Right Ventricular Length Research Articles

Computed tomography anatomic predictors of outcomes in patients undergoing tricuspid transcatheter edge-to-edge repair

AimTo identify anatomical computed tomography (CT) predictors of procedural and clinical outcomes in patients undergoing tricuspid transcatheter edge-to-edge repair (T-TEER). Methods and resultsConsecutive patients undergoing T-TEER between March 2018 to December 2022 who had cardiac CT prior to the procedure were included. CT scans were automatically analyzed using a dedicated software that employs deep learning techniques to provide precise anatomical measurements and volumetric calculations. Technical success was defined as successful placement of at least one implant in the planned anatomic location without single leaflet device attachment. Procedural success was defined as tricuspid regurgitation reduction to moderate or less. Procedural complexity was assessed by measuring the fluoroscopy time. The clinical endpoint was a composite of death, heart failure hospitalization, or tricuspid re-intervention throughout two years. A total of 33 patients (63.6% male) were included. Procedural success was achieved in 22 patients (66.7%). Shorter end-systolic (ES) height between the inferior vena cava (IVC) and tricuspid annulus (TA) (r ​= ​- 0.398, p ​= ​0.044) and longer ES RV length (r ​= ​0.551, p ​= ​0.006) correlated with higher procedural complexity. ES RV length was independently associated with lower technical(adjusted Odds ratio [OR] 0.812 [95% CI 0.665–0.991], p ​= ​0.040) and procedural success (adjusted OR 0.766, CI [0.591–0.992], p ​= ​0.043). Patients with ES right ventricular (RV) length of >77.4 ​mm had a four-fold increased risk of experiencing the composite clinical endpoint compared to patients with ES RV length ≤77.4 ​mm (HR ​= ​3.964 [95% CI, 1.018–15.434]; p ​= ​0,034]). ConclusionCT-derived RV length and IVC-to-TA height may be helpful to identify patients at increased risk for procedural complexity and adverse outcomes when undergoing T-TEER. CT provides valuable information for preprocedural decision-making and device selection.

One-year cardiac follow-up of COVID-19 pneumonia: dynamics of right heart echocardiographic parameters three months and one year after discharge

