Relation of changes in left ventricular peak filling rate during exercise to exercise performance in systemic hypertension and in healed myocardial infarction.

Patients with systemic hypertension and coronary artery disease (CAD) often manifest abnormalities at rest in left ventricular (LV) diastolic function and reduced exercise tolerance. It is possible that abnormalities in filling persist during exercise and are partially related to abnormal exercise tolerance. We examined rest and exercise peak filling rate (PFR) to determine if changes in PFR during exercise influence exercise performance. We studied 20 patients with systemic hypertension who had no evidence of CAD (negative thallium-201 stress imaging) and 15 patients with prior myocardial infarction, preserved ejection fraction, and no ischemia by thallium-201 stress imaging. Results were compared with 20 normal subjects. All 55 subjects had rest and exercise radionuclide angiograms Peak workload, exercise time, and LV ejection fraction were reduced in subjects with CAD (57 +/- 24 W, 7.41 +/- 2.91 min, and 60 +/- 9%) compared with subjects with hypertension (72 +/- 21 W, 9.69 +/- 3.03 min, and 70 +/- 6%, p <0.05) and controls (80 +/- 30 W, 10.82 +/- 3.50 min, and 67 +/- 6%, p <0.05). PFR at rest was reduced in CAD subjects (2.40 +/- 0.70 end-diastolic volume per second [EDV/s]) compared with those with hypertension (2.89 +/- 0.70 EDV/s, p <0.02) and controls (3.23 +/- 0.52 EDV/s, p <0.0002). The increments in PFR during exercise were reduced in CAD patients (+1.76 +/- 0.95 EDV/s) compared with hypertensive subjects (+2.93 +/- 1.7 EDV/s) and controls (+3.22 +/- 1.4 EDV/s, p <0.05). The increment in PFR during exercise was related to exercise performance (r = 0.49, p <0.0002). These findings suggest that alterations in LV diastolic filling during exercise are important determinants of exercise performance.

Correlations between coronary flow reserve measured with a Doppler guide wire and treadmill exercise testing.

We compared exercise test results to a physiologic depiction of stenosis severity, coronary flow reserve (CFR), measured with a Doppler guide wire in 35 patients with single-vessel coronary disease. Group 1 (n = 21) had abnormal CFR, and group 2 (n = 14) had normal CFR. In group 1, 14 of 21 had ST-segment depression versus 3 of 14 in group 2 (p < 0.01). Exercise treadmill time (Bruce protocol) was normalized to the age- and sex-predicted time. Exercise time and normalized exercise time were less in group 1 (5.6 +/- 2.3 vs 9.9 +/- 1.8 min and 0.82 +/- 0.32 vs 1.25 +/- 0.23, p < 0.00001). Having either ST-segment depression or a normalized exercise time <1 during exercise had a 95% sensitivity, 71% specificity, and 86% predictive accuracy in identifying abnormal CFR. Coronary stenoses and minimal lumen diameter were similar in groups 1 and 2. By using stepwise logistical regression analysis, exercise time and ST-segment depression predicted CFR with a total r2 of 0.51. Minimal lumen diameter did not significantly add to the model. Exercise test variables, ST-segment depression, and exercise time are predictive of the physiologic significance of coronary lesions.

Clinical application of coronary flow reserve using an intracoronary Doppler guide wire.

Coronary flow reserve (CFR) is a critical measurement in the assessment of the coronary circulation. The development of this physiologic variable in animal and human studies is reviewed. Human studies documenting the limitations of coronary angiography, especially in the setting of severe diffuse coronary artery disease, are analyzed. Furthermore, the important variables that must be accounted for when CFR is measured are examined. With this background, the application of CFR in a variety of clinical settings and the development and use of the Doppler FloWire for its measurement are discussed.

Antihypertensive treatment in hypertensive patients with normal left ventricular mass is associated with left ventricular remodeling and improved diastolic function.

