Reduced left ventricular compliance in human mitral stenosis. Role of reversible internal constraint

Global Left Ventricular Myocardial Work Efficiency in Patients With Severe Rheumatic Mitral Stenosis and Preserved Left Ventricular Ejection Fraction

BACKGROUND

Assessment of left ventricular (LV) function plays a pivotal role in the management of patients with valvular heart disease, including those caused by rheumatic heart disease. Noninvasive LV pressure-strain loop analysis is emerging as a new echocardiographic method to evaluate global LV systolic function, integrating longitudinal strain by speckle-tracking analysis and noninvasively measured blood pressure to estimate myocardial work. The aim of this study was to characterize global LV myocardial work efficiency in patients with severe rheumatic mitral stenosis (MS) with preserved ejection fraction (EF).

METHODS

We retrospectively included adult patients with severe rheumatic MS with preserved EF (> 50%) and sinus rhythm. Healthy individuals without structural heart disease were included as a control group. Global LV myocardial work efficiency was estimated with a proprietary algorithm from speckle-tracking strain analyses, as well as noninvasive blood pressure measurements.

RESULTS

A total of 45 individuals with isolated severe rheumatic MS with sinus rhythm and 45 healthy individuals were included. In healthy individuals without structural heart disease, the mean global LV myocardial work efficiency was 96% (standard deviation [SD], 2), Compared with healthy individuals, median global LV myocardial work efficiency was significantly worse in MS patients (89%; SD, 4; p < 0.001) although the LVEF was similar.

CONCLUSIONS

Individuals with isolated severe rheumatic MS and preserved EF, had global LV myocardial work efficiencies lower than normal controls.

Influence of Respiration on Collateral Flow in the Fontan Population Using Real-time Phase-contrast Cardiovascular Magnetic Resonance: Collateral Flow Does Not Protect the Ventricle From Volume Deficiency and Diastolic Dysfunction

PURPOSE

The clinical significance of collateral flow for the ventricular function of patients with univentricular hearts is often debated. This study evaluates the impact of collateral flow on respiration-dependent preload modification and diastolic function in Fontan patients assessed by systemic and pulmonary vein (PV) flow patterns.

MATERIALS AND METHODS

Real-time phase-contrast cardiovascular magnetic resonance was performed in the right upper PV, ascending aorta, superior, and inferior vena cava (IVC) in 21 Fontan patients and 11 healthy individuals. The patients' respiratory cycle was divided into 4 periods to generate respiratory-dependent stroke volumes (SV i ). Conventional quantitative blood flow measurements were used to quantify and differentiate between low (group A) and high (group B) collateral flow.

RESULTS

Group B showed significantly lower SV i IVC in inspiration, end-inspiration, expiration, and SV i ΔIVC compared with group A (23.6±4.8 mL/m 2 to 33.4±8.0; P =0.005). PV flow resulted in a lower mean SV i PV (11.6±7.6 mL/m 2 , vs. 14.0±11.4 mL/m 2 ) as well as a significantly lower peak systolic S-wave velocity (S max ) ( P =0.005), S/D-ratio (S max /peak diastolic wave velocity) ( P =0.015), and shorter diastolic deceleration time (DT D ; P =0.030; median DT D =134 ms) compared with group A (DT D =202 ms).

CONCLUSIONS

This study demonstrates the incapability of Fontan patients to properly increase preload by inspiration in the presence of significant collateral flow. The results further show that collateral flow is associated with a volume-deprived ventricle and impaired diastolic function.

