Mean Atrial Pressure Research Articles

Improved resting hemodynamics after total vs standard orthotopic heart transplantation in patients with high preoperative pulmonary vascular resistance

Objective: Pretransplant pulmonary vascular resistance ] 4 Wood-units predisposes to right ventricular failure after heart transplantation. Total orthotopic heart transplantation with bicaval and pulmonary venous anastomoses offers synchronous contractions of the atria and a normal ventricular filling pattern, but requires longer ischemic time than standard orthotopic heart transplantation. To test if total orthotopic heart transplantation improves resting hemodynamics in pts with high preoperative pulmonary vascular resistance, we analyzed 65 pts with standard and 65 with total orthotopic heart transplantation transplanted between 12:88 and 7:94. Of these, 18 with total and 15 with standard orthotopic heart transplantation had a preoperative pulmonary vascular resistance ]4 Wood-units. Methods: Right heart catheterization data were obtained at each endomyocardial biopsy. All data from biopsies at both 2 weeks and 1 year posttransplant that were free from humoral or greater than 1A cellular rejection (9 versus 13 pts) were included in a two way ANOVA. Pts with postop pacemakers, atrial fib or b-blocker therapy at the time of biopsy were excluded. Results: Ischemic time was different (1729 44 versus 1429 28 min, P 0.03). Demographics, NYHA class, pre-TX hemodynamics, donor age and inotropes were similar. Cardiac output and index were higher in the total orthotopic group at 2 weeks (6.591.7 versus 5.191.0 l:min; 3.49 0.9 versus 2.89 0.6 l:min per m 2 ) and 1 year (7.19 2.0 versus 4.99 1.1 l:min, P0.002; 3.691.1 versus 2.690.5 l:min per m 2 , P 0.009). Right atrial and pulmonary arterial mean pressure (mmHg) were lower with total orthotopic heart transplantation at 2 weeks (69 4 versus 99 5, P 0.04; 229 3 versus 2597, P0.1) and 1 year (592 versus 793, P0.02; 1994 versus 259 7, P 0.03). Pulmonary capillary wedge pressure (mmHg) was borderline nonsignificant (1194 versus 1397 at 2 weeks, 89 3 versus 149 5 at 1 year, P 0.055), as well as pulmonary vascular resistance (1.991 versus 2.591 at 2 weeks, 1.59 0.6 versus 2.79 1.7 WU at 1 year, P 0.051). Conclusions: Total orthotopic heart transplantation improves cardiac output and index in pts with high preoperative pulmonary vacular resistance. There is a lower mean RA and PA pressure perhaps due to less tricuspid and mitral regurgitation. In view of the frequently observed restrictive filling pattern after cardiac transplantation, total orthotopic heart transplantation can be beneficial until this pattern has subsided by preserving atrioventricular synchrony and offering better atrial transport. © 1997 Elsevier Science B.V.

Relationship of pulmonary venous flow pattern to mean left atrial pressure and phasic pressure change.

To assess the correlation of pulmonary venous flow pattern with the magnitude of the dynamic change in left atrial pressure (i.e. x and y descents) and to elucidate the way how pulmonary venous flow pattern reflects left atrial pressure, we studied 35 patients with normal sinus rhythm undergoing transesophageal echocardiography and cardiac catheterization. The ratio of peak systolic/diastolic flow correlated well with the ratio of x/y descent (r = 0.88) and the ratio of systolic/diastolic velocity-time integral (r = 0.89). The correlation between the ratio of systolic/diastolic flow or velocity-time integral and mean atrial pressure was less strong (r = -0.49 and -0.70, respectively). We conclude that the ratio of peak systolic/diastolic flow velocity, or the ratio of systolic/diastolic velocity-time integral of pulmonary venous flow reflects the phasic change in left atrial pressure more appropriately than the mean left atrial pressure. Due to the good correlation between the phasic change in left atrial pressure and pulmonary venous flow pattern, the flow pattern of pulmonary veins could be used to identify diseases with specific patterns of left atrial pressure.