Antihypertensive therapy in hypertensive patients with left ventricular (LV) hypertrophy causes hypertrophy regression and improved diastolic filling. Whether similar changes occur in hypertensive patients with diastolic dysfunction and no hypertrophy is unknown. We determined the effect of antihypertensive therapy of LV geometry and function in hypertensive patients without hypertrophy. In 18 mild to moderate hypertensive patients without significant hypertrophy, baseline echocardiograms and rest and exercise and radionuclide angiograms were performed. Subjects were treated for 8 to 12 months with the calcium channel blocker felodipine and then restudied 2 weeks after treatment withdrawal. Blood pressure normalized with treatment (165 +/- 22/98 +/- 9 to 128 +/- 12/80 +/- 5 mm Hg, p <0.001) and returned to pretreatment levels after therapy withdrawal. Rest ejection fraction and peak oxygen consumption and cardiac outputs were unchanged after treatment, but rest peak filling rate increased (2.63 +/- 0.57 to 3.11 +/- 0.95 end-diastolic volume/second, p <0.05). Ejection fraction increased with exercise only after treatment (64 +/- 5% at rest to 71 +/- 8% at peak exercise, p <0.05). LV mass index was unchanged (97 +/- 18 to 101 +/- 23 g/m2), but relative wall thickness declined (0.41 +/- 0.05 to 0.37 +/- 0.05) and LV end-diastolic dimension increased (4.9 +/- 0.4 to 5.2 +/- 0.4, p = 0.01). Blood pressures control in hypertensive patients without hypertrophy leads to improved peak filling rates and remodeling with decreased relative wall thickness. Improved diastolic function can occur without alterations in LV mass.

Assessment of the right ventricle with radionuclide techniques.

The right ventricle has a prominent role in determining overall cardiac function. Thus an accurate measurement of right ventricular (RV) function is important. Radionuclide angiography has advanced our ability to measure RV function. In this way, it has furthered our understanding of the pathophysiology of disease states involving the right ventricle. This article reviews the current methods of measuring RV function by radionuclide angiography. The physiology of normal RV function is discussed. Then several common disease states in which RV dysfunction is prominent are addressed.

Left ventricular ejection fraction during supine and upright exercise in patients with systemic hypertension and its relation to peak filling rate.

In hypertensive patients with hypertrophy, abnormal peak filling rate (PFR) is related to a decline in left ventricular (LV) ejection fraction (EF) during supine exercise. Because an increased LV preload is more common during upright exercise, we determined this relation during upright and supine exercise. In 20 hypertensive patients, rest and exercise radionuclide angiography in the supine and upright positions, as well as echocardiography, were performed and compared with 20 age-matched controls. At rest in the supine and upright positions, blood pressure, LVEF, and PFR were 164 +/- 20/94 +/- 10 and 164 +/- 24/94 +/- 10 mm Hg, 65 +/- 8% and 65 +/- 6%, and 2.77 +/- 0.59 and 2.70 +/- 0.52 end-diastolic volumes/s, respectively. PFR was reduced compared with controls (3.29 +/- 0.3 and 3.27 +/- 0.27 end-diastolic volumes/s, supine and upright). LV mass index was normal (94 +/- 19 g/m2). LVEF increased during upright but not during supine exercise in the hypertensives. Four patients had a decline in each position versus none of the controls. There was no relation between the change in LVEF and rest PFR. In patients with mild to moderate hypertension without extensive hypertrophy, abnormal filling rates were present but did not correlate with the change in LVEF with exercise.

Abnormal left ventricular ejection fraction response to mental stress and exercise in cardiomyopathy.