Recommendations for the Use of Echocardiography in the Evaluation of Rheumatic Heart Disease: A Report from the American Society of Echocardiography

Acute rheumatic fever and its chronic sequela, rheumatic heart disease (RHD), pose major health problems globally, and remain the most common cardiovascular disease in children and young people worldwide. Echocardiography is the most important diagnostic tool in recognizing this preventable and treatable disease and plays an invaluable role in detecting the presence of subclinical disease needing prompt therapy or follow-up assessment. This document provides recommendations for the comprehensive use of echocardiography in the diagnosis and therapeutic intervention of RHD. Echocardiographic diagnosis of RHD is made when typical findings of valvular and subvalvular abnormalities are seen, including commissural fusion, leaflet thickening, and restricted leaflet mobility, with varying degrees of calcification. The mitral valve is predominantly affected, most often leading to mitral stenosis. Mixed valve disease and associated cardiopulmonary pathology are common. The severity of valvular lesions and hemodynamic effects on the cardiac chambers and pulmonary artery pressures should be rigorously examined. It is essential to take advantage of all available modalities of echocardiography to obtain accurate anatomic and hemodynamic details of the affected valve lesion(s) for diagnostic and strategic pre-treatment planning. Intraprocedural echocardiographic guidance is critical during catheter-based or surgical treatment of RHD, as is echocardiographic surveillance for post-intervention complications or disease progression. The role of echocardiography is indispensable in the entire spectrum of RHD management.

Impact of Udenafil on Echocardiographic Indices of Single Ventricle Size and Function in FUEL Study Participants

BACKGROUND

The FUEL trial (Fontan Udenafil Exercise Longitudinal) demonstrated statistical improvements in exercise capacity following 6 months of treatment with udenafil (87.5 mg po BID). The effect of udenafil on echocardiographic measures of single ventricle function in this cohort has not been studied.

METHODS

The 400 enrolled participants were randomized 1:1 to udenafil or placebo. Protocol echocardiograms were obtained at baseline and 26 weeks after initiation of udenafil/placebo. Linear regression compared change from baseline indices of single ventricle systolic, diastolic and global function, atrioventricular valve regurgitation, and mean Fontan fenestration gradient in the udenafil cohort versus placebo, controlling for ventricular morphology (left ventricle versus right ventricle/other) and baseline value.

RESULTS

The udenafil participants (n=191) had significantly improved between baseline and 26 weeks visits compared to placebo participants (n=195) in myocardial performance index (P=0.03, adjusted mean difference [SE] of changes between groups -0.03[0.01]), atrioventricular valve inflow peak E (P=0.009, 3.95 [1.50]), and A velocities (P=0.034, 3.46 [1.62]), and annular Doppler tissue imaging-derived peak e' velocity (P=0.008, 0.60[0.23]). There were no significant differences in change in single ventricle size, systolic function, atrioventricular valve regurgitation severity, or mean fenestration gradient. Participants with a dominant left ventricle had significantly more favorable baseline values of indices of single ventricle size and function (lower volumes and areas, E/e' ratio, systolic:diastolic time and atrioventricular valve regurgitation, and higher annular s' and e' velocity).

CONCLUSIONS

FUEL participants who received udenafil demonstrated a statistically significant improvement in some global and diastolic echo indices. Although small, the changes in diastolic function suggest improvement in pulmonary venous return and/or augmented ventricular compliance, which may help explain improved exercise performance in that cohort.

REGISTRATION

URL: https://clinicaltrials.gov; Unique Identifier: NCT02741115.

Pulmonary artery pressure response to percutaneous mitral valvuloplasty: Associated factors and clinical implications

BACKGROUND

Pulmonary hypertension (PH) is a marker of poor outcome in mitral stenosis (MS), which improves after percutaneous mitral valvuloplasty (PMV). However, mechanical interventions for relief of valve obstruction often but not always reduce pulmonary pressures. This study aimed to assess the parameters associated with abnormal pulmonary artery pressure (PAP) response immediately after a successful PMV, and also its impact on long-term outcome.

METHODS

A total of 181 patients undergoing PMV for rheumatic MS were prospectively enrolled. Invasive hemodynamic and echocardiographic measures were examined in all patients. Abnormal PAP response was defined as the mean PAP (mPAP) values unchanged at the end of the procedure. Long-term outcome was a composite endpoint of death, mitral valve replacement, repeat PMV, new onset of atrial fibrillation (AF), or stroke.

