Elevated Right Atrial Pressure Research Articles

The Relationship of Right- and Left-Sided Filling Pressures in Patients With Heart Failure and a Preserved Ejection Fraction

Although right-sided filling pressures often mirror left-sided filling pressures in systolic heart failure, it is not known whether a similar relationship exists in heart failure with preserved ejection fraction. Eleven subjects with heart failure with preserved ejection fraction underwent right heart catheterization at rest and under loading conditions manipulated by lower body negative pressure and saline infusion. Right atrial pressure (RAP) was classified as elevated when >or=10 mm Hg and pulmonary capillary wedge pressure (PCWP) when >or=22 mm Hg. If both the RAP and the PCWP were elevated or both not elevated, they were classified as concordant; otherwise, they were classified as discordant. Correlation of RAP and PCWP was determined by a repeated measures model. Among 66 paired measurements of RAP and PCWP, 44 (67%) had a low RAP and PCWP and 8 (12%) a high RAP and PCWP, yielding a concordance rate of 79%. In a sensitivity analysis performed by varying the definition of elevated RAP (from 8 to 12 mm Hg) and PCWP (from 15 to 25 mm Hg), the mean+/-SD concordance of RAP and PCWP was 76+/-10%. The correlation coefficient of RAP and PCWP for the overall cohort was r=0.86 (P<0.0001). Right-sided filling pressures often reflect left-sided filling pressures in heart failure with preserved ejection fraction, supporting the role of estimation of jugular venous pressure to assess volume status in this condition.

Detection of elevated right atrial pressure using a simple bedside ultrasound measure

Accurate assessment of right atrial pressure (RAP) often requires invasive measurement. With normal RAP, Valsalva increases right internal jugular vein (RIJV) cross sectional area (CSA) 20% to 30%. With high RAP, when venous compliance is low, we hypothesized that the increase in CSA would be blunted and could be detected non-invasively with bedside ultrasound. RIJV ultrasound images were obtained in 67 patients undergoing right heart catheterization. The median RAP at end-expiration was 7 mm Hg (interquartile range [IQR] 5-9 mm Hg) in patients with normal RAP (n = 47) versus 15 mm Hg (IQR 12-22 mm Hg) in patients with elevated RAP (n = 20). With Valsalva, the median percent change in RIJV CSA was 35% (IQR 19%-79%) versus 5% (IQR 3%-14%) for normal and high RAP, respectively. By receiver operating curve analysis, a <17% increase in RIJV CSA with Valsalva predicted elevated RAP (> or =12 mmHg) with 90% sensitivity, 74% specificity, 94% negative predictive value, and 60% positive predictive value (area under the curve 0.86, P < .001). An increase in RIJV CSA >17% during Valsalva effectively rules out elevated RAP. This simple bedside technique may be useful to assess central venous pressure and reduce the need for invasive pressure measurement.

Examining the Jugular Vein Is Never in Vain

In this issue of Circulation: Heart Failure , Drazner et al1 report the findings of their study on the relationship of right and left ventricular (LV) filling pressures in patients with heart failure and preserved LV ejection fraction (HFPEF) (also referred to as heart failure with preserved systolic function, diastolic heart failure). They noted good concordance (79%) in this patient population between right atrial pressure (RAP), indicative of right ventricular filling pressure, and pulmonary artery occlusive pressure (pulmonary capillary wedge pressure [PCWP]), indicative of LV filling pressure. These pressures, modulated by various loading and unloading maneuvers, ranged from low to normal to high. Nonconcordance was noted in only 21% of the measurements, and, in these, the PCWP did not match the elevation of RAP. Article see p 202 The weaknesses and limitations of this study are overshadowed by its strengths. PCWP is not a direct measurement of left atrial pressure, and RAP and PCWP are not direct measurements of right and LV filling pressures, respectively. But their relationships (RAP to right ventricular filling pressure; PCWP to left atrial pressure and LV filling pressure) are closely linked, and correlations are generally quite high,2–5 such that RAP and PCWP are routinely used in clinical medicine as respective indicators of right and LV filling pressures. Only 11 patients with HFPEF were studied by Drazner et al.1 However, the study was performed in an experienced laboratory by seasoned investigators of human heart failure, using the standard techniques to generate a spectrum of ventricular-loading conditions. The lead author has a noteworthy record of studying fundamental hemodynamic questions in human heart failure.6–9 The question itself, namely the relationship between right and left heart filling pressures, had not been adequately examined in HFPEF. The favorable concordance of right and left heart filling pressures …