Funding AcknowledgementsType of funding sources: None.BackgroundCOVID-19 affects firstly the respiratory system, however the cardiovascular system is also damaged. To study the long-term effect of COVID-19 pneumonia on cardiovascular system, in particular on echocardiography (EchoCG) parameters of right heart is important for patients rehabilitation.PurposeTo compare EchoCG parameters of right heart in patients with proven COVID-19 pneumonia 3 months and one year after discharge.MethodsA total of 116 patients with confirmed COVID-19 pneumonia were included from April 2020 to July 2021. All patients underwent clinical examination including transthoracic EchoCG 3 months ±2 weeks and one year ±3 weeks after discharge. Mean age of patients was 49.0 ± 14.4 years (19-84 years), females were 49.6%. During hospitalization, chest computed tomography (CT) detected mild lesions in 31.3%, moderate lesions in 33.3%, severe lesions in 29.3% and critical lesions in 6.1%.ResultsThe rate of resolution of lung abnormalities according to CT was 55.9%. Mean body mass index was 28.7 ± 5.8 kg/m2 3 months after discharge, and it significantly increased to one year after discharge – 29.4 ± 6.1 kg/m2 (p < 0,001). The mean anteroposterior right ventricular (RV) diameter index decreased over the observation period (13.5 ± 1.9 vs 13.0 ± 1.5 mm/m2, p <0.001), as well as the indices of end-diastolic and end-systolic RV area (8.0 ± 1.8 vs 7.5 ± 1.5 cm2/m2 and 3.8 ± 1.1 vs 3.3 ± 0.8 cm2/m2, respectively, both p < 0.001). The basal RV diameter increased (30.4 ± 5.4 versus 31.1 ± 4.1 mm, p = 0.045), the mid-cavitary RV diameter did not change (25.8 ± 5.4 and 25.8 ± 4.2 mm, p = 0.852), and the base to apex RV length decreased (69.5 ± 8.8 vs 63.9 ± 8.3 mm, p < 0.001). Basal and mid RV sphericity indices (RVSI) increased (0.44 ± 0.07 vs 0.49 ± 0.07 and 0.37 ± 0.07 vs 0.41 ± 0.07, respectively, both p < 0.001). The systolic excursion of the fibrous ring of the tricuspid valve (TAPSE) (22.7 ± 3.2 and 22.8 ± 2.3 mm, p = 0.637) and the tricuspid annular peak systolic velocity S" did not change significantly (10.4 ± 2.6 and 10,1 ± 3.0 cm/s, p = 0.289). The fraction of change in the RV area (FAC RV) increased (52.6 ± 8.2 vs 55.0 ± 8.9%, p = 0.019). The right ventricular outflow tract velocity time integral (RVOT VTI) decreased (18.1 ± 4.0 vs 16.4 ± 3.7 cm, p < 0.001). There were tendencies to increase in the systolic pulmonary artery pressure (PAPs) (22.5 ± 7.1 and 23.3 ± 6.3 mm Hg, p = 0.076) and to increase of the right atrium (RA) long axis dimension (48.7 ± 6.5 vs 49.5 ± 6.3 mm, p = 0.074).ConclusionsCompared to three months after discharge, in patients one year after COVID-19 pneumonia EchoCG showed the anteroposterior RV diameter and the end-diastolic RV area decreased, the FAC RV increased. However, increase of the basal and mid RVSI, decrease in the RVOT VTI and tendencies to increase of the PAPs and the RA long axis dimension was observed. A subgroup analysis is planned depending on the severity of lung damage during hospitalization.

Echocardiographic assessment of right ventricular volume in repaired tetralogy of Fallot: a novel approach to an older technique.

In repaired tetralogy of Fallot (rTOF), right ventricular (RV) enlargement leads to poor outcomes. However, evaluating the RV has limitations; cardiac magnetic resonance (CMR) and 3D echocardiography have barriers including cost and accessibility. Traditional echocardiography is limited given the complex geometry and anterior location of the RV. We propose a novel echocardiographic evaluation of RV volume using 2 separate views. This is a retrospective study of rTOF patients with echocardiogram, CMR, and exercise tests. By echocardiogram, we collected RV length in parasternal long axis (PLAX), area in 4-chamber (4C) view, and measurements per standard guidelines. RV end-diastolic and end-systolic volume (RVEDV and RVESV) were calculated as 5/9 (4C area * PLAX length). Forty-five patients with 66 sets of CMR, echocardiogram, and exercise tests were included (mean age 13.3 ± 3.2years). The echocardiographic RVEDV and RVESV showed strong correlation with CMR parameters (r = 0.81 and 0.72; p≤ 0.0001), and moderate correlation with peak oxygen pulse (0.63 and 0.49; p≤0.0001). Guideline measurements had no significant correlation. Echocardiographic RVEDV and RVESV were higher in those requiring subsequent pulmonary valve replacement. Indexed echocardiographic RVEDV of 93ml/m2 had 92% sensitivity and 50% specificity (area under curve 0.75 (p = 0.001)) in predicting CMR RV/LV EDV ratio > 2, which is an early indicator for pulmonary valve replacement. This novel technique correlates strongly with CMR, better than traditional parameters. While echocardiogram will not replace CMR, this method would be useful in predicting the RV volume, progression of dilation, and timing of CMR.

