and/or septal regions of the right ventricle, indicating wall motion abnormalities at the corresponding sites. 4. Six patients in group III were examined by coronary angiography and all had definite lesions in the proximal portion of the right coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of controlled oxygen therapy on ventricular function in patients with stable and decompensated cor pulmonale

We made simultaneous measurements of pulmonary hemodynamics, cardiac output, and right ventricular ejection fraction (RVEF) to assess the right ventricular function in 14 patients with pulmonary arterial hypertension as a result of chronic obstructive pulmonary disease (COPD). From these measurements, the right ventricular end-systolic pressure/volume relationship could be calculated and used to assess right ventricular contractility. Eight of the patients were clinically stable, without edema, and 6 presented acutely with gross edema, indicating decompensated cor pulmonale. Measurements were made at rest, while breathing air and oxygen. Although mean pulmonary arterial pressure (Ppa) was similar in those with (Ppa = 33 +/- 6 mm Hg) and without edema (Ppa = 30 +/- 8 mm Hg, p greater than 0.05), RVEF was lower in edematous (RVEF = 0.23 +/- 0.11) compared with non-edematous patients (RVEF = 0.47 +/- 0.04, p less than 0.01). Cardiac output was normal in both groups. The mean right ventricular end-systolic pressure/volume ratio (P/V) was lower in those patients with edema (P/V = 0.41 +/- 0.27), as compared with those without edema (P/V = 1.69 +/- 0.35, p less than 0.05), as a result of an increase in right ventricular end-systolic volume index. Similarly, left ventricular end-systolic volumes were higher in edematous than in non-edematous patients. Breathing 1 to 3 L/min of oxygen for 30 min decreased total pulmonary vascular resistance (p less than 0.05) in those patients without edema, but not in patients with edema. Oxygen did not change RVEF, left ventricular ejection fraction (LVEF), or the ventricular end-systolic P/V relationships.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thermodilution measurement of the right ventricular ejection fraction

This study addressed the clinical reproducibility and validity of the thermodilution (TD) measurement of the right ventricular ejection fraction (RVEF). Forty-one patients underwent right heart catheterization, including TD RVEF, within 2 h of gated first pass (GFP) and gated blood pool (GBP) radionuclide ventriculography; 21 had single plane contrast right ventricular angiography (ANGIO) during the same catheterization. Analysis of variance showed no difference among three successive TD RVEF measurements. (table; see text) Stroke volume by RV ANGIO correlated with Fick (n = 10, r = .86) and thermodilution stroke volume (n = 21, r = .88). It is concluded that although the thermodilution method is an accurate way to measure flow, it is not an accurate way to measure right ventricular ejection fraction, and by inference, ventricular volumes. The most likely explanation for this finding is incomplete mixing as in previous studies of indicator methods of measuring left ventricular volumes.     

Right ventricular function after extracardiac conduit repair for tetralogy of Fallot. A comparison among surgical approaches

Right ventricular volume measurements and hemodynamic studies were performed in 20 patients after total correction of tetralogy of Fallot. There were 6 patients with an extracardiac conduit and Hancock xenograft (G-1), 8 with an outflow tract patch (G-2) and 6 without or with a minimal right ventriculotomy and repair of pulmonary valve (G-3). The age at the time of operation was over 3 years in each patient and averaged 5 +/- 2 (mean +/- SD) years. Right ventricular systolic pressure averaged 81 +/- 22, 55 +/- 22 and 58 +/- 30 mmHg in G-1, G-2 and G-3, respectively. Right ventriculography showed no contraction of the right ventricular free wall at the anastomosis to the conduit and poor contraction around the anastomosis in G-1. The right ventricular enddiastolic volume index (RVEDVI) was 114 +/- 31, 155 +/- 57 and 115 +/- 28 ml/m2 in G-1, G-2 and G-3, respectively. The right ventricular ejection fraction (RVEF) was 0.42 +/- 0.11 in G-1, 0.53 +/- 0.04 in G-2 (p less than 0.05, vs G-1) and 0.57 +/- 0.04 in G-3 (p less than 0.02, vs G-1). Pulmonary regurgitation was evident in 17 patients, and RVEDVI correlated well with degrees of pulmonary incompetence. Fourteen patients in G-2 and G-3 were divided into G-A and G-B to evaluate right ventricular function with or without pressure overloading of the right ventricle. G-A consisted of 7 patients with a right ventricular systolic pressure of more than 50 mmHg (74 +/- 26) and G-B of 7 patients with a value less than 50 mmHg (39 +/- 4). There was no difference in RVEDVI and RVEF between G-A and G-B. RVEF was significantly lower in G-1 than G-A (p less than 0.02) and G-B (p less than 0.05). These results suggested that an extracardiac conduit with Hancock xenograft reduced the contraction of the right ventricular free wall and induced a depressed right ventricular pump function in patients with a high right ventricular pressure.     