The Relationship of Right- and Left-Sided Filling Pressures in Patients With Heart Failure and a Preserved Ejection Fraction

Background— Although right-sided filling pressures often mirror left-sided filling pressures in systolic heart failure, it is not known whether a similar relationship exists in heart failure with preserved ejection fraction. Methods and Results— Eleven subjects with heart failure with preserved ejection fraction underwent right heart catheterization at rest and under loading conditions manipulated by lower body negative pressure and saline infusion. Right atrial pressure (RAP) was classified as elevated when ≥10 mm Hg and pulmonary capillary wedge pressure (PCWP) when ≥22 mm Hg. If both the RAP and the PCWP were elevated or both not elevated, they were classified as concordant; otherwise, they were classified as discordant. Correlation of RAP and PCWP was determined by a repeated measures model. Among 66 paired measurements of RAP and PCWP, 44 (67%) had a low RAP and PCWP and 8 (12%) a high RAP and PCWP, yielding a concordance rate of 79%. In a sensitivity analysis performed by varying the definition of elevated RAP (from 8 to 12 mm Hg) and PCWP (from 15 to 25 mm Hg), the mean±SD concordance of RAP and PCWP was 76±10%. The correlation coefficient of RAP and PCWP for the overall cohort was r =0.86 ( P &lt;0.0001). Conclusions— Right-sided filling pressures often reflect left-sided filling pressures in heart failure with preserved ejection fraction, supporting the role of estimation of jugular venous pressure to assess volume status in this condition.

RESEARCH FROM THE UNIVERSITY OF ALABAMA AT BIRMINGHAM: Patent Foramen Ovale in a Large Population of Ischemic Stroke Patients: Diagnosis, Age Distribution, Gender, and Race

Patent foramen ovale (PFO) is a well-recognized risk factor for ischemic strokes. The true prevalence of PFO among stroke patients is still under debate. Transesophageal echocardiography (TEE) is the "gold standard" in diagnosing PFO but the physiology requires right-to-left atrial shunting. In this report, we evaluate the prevalence of PFO in a diverse group of ischemic stroke patients studied by TEE. TEE of 1,663 ischemic stroke patients were reviewed for cardiac source of embolism, including PFO and atrial septal aneurysm (ASA). Agitated saline bubble injection was performed to look for right to left atrial shunting. Success of maneuvers to elevate right atrial pressure (RAP) was noted by looking at the atrial septal bulge. Among 1,435 ischemic stroke patients analyzed, the presence or absence of PFO could not be determined in 32.1% because bulging of the septum could not be demonstrated in patients with negative contrast study despite aggressive maneuvers to elevate RAP. Of the remaining 974 patients, 294 patients (30.2%) had a PFO. The mean age was 61.5 years in both groups, with a bimodal distribution of PFO and the highest prevalence occurring in < or =30-year-old group. Prevalence of PFO was similar in men (32.4%) and women (28.15%, P = 0.15); and in Caucasian (32.1%) and African American (27.7%; P = 0.15). ASA was present in 2.02% and hypermobile septum in 2.49% of the 1,435 patients. PFO was seen in 79.3% of the patients with ASA. Successful elevation of RAP cannot be achieved in a significant number of patients undergoing TEE and determination of PFO may be difficult. In our series, the true prevalence of PFO among ischemic stroke patients was 30.2% taking into account only those patients who showed no shunting despite bulging of the atrium septum into the left atrium (PFO absent group) during the contrast study. There was no gender or racial difference in the prevalence of PFO, but there was a bimodal distribution in prevalence with age.