BACKGROUND: A decline in left ventricular (LV) ejection fraction in response to mental stress and exercise is regarded as an indicator of myocardial ischemia. In patients with LV dysfunction, the ejection fraction is sensitive to afterload, which increases during stress. Thus, the effects of mental stress and exercise on LV systolic function in patients with cardiomyopathy were examined. METHODS: The ambulatory nuclear VEST (Capintec, Inc., Ramsey, N.J.) was used to monitor LV ejection fraction in patients with cardiomyopathy (10 idiopathic and 9 ischemic). Patients underwent a series of mental stress tests (serial 7s, Stroop color, and Paced auditory addition) and treadmill exercise. Heart rate, systolic blood pressure, and LV ejection fraction were measured. RESULTS: Mental stress and exercise increased heart rate and systolic blood pressure. For idiopathic cardiomyopathy, LV ejection fraction decreased during serial 7s, Stroop color, Paced auditory addition and exercise by -8% +/- 6%, -7% +/- 5%, -7% +/- 3%, -9% +/- 10%, respectively. For ischemic cardiomyopathy, LV ejection fraction declined by -4% +/- 3%, -7% +/- 5%, -6% +/- 3%, -2% +/- 6% during the same stress tests. There was no difference between the idiopathic and ischemic groups. Each patient showed a 5% or greater decline in LV ejection fraction during one mental stress test. There was an inverse relation between changes in LV ejection fraction and systolic blood pressure during all mental stress tests and exercise (r = -0.47, p < 0.0001). CONCLUSIONS: In patients with depressed baseline systolic function, the decline in systolic function during mental stress and exercise could be related in part to increases in LV afterload.

Rest-redistribution thallium-201 scintigraphy to determine myocardial viability early after myocardial infarction.

OBJECTIVES: This study attempted to determine the utility of early rest-redistribution thallium-201 imaging in detecting residual myocardial viability after myocardial infarction. BACKGROUND: The early detection of myocardial viability after myocardial infarction would have clinical relevance. METHODS: Thirty-one patients with acute myocardial infarction had early (mean [+/- SD] 2 +/- 1 day) rest-redistribution thallium-201 imaging followed by radionuclide and coronary angiography. Late studies included stress-redistribution-reinjection thallium-201 imaging or radionuclide angiography, or both. Viability was defined by the rest thallium-201 scan as an initial mild rest defect or any defect that demonstrated redistribution. RESULTS: Group 1 (n = 15) was predicted to have viable and Group 2 (n = 16) nonviable myocardium in the infarct zone. Group 1 patients were more likely to have a patent infarct-related artery (15 of 15 vs. 10 of 16, p < 0.03), higher initial ejection fraction (61 +/- 12% vs. 53 +/- 9%, p < 0.05), higher infarct wall motion score (p < 0.0001) and fewer abnormal thallium-201 segments (p < 0.0001). On follow-up studies, ejection fraction improved in Group 1 (from 57 +/- 13% to 66 +/- 10%, p < 0.05, n = 9) and deteriorated in Group 2 (from 53 +/- 10% to 46 +/- 8%, p < 0.05, n = 13). On late stress testing with thallium-201 reinjection, Group 1 patients had fewer abnormal segments (p < 0.03) and higher infarct zone counts during exercise (p < 0.05) and after reinjection (p < 0.05) than Group 2 patients. CONCLUSIONS: If confirmed by larger studies, early rest-redistribution thallium-201 imaging may be a useful technique for identifying residual viability after myocardial infarction.

Relationship between hemodynamics and right ventricular function in patients with cardiomyopathy. Important role of tricuspid regurgitation.

STUDY OBJECTIVE: Right ventricular (RV) ejection fraction is load sensitive, varying inversely with pulmonary artery pressure. We tested whether this relationship exists in dilated cardiomyopathy. DESIGN: Retrospective chart review. SETTING: Tertiary care referral medical center. PATIENTS: In 25 patients with cardiomyopathy referred for heart transplant evaluation (left ventricular ejection fraction 27 +/- 12%), hemodynamics, radionuclide angiograms, and Doppler echocardiograms were obtained initially (study A) and 8 +/- 8 months later (study B). RESULTS: Right ventricular ejection fraction was 40 +/- 17% on study A and 41 +/- 16% on study B, with a wide range of change between studies (+38 to -28%). Pulmonary artery systolic pressure (PASP) and right atrial pressure increased (52 +/- 9 to 61 +/- 10 mm Hg and 10 +/- 4 to 14 +/- 4 mm Hg, respectively, p < 0.05). There was no relation between PASP and RV ejection fraction (n = 50, r = -0.02, p = 0.87). Also, there was no relation between changes in PASP and RV ejection fraction (n = 25, r = 0.25, p = 0.15) between study A and B. However, there was a significant relation between interstudy changes in PASP and RV ejection fraction (n = 14, r = -0.71, p = 0.005) and end-systolic volume (n = 14, r = 0.53, p < 0.05) in patients in whom the degree of tricuspid regurgitation was either none or mild on both study A and B. CONCLUSIONS: In patients with cardiomyopathy, RV ejection fraction cannot be used as a noninvasive marker of pulmonary hypertension. Owing to variation in tricuspid regurgitation, alterations in pulmonary artery pressure over time may not lead to the expected change in RV ejection fraction or end-systolic volume.