Echocardiographic and right-sidedcardiac pressure comparison of the mule and horse

There are few physiologic studies that substantiate thepopular belief that mules are superior to horses as working animals. The purpose of this study was to compare selected cardiac dimensions and right-sided cardiac pressures of mules and horses. Using 2-D real time and M-mode echocardiography and transjugular cardiac catheterization resting cardiac dimensions and right-sided pressures were recorded from 10 adult mules and 10 adult horses. The mules and horses were similar in size and physical condition, and both groups had served equally as pack animals. The end diastolic left ventricular lumen diameter, interventricular septal thickness, left ventricular free wall thickness, and aortic root diameter measured (mean ± SD) 9.51 ±0.92 cm, 2.63±0.34 cm, 2.28±0.31 cm, 7.9±0.57 cm, respectively, in mules, and 9.83±0.87 cm, 2.83±0.29 cm, 2.39±0.33 cm, 7.9±0.36 cm, respectively, in horses. The end systolic left ventricular lumen diameter measured 5.79 cm in mules and 5.94±0.99 cm in horses, yielding left ventricular luminal shortening fractions of 39.2±7.15% in mules and 39.7±6.91% in horses. Right atrial mean pressure was 5.3±2.3 mm of Hg in mules and 5.8±1.2 mm Hg in horses. Right ventricular peak systolic pressure was 47.9±4.9 mm Hg in mules and 47.7±3.5 mm Hg in horses. Pulmonary artery mean pressure was 27.3±3.2 mm Hg in mules and 28.1±3.6 mm Hg in horses. No significant differences were detected between mules and horses for the resting cardiac dimensions examined or right-sided pressures measured.

Influence of negative intrathoracic pressure on right atrial and systemic venous dynamics.

To investigate the effect of a sustained fall in intrathoracic pressure (Mueller manoeuvre) on blood flow through the right heart and on systemic venous dynamics, 16 patients were studied using thermodilution, cinevenograms and simultaneous pressure recordings with two micromanometric transducers. The reductions in airway pressure (median [range]) during two graded Mueller manoeuvres were 25 (20-30) and 42 (22-52) mmHg. Right atrial mean pressure decreased by 17 (2-25) mmHg during the former and 38 (0-49) mmHg during the latter, and simultaneously, pressure gradients of 23 (1-32) and 45 (1-82) mmHg developed between the inferior vena cava and right atrium (P < 0.003 for all). Internal jugular venous pressure decreased by 16 (4-25) and 24 (4-43) mmHg (P < 0.03 for both), respectively, and no pressure gradient developed between internal jugular and superior caval veins. The minimum diameter of the proximal inferior vena cava decreased by 69 (-49-84)% (P = 0.002) during the greater manoeuvre. Cardiac index tended to increase by 26 (-17-40)% (P < 0.066) during the lesser manoeuvre but did not change statistically significantly during the greater. In conclusion, during negative intrathoracic pressure caused acutely by the Mueller manoeuvre, right atrial pressure decreases and the inferior vena cava collapses partially at or below the diaphragm. Despite a significant venous obstruction between the lower body and right atrium, blood flow through the right heart increases or remains constant.

Selected echocardiographic parameters and right sided pressures of the mule

SummaryAlthough there are references to mules having an innate ability to withstand higher work loads than horses, there are relatively few physiological studies that substantiate these statements. The purpose of this study was to establish baseline information on cardiac dimensions and right sided pressures of the normal mule using echocardiography and cardiac catheterisation. Selected cardiac dimensions of 10 adult non‐sedated mules were measured with 2‐D real time and M‐mode echocardiography. This was followed by catheterisation of the pulmonary artery, right ventricle and right atrium for measurement of pressures. End‐diastolic left ventricular lumen diameter, interventricular septum thickness, left ventricular free wall thickness and aortic root diameter measured mean ± s.d. 11.1 ± 1.5 cm, 2.8 ± 0.3 cm, 3.3 ± 0.3 cm and 7.0 ± 0.9 cm, respectively and the end‐systolic diameter for the left ventricular lumen measured 6.7 ± 1.3 cm yielding a fractional shortening of mean ± s.d. 40.4 ± 5.7%. Right atrial mean pressure, right ventricular peak systolic pressure and pulmonary arterial mean ± s.d. pressure measured 6.28 ± 1.6 mmHg, 55.3 ± 7.3 mmHg and 31.4 ± 5.4 mmHg, respectively. Although data collected from this study were limited to 10 normal animals, no significant difference in cardiac dimensions or right sided pressures were found compared to reported values in horses of similar size.

Effects of pulmonary venous flow direction on mitral regurgitation jet area as imaged by color Doppler flow mapping. An in vitro study.