Reappraisal of the Use of Inferior Vena Cava for Estimating Right Atrial Pressure

Estimation of right atrial pressure (RAP) using echocardiographic measurement of the inferior vena caval (IVC) size along with its respirophasic variation is commonly performed despite the paucity of data that critically evaluates this technique. In this study, we systematically evaluated echocardiographic imaging of the IVC for estimation of RAP in 102 patients undergoing right heart catheterization. This study established cut-off values using receiver operating characteristic analysis for 8 different IVC parameters and then prospectively tested these parameters for their ability to predict an elevated RAP. The IVC size cutoff with optimum predictive use for RAP above or below 10 mm Hg was 2.0 cm (sensitivity 73% and specificity 85%) and the optimal IVC collapsibility cutoff was 40% (sensitivity 73% and specificity 84%). Traditional classification of RAP into 5-mm Hg ranges based on IVC size and collapsibility performed poorly (43% accurate) and a new classification scheme is proposed.

A Comparison by Medicine Residents of Physical Examination Versus Hand-Carried Ultrasound for Estimation of Right Atrial Pressure

Physicians' ability to accurately estimate right atrial (RA) pressure from bedside evaluation of the jugular venous waveform is poor, particularly when performed by physicians in training. Conventional ultrasound measurement of the inferior vena cava (IVC) accurately predicts RA pressure, but the cost, lack of portability, and specialized training required to acquire and interpret the data render this modality impractical for routine clinical use. The objective of this study was to compare physical examination with hand-carried ultrasound (HCU) in the detection of elevated RA pressure (>10 mm Hg). After limited training (4 hours didactic and 20 studies), 4 internal medicine residents using an HCU device estimated RA pressure from images of the IVC in 40 consecutive patients <1 hour after right-sided cardiac catheterization. RA pressure was also estimated from examination of the jugular venous pulse (JVP) in 40 patients before right-sided cardiac catheterization. RA pressure was successfully estimated from HCU images of the IVC in 90% of patients, compared with 63% from JVP examination. The sensitivity for predicting RA pressure >10 mm Hg was 82% with HCU and 14% from JVP inspection. Specificities were similar between the techniques. Overall accuracies were 71% using HCU and 60% with JVP assessment. In conclusion, internal medicine residents with brief training in echocardiography can more frequently and more accurately predict elevated RA pressure using HCU measurements of the IVC than with physical examination of the JVP.

Patent Foramen Ovale and Recurrent Stroke

Clinical management of patients with acute stroke and the approach used for secondary prevention depends upon clarification of pathogenesis. Although most strokes are a consequence of cerebrovascular disease, ≈15% to 20% of ischemic (nonhemorrhagic) strokes have been attributed to cardiogenic embolism.1 In practice, determination of the stroke mechanism is fraught with uncertainty, particularly when the possibility of thromboembolism emanating from atherosclerotic lesions in the aorta or cervical arteries is considered. When cardiogenic embolism is suspected, cardiac ultrasound is the principal method used to identify the potential source. The finding of left atrial enlargement has been shown to bear a significant relationship to the risk of stroke in a multivariate analysis of population-based data from the Framingham Heart Study2. The most frequent confounding variable is atrial fibrillation, occurring in >2 million patients in North America and in over half of all patients with cardiogenic embolism. Criteria for selection of patients with acute ischemic stroke for transesophageal echocardiography (TEE) to search for a potential cardiac source of embolism are controversial, particularly because cardiogenic embolism is often an uncertain diagnosis that is inferred merely on the basis of the finding of potential cardiac source. Even after extensive investigation, ≈40% of ischemic stroke patients have no clearly identifiable pathogenesis (cryptogenic stroke).3 In one study, 62% of patients younger than 60 years of age without an obvious source of cerebral infarction and 23% of those with arterial lesions had potential sources of cardiogenic embolism identified by TEE ( P =0.0007 for the difference).4 See p 2625 Among the cardiac anomalies detected by TEE that have been implicated as risk factors for stroke are patent foramen ovale (PFO) and atrial septal aneurysm (ASA).5,6⇓ The foramen ovale, a remnant of the fetal circulation, remains patent through adulthood in ≈1 in 4 …

Perfusion-contractility matching during Fontan circulation.