Maximal exercise tolerance in chronic congestive heart failure. Relationship to resting left ventricular function.

The relationship between maximal exercise tolerance and resting radionuclide indexes of left ventricular systolic and diastolic function were evaluated in 20 ischemic and 44 idiopathic cardiomyopathy patients with New York Heart Association class 2-4 chronic congestive heart failure. Left ventricular ejection fraction, peak systolic ejection rate, peak diastolic filling rate, time to peak filling from end-systolic volume, and fractional filling in early diastole were measured from the radionuclide ventriculogram. All patients underwent symptom-limited exercise testing with on-line measurement of oxygen consumption. In the ischemic group, all of the radionuclide indexes correlated poorly with maximal exercise oxygen consumption (VO2max) except the peak systolic ejection rate which correlated modestly (r = 0.58, p < 0.05). Peak systolic ejection rate was significantly lower (p < 0.01) as were the peak diastolic filling rate and fractional filling in the first third of diastole (p < 0.05) in ischemic patients with marked exercise intolerance (VO2max < or = 14 mL/kg/min) compared with those with preserved exercise tolerance (VO2max > 14 mL/kg/min). In the idiopathic group, none of the radionuclide indexes correlated well with VO2max; and all indexes were similar in patients with and without marked exercise intolerance. These data suggest that (1) resting left ventricular ejection fraction poorly predicts maximal exercise capacity in both ischemic and idiopathic cardiomyopathy and (2) resting peak systolic ejection rate, peak diastolic filling rate, and fractional filling in early diastole may predict exercise tolerance in ischemic but not idiopathic cardiomyopathy.

Intracoronary Doppler guide wire versus stress single-photon emission computed tomographic thallium-201 imaging in assessment of intermediate coronary stenoses.

OBJECTIVES: The purpose of this study was to compare measures of coronary flow reserve by an intracoronary Doppler guide wire with results of stress single-photon emission computed tomographic (SPECT) thallium-201 imaging in patients with intermediate coronary artery disease (40% to 70% stenosis). BACKGROUND: Visual assessment of the coronary arteriogram as a means of predicting the physiologic significance of intermediate coronary stenoses is inaccurate. Coronary flow reserve is a reliable marker of the functional importance of a coronary lesion. The recent development of an intracoronary Doppler guide wire permits routine assessment of coronary flow reserve distal to coronary artery stenoses. METHODS: We prospectively evaluated coronary flow reserve in 30 subjects with intermediate stenoses using an intracoronary Doppler guide wire during elective coronary angiography. Patients subsequently underwent stress SPECT thallium-201 testing, and the blinded interpretations were correlated. Coronary flow reserve in a control group with normal coronary arteries classified our sample into group 1 (abnormal flow reserve, < 2.0) and group 2 (normal flow reserve, > or = 2.0). RESULTS: As defined, the coronary flow reserve of 16 vessels in group 1 was diminished in comparison to that of 19 vessels in group 2 (p = 0.0001). Qualitative and quantitative analysis of stress SPECT thallium-201 images confirmed perfusion defects in 15 of 16 vascular territories in group 1 in contrast to 1 of 19 regions in group 2. The sensitivity, specificity and overall predictive accuracy of Doppler-determined coronary flow reserve for stress SPECT thallium-201 results were 94%, 95% and 94%, respectively. CONCLUSIONS: In appropriately selected patients with intermediate coronary artery stenoses, Doppler guide wire determination of lesion significance provides equivalent data to those acquired by stress SPECT thallium-201 imaging.