Although the effects of adjacent walls and left atrial pressure on mitral regurgitation (MR) jet area imaged by color Doppler have been examined, few data exist regarding the influence of pulmonary venous (PV) filling flow on regurgitant jets. Therefore, we designed a left atrial model to examine the relation between PV flow direction and MR jet area. The left atrial chamber (7.6 cm in diameter) was built with a PV inflow (1.0 cm in diameter) and mitral valve regurgitant orifice in the same plane. The MR jet was simulated as fixed in volume and velocity (3.5 m/s) and directed with a pulsatile pump into the left atrial model. PV flow with a constant velocity (30 cm/s) was driven by gravity (83 cm H2O). With left atrial mean pressure at either 10, 30, or 50 mm Hg, four flow patterns were examined: (1) PV flow away from the mitral valve, MR jet toward the pulmonary vein; (2) PV flow toward the mitral valve, MR jet toward the pulmonary vein; (3) PV flow away from the mitral valve, MR jet away from the pulmonary vein; and (4) PV flow toward the mitral valve, MR jet away from the pulmonary vein. MR color Doppler images were recorded with a 3.5-mHz frequency transducer and at 7-kHz pulse repetition frequency. For each condition, we compared jet area, length, and width of the MR signal. MR jet areas for conditions 3 and 4 were larger at 10 mm Hg than at 30 or 50 mm Hg left atrial pressure. Especially at the lower pressures, PV flow diminished the MR jet area in condition 4 compared with that in condition 3, such that MR jets were smaller in condition 4. In conditions 1 and 2, the jets were imaged at an oblique angle and were smaller than in conditions 3 and 4 (P < .001), but they were not significantly different from each other as imaged. In this model, factors including the direction of PV flow, the direction of MR as relates to the angle of interrogation, and the level of left atrial pressure influenced the size of MR jets. The effect of PV flow direction was diminished by increased left atrial pressure. PV flow directed away from the mitral valve was associated with larger MR jets than when PV flow was directed toward it (condition 4), probably because of jet distortion and flattening.

Predictors of outcome of tricuspid valve replacement in carcinoid heart disease

The cardiac valvular surgical experience of patients in the Duke Carcinoid Database was reviewed to assess operative outcome. Of the 604 patients in the database, 19 patients with carcinoid heart disease were identified by cardiac catheterization or echocardiography, or both. Eight of these underwent tricuspid valve replacement surgery with bioprostheses (2 also had open pulmonic valvuloplasty). Compared with patients medically managed, surgically treated patiente were similar with the exception that they had higher right atrial mean (17 ± 6 vs 9 ± 4 mm Hg, p = 0.03) and v-wave (27 ± 6 vs 17 ± 7 mm Hg, p = 0.04) pressures. Of the 8 surgical patients, 5 (63%) died within 30 days. Causes of death included tricuspid valve thrombosis, cerebral vascular accident, coagulopathy, renal failure, and intractable right heart failure. High comorbidity was present in all 8 patients. There was a weak trend (p = 0.17) toward lower Charlson comorbidity indexes in survivors (6.7 ± 0.6) compared with nonsurvivors (7.6 ± 0.9). Age was significantly lower (p = 0.036) in survivors (46 ± 13 years) compared with nonsurvivors (69 ± 4 years). Extended follow-up revealed 2 patients who survived beyond a decade. Review of 47 carcinoid valve replacement cases (Duke Carcinoid Database and 39 published cases) revealed a 30-day mortality of 56% for patients > 60 years of age, and 0% for those ≤60 years of age (p < 0.0001). Although valve replacement surgery can afford prolonged palliation from carcinoid heart disease, it is associated with a significant mortality risk. Careful preoperative risk stratification by age and comorbidity may provide a means for optimal selection of surgical candidates.

733-2 Total Versus Standard Orthotopic Heart Transplantation: Prolonged Ischemic Time Does not Impair Resting Hemodynamics