We investigated the relationship between coronary perfusion pressure (CPP) and myocardial contractility and the effects of an acute elevation of right atrial pressure (RAP) on this relationship in an experimental model of Fontan circulation in 6 anesthetized open-chest dogs with isolated perfused coronary arteries. The relationship between CPP and Ees could be described by biphasic J-shaped curves which were nearly identical before and under Fontan circulation. While above a "critical" CPP (72 +/- 9 mmHg vs. 81 +/- 8 mmHg, n.s.) the changes of CPP did not affect Ees, below this level the decrease of CPP resulted in a progressive decrease of Ees. Under Fontan circulation, the progressive increase of RAP did not influence Ees at CPP = 100 mmHg, led to a moderate decrease of Ees at CPP = 75 mmHg and severe decrease at CPP = 60 mmHg. Thus, both coronary arterial and venous pressure affect myocardial contractility after Fontan procedure.

Right ventricular ischemia in patients with primary pulmonary hypertension

OBJECTIVESThe goal of this study was to determine whether right ventricular (RV) ischemia is a contributory factor in the development of RV dysfunction in patients with primary pulmonary hypertension (PPH).BACKGROUNDPatients with advanced PPH develop RV dysfunction, characterized by a decreased cardiac output, increased right atrial pressure (RAP) and/or elevated RV end-diastolic pressure, which progresses to heart failure and death. The cause of this dysfunction is unknown. Right ventricular ischemia may play a role in its development.METHODSFrom 1992 to 1999, a prospective study involving 23 patients with PPH at the Instituto Nacional de Cardiologia “Ignacio Chavez” (Mexico City, Mexico) was undertaken. These patients were evaluated clinically and further studied by echocardiography, right heart catheterization and stress myocardial scintigraphy using technetium 99m sestamibi.RESULTSNine patients of 23 were found to have scintigraphic images consistent with RV ischemia. Significant correlation was found between RV ischemia obtained through myocardial perfusion scintigraphy and elevation of RV end-diastolic pressure (p < 0.001), elevation of RAP (p < 0.037) and a decrease in mixed venous oxygen saturation (p < 0.0001). No other clinical or hemodynamic variables showed a significant correlation with RV ischemia.CONCLUSIONSA direct correlation exists between RV ischemia, as determined by myocardial scintigraphy, and hemodynamic alterations suggestive of RV dysfunction in patients with PPH.

Characteristics and Outcomes of Patients With Sarcoidosis Listed for Lung Transplantation

Study objectivesTo characterize the course of patients with advanced sarcoidosis who have been listed for lung transplantation and to identify prognostic factors for death while they are on the waiting list. DesignRetrospective cohort study. SettingTertiary-care university hospital. PatientsForty-three patients with sarcoidosis who have been listed for lung transplantation at the University of Pennsylvania Medical Center. MethodsA multivariable explanatory analysis using a Cox proportional hazards model was performed to determine risk factors that are independently associated with mortality while patients await transplantation. ResultsTwenty-three of the 43 patients (53%) died while awaiting transplantation. The survival rate of listed patients (as determined by the Kaplan-Meier method) was 66% at 1 year, 40% at 2 years, and 31% at 3 years. In a univariate analysis, the following factors were significantly associated with death on the waiting list: Pao2 ≤ 60 mm Hg (relative risk [RR], 3.4; 95% confidence interval [CI], 1.2 to 9.3); mean pulmonary artery pressure ≥ 35 mm Hg (RR, 3.2; 95% CI, 1.1 to 9.5); cardiac index≤ 2 L/min/m2 (RR, 2.8; 95% CI, 1.2 to 6.6), and right atrial pressure (RAP) ≥ 15 mm Hg (RR, 7.6; 95% CI, 3.0 to 19.3). Multivariable analysis revealed that RAP ≥ 15 mm Hg was the only independent prognostic variable (RR, 5.2; 95% CI, 1.6 to 16.7; p = 0.006). Twelve patients underwent lung transplantation. Survival after transplantation determined by the Kaplan-Meier method was 62% at both 1 and 2 years, and 50% at 3 years. ConclusionsPatients with advanced sarcoidosis awaiting lung transplantation have a high mortality rate with a median survival of < 2 years. Mortality is most closely linked to elevated RAP. While earlier referral may diminish the mortality rate of patients on the waiting list for transplantation, further improvements in posttransplantation outcomes will be necessary to ensure that this procedure truly bestows a survival benefit.