Abstract 13277: Deep Learning Networks Trained on Routine Echocardiography Images Provide Expert Level Prognostication in Patients With Pulmonary Hypertension: A Study on 408 Patients From an Expert Centre

Background: Pulmonary arterial hypertension (PAH) is a progressive disease with high morbidity and mortality. Assessing PAH prognosis is paramount for guiding therapy and transthoracic echocardiography (TTE) remains the mainstay of regular assessment. We hypothesized that deep learning networks (DL) could provide essential prognostic information of comparable quality as a comprehensive expert assessment. Methods: All PAH pts. with routine TTE between 2005 and 2018 were included. A combination of U-Net DL-frameworks was developed to automatically segment cardiac chambers and extract geometric information throughout the cardiac cycle (see Figure ). The prognostic value of chamber dimensions and functional parameters for all-cause mortality was assessed using Cox proportional-hazard analyses. Results: Overall, 408 PAH patients (median age 59 years, 74% female; 34% idiopathic PAH, 66% associated PAH) were included. Over a median follow-up of 0.6 years , 196 patients died. On univariable Cox analysis automatically determined right atrial area, right ventricular (RV) area, RV fractional area change, RV inflow diameter, RV length, left ventricular (LV) eccentricity index (p&lt;0.001 for all) were significantly related to mortality. On multivariable analysis DL-based RV fractional area change (HR 0.97/%, p=0.004), right atrial area (HR 1.03/cm 2 , p=0.01) and LV longitudinal diameter (HR 0.92/cm, p=0.02) emerged as independent predictors of outcome. The prognostic value of all EDL parameters was non-inferior to traditional measures obtained by expert echocardiographers (p&gt;0.05 for all concordance-C comparisons). Conclusions: The current study demonstrates for the first-time the utility of ensemble-based DL algorithms to assess prognosis of PAH based on a large tertiary centre dataset. Due to the automated process, these DL algorithms can ultimately serve as online based decision-making tools and the performance is comparable to expert investigators.

Right Ventricular Volumes, Ejection Fraction, and Systolic Function Indices in Normal Neonates by Three-Dimensional Speckle-Tracking Echocardiography.

The aim of this study was to test the feasibility of measuring right ventricular (RV) volumes, ejection fraction (EF), and systolic function indices in neonates using three-dimensional speckle-tracking echocardiography (3D-STE). Thirty-eight neonates underwent complete echocardiographic evaluation, including the acquisition of three full-volume 3D datasets or more from each of the apical, parasternal, and subcostal windows while naturally sleeping. Datasets were analyzed using a commercially available software (Tomtec). Global RV 3D volumes and EF were measured. In addition, 2D free wall longitudinal strain (LS), tricuspid valve annulus (TVA), tricuspid annular plane systolic excursion (TAPSE) and its index to RV length (TAPSEi), and fractional area change (FAC) were obtained from a non-shortened apical 4-chamber view of the RV, derived from the 3D dataset. Three or more datasets obtained from the apical window were available for analysis for each subject. At least one dataset was adequate for analysis in all subjects. Mean indexed 3D diastolic, systolic, stroke volumes, and EF were measured at 28.5 ± 3.4ml/m2, 13 ± 2.0ml/m2, 15.6 ± 1.9ml/m2, and 54.6 ± 3.2%, respectively. Free wall 2D LS was calculated at (- 27.9 ± 2.5%). In addition, mean TVA measured 11.1 ± 0.8mm, TAPSE measured 6.8 ± 0.9mm, and TAPSEi and FAC were calculated at 24.2 ± 2.1 and 46 ± 3.4%, respectively. 3D-STE is feasible in normal neonates without the need for sedation. Reference values of RV 3D volumes and 2D indices of systolic function were obtained. These data could be helpful in patients where the size or systolic function of the RV is in question. Larger studies are required to establish nomograms for the above indices in this age group.