Total orthotopic heart transplantation (TOHT) requires longer ischemic time than standard orthotopic heart transplantation (SOHT) due to bicaval and pulmonary venous anastomoses, but offers normal anatomy and synchronous contractions of the atria as well as a normal ventricular filling pattern To test if TOHT improves resting hemodynamics despite prolonged ischemic time, we analyzed 60 pts with SOHT and 66 with TOHT transplanted between 12/89 and 2/93. Ischemic time was different (142 ± 37 vs 161 ± 36 min, p = 0.004). Demographics, NYHA class, LVEF, myopathy, donor demographics and inotropes were similar. Right heart catheterization data were obtained at each endomyocardial biopsy. We included data from biopsies at 2 weeks (47 vs 50 pts) and 6 months (46 vs 46 pts) posttransplant that were free from humoral or ≥IB cellular rejection. Pts with pacemaker insertion, atrial fibrillation or β-blocker therapy at the time of biopsy were excluded Cardiac output and index were higher in the TOHT group at 2 weeks (6.1 ± 1.4 vs 5.4 ± 1.0 I/min, p = 0.01; 3.3 ± 0.7 vs 2.9 ± 0.6 I/min/m 2 , p = 0.005) but similar at 6 months (5.9 ± 1.2 vs 5.6 ± 1.4 I/min. p = NS; 3.0 ± 0.6 vs 2.9 ± 0.7 I/min/m 2 , p = NS). Right atrial mean pressure (RAM, mmHgI was lower with TOHT vs SOHT at both time intervals (7 ± 4 vs 9 ± 4, p = 0.02 and 5 ± 2 vs 7 ± 3, p = 0.0006). Pulmonary arterial (PAM) and left atrial mean pressure (PCWP) (mmHg) were similar at 2 weeks (21 ± 6 vs 23 ± 6, p = NS; 12 ± 5 vs 13 ± 5, p = NS). At 6 months PAM was similar (20 ± 7 vs 22 ± 6, P = NS) but PCWP was lower in the TOHT group (11 ± 5 vs 13 ± 5, p = 0.045). Pulmonary vascular resistance (PVR, Wood-Units) was similar at 2 weeks (16 ± 0.7 vs 1.9 ± 1.0, p = NS) and 6 months (1.6 ± 0.7 vs 1.7 ± 1.0, P = NS). Heart rate (bpm) was higher at 2 weeks and 6 months with TOHT than SOHT (84 ± 10 vs 75 ± 12, P = 0.0003 and 90 ± 12 vs 82 ± 9, p = 0.0006). Despite a longer ischemic time, total orthotopic heart transplantation does not impair postoperative cardiac function. There is an early improvement in cardiac output, a sustained higher heart rate reflecting preservation of donor sinus node function, and a lower RA pressure, perhaps due to less tricuspid regurgitation.

On Line Echocardiography in Evaluating Left Atrial Changes in Acute Mitral Regurgitation and in Monitoring a Catheter-Mounted Balloon for its Correction

The purpose of this study was to evaluate changes in the left atrial size in acute mitral regurgitation (AMR) and monitor its correction by a catheter-mounted balloon (B). In 16 dogs, pressure changes in the left atrium (LA) were related to LA size and regurgitant mitral flow after the production of AMR by severing the mitral cusps. TEE was used for evaluating LA area (ALA) and the mitral regurgitation flow area (AMRF). TEE was also used in monitoring the position of a catheter-mounted B inserted through the LV apex and positioned on the mitral ring to relieve AMR. The B was inflated during systole and deflated during diastole. The ALA increased by 4.89 +/- 1.21 cm2 (mean +/- 1 SD) (p < 0.001) after AMR, the AMRF increased by 3.01 +/- 0.85 cm2 (p < 0.001) and the mean atrial pressure (LAP) by 9.38 +/- 2.43 mmHg (p < 0.001). In all experiments the position of the B could be confirmed in the 2D image and in 4 the reduction of AMRF by the function of the B was documented by the colour flow Doppler. It is concluded that after AMR the size of the LA increases along with the increase in LA pressure and a phasically inflated balloon and its effect on AMR can be easily identified and monitored by TEE.

Plasma atrial and brain natriuretic peptides in mitral stenosis treated by valvulotomy.

1. In order to appreciate the effect of changes in left atrial pressure on plasma brain natriuretic peptide, 20 patients with mitral stenosis treated by percutaneous valvulotomy were studied 10 min before and 15 min after the first balloon inflation. They were also studied 24 h before and 48 h after the valvulotomy. At these times the effect of postural changes on brain natriuretic peptide secretion was examined. A group of 10 control subjects was also studied under basal conditions. In each case, plasma atrial natriuretic peptide was measured in parallel with plasma brain natriuretic peptide. 2. Similarly to plasma atrial natriuretic peptide, plasma brain natriuretic peptide was elevated in patients with mitral stenosis (32 +/- 2.9 and 32 +/- 2.8 pg/ml in the upright and supine position respectively versus 13.5 +/- 0.5 and 13.8 +/- 1.8 pg/ml in controls; P < 0.01). Changing from standing to lying did not modify plasma brain natriuretic peptide, whereas it produced an increase in plasma atrial natriuretic peptide in controls (13.3 +/- 1.6 versus 24.8 +/- 5.2 pg/ml; P < 0.01) and in patients 48 h after valvulotomy (52.5 +/- 4.6 versus 66.9 +/- 6.6 pg/ml; P < 0.01). Plasma brain natriuretic peptide also fell at this time (18.8 +/- 1.1 and 19.1 +/- 1.1 pg/ml in the upright and supine position respectively; P < 0.01) similarly to plasma atrial natriuretic peptide and cyclic GMP (P < 0.01). The acute left atrial mean pressure variation was significantly correlated with the parallel change in plasma atrial natriuretic peptide (P < 0.001) but not in plasma brain natriuretic peptide.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased plasma atrial natriuretic peptide levels after heart transplant: Relation to ventricular expression and severity of rejection