Myocardial ischemia after orthotopic liver transplantation.

A hypercoagulable state exists after orthotopic liver transplantation. This hematologic abnormality may predispose patients to coronary thrombosis and unstable angina. The incidence of postoperative myocardial ischemia in such patients is unknown. Suitable electrocardiograms and clinical events of consecutive patients undergoing orthotopic liver transplantation (n = 45) and major intraabdominal surgery (n = 28) during a 3-month period at a major university teaching hospital and transplant center were examined retrospectively. Clinical myocardial ischemia or ischemic electrocardiographic changes, or both, occurred in 6 transplant patients compared with no patient in the nontransplant or comparison group. In 4 of the 6 patients with dramatic electrocardiographic changes and ischemic events, coronary arteriography failed to demonstrate significant obstructive disease. It is concluded that severe myocardial ischemia may occur in patients after orthotopic liver transplantation in the absence of significant coronary disease. A hypercoagulable state may predispose to coronary thrombosis in this setting, providing insight (and a future model for study) into the development of unstable angina.

Effects of chronic right ventricular pressure overload on left ventricular diastolic function.

Right ventricular (RV) function influences left ventricular (LV) diastolic filling in various clinical and experimental models. The influence of RV systolic function on LV diastolic performance was examined in patients with severe RV pressure overload. Eighty-two patients with pulmonary vascular or parenchymal disease who were referred for heart-lung or lung transplant evaluation were studied. All patients had radionuclide angiography from which RV ejection fraction and LV peak filling rate were measured. Most patients (n = 51) had right-sided cardiac catheterization. In 24 patients (group 1), RV ejection fraction was < 30%, whereas in 58 (group 2), it was > 30%. Mean pulmonary artery pressure was greater in group 1 than in 2 (57 +/- 16 vs 34 +/- 20 mm Hg; p < 0.0001). Pulmonary artery wedge pressure was also greater in group 1 than in 2 (14 +/- 9 vs 7 +/- 2 mm Hg; p < 0.0001), whereas peak filling rate was decreased (2.16 +/- 0.88 vs 2.97 +/- 0.79 end-diastolic volumes/s; p < 0.0001). LV ejection fraction was normal in all patients. There was an inverse relation between RV ejection fraction and pulmonary artery wedge pressure (r = 0.45; p < 0.001; SEE 5.3). There was a direct relation between RV ejection fraction and LV peak filling rate (r = 0.49; p < 0.0001; SEE 1.34). In patients with RV pressure overload, RV systolic function is related to LV diastolic performance. This effect is most likely mediated by ventricular interdependence.

Right ventricular thallium-201 kinetics in pulmonary hypertension: relation to right ventricular size and function.

Right ventricular ischemia occurs in experimental models of pulmonary hypertension. We analyzed right ventricular size and function and 201Tl uptake to determine if there was a relationship between 201Tl uptake and systolic function in 19 patients with pulmonary artery hypertension who were being evaluated for heart-lung transplantation. All patients had dipyridamole stress 201Tl scintigraphy, radionuclide angiography and echocardiography. In nine patients (Group 1), right ventricular ejection fraction was < 30% (mean 22% +/- 8%). In 10 patients (Group 2) it was > 30% (mean 45% +/- 11%). In Group 1, right ventricular 201Tl uptake in the lateral wall after dipyridamole was increased compared to Group 2 (40% +/- 7% versus 28% +/- 15% counts/pixel, p < 0.05) while left ventricular free wall uptake was similar. The ratio of right to left ventricular 201Tl uptake was increased in Group 1 versus Group 2 (0.81% +/- 0.30% versus 0.49% +/- 0.18%, p < 0.05). At 4 hr, right ventricular free wall 201Tl clearance was comparable, 51% +/- 13% versus 51% +/- 18% in Groups 1 and 2, respectively. No patient had perfusion abnormalities. Right ventricular ejection fraction was inversely related to dipyridamole stress right ventricular 201Tl uptake, r = -0.49, p < 0.03, s.e.e. = 13.6. Right ventricular 201Tl uptake was directly related to right ventricular wall thickness (r = 0.56, p = 0.18, s.e.e. = 10.4). Therefore, patients with more severe right ventricular systolic dysfunction have greater 201Tl uptake after dipyridamole stress, suggesting increased myocardial mass and possibly blood flow in response to hypertrophy. Patients with the most marked hypertrophy have impairment of right ventricular systolic function, independent of ischemia.