Associations of (pre)diabetes with right ventricular and atrial structure and function: the Maastricht Study

BackgroundsThe role of right ventricular (RV) and atrial (RA) structure and function, in the increased heart failure risk in (pre)diabetes is incompletely understood. The purpose of this study is to investigate the associations between (pre)diabetes and RV and RA structure and function, and whether these are mediated by left ventricular (LV) alterations or pulmonary pressure.MethodsParticipants of the Maastricht Study; a population-based cohort study (426 normal glucose metabolism (NGM), 142 prediabetes, 224 diabetes), underwent two-dimensional and tissue Doppler echocardiography. Multiple linear regression analyses with pairwise comparisons of (pre)diabetes versus NGM, adjusted for cardiovascular risk factors, and mediation analyses were used.ResultsIn general, differences were small. Nevertheless, in individuals with prediabetes and diabetes compared to NGM; RA volume index was lower (both p < 0.01, ptrend < 0.01), RV diameter was lower (both p < 0.01, ptrend < 0.01) and RV length was significantly smaller in diabetes (p = 0.67 and p = 0.03 respectively, ptrend = 0.04), TDI S′RV was lower (p = 0.08 and p < 0.01 respectively, ptrend < 0.01), TDI E′RV was lower (p = 0.01 and p = 0.02 respectively, ptrend = 0.01) and TDI A′RV was lower (p < 0.01 and p = 0.07 respectively, ptrend = 0.04). Only the differences in RA volume index (7.8%) and RV diameter (6.2%) were mediated by the maximum tricuspid gradient, but no other LV structure and function measurements.Conclusions(Pre)diabetes is associated with structural RA and RV changes, and impaired RV systolic and diastolic function, independent of cardiovascular risk factors. These associations were largely not mediated by indices of LV structure, LV function or pulmonary pressure. This suggests that (pre)diabetes affects RA and RV structure and function due to direct myocardial involvement.

Value of tissue-tracking tricuspid annular plane by speckle-tracking echocardiography for the assessment of right ventricular systolic dysfunction.

Assessment of right ventricular (RV) function remains challenging because of its complex geometry. Application of speckle-tracking echocardiography (STE) to the tricuspid annulus provides rapid and automated assessment of the midpoint of the tricuspid annular plane displacement (TAD). The aim of this study was to investigate the value of tissue-tracking TAD for the assessment of RV systolic dysfunction. We retrospectively studied 61 patients in whom RV ejection fraction (EF) measured by 3-dimensional echocardiography was performed. STE-derived displacement of the midpoint between the septal and lateral tricuspid annulus and its percentage of RV length at end-diastole (MTAD) were automatically assessed. We performed comparative analyses between the RVEF ≥45% group and the RVEF <45% group in each parameter for the assessment of RV systolic function. MTAD was successfully assessed in 56 (91.2%). According to receiver operating characteristics analysis, RVEF <45% was best detected by MTAD <14.7% with area under curve (AUC) 0.97, sensitivity 93%, specificity 95%, followed by RV free wall longitudinal strain (AUC 0.86), RV fractional area change (AUC 0.84), tricuspid annular plane systolic excursion (AUC 0.79), and systolic peak velocity of tricuspid annulus (AUC 0.70), although there was no significant difference between MTAD and RV free wall strain (P=0.14). The present study showed that MTAD was simple index and useful for the assessment of RV systolic dysfunction.

Regional right ventricular remodeling and function in children with idiopathic pulmonary arterial hypertension vs those with pulmonary valve stenosis: Insights into mechanics of right ventricular dysfunction.