Elevated right atrial pressure does not reduce collateral blood flow to ischemic myocardium.

Right atrial pressure (RAP) may become substantially elevated during heart failure and has been reported to reduce collateral flow to the ischemic myocardium of isolated hearts. The effect of elevated RAP on blood flow to collateral-dependent and normal myocardium of in situ hearts was studied in 20 open-chest anesthetized dogs with acute occlusion of the left anterior descending coronary artery. Regional myocardial blood flow was measured with radioactive microspheres while RAP was elevated by restricting right ventricular (RV) outflow with constant aortic pressure. Increasing RAP from 3.8 +/- 0.5 to 21.5 +/- 0.8 and then to 34.3 +/- 0.9 mmHg did not reduce blood flow to any transmural region of LV normal or collateral-dependent myocardium. Further elevation of RAP to 49.3 +/- 1.1 mmHg reduced subepicardial but not subendocardial collateral flow. Blood flow to normal RV increased. Retrograde flow and peripheral coronary pressure increased as RAP was elevated. Previously injected 11-micron microspheres were present in the retrograde flow when RAP was elevated; thus retrograde capillary flow contributed to the retrograde flow. The results explain discrepancies among previous reports, and they are consistent with a waterfall phenomenon in the coronary collateral circulation.

Atrial plasma ANP and NH2-terminal proANP during right atrial pressure increase in humans.

To compare plasma NT-proANP, a stable and biologically inactive N-terminal portion of ANP prohormone, with the known plasma ANP response to increased right atrial pressure a Swan-Ganz catheter was inserted into the right atrium of five normal healthy male volunteers. The elevation of right atrial pressure was produced by a head-down tilt after a hypertonic saline infusion. Blood samples were drawn from the lumen of the right atrium. After 5 min of starting the tilt the right atrial pressure had increased from 7.0 +/- 1.0 to 11.6 +/- 0.9 mmHg (P < 0.05) and then began to normalize in spite of the constant tile. Atrial plasma ANP increased in relation to the pressure increase and peaked at 15 min after the start of the tilt. The change was from 27.9 +/- 6.5 to 53.9 +/- 9.7 pmol L-1 (P < 0.05). Atrial plasma NT-proANP increased significantly from 357 +/- 91.2 to 529.1 +/- 116.0 pmol L-1 (P < 0.05) at 10 min and remained high throughout the experiment. The molar ratio of NT-proANP to ANP varied in atrial plasma from 9.5 +/- 1.2 to 13.9 +/- 2.7 showing that the plasma clearance of ANP from plasma was much higher than that of NT-proANP.

Effects of right ventricular failure on renal function during pneumatic left ventricular assist.

In an experiment dog model of acute biventricular failure, the effects of left ventricular (LV) assist on renal hemodynamics and function were evaluated. After the induction of severe cardiac failure by multiple ligation of the coronary arteries, LV assist with a 40 ml pneumatic pulsatile pump was initiated, and the aortic flow was maintained at control values. The right atrial pressure (RAP) rose to 21.3 mm Hg with the appearance of profound right ventricular (RV) failure. Renal arterial blood flow (RAF) decreased to about 60% of the control value after 2 h of LV assist. The urine volume decreased and renal function deteriorated progressively. RV assist decreased the RAP to 4.8 mm Hg, and the reduced RAF recovered. After 3 h of RV assist, the RAF returned to initial values and the urine volume increased, but renal function did not recover. Advanced biventricular failure with elevated RAP during LV assist reduced renal perfusion and impaired renal function and may be an indication for early RV assist.