To determine whether elevated plasma atrial natriuretic peptide (ANP) levels observed after cardiac transplant are related to ventricular ANP expression and/or the severity of rejection, 59 ambulatory patients with cardiac transplant underwent hemodynamic evaluation, endomyocardial biopsy, and plasma ANP sampling. Forty-two of the 59 patients had right ventricular (RV) biopsy specimens immunohistochemically stained for the presence of ANP. Plasma ANP levels were elevated ( p < 0.0001) in transplant patients (172 ± 12 pg/ml) compared to normal subjects (36 ± 4 pg/ml). Sixty-four percent of transplant patients showed stainable RV ANP on endomyocardial biopsy. There was no significant difference in plasma ANP levels between patients with or without RV ANP. The degree of RV staining did not correlate with plasma ANP levels, degree of rejection, mean atrial or systemic pressures, or specific immunosuppressive regimen. Plasma ANP levels were higher in patients with moderate or severe rejection (237 ± 17 pg/ml) compared to patients with mild or no rejection (163 ± 12 pg/ml; p 0.03), but there was significant overlap of values. These data suggest that ventricular ANP secretion may account for some of the increase in plasma ANP levels in cardiac transplant patients. However, increased plasma ANP levels in some transplant patients who have no RV ANP and the lack of correlation between the amount of stainable RV ANP and plasma ANP levels suggest that other mechanisms are also likely responsible for plasma ANP elevations in this setting.

Color Doppler regurgitant jet area for evaluating eccenteric mitral regurgitation: An animal study with quantified mitral regurgitation

Objectives. The purpose of the present study was to rigorously evaluate the accuracy of the color Doppler jet area planimetry method for quantifying chronic mitral regurgitation.Background. Although the color Doppler jet area has been widely used clinically for evaluating the severity of mitral regurgitation, there have been no studies comparing the color jet area with a strictly quantifiable reference standard for determining regurgitant volume.Methods. In six sheep with surgically produced chronic mitral regurgitation, 24 hemodynamically different states were obtained. Maximal color Doppler jet area for each state was obtained with a Vingmed 750. Image data were directly transferred in digital format to a microcomputer. Mitral regurgitation was quantified by the peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions determined using mitral and aortic electromagnetic flow probes.Results. Mean regurgitant volumes varied from 0.19 to 2.4 liters/ min (mean [±SD] 1.2 ± 0.59), regurgitant stroke volumes from 1.8 to 29 ml/beat (mean 11 ± 6.2), peak regurgitant volumes from 1.0 to 8.1 liters/min (mean 3.5 ± 2.1) and regurgitant fractions from 8.0% to 54% (mean 29 ± 12%). Twenty-two of 24 jets were eccentric. Simple linear regression analysis between maximal color jet areas and peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions showed correlation, with r = 0.68 (SEE 0.64 cm2), r = 0.63 (SEE 0.67 cm2), r = 0.63 (SEE 0.67 cm2) and r = 0.58 (SEE 0.71 cm2), respectively. Univariate regression comparing regurgitant jet area with cardiac output, stroke volume, systolic left ventricular pressure, pressure gradient, left ventricular/ left atrial pressure gradient, left atrial mean pressure, left atrial vwave pressure, systemic vascular resistance and maximal jet velocity showed poor correlation (0.08 < r < 0.53, SEE > 0.76 cm2).Conclusions. This study demonstrates that color Doppler jet area has limited use for evaluating the severity of mitral regurgitation with eccentric jets.