Right ventricular (RV) pressure overload in the context of pulmonary stenosis (PS) has a much better prognosis than in the context of idiopathic pulmonary arterial hypertension (iPAH), which may be related to differences in global and regional RV remodeling and systolic function. We compared RV mechanics in children with PS to those with iPAH, aiming to identify mechanisms and markers of RV dysfunction. Eighteen controls, 18 iPAH and 16 PS patients were retrospectively studied. Age, BSA, and sex distribution were comparable. Two-dimensional echocardiography, blood flow and tissue Doppler, and longitudinal RV deformation were analyzed. ANCOVA-including RV systolic pressure (RVSP) and length as covariates-was used to compare patient groups. RV systolic pressure was higher in iPAH vs PS (96.8±25.4 vs 75.4±18.9mm Hg, P=.011). Compared to controls, PS patients showed mild dilation (P<.01) and decreased longitudinal deformation (P<.001) at the RV apex. Compared to both PS and controls, iPAH patients showed marked spherical RV dilation (P<.001), reduced global, RV free wall and septal longitudinal deformation (iPAH -22.07%±4.35% vs controls -28.18%±1.69%; -9.98%±4.30% vs -17.45%±2.52%; P<.001) and RV postsystolic shortening (P<.001). RV transverse shortening (radial performance) was increased in PS (31.75%±10.35%; P<.001) but reduced in iPAH (-1.62%±11.11% vs controls 12.00%±7.74%; P<.001). Children with iPAH demonstrate adverse global and regional RV remodeling and mechanics compared to those with PS. Mechanisms of RV systolic dysfunction in iPAH include decreased longitudinal deformation, decreased or absent transverse shortening, and postsystolic shortening. These markers may be useful to identify children at risk of RV failure.

Echocardiographic Linear Dimensions for Assessment of Right Ventricular Chamber Volume as Demonstrated by Cardiac Magnetic Resonance

Echocardiography-derived linear dimensions offer straightforward indices of right ventricular (RV) structure but have not been systematically compared with RV volumes on cardiac magnetic resonance (CMR). Echocardiography and CMR were interpreted among patients with coronary artery disease imaged via prospective (90%) and retrospective (10%) registries. For echocardiography, American Society of Echocardiography-recommended RV dimensions were measured in apical four-chamber (basal RV width, mid RV width, and RV length), parasternal long-axis (proximal RV outflow tract [RVOT]), and short-axis (distal RVOT) views. For CMR, RV end-diastolic volume and RV end-systolic volume were quantified using border planimetry. Two hundred seventy-two patients underwent echocardiography and CMR within a narrow interval (0.4±1.0days); complete acquisition of all American Society of Echocardiography-recommended dimensions was feasible in 98%. All echocardiographic dimensions differed between patients with and those without RV dilation on CMR (P<.05). Basal RV width (r=0.70), proximal RVOT width (r=0.68), and RV length (r=0.61) yielded the highest correlations with RV end-diastolic volume on CMR; end-systolic dimensions yielded similar correlations (r=0.68, r=0.66, and r=0.65, respectively). In multivariate regression, basal RV width (regression coefficient=1.96 per mm; 95% CI, 1.22-2.70; P<.001), RV length (regression coefficient=0.97; 95% CI, 0.56-1.37; P<.001), and proximal RVOT width (regression coefficient=2.62; 95% CI, 1.79-3.44; P<.001) were independently associated with CMR RV end-diastolic volume (r=0.80). RV end-systolic volume was similarly associated with echocardiographic dimensions (basal RV width: 1.59 per mm [95% CI, 1.06-2.13], P<.001; RV length: 1.00 [95% CI, 0.66-1.34], P<.001; proximal RVOT width: 1.80 [95% CI, 1.22-2.39], P<.001) (r=0.79). RV linear dimensions provide readily obtainable markers of RV chamber size. Proximal RVOT and basal width are independently associated with CMR volumes, supporting the use of multiple linear dimensions when assessing RV size on echocardiography.

Differential effect of right ventricular dilatation on myocardial deformation in patients with atrial septal defects and patients after tetralogy of Fallot repair