RESULTS

The mean age was 44.1 ± 12.6 years, and 157 patients were women (86.7%). In the overall population, mPAP decreased from 33.4 ± 13.1 mmHg pre to 27.6 ± 9.8 mmHg post (p < 0.001). Following PMV, 52 patients (28.7%) did not have any reduction of mPAP immediately after the PMV. Multivariable analysis adjusting for baseline values of PAP and mitral valve area revealed that AF (Odds ratio [OR] 2.7, 95% [confidence interval] CI 1.3 to 6.7), maximum mitral valve leaflets displacement (OR 0.8, 95% CI 0.7 to 0.9), and post-procedural left ventricular compliance (OR 0.7, 95% CI 0.5 to 0.9) were predictors of a lack of improvement in mPAP. During a median follow-up of 4.4 years, the endpoint was reached in 56 patients (31%). The pulmonary pressure response to PMV was not an independent predictor of long-term events.

CONCLUSIONS

In patients with MS undergoing PMV, pulmonary pressures may not reduce immediately after the procedure, despite adequate opening of the valve. Abnormal PAP response can be predicted from baseline clinical and valvular characteristics as well as post-procedural left ventricular compliance. The lack of any immediate reduction in mPAP is not associated with long-term adverse outcomes.

Left Ventricular Remodeling Shortly after Open Mitral Valve Replacement for Rheumatic Mitral Stenosis

Introduction

Left ventricular dysfunction after surgical treatment of mitral stenosis is uncommon. We intend to determine the pattern of left ventricular remodeling, shortly after open mitral valve replacement for rheumatic mitral stenosis, with in-hospital postoperative outcomes and the determinants of postoperative worsening of left ventricular ejection fraction.

Methods

From January 2008 to January 2015, 107 adult patients with rheumatic mitral stenosis were submitted to open mitral valve replacement. Their mean age was 45±11 years and 93 (86.9%) were women. Left ventricular morphology and function were studied longitudinally with echocardiography. The end point was postoperative worsening of left ventricular ejection fraction, defined by a decrease of 10% compared to preoperative basal assessment. Determinants of worsening left ventricular ejection fraction were determined by multivariable logistic regression analysis.

Results

The end point occurred in 18 patients (16.8%). We tested clinical and echocardiographic parameters to verify independent variables related to the decrease in postoperative ejection fraction. Lower body weight (P=0.005; odds ratio [OR]=0.89) and smaller preoperative mitral valve area (P=0.02; OR=0.02) were independent predictors of left ventricular dysfunction. These patients presented higher mortality and morbidity rates.

Conclusion

Left ventricular remodeling patterns differed among patients with predominant rheumatic mitral stenosis undergoing open mitral valve replacement. Lower preoperative body weight and mitral valve area were independent determinants of deteriorating ejection fraction with increased end-systolic volumes, indicating that this specific problem may occur in anthropometric smaller patients with more extensive rheumatic disease.

The pulmonary vascular bed in patients with functionally univentricular physiology and a Fontan circulation

Fontan palliation represents one of the most remarkable surgical advances in the management of individuals born with functionally univentricular physiology. The operation secures adult survival for all but a few with unfavourable anatomy and/or physiology. Inherent to the physiology is passive transpulmonary blood flow, which produces a vulnerability to adequate filling of the systemic ventricle at rest and during exertion. Similarly, the upstream effects of passive flow in the lungs are venous congestion and venous hypertension, especially marked during physical activity. The pulmonary vascular bed has emerged as a defining character on the stage of Fontan circulatory behaviour and clinical outcomes. Its pharmacologic regulation and anatomic rehabilitation therefore seem important strategic therapeutic targets. This review seeks to delineate the important aspects of pulmonary artery development and maturation in functionally univentricular physiology patients, pulmonary artery biology, pulmonary vascular reserve with exercise, and pulmonary artery morphologic and pharmacologic rehabilitation.