1003-6 Doppler Assessment of Pulmonary Artery Diastolic Pressure in Patients with Tricuspid Regurgitation

A reliable Doppler echo method to assess pulmonary artery diastolic pressure (PAD) would be clinically useful. By applying the Bernoulli equation, ΔP = 4(V) 2 , an indirect estimate of RV pressure can be obtained from tricuspid regurgitant velocity (TV), if right atrial pressure is not significantly elevated. Since PAD and RV pressures equilibrate at the time of pulmonic valve opening (PVO), 4(TV) 2 measured at pva should approximate PAD. To test this hypothesis, we studied pts undergoing Swan Ganz monitoring who had tricuspid regurgitation detected by color flow Doppler. To avoid pts with marked elevation of right atrial pressure, we excluded pts with severe tricuspid regurgitation or evidence of right heart failure. The study group consisted of 20 pts. In each pt, TV was obtained by continuous wave Doppler. The time of PVO was determined by pulsed wave Doppler as the onset of systolic flow in the pulmonary artery, and the interval between the onset of the ORS and pva was measured. This interval was then used to determine the point on the TV envelope that corresponded to the time of PVO. TV was measured at this point and 4(TV) 2 was calculated using the Bernoulli equation. We compared 4(TV) 2 at PVO obtained by Doppler with PAD measured invasively. PAD by cath ranged from 9 to 36 mmHg (mean 20). Measurement of 4(TV) 2 at PVO ranged from 9 to 27 mmHg (mean 17) and showed an excellent correlation with cath PAD (r = 0.91, Y = 4.4 + 0.68x, SEE = 1.8). Doppler estimation of tricuspid regurgitant gradient at PVO is a reliable new method for estimation of PAD.

Atrial natriuretic peptide fragments in dogs with experimental heart failure.

1. This study in the canine arteriovenous (AV) fistula model of high-output heart failure (HOHF) evaluated the chronic temporal changes in plasma ANF and pro ANF 31-67 and their relationship to body-fluid balance and the renin-aldosterone axis. In addition, the haemodynamic, hormonal and renal excretory effects of synthetic pro ANF 31-67 infusions were examined in normal and AV fistula dogs with compensated HOHF. 2. Following the construction of the AV fistula, the dogs exhibited chronic parallel elevations in right atrial pressure and the plasma concentrations of ANF and pro ANF 31-67. The gradual increases in the two peptides were associated with a gradual decrease in plasma renin activity and the re-establishment of sodium balance. 3. In normal and compensated AV fistula dogs, synthetic pro ANF 31-67 produced similar significant reductions in arterial blood pressure, right atrial pressure and elevations in urinary sodium excretion. These effects were not associated with increases in plasma or urinary cyclic GMP (cGMP). 4. These results suggest that the elevation in the endogenous circulating levels of pro ANF 31-67 in the AV fistula dogs may represent one chronic adaptive mechanism to achieve body fluid homeostasis. Furthermore, via potentially different mechanisms of action, ANF and pro ANF 31-67 may coordinate and contribute to the regulation of haemodynamic and renal function during physiological and pathophysiological situations.

Reduced collateral perfusion is a direct consequence of elevated right atrial pressure

In the present study we determined quantitatively the effects of increased right atrial pressure (RAP) on coronary and collateral flows. In an isolated, blood-perfused, maximally vasodilated dog heart preparation in which the left ventricle was vented, we used the retrograde flow method to assess collateral flow. When RAP was elevated from 5 +/- 1 (control) to 13 +/- 1 and 23 +/- 1 mmHg, retrograde flow from the left circumflex coronary artery (which was open to atmospheric pressure) increased 29 +/- 8 and 97 +/- 21% relative to control while left anterior descending flow decreased 5 +/- 1 and 14 +/- 2%, respectively (P < 0.01; n = 7). The increase in retrograde flow could be due to 1) an increase in collateral flow due to increased pressure at the origin of the collaterals or 2) the elevated RAP (venous outflow pressure), which forces the antegrade collateral flow component in the retrograde direction. To distinguish between these possibilities we embolized the circumflex with 30-microns spheres to eliminate the antegrade flow component. After embolization there was no significant change in retrograde flow with elevated RAP, indicating that the second supposition was correct. We conclude that increased RAP 1) results in a reduction of flow to the collateral-dependent myocardium and 2) reduces perfusion of the unoccluded coronary vessel. Furthermore, we found that under conditions of varying venous outflow pressure, retrograde flow may not serve as a reliable index of collateral flow.