Right ventricular (RV) volume overload results in RV dilatation in patients with atrial septal defect (ASD) and after tetralogy of Fallot (ToF) repair with pulmonary regurgitation. Study the differential effects of chronic RV volume loading on regional and global RV deformation in patients with ASD and after TOF repair. We studied 85 subjects: 50 patients after ToF repair, 15 patients with unrepaired ASD and 20 age-matched controls. The ToF patients and controls underwent an echocardiography at the time of a clinically indicated MRI. The ASD patients had a routine echocardiogram including RV volume calculations. Longitudinal deformation was analyzed using 2-D speckle tracking echocardiography. RV free wall global and segmental longitudinal deformation was significantly lower in ToF patients compared with ASD and controls (p<0.001). In ToF patients, there was a progressive decrease in strain values from base to apex (p<0.001), while in the ASD group there was a progressive increase (p=0.04). We found strong negative correlations between RV size and RV longitudinal strain measurements, strongest with RV length (R=0.72). When corrected for RV size, all ASD patients had normal or higher deformation values while half of the TOF patients had significantly lower values. Global and regional myocardial RV deformation is differently affected by chronic volume loading in ASD versus TOF patients, especially regarding the apical function. This suggests a different adaptation mechanism in both diseases. Our data also suggest that strain measurements are strongly influenced by ventricular size, which should be taken into consideration when interpreting strain values.

The Right Ventricle of the Endurance Athlete: The Relationship between Morphology and Deformation

The aims of this study were to establish absolute ranges for right ventricular (RV) structural and functional parameters for endurance athletes and to establish any impact of body size. These data may help differentiate physiologic conditioning from arrhythmogenic RV cardiomyopathy. A prospective observational study design was used, and standard two-dimensional echocardiography was performed on 102 endurance athletes, providing RV structural indices. A two-dimensional strain (ε)technique was used to provide indices of RV ε and strain rate. The association of RV chamber size to body surface area (BSA) and functional indices was examined by simple ratio scaling as well as adoption of the general, nonlinear allometric model. The values for RV inflow, outflow, length, and diastolic area were greater than published "normal ranges" in 57%, 40%, 69%, and 59% of the population, respectively, while 28% of the population had RV outflow tract values greater than the proposed "major criteria" for arrhythmogenic RV cardiomyopathy. Simple ratio scaling for all RV dimensions to BSA did not produce size independence, whereas scaling for BSA allometrically did. Strain and strain rate values were consistent with published normal ranges, and there is no evidence to suggest that scaling is required. RV chamber dimensions are larger in endurance athletes than those described by "normal ranges" and frequently meet the major criteria for the diagnosis of arrhythmogenic RV cardiomyopathy. Functional assessment of RV ε may aid in this differential diagnosis. RV size is allometrically related to BSA and therefore scaling for population-specific b exponents is encouraged.

Three-Dimensional Shape Analysis of Right Ventricular Remodeling in Repaired Tetralogy of Fallot

Understanding of right ventricular (RV) remodeling is needed to elucidate the mechanism of RV dysfunction in the overloaded right ventricle, but is hampered by the chamber's complex shape. We imaged 15 patients with repaired tetralogy of Fallot (TOF) and 8 normal subjects by magnetic resonance imaging in long- and short-axis views. We reconstructed the right ventricles in 3 dimensions using the piecewise smooth subdivision surface method. Shape was analyzed from cross-sectional contours generated by intersecting the right ventricle with 20 planes evenly spaced from apex to tricuspid annulus. Patients with TOF had dilated right ventricles compared with normal (end-diastolic volume index 216 ± 99 vs 81 ± 16 ml/m², p <0.001) but near-normal function (ejection fraction 40 ± 9% vs 48 ± 12%, respectively, p=NS). RV shape in patients with TOF differed from normal subjects in several ways. First, the right ventricle had a larger normalized cross-sectional area in patients with TOF (p <0.01 in apical planes). Second, the cross-sectional shape was rounder in patients with TOF (p <0.05 in apical planes). Also, the interventricular septum underwent relatively less enlargement so that it comprised only 27 ± 4% of total RV surface area in patients with TOF, compared with 33 ± 2% in normal subjects (p = 0.0001). In addition, the right ventricle in patients with TOF exhibited bulging basal to the tricuspid valve (4 ± 4% of total RV length), unlike normals (1 ± 2%, p <0.001). This basal bulging was amplified by tilting of the tricuspid annulus (29 ± 11° vs 15 ± 7°, respectively, p <0.005). In conclusion, the right ventricle remodels in several directions rather than following a shape continuum. Characterization of RV remodeling from 3-dimensional reconstructions provides novel insights.