Invasive left ventricle pressure-volume analysis: overview and practical clinical implications

Ventricular pressure–volume (PV) analysis is the reference method for the study of cardiac mechanics. Advances in calibration algorithms and measuring techniques brought new perspectives for its application in different research and clinical settings. Simultaneous PV measurement in the heart chambers offers unique insights into mechanical cardiac efficiency. Beat to beat invasive PV monitoring can be instrumental in the understanding and management of heart failure, valvular heart disease, and mechanical cardiac support. This review focuses on intra cardiac left ventricular PV analysis principles, interpretation of signals, and potential clinical applications.

Evaluation of left and right ventricular functions with three-dimensional speckle tracking in patients with mitral stenosis

BACKGROUND

The function of both ventricles has been suggested to be affected in patients with mitral stenosis. In this study, it was aimed to investigate deformation properties of right (RV) and left ventricle (LV) in rheumatic mitral stenosis (MS) patients with three-dimensional speckle tracking echocardiography (3D-STE).

METHODS

A total of 60 patients were included in the study (20 patients with mild MS diagnosis, 20 patients with moderate MS diagnosis, and 20 healthy volunteers). Three-dimensional echocardiography datasets were obtained for both ventricles in all patients. LV global longitudinal strain (GLS), LV torsion, RV free wall (FW) LS, and interventricular septal (IVS) LS measurements were analyzed.

RESULTS

The LV ejection fraction (EF), RV fractional area change, peak systolic velocity of the tricuspit annulus, isovolumic acceleration, and tricuspid annular plane systolic excursion values were statistically similar and in the normal range. The LV GLS measurements were significantly different among the groups by being highest in the control group and least in the moderate stenosis group. Patients with MS showed higher torsional values, correlated with MS severity. IVS LS, RVFW LS values obtained by RV analysis also differed significantly among groups. The RVFW-GLS values only showed significant difference between the control group and moderate MS group.

CONCLUSION

Patients with MS showed lower LV-GLS and higher LV torsion values. RV deformation indices showed significant decrease in correlation with the severity of the mitral stenosis. In conclusion, our data suggest that subclinical LV and RV systolic dysfunction is present in mild-moderate MS patients and this dysfunction can be detected by 3D-STE.

Acute and short term effects of successful mitral valvuloplasty on net atrio ventricular compliance and its correlation with clinical outcome

Aim of the study

Patients undergoing successful balloon mitral valvuloplasty (BMV) have variable improvement in New York Heart Association (NYHA) functional class (FC), exercise capacity (EC) and regression of systolic pulmonary artery pressure (sPAP). Improvement in net atrioventricular compliance (Cn), one of the major determinants of above factors is not routinely assessed. Aim of present study was to assess the change in Cn after successful BMV and its correlation with above factors.

Methods

50 patients of very severe mitral stenosis in sinus rhythm who underwent successful BMV have been studied. NYHA FC, 6 min walk test (6 MWT) and echocardiographic evaluation was done 24 h before and at 2 weeks, 12 weeks and 24 weeks after BMV. Echocardiographic parameters of patients with improvement in NYHA class of ≥2 (group A) were also compared with those with improvement in NYHA class of ≤1 (group B).

Results

Following successful BMV, there was progressive improvement in Cn upto 12 weeks with no further significant improvement till 24 weeks. Change in Cn showed very good correlation with change in NYHA class [r = 0.62, p < 0.01], 6 MWT [r = 0.30, p0.03] and regression of sPAP assessed at 12 weeks and was maintained upto 24 weeks. Change in MVA did not show any correlation with above factors. Group B patients had significantly lower Cn post BMV as compared to group A patients inspite of comparable MVA and trans valvular gradients.

Conclusion

Improvement in Cn following BMV has good correlation with clinical improvement. So Cn should also be assessed along with MVA to better predict clinical outcome.

Relation between left atrial strain and exercise tolerance in patients with mild mitral stenosis: An insight from 2D speckle-tracking echocardiography

BACKGROUND

Mild mitral stenosis (MS) is a progressive disease but unfortunately, its clinical course is still unclearly studied. We aimed to study the left atrial (LA) deformation in such patients and how it is related to exercise intolerance.