Coronary Artery Bypass Supplemented by Grafting of the Right Ventricular Branches—Case Reports

Seventeen patients presented with angina pectoris class IV with or without dyspnea, or with dyspnea alone. Cardiac catheterization revealed an elevated right atrial mean (6.5±3.2 mmHg), right ventricular systolic (31.3±10.3 mmHg) and diastolic (7.3±3.8 mmHg), pulmonary artery systolic (32.9±10.3 mmHg) and diastolic (15.4±5.8 mmHg), pulmonary capillary wedge (15.2±4.8 mmHg), and left ventricular end-diastolic (22.4±8.4 mmHg) pressures. The cardiac index was reduced (2.3±0.6 L/min/m2), as was the left ventricular ejection fraction (39.6±8.6%). Significant and diffuse coronary artery disease was present in 16 patients. In addition, their significant disease involved the proximal acute marginal (n = 6), or the anterior ventricular (n=5), or the anterior ventricular and acute marginal (n=1), or the conus and anterior ventricular (n=1) branches of the right coronary artery. In the remaining patients (n = 4), the latter artery had a significant lesion above or below the origin of those branches, which were free of disease per se. The right ventricular branches provided intercoronary or intracoronary collaterals, or both, in 12 patients. Coronary artery bypass (4.6 grafts per patient) included vein grafts to the circumflex artery system (n = 22) ; the internal thoracic artery (n=8), or vein (n=6), or both (n=2) grafts to the left anterior descending artery; and vein grafts to the posterior descending artery (n = 8), diagonal branch (n = 7), ramus intermedius and right coronary artery (each, n = 3), and posterior left ventricular branch (n=1). It was supplemented by the vein grafts to the anterior ventricular (n=9), the acute marginal (n=7), or the acute marginal and conus (n=1) branches. One patient also had an aortic valve replacement. Hemodynamics after the operation without pharmacologic support revealed significant decreases of the right atrial mean pressure to 4.7±2.5 mmHg (p &lt; 0.01), pulmonary artery systolic pressure to 24±7.0 mmHg (p &lt; 0.01), pulmonary artery diastolic pressure to 11.9±3.4 mmHg (p &lt; 0.01), and pulmonary capillary wedge pressure to 9.6±2.9 (p &lt; 0.01). There was a highly significant decrease of the left ventricular end-diastolic pressure as measured indirectly by pulmonary artery diastolic pressure to 11.9±3.4 mmHg (p &lt; 0.001) and by pulmonary capillary wedge pressure to 9.6±2.9 mmHg (p &lt; 0.001). Cardiac index increased significantly to 3.2±0.9 L/min/m2 (p &lt; 0.01). All patients are alive and free of angina and dyspnea. Did the revascularization of the right ventricular branches contribute to a functional improvement of the right and adjacent segments of the left ventricles and the septum?

Cardiac compression with mitral stenosis: a haemodynamic challenge

The hemodynamics of pericardial restriction (diastolic equilibration of pressures in all the four chambers of heart) and that of mitral stenosis (presence of an end diastolic gradient between the left atrium and the left ventricle) appear mutually exclusive. We describe herein hemodynamic findings in two patients of rheumatic mitral stenosis associated with pericardial constriction in one patient and pericardial effusion with tamponade in the other. Disproportionate elevation of the pulmonary artery diastolic and wedge pressures as compared to the right atrial mean, and left and right ventricular end diastolic pressures was present in both patients. In constrictive pericarditis, the respiratory variation in pressure was reflected in the pulmonary artery wedge pressure but not in the left ventricular end diastolic pressure. The gradient between the pulmonary artery wedge pressure and the left ventricular end diastolic pressure was abolished completely during the inspiratory phase of respiration despite significant mitral stenosis. The difference in the pressure, however, was maintained throughout inspiration and expiration in pericardial effusion with tamponade. In patients with constrictive pericarditis and mitral stenosis, the pulmonary artery wedge pressure does not appear to be a true indicator of the left atrial pressure.

Left ventricular diastolic pressure-volume response immediately after successful percutaneous transvenous mitral commissurotomy