Colorectal cancer risk among post-menopausal hormone users in a population-based familial case-control study

Echocardiography-derived linear dimensions offer straightforward indices of right ventricular (RV) structure but have not been systematically compared with RV volumes on cardiac magnetic resonance (CMR).Echocardiography and CMR were interpreted among patients with coronary artery disease imaged via prospective (90%) and retrospective (10%) registries. For echocardiography, American Society of Echocardiography–recommended RV dimensions were measured in apical four-chamber (basal RV width, mid RV width, and RV length), parasternal long-axis (proximal RV outflow tract [RVOT]), and short-axis (distal RVOT) views. For CMR, RV end-diastolic volume and RV end-systolic volume were quantified using border planimetry.Two hundred seventy-two patients underwent echocardiography and CMR within a narrow interval (0.4 ± 1.0 days); complete acquisition of all American Society of Echocardiography–recommended dimensions was feasible in 98%. All echocardiographic dimensions differed between patients with and those without RV dilation on CMR (P < .05). Basal RV width (r = 0.70), proximal RVOT width (r = 0.68), and RV length (r = 0.61) yielded the highest correlations with RV end-diastolic volume on CMR; end-systolic dimensions yielded similar correlations (r = 0.68, r = 0.66, and r = 0.65, respectively). In multivariate regression, basal RV width (regression coefficient = 1.96 per mm; 95% CI, 1.22-2.70; P < .001), RV length (regression coefficient = 0.97; 95% CI, 0.56-1.37; P < .001), and proximal RVOT width (regression coefficient = 2.62; 95% CI, 1.79-3.44; P < .001) were independently associated with CMR RV end-diastolic volume (r = 0.80). RV end-systolic volume was similarly associated with echocardiographic dimensions (basal RV width: 1.59 per mm [95% CI, 1.06-2.13], P < .001; RV length: 1.00 [95% CI, 0.66-1.34], P < .001; proximal RVOT width: 1.80 [95% CI, 1.22-2.39], P < .001) (r = 0.79).RV linear dimensions provide readily obtainable markers of RV chamber size. Proximal RVOT and basal width are independently associated with CMR volumes, supporting the use of multiple linear dimensions when assessing RV size on echocardiography.

Cardiac end-diastolic dilation during acute blood pressure elevation is inotropy dependent.

To examine if the degree of left ventricular (LV) end-diastolic dilation during an acute blood pressure elevation is inotropy dependent, the descending thoracic aorta was occluded before and during a continuous isoproterenol infusion into the left coronary artery in 10 open-chest pigs. The increase in peak LV systolic pressure and in LV tension-time-index induced by aortic occlusion, were equal before and during the isoproterenol infusion. Left and right ventricular (RV) segment lengths were continuously recorded in the free walls of both ventricles, by an ultrasonic technique. A slight fall in LV end-diastolic segment length by the intracoronary isoproterenol infusion was corrected by an i.v. saline infusion. Left ventricular end-diastolic volume was therefore equal at both levels of inotropy when the aorta was occluded, and the heart rate was kept constant by right atrial pacing. At control inotropy, aortic occlusion induced a rise in LV end-diastolic segment length; 6.0 (4.0-8.2)% (median and 95% confidence interval), compared with the smaller (P less than 0.05) increase of 3.8 (2.6-5.5)% during isoproterenol infusion. The end-systolic segment length increased more (P less than 0.01) at control inotropy than during intracoronary isoproterenol infusion: 10.9 (6.9-14.4)% and 4.1 (1.5-7.4)%, respectively. In the RV, both end-diastolic and end-systolic segment length increased slightly during aortic occlusion but only at control inotropy. Thus during an acute blood pressure elevation, the end-diastolic and end-systolic ventricular volumes are better maintained at high than at control inotropy.