METHODS

Seventy-five patients with mitral valve area of 1.81 ± 0.13 cm² and 40 healthy control subjects were enrolled. All participants had sinus rhythm, and they underwent conventional echocardiography and LA strain analysis with speckle-tracking study. The following parameters were obtained: left atrial reservoir strain (LAS-s), LA conduit strain (LAS-e), and LA contraction strain (LAS-a). All participants underwent symptoms limited stress ECG using modified Bruce protocol.

RESULTS

Comparing with control subjects, patients with mild MS had significant lower LAS-s value (P < .01) and LAS-e (<0.03). Patients with exercise intolerance (METs < 8) had lower LAS-s (P < .001), LAS-e (P < .01), and LAS-a (P < .05) values compared to those with METs ≥ 8. We found that METs was significantly related to LAS-s (P < .001), brain natriuretic peptide (P < .001), and Δ TAPSE (P < .03). Multivariate analysis showed that LAS-s was an independent predictor of reduced exercise capacity. With ROC analysis, LAS-s ≤ 26.5% was the optimal value for prediction of exercise intolerance in patients with mild MS.

CONCLUSION

A significant percentage of patients with mild mitral stenosis had exercise intolerance. We found that LAS-s was significantly associated with exercise capacity in patients with mild MS. Hence, we thought that LA deformation could be of great value in the follow-up of patients with mild MS.

Left ventricular diastolic function in mitral stenosis

The assessment of left ventricular (LV) function in the setting of mitral stenosis (MS) has been critically examined for decades. Accurate assessment of aberrations in diastolic function is important as these subjects often present with signs and symptoms of heart failure and pulmonary congestion that cannot be solely explained by the severity of mechanical obstruction. Echocardiographic evaluation of diastolic dysfunction includes an evaluation of reduced LV compliance, diminished restoring forces, and enhanced stiffness, which are challenging in the setting of MS owing to altered hemodynamic loading. Conventional echocardiographic and Doppler measures offer limited information. Novel assessments employing speckle tracking echocardiography are relatively less studied. A more comprehensive assessment including clinical evaluation, identification of concomitant disorders, and comorbidities is particularly warranted in older subjects with degenerative MS to suspect diastolic dysfunction and arrive at optimal medical therapy or intervention. This review provides an overview of etiological, pathophysiological, echocardiographic, and invasive assessment of diastolic dysfunction in the setting of MS, with specific focus on strengths and limitations of available echocardiographic and Doppler techniques.

Heart failure in single right ventricle congenital heart disease: physiological and molecular considerations

Because of remarkable surgical and medical advances over the past several decades, there are growing numbers of infants and children living with single ventricle congenital heart disease (SV), where there is only one functional cardiac pumping chamber. Nevertheless, cardiac dysfunction (and ultimately heart failure) is a common complication in the SV population, and pharmacological heart failure therapies have largely been ineffective in mitigating the need for heart transplantation. Given that there are several inherent risk factors for ventricular dysfunction in the setting of SV in addition to probable differences in molecular adaptations to heart failure between children and adults, it is perhaps not surprising that extrapolated adult heart failure medications have had limited benefit in children with SV heart failure. Further investigations into the molecular mechanisms involved in pediatric SV heart failure may assist with risk stratification as well as development of targeted, efficacious therapies specific to this patient population. In this review, we present a brief overview of SV anatomy and physiology, with a focus on patients with a single morphological right ventricle requiring staged surgical palliation. Additionally, we discuss outcomes in the current era, risk factors associated with the progression to heart failure, present state of knowledge regarding molecular alterations in end-stage SV heart failure, and current therapeutic interventions. Potential avenues for improving SV outcomes, including identification of biomarkers of heart failure progression, implications of personalized medicine and stem cell-derived therapies, and applications of novel models of SV disease, are proposed as future directions.