Comparison of left ventricular function by echocardiographic automated border detection and by radionuclide ejection fraction.

Echocardiographic automated border detection can provide on-line estimates of left ventricular cavity area by differentiating blood from tissue backscatter characteristics. The objective of this study was to assess the ability of short-axis measurements of left ventricular cavity area by automated border detection to determine left ventricular function by comparing these measurements to radionuclide measures of ejection fraction in the same patients. Eighty-eight consecutive patients, aged 53 +/- 14 years, underwent automated border detection studies within 2 hours of radionuclide ventriculography. Short-axis imaging with automated border detection was attempted at basal, midpapillary muscle, and apical levels. Maximal left ventricular length was also measured from apical 4- and 2-chamber views by standard imaging. Fractional area change--(end-diastolic area-end-systolic area)/end-diastolic area--was determined at each short-axis level. Volumes and ejection fractions were calculated using: volume = 5/6 (midventricular area).length. Simpson's rule for 3 short-axis measurements was calculated using: volume = (length/12) (5.basal area + 2.mid-area + 4.apical area). Technically adequate automated border detection data could be obtained on 69 patients (78%) at basal and mid-levels, and at all 3 short-axis levels in 66 patients (75%). Correlations with radionuclide ejection fraction were as follows: midventricular fractional area change--R = 0.84, SEE = 12%, y = 0.86 x - 7; area-length ejection fraction--R = 0.89, SEE = 9%, y = 0.96 x - 4; and Simpson's rule--R = 0.91, SEE = 8%, y = 0.89 x + 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect on verapamil on ventricular function: studies in denervated human heart.

Verapamil has complex influences on ventricular function owing to its direct myocardial effects, vasodilation, and reflex activation of the sympathetic nervous system. To investigate the direct myocardial effects of verapamil in humans independent of reflex sympathetic stimulation, we administered the drug to 13 recent heart transplant recipients with denervated ventricles. Hemodynamics and radionuclide angiograms were recorded at baseline, with altered loading conditions, and after intravenous (i.v.) verapamil (median dose 4 mg). Left ventricular (LV) systolic and diastolic function was analyzed by systolic pressure-volume relations (SPVR) and peak filling rate (PFR), respectively. Verapamil caused a decrease in blood pressure (BP) and heart rate (HR) with increases in right atrial pressure (RAP 6 +/- 3-8 +/- 3, p < 0.01) and pulmonary artery wedge pressure (PAWP, 9 +/- 3-11 +/- 3 mm Hg, p < 0.01) pressures. LV ejection fraction (EF) decreased (69 +/- 7-66 +/- 8%, p < 0.02) in association with an increase in LV end-systolic counts (3.45 +/- 1.27 to 4.72 +/- 1.78 kcts, p < 0.001). In 11 of 13 patients, the SPV point after verapamil administration was decreased from the line established during altered loading conditions. PFR (4.05 +/- 0.81 to 4.11 +/- 0.76 EDV/s) was unchanged. In the denervated ventricle, verapamil has negative chronotropic and inotropic effects with minimal effects on PFR.

Diastolic dysfunction in cardiac transplant recipients: an important role in the response to increased afterload.