The left ventricular (LV) diastolic pressure-volume response after percutaneous transvenous mitral commissurotomy (PTMC) was investigated to determine whether rt was related to the baseline conditions of the left ventricle. Left ventriculography was performed, and the measurements of LV pressure were obtained in 32 patients before and after PTMC. Mitral valve area increased from 1.0 ± 0.3 to 1.9 ± 0.4 cm 2 (p < 0.005) after PTMC, which caused a decrease in left atrial mean pressure (14.8 ± 5.9 to 7.4 ± 2.7 mm Hg; p < 0.005). LV end-diastolic pressure increased in all patients 5 minutes after PTMC. However, patients could be divided into 2 groups according to the following changes in LV end-diastolic pressure 20 minutes after PTMC: In 22 patients, LV end-diastolic pressure returned to the near-baseline level 20 minutes after PTMC (before 5.0 ± 2.2, 5 minutes after 8.6 ± 3.1, and 20 minutes after 6.3 ± 2.5 mm Hg) with a significant increase in LV end-diastolic volume index (64 ± 12 to 74 ± 14 ml/m 2; p < 0.001) and augmentation of LV stroke volume index (39 ± 9 to 47 ± 11 ml/m 2; p < 0.001). However, in the remaining 10 patients with a larger LV volume (>80 ml/m 2) and reduced ejection fraction (<50%) at baseline, LV end-diastolic pressure further increased 20 minutes after PTMC (before 5.5 ± 2.8, 5 minutes after 7.8 ± 2.7, and 20 minutes after 11.0 ± 2.9 mm Hg) without significant changes in LV volume. These findings suggest that the increase in LV end-diastolic pressure immediately after PTMC increased LV volume with the augmentation of LV stroke volume and that this diastolic pressure-volume response was affected by the baseline LV condition.

Two-dimensional echocardiographic assessment of right cardiac pressure overload in patients with chronic obstructive airway disease.

Two-dimensional echocardiography was used to estimate right cardiac pressure overload in patients with chronic obstructive airway disease. Area measurements of the four heart chambers were carried out from the apical four-chamber view. Additionally, the respiratory behaviour of the inferior vena cava was examined from the subcostal view. A good apical imaging of the four-chamber view for area measurement was obtained in 44 out of 48 patients with chronic obstructive airway disease. The respiratory behaviour of the inferior vena cava was investigated from the subcostal view in 38 patients. Within 8 days after echocardiography, right cardiac catheterization was carried out in order to measure pulmonary artery and right atrial mean pressures and to determine pulmonary vascular resistance. A good correlation was found between pulmonary artery mean pressure and the following echocardiographic parameters: area index (area/body surface) of the two right heart cavities (r = 0.83), right-to-left ventricular area ratio (r = 0.82) and right-to-left cardiac area ratio (ratio between the added areas of both right heart cavities on the one side and the added areas of both left heart cavities on the other; r = 0.82). Correlation between these parameters and pulmonary vascular resistance (r = 0.71, 0.66 and 0.71, respectively) and between the right atrial mean pressure and the right atrial area index was less close (r = 0.64). On the other hand, the respiratory behaviour of the inferior vena cava proved to be highly specific but not very sensitive in predicting a pathological right atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary venous flow dynamics before and after balloon mitral valvuloplasty as determined by transesophageal Doppler echocardiography

The pattern of left atrial filling was studied in 14 patients with severe mitral stenosis in sinus rhythm before and immediately after successful balloon mitral valvuloplasty by transesophageal pulsed Doppler echocardiography of the left superior pulmonary vein. Mean mitral valve orifice area increased from 0.8 ± 0.1 to 2.2 ± 0.3 cm 2 (p < 0.0001), and left atrial mean pressure decreased from 30 ± 5 to 12 ± 4 mm Hg (p < 0.0001) after the procedure. After balloon mitral valvuloplasty, significant increases in peak systolic pulmonary velocity (35 ± 16 to 44 ± 10 cm/s; p < 0.01), systolic flow velocity time integral (3.3 ± 1.5 to 5.9 ±2.0 cm; p < 0.001) and the ratio of systolic/diastolic pulmonary venous flow velocity time integrals (0.8 ± 0.4 to 1.4 ± 0.5; p < 0.001) were observed. An acute increase in mitral valve orifice area caused no significant changes in peak diastolic forward flow velocity (40 ± 7 to 41 ± 9 cm/s; p = not significant [NS]), diastolic forward flow velocity time integral (4.3 ± 1.7 to 4.6 ± 1.8 cm; p = NS) and atrial flow reversal velocity (30 ±3 to 35 ± 3 cm/s; p = NS) compared with at baseline. The results suggest that in patients with severe mitral stenosis and sinus rhythm, left atrial filling is biphasic with a diastolic preponderance, and successful mitral valvuloplasty is associated with an immediate increase in pulmonary venous systolic forward flow.