Survival in patients with univentricular hearts: the impact of right versus left ventricular morphology

Objective

Patients with univentricular hearts (UVH) have high mortality despite modern treatment, and better methods to identify patients at highest risk are needed. We wanted to improve risk stratification in patients with UVH by focusing on the prognostic significance of single right versus single left ventricular morphology (SRV vs SLV).

Methods

All 395 patients with UVH operated at our centre were prospectively included from 1972 to 2016 (195 SRV, 166 SLV, 34 mixed or indeterminate ventricular morphology). Diagnoses, UVH morphology, types of all operations and time and causes of death or heart transplantation (HTX) were recorded. The primary endpoint was death or HTX.

Results

Among the 111 non-Fontan patients, 88 died (SRV 62 vs SLV 20; p<0.0001), 32 due to heart failure (SRV 23 vs SLV 5; p=0.0012). Twenty-five  years of cumulative SRV versus SLV survival among the 284 Fontan patients (41 deaths/HTX) was 66.9% vs 87.9% (p=0.0027), partly explained by more deaths/HTX due to heart failure among patients with SRV (p=0.0006). Survival in patients with SRV with and without hypoplastic left heart syndrome (HLHS) was similar. SRV versus SLV was a strong predictor of death/HTX in multivariable proportional hazards analyses (RR 3.3, 95% CI 1.6 to 6.6).

Conclusion

SRV versus SLV is a strong short-term and long-term predictor of survival among patients with UVH, mainly explained by higher rates of death/HTX due to heart failure in the SRV group. Our findings apply to patients with SRV both with and without HLHS.

Impact of left atrial compliance improvement on functional status after percutaneous mitral valvuloplasty

BACKGROUND

Conventional hemodynamic parameters may not accurately predict symptomatic improvement after percutaneous mitral valvuloplasty (PMV). Changes in left heart chamber compliance following adequate relief o0066 mitral stenosis (MS) may be useful in determining functional capacity after PMV. This study aims to determine the acute effects of PMV on compliance of the left heart and whether its changes relate to the patient's functional capacity.

METHODS

One-hundred thirty-seven patients with severe MS undergoing PMV were enrolled. Left atrial (C_a ) and left ventricular (C_v ) compliance were invasively estimated and net atrioventricular compliance (C_av ) was calculated before and immediately after the procedure. B-type natriuretic peptide (BNP) levels were obtained before and 24 hr after the procedure. The primary endpoint was functional status at 6-month follow-up, and the secondary endpoint was a composite of death, mitral valve (MV) replacement, repeat PMV, new onset of atrial fibrillation, or stroke in patients in whom PMV was successful.

RESULTS

The mean age was 43 ± 12 years, and 119 patients were female (87%). After PMV, C_a and C_av improved significantly from 5.3 [IQR 3.2-8.2] mL/mmHg to 8.7 [5.3-19.2] mL/mmHg (P < 0.001) and 2.2 [1.6-3.4] to 2.8 [2.1-4.1] mL/mmHg (P < 0.001), respectively, whereas C_v did not change (4.6 [3.2-6.8] to 4.4 [3.1-5.6]; P = 0.637). Plasma BNP levels significantly decreased after PMV, with no correlation between its variation and changes in left chamber compliance. At 6-month follow-up, NYHA functional class remained unchanged in 32 patients (23%). By multivariable analyses, changes in C_a immediately after PMV (adjusted OR 1.42; 95% CI 95% 1.02 to 1.97; P = 0.037) and younger age (adjusted OR 0.95; CI 95% 0.92-0.98; P = 0.004), predicted improvement in functional capacity at 6-month follow-up, independent of postprocedural data. The secondary endpoint were predicted by post-PMV mean gradient (adjusted HR 1.363; 95% CI 95% 1.027-1.809; P = 0.032), and lack of functional improvement at 6-month follow-up (adjusted HR 4.959; 95% 1.708-14.403; P = 0.003).