We evaluated the hemodynamic and functional response to acute elevations in left ventricular (LV) afterload in 22 recent recipients of cardiac transplants to determine whether abnormalities in LV diastolic function influence the response to this intervention. In seven patients (group 1) LV ejection fraction decreased significantly from baseline values (> or = 5%) during methoxamine infusion, whereas in 15 patients (group 2) LV ejection fraction was maintained. Peak filling rate was lower in group 1 versus group 2 (3.36 +/- 0.46 vs 4.23 +/- 0.68 end-diastolic volumes/sec, p < 0.01). In addition, patients in group 1 did not have LV dilatation during methoxamine (percentage change in end-diastolic counts, -3.4 +/- 6.9%) and had a large increase in pulmonary artery wedge pressure. In contrast, patients in group 2 had LV dilatation (percentage change in end-diastolic counts, +10.7 +/- 14.7%) and a smaller increase in pulmonary artery wedge pressure. There was a relationship between the baseline peak filling rate and the change in LV ejection fraction during methoxamine (r = 0.65, p = 0.001). Therefore in a subset of cardiac transplant patients, abnormalities in LV filling can have an impact on the response to increased afterload.

Right ventricular function at rest and during exercise in chronic obstructive pulmonary disease.

Right ventricular ejection fraction (RVEF), a measure of systolic pump performance of the right ventricle, is frequently depressed at rest or during exercise in patients with chronic obstructive pulmonary disease (COPD). The most common cause of reduced RVEF in COPD is augmentation of right ventricular afterload, namely an increase in pulmonary artery pressure and pulmonary vascular resistance. Therapy with agents that decrease the afterload on the right ventricle have the potential to improve the systolic performance of this chamber. Oxygen, vasodilators such as hydralazine and nifedipine, theophylline, and sympathomimetics all may augment RVEF in part by reducing pulmonary vascular resistance and, in some cases, pulmonary artery pressures in patients with COPD and cor pulmonale. However, only oxygen therapy has been shown to improve survival.

Propionibacterium acnes prosthetic valve endocarditis: a case of severe aortic insufficiency.

Propionibacterium acnes rarely causes systemic disease. Few cases of P. acnes endocarditis have been reported. This report describes a 63-year-old man who presented with severe congestive heart failure. He had prosthetic valve endocarditis which resulted in severe acute aortic insufficiency. During surgery he was found to have complete disruption of the aorta and left ventricle with a false aneurysm encompassing the circumference of the aortic annulus. Cultures of the valve grew P. acnes. Thus, although P. acnes is a rare cause of endocarditis, it may pursue a very aggressive course, especially in the setting of a prosthetic valve.

Left ventricular diastolic function during positive end-expiratory pressure. Impact of right ventricular ischemia and ventricular interaction.

The individual and additive effects of positive end-expiratory pressure (PEEP) and right coronary artery (RCA) occlusion on left ventricular end-diastolic pressure-volume relations (LVEDPVR) were examined in six anesthetized dogs. Right ventricular (RV) and left ventricular (LV) ejection fractions (EF), end-diastolic volume (EDV) and end-systolic volumes (ESV) were measured by thermodilution as PEEP was added before and after RCA occlusion. PEEP alone caused a decline in cardiac output, transmural left atrial pressure (LAP) (6.0 +/- 0.6 to 3.2 +/- 1.4 mm Hg, p less than 0.05), and LVEDV (49 +/- 3 to 36 +/- 4 ml, p less than 0.05). RVEDV, the mean slope (+/- SD) of the LVEDPVR (0.37 +/- 0.16 to 0.30 +/- 0.19) and LAP at a common LV volume (35 ml, V35) did not change with PEEP. RCA occlusion caused cardiac output and RVEF (38 +/- 5 to 27 +/- 5%, p less than 0.05) to decline and RVESV (25 +/- 4 to 33 +/- 6 ml, p less than 0.05) to increase. RVEDV, the slope of the LVEDPVR, and LAP at V35 were unchanged from baseline. The addition of PEEP after RCA occlusion caused cardiac output to decline further. However, unlike before occlusion, there was no change in LAP (6.5 +/- 1.3 to 5.0 +/- 1.4 mm Hg) despite a decline in LVEDV (47 +/- 3 to 29 +/- 6 ml, p less than 0.05). RVESV and RVEDV increased with PEEP after RCA occlusion as did LAP at V35. The slope of the mean LVEDPVR tended to increase (0.98 +/- 1.03).(ABSTRACT TRUNCATED AT 250 WORDS)