Decreased plasma atriopeptin response to volume-overloading maneuvers and exercise after atriopulmonary anastomosis of fontan

Atriopulmonary anastomosis results in a chronic right atrial pressure-volume overload. Water and salt retention is a frequent clinical observation in patients after atriopulmonary anastomosis. The purpose of this study was to examine if this could be related to an inability to increase already elevated circulating atriopeptin (ANP) in response to central volume-overloading conditions. Eighteen patients (mean age 16 ± 6 years) with an atriopulmonary anastomosis underwent routine cardiac catheterization during which a 5-minute head-down 10 ° tilt was performed. Peripheral venous and right atrial blood samples were obtained under basal conditions, and after tilting and angiography for determination of ANP concentrations. At a different time, circulating ANP levels were measured during a maximal graded exercise protocol. Increased circulating ANP concentrations were found under basal conditions (114 ± 10 μg/ml). Tilting and cardioangiography resulted in significant increases in mean atrial pressure (basal: 12 ± 0.7 mm Hg; tilt: 13.4 ± 0.63 mm Hg; after angiography: 15.8 ± 0.8 mm Hg), but not in atrial or peripheral ANP. Compared with the expected threefold increase in plasma ANP induced by maximal exercise in healthy control subjects, only a slight (0.25-fold) increase was found in patients. These observations suggest a reduced stimulus-release response after atriopulmonary anastomosis, which could be related to a loss of atrial stretch receptor sensitivity, achievement of the limit for maximal right atrial secretion, or an alteration in right atrial compliance, or a combination.

Induced hypothermia in the management of refractory low cardiac output states following cardiac surgery in infants and children

Post-operative low cardiac output states remain a major cause of mortality following cardiac surgery in infants and children. Since 1979 we have used moderate induced whole-body hypothermia in the management of low-output states refractory to conventional modes of therapy. This is based not only upon the relationship between body temperature and oxygen consumption, but also on experimental work showing a beneficial effect of cooling upon myocardial contractility, particularly when there is pre-existing impairment of ventricular function. Between July 1986 and June 1990, 20 children with refractory low-output states were cooled by means of a thermostatically controlled water blanket to a rectal temperature of 32-33 degrees C. The median age was 12 months (1 week-11 years) with a median weight of 6 kg (3.5-33 kg). Ten children survived to leave hospital while a further two made a haemodynamic recovery. There was a marked reduction in heart rate (P < 0.001). The mean arterial pressure rose (P = 0.037) while there was a fall in mean atrial pressure (P < 0.001). There was a significant improvement in the urine output (P = 0.002). A fall in the platelet count (P < 0.001) was not accompanied by any change in the white cell count (P = 0.15). Although it is impossible to say whether cooling influenced the outcome in any of these children, it was usually effective in stabilising their clinical condition. The technique is simple and has a sound theoretical basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Dynamic aspects of regulatory lung peptides in chronic hypoxic pulmonary hypertension.

Male Sprague-Dawley rats were placed in hypobaric hypoxia for 17-21 d (FIO2 10%) to establish pulmonary hypertension (PH) and control rats were kept in normobaric room air. Right mean atrial and ventricular pressures (PRA, PRV) were recorded, left ventricular (LV) blood was collected, and lungs were perfused with heparinized saline. Hearts were removed to evaluate right ventricular (RV) hypertrophy (RV/(LV+septum)%). Peptides were quantitated with radioimmunoassay in lung tissue extracts and plasma. Wet lung weight, PRA, PRV, and RV/(LV+S)% were higher and body weight was lower in hypoxia rats, and lung morphometry revealed increased arterial medial thickness (MT/OD%) and elastification of arterioles and capillaries. Lung tissue CGRP, PYY, gamma 2-MSH, and SOM were higher in PH rats and ANP was unchanged. Blood AVP, CGRP, PYY, VIP, and SOM were reduced in PH rats and ANP was unchanged. Lung levels of PYY and SOM correlated significantly with the time in hypoxia and with all parameters examined and CGRP and gamma 2-MSH correlated with all but medial thickness. PYY had the highest correlation of the peptides with body weight, PRV, and RV/(LV+S)%, and SOM the highest with time in hypoxia, wet lung weight, PRA, MT/OD%, and elastification of arterioles and capillaries. Blood peptides correlated inversely with these parameters. ANP had the overall weakest correlations and CGRP, PYY, and SOM had the highest. SOM correlated the highest with arterial medial hypertrophy, PRV, RV hypertrophy, and elastification of peripheral capillaries. VIP correlated the highest of the blood peptides with body weight and wet lung weight. Statistically significant correlations do not necessarily imply causal relationships. The putative roles of these peptides in pulmonary function are discussed.