Left ventricular volume characteristics and its relationship with right ventricle after repair of tetralogy of Fallot

In order to study the left ventricular volume characteristics and right ventricular influence on left ventricle, cardiac catheterization and biplane cineangiography was performed in 61 patients after repair of tetralogy of Fallot. Preoperative left ventricular volume size was also measured in 25 patients. Postoperative left ventricular end-diastolic volume index (LVEDVI) was 93 +/- 22 ml/m2 (mean +/- standard deviation) and it was 140 +/- 29% of normal left ventricular volume. Left ventricular ejection fraction (LVEF) was 60 +/- 6%. Left ventricular size significantly increased from 109 +/- 25% to 140 +/- 23% of normal by corrective surgery (p less than 0.001). Left ventricular volume characteristics are correlated with right ventricle. LVEDVI increased with increasing right ventricular end-diastolic volume index (RVEDVI) and decreased right ventricular ejection fraction (RVEF). LVEDVI (ml/m2) = 60 + 0.29 RVEDVI (ml/m2), r = 0.52, p less than 0.001, LVEDVI (ml/m2) = 141 - 0.90 RVEF (%), r = -0.30, p less than 0.02. LVEF decreased with increasing RVEDVI and decreased RVEF. LVEF (%) = 68 - 0.075 RVEDVI (ml/m2), r = -0.51, p less than 0.001, LVEF (%) = 43 + 0.32 RVEF (%), r = 0.40, p less than 0.001. On the contrary there was no relationship between right ventricular volume characteristics and right ventricular systolic pressure. There were two cases whose LVEF was less than 50%. In one case right ventricular systolic pressure was as high as 98 mmHg. In the other patient RVEDVI was 299 ml/m2 (453% of normal right ventricular volume) because of severe pulmonary regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Determination of right ventricular ejection fraction in children with cystic fibrosis

The radionuclide right ventricular ejection fraction (RVEF) determined by means of Krypton-81m represents a simple, noninvasive, and accurate procedure to quantify the right ventricular contractility. This procedure was applied to 25 young patients with cystic fibrosis. The RVEF tended to decrease with the progression of the lung disease, as assessed by the clinical S-K score, the degree of the defects on lung scintigraphy, the PaO2, and the lung function tests. However, the decrease of RVEF in patients with marked lung function tests. However, the decrease of RVEF in patients with marked lung involvement was moderate, and terminal lung disease was sometimes associated with normal right heart contractility.     

Measurement of the right ventricular ejection fraction during the acute phase of myocardial infarction using 81m krypton infusion. Comparison with the left ejection fraction