Effects of renal denervation on postprandial sodium excretion in experimental heart failure

The hormonal, hemodynamic and renal excretory changes after an oral load of sodium were examined in renal-denervated dogs with an arteriovenous (AV) fistula and the syndrome of compensated high-output heart failure. After ingestion of a meal containing 125 meq of sodium, the total postprandial urinary sodium excretion and fractional sodium excretion were approximately twofold higher in the renal-denervated AV fistula dogs, compared with a control group with intact renal nerves (P < 0.05). The postprandial elevations in right atrial pressure, plasma atrial natriuretic factor, and filtered load of sodium were similar in the two groups (P > 0.05). Mean arterial pressure and plasma renin activity remained unchanged from baseline in the two subsets of animals (P > 0.05). In the renal-denervated AV fistula dogs, ingestion of a low-salt meal containing 2-3 meq of sodium produced elevations in creatinine clearance and filtered load of sodium of similar magnitude to the high-salt meal. However, the increases in sodium excretion and plasma atrial natriuretic factor were modest and inconsistent. These results demonstrate that the renal nerves play an important modulatory role for postprandial sodium metabolism after a high-salt meal in experimental compensated high-output heart failure. It is suggested that the renal nerves attenuate the expression of postprandial natriuretic mechanisms via a direct tubular mechanism of action.

Determinants of immediate and follow‐up results of pulmonary balloon valvuloplasty

The data of 93 patients (age 11.4 +/- 9.4 years, range 8 months-56 years) who underwent pulmonary balloon valvuloplasty (PBV) for valvular pulmonic stenosis (PS) in our institution are reviewed. The patients were classified into three groups: Group I (34 patients) had a right ventricular (RV) to aortic systolic pressure ratio of < 1, Group II (39 patients) had suprasystemic RV systolic pressures, and Group III (20 patients) included patients with elevated mean right atrial (RA) pressures irrespective of the RV systolic pressures. The percentage drop in immediate postdilatation peak systolic gradients (PSG) and the follow-up PSG were similar in the three groups and were not influenced by any predilatation patient characteristics. A balloon-annulus ratio < 1 predicted a poorer follow-up outcome. Nine patients, eight of Group III and one of Group II, experienced difficult procedures requiring sequential use of progressively larger balloon catheters. Eleven patients, six of Group II and five of Group III, experienced procedure-related events (hypotension, bradycardia/asystole, hypoxia, apnea, tachyarrhythmias, and seizures) and one patient (Group II) died. Although changes in immediate and follow-up gradients after PBV are not influenced by the severity of PS, difficult procedures and procedure-related events are particularly common in patients with severe PS and elevated RA pressures. A cautious and planned approach is therefore indicated in these patients.

Role of the septal leaflet in tricuspid valve closure: Consideration for treatment of complete atrioventricular canal

A septal leaflet of the tricuspid valve is thought to work differently from other anterior and posterior leaflets. We studied its role in valve closure in dogs by means of a dynamic area meter. During the control state, the tricuspid valve orifice area increased twice in diastole coincidentally with either atrial systole or rapid ventricular filling. We observed several findings after the septal leaflet resection: (1) two peak area patterns of the tricuspid valve orifice in diastole, (2) no elevation of right atrial pressure on ventricular systole (there was no V wave), (3) no tricuspid valve regurgitation on right ventriculography. These findings suggest that a complete valve closure occurred without the septal leaflet in regular sinus rhythm. An elevation of the right ventricular pressure produced by pulmonary artery stenosis without septal leaflet, however, easily caused tricuspid valve regurgitation in contrast to the same pressure of the right ventricle with the normal tricuspid valve. The right ventricular pacing caused severe valve regurgitation without the septal leaflet. Results indicate that in the repair of the complete atrioventricular canal defect and other tricuspid valve lesions, the septal leaflet of the tricuspid valve rarely requires attention. An atrioventricular block should be avoided, however, because electrical cardiac pacing on the right ventricle causes severe valve regurgitation without the septal leaflet.