The right ventricular ejection fraction is rarely measured, as conventional diagnostic methods (radiology, echocardiography) are confronted with the problem of representing the right ventricle as a simple tridimensional geometrical model. This is not necessary with the radio-isotopic techniques. However, all those used for the measurement of right ventricular ejection fraction lead to important methodological problems. We have therefore developed a technique of measuring this parameter with an infusion of 81 m Kr. This radioactive gas is pure gamma-ray emitter with a 13 second period. Dissolved and infused intravenously, it is eliminated during the first passage through the lung. The continuous separation of the generator of 81 m Kr is performed with isotonic dextrose solution which is then infused for a period of 7 minutes. During this time, the activity detected by the scintillation camera inclined in the 30 degrees RAO projection is stored, together with the electrocardiogram in a computer. The precordial radioactivity of the retrocardiac lung tissue is subtracted after injection of 74 MBq of 99 mTc microspheres. A graph of right ventricular activity can then be reconstructed and the right ventricular ejection fraction calculated. The left ventricular ejection fraction is then measured with 99 mTc--labelled RBCs. This method allows the right ventricular ejection fraction to be measured in the RAO projection, the best incidence for the separation of the right atrial from the right ventricular activity without interference from left ventricular activity because of the pulmonary elimination of the Krypton radioactivity. The measurement performed on a large number of cardiac cycles allows a continuous study of the right ventricular ejection fraction. At the end of the infusion there is no circulating radioactivity so that the measurement can be repeated. This technique was used in 17 patients with acute myocardial infarction. In the 7 patients with anterior infarcts reduction of the left ventricular ejection fraction was the predominant finding (21,6 +/- 6,8%). The right ventricular ejection fraction was 34,2 +/- 6,4%. On the other hand, patients with a postero-inferior infarction had little change in left ventricular ejection fraction (59,2 +/- 12%) but those with right ventricular extension of their infarcts had very reduced right ventricular ejection fractions (less than 23%). The measurement of right ventricular ejection fraction with 81 m Kr is a reliable atraumatic method for diagnosing right ventricular infarction by the quantification of its functional impairment.     

Right ventricular function in valvular heart disease: relation to pulmonary artery pressure

Right ventricular angiography was performed in 46 patients with acquired valvular heart disease and 8 normal subjects. Right ventricular ejection fraction (RVEF) correlated highly only with right ventricular peak systolic pressure (RVPSP) and mean pulmonary artery pressure, both in patients with and without tricuspid insufficiency. For the group, RVEF = -0.33 RVPSP + 63 (correlation coefficient [r] = -0.76, probability [p] less than 0.001). Of 20 patients with moderate or severe elevation of pulmonary artery pressure, 17 (85%) had an abnormally low ejection fraction (less than 47%), while 19 (73%) of 26 patients with normal or mildly elevated pulmonary artery pressure had a normal right ventricular ejection fraction. In seven patients with elevated pulmonary artery pressure, a second ventriculogram was performed during intravenous nitroglycerin administration. Nitroglycerin produced a significant decrease in right ventricular peak systolic pressure (59 +/- 22 to 49 +/- 18 mm Hg, mean +/- standard deviation) (p less than 0.05) and in end-systolic volume (71 +/- 16 to 59 +/- 11 m1/m2) (p less than 0.05), and an increase in ejection fraction (43 +/- 9 to 48 +/- 7%) (p less than 0.05). Thus, at least part of the depression of ejection fraction in patients with elevated pulmonary pressure is reversible with a decrease in pulmonary artery pressure.     

Right ventricular volume and mass determined by cine magnetic resonance imaging in HIV patients with possible right ventricular dysfunction

Impaired right ventricular (RV) function has been reported to occur in patients with HIV when studied by echocardiography. However, for accurate evaluation of RV function and morphology, first-pass radionuclide ventriculography (RNV) and cine magnetic resonance imaging (cine-MRI) are methods of choice. Studies of RV involvement in patients with HIV are of interest since pulmonary hypertension is a known serious complication of HIV recognized with increasing frequency. The aim of the present study was to characterize cardiac function and geometry in patients with HIV and reduced right ventricular ejection fraction (RVEF). To do so, we screened patients with RNV and performed an additional cine-MRI in those with reduced RVEF determined by RNV. Ninety patients with HIV were included. To evaluate the MRI measures exactly we included 18 age- and gender-matched healthy volunteers to establish reference values. RNV showed in 13 of the 90 patients a reduced RVEF with a standard cutoff value for RVEF of 0.50. Six of these agreed to have an additional MRI investigation performed. These 6 patients with HIV had an RVEF measured by RNV between 0.41-0.49. Measured by MRI the range of RVEF was 0.47-0.55 with 3 below the lower 95% reference limit according to the control group (lower reference limit: 0.49). None of the 6 patients with HIV had dilated right ventricle and only 1 had a marginally increased right ventricular mass index of 43 g/m(2) (reference: <41 g/m(2)). With use of MRI, a few patients with HIV may have a marginally reduced RVEF but normal RV dimensions and mass. Thus, RV dysfunction does not seem to constitute a major clinical problem in this antivirally treated HIV population.     

Effect of beta-blockade on right ventricular performance in patients with and without right ventricular dysfunction due to coronary artery disease

To assess the effects of beta-blockade on right ventricular performance in patients with and without right ventricular dysfunction due to coronary artery disease, we performed radionuclide ventriculography on eight patients with normal right ventricular ejection fraction (RVEF greater than or equal to 35%) and 14 patients with mild to moderate right ventricular dysfunction (RVEF less than 35%) at rest. All patients had chronic stable angina pectoris, and nine patients had prior myocardial infarction. Radionuclide ventriculography was performed on placebo and during clinical beta-blockade (heart rate, 50 to 60 beats per minute and less than or equal to 20% increase in heart rate over baseline during stage I treadmill exercise, Bruce protocol) with the oral, cardioselective beta-blocking agent, betaxolol. The resting RVEF (mean +/- 1 SD) was 33% +/- 7% on placebo and 34% +/- 7% during clinical beta-blockade. Mean exercise RVEF was 40% +/- 8% on placebo and 39% +/- 8% during clinical beta-blockade. These differences were not statistically significant. Resting left ventricular ejection fraction ranged from 22% to 60% (mean, 42% +/- 8%). On placebo, one of eight patients with a resting RVEF greater than or equal to 35% had a normal exercise RVEF response (greater than or equal to 5% increment) whereas nine of 14 patients with resting RVEF less than 35% had normal exercise response. The discordant relationship between baseline RVEF and exercise response on placebo became less marked during clinical beta-blockade. We conclude that beta-blockade does not produce significant deterioration of right ventricular systolic function or right ventricular reserve either in patients with normal or in those with mild to moderately impaired resting right ventricular systolic function.     

Clinical use of ultrashort-lived radionuclide krypton-81m for noninvasive analysis of right ventricular performance in normal subjects and patients with right ventricular dysfunction

The ultrashort-lived radionuclide krypton-81m, eluted in 5% dextrose from a bedside rubidium-81m generator, was intravenously infused for rapid imaging of the right-sided heart chambers in the right anterior oblique projection adjusted for optimal right atrioventricular separation. Left-sided heart and lung background was minimized by rapid decay and efficient exhalation of krypton-81m, requiring no algorithm for background correction. A double region of interest method decreased the variability in the assessment of ejection fraction to 5%. In 10 normal subjects, 11 patients with pulmonary hypertension, 4 patients with right ventricular outflow tract obstruction and 4 patients with right ventricular infarction, right ventricular ejection fraction determined by krypton-81m equilibrium blood pool imaging ranged from 14 to 76%. The correlation between these values and those determined by cineangiography according to Simpson's rule was close: r = 0.93 for all data points (p less than 0.001), r = 0.92 for studies at rest (p less than 0.001) and r = 0.93 for exercise studies (p less than 0.001). Exercise-related changes in right ventricular function revealed a disturbed functional reserve with pulmonary hypertension and right ventricular infarction, whereas in compensated right ventricular outflow tract obstruction there was a physiologic increase in ejection fraction with exercise (p less than 0.001). Thus, equilibrium-gated right ventricular imaging using ultrashort-lived krypton-81m is a simple, accurate and reproducible method with potential for serial assessment of right ventricular ejection fraction in a variety of right ventricular anatomic and functional abnormalities, both at rest and during exercise. Advantages of this method include an extremely low radiation dose to patients and clear right atrioventricular separation without the need to correct for background activity.     

Pathologic involvement of the left ventricle in chronic cor pulmonale

To determine whether or not the left ventricle is pathologically involved in patients with chronic cor pulmonale, right and left ventricular weights, wall thickness, myocyte diameters, and percentage of fibrosis in 18 autopsied hearts were examined in patients with chronic pulmonary disease (CPD); ten had right ventricular hypertrophy on their electrocardiograms, and eight were without right ventricular hypertrophy. Five with extracardiopulmonary disease were used as controls. The weight of the right ventricle was significantly increased in CPD when compared to control subjects. Walls of both ventricles were significantly thicker in CPD. Myocyte diameters of both ventricles were significantly greater in CPD. The percentage of fibrosis in the right ventricle was significantly greater in CPD. The percentage of fibrosis in the left ventricle was significantly greater only in patients with right ventricular hypertrophy. We concluded that the left ventricle was also involved pathologically in patients with chronic cor pulmonale in the end stage of the disease.