CONCLUSIONS

C_a and C_av increase significantly after PMV with no change in C_v . The improvement of C_a is an important predictor of functional status at 6-month follow up, independently of other hemodynamic data. Postprocedural mean gradient and lack of short-term symptomatic improvement were predictors of adverse outcome.

Left Ventricular Diastolic Myocardial Stiffness and End-Diastolic Myofibre Stress in Human Heart Failure Using Personalised Biomechanical Analysis

Understanding the aetiology of heart failure with preserved (HFpEF) and reduced (HFrEF) ejection fraction requires knowledge of biomechanical factors such as diastolic myocardial stiffness and stress. Cine CMR images and intra-ventricular pressure recordings were acquired in 8 HFrEF, 11 HFpEF and 5 control subjects. Diastolic myocardial stiffness was estimated using biomechanical models and found to be greater in HFrEF (6.4 ± 1.2 kPa) than HFpEF (2.7 ± 0.6 kPa, p < 0.05) and also greater than control (1.2 ± 0.4 kPa, p < 0.005). End-diastolic mid-ventricular myofibre stress derived from the personalised biomechanics model was higher in HFrEF (2.9 ± 0.3 kPa) than control (0.9 ± 0.3 kPa, p < 0.01). Chamber stiffness, measured from the slope of the diastolic pressure-volume relationship, is determined by the intrinsic tissue properties as well as the size and shape of the heart, and was unable to distinguish between any of the three groups (p > 0.05). Personalised biomechanical analysis may provide more specific information about myocardial mechanical behaviour than global chamber indices, which are confounded by variations in ventricular geometry.

Impact of percutaneous mitral valvuloplasty on left ventricular function in patients with mitral stenosis assessed by 3D echocardiography

BACKGROUND

The status of intrinsic left ventricular (LV) contractility in patients with isolated rheumatic mitral stenosis (MS) has been debated. The acute changes in loading conditions after percutaneous mitral valvuloplasty (PMV) may affect LV performance. We aimed to examine the acute effects of PMV on LV function and identify factors associated with LV ejection fraction (LVEF) changes, and determinants of long-term events following the procedure.

METHODS

One hundred and forty-two patients who underwent PMV for symptomatic rheumatic MS (valve area of 0.99±0.3cm²) were prospectively enrolled. LV volumes and LVEF were measured by three-dimensional (3D) echocardiography. Long-term outcome was a composite endpoint of death, mitral valve (MV) replacement, repeat PMV, new onset of atrial fibrillation, and stroke.

RESULTS

The mean age was 42.3±12.1years, and 125 patients were women (88%). After PMV, LVEF increased significantly (51.4 vs 56.5%, p<0.001), primary due to a significant increase in LV end-diastolic volume (65.8mL vs 67.9mL, p=0.002), and resultant increase in the stroke volume (33.9mL vs 39.6mL, p<0.001). Changes in cardiac index and systolic pulmonary artery pressure were associated with LVEF changes after PMV. During a mean follow-up period of 30.8months, 28 adverse clinical events were observed. Postprocedural mitral regurgitation, MV area, and mean gradient were independent predictors of composite endpoints.

CONCLUSIONS

In patients with rheumatic MS, PMV resulted in a significant improvement in LV end-diastolic volume, stroke volume and consequently increased in LVEF. Changes in cardiac index and systolic pulmonary artery pressure were associated with LVEF changes after PMV. The predictors of long-term adverse events following PMV were post-procedural variables, including mitral regurgitation, valve area, and mean gradient.

Myocardial deformation in fetuses with coarctation of the aorta: a case-control study

OBJECTIVE

To study myocardial deformation by speckle tracking echocardiography in fetuses with coarctation of the aorta (CoA) compared with gestational age-matched normal controls.

METHODS

This was a retrospective study of 12 fetuses with postnatally confirmed CoA and 12 gestational age-matched controls seen at a tertiary fetal cardiology unit between January 2013 and July 2014. Two-dimensional speckle tracking in standard grayscale four-chamber view of the fetal heart was performed to assess left and right myocardial deformation. Global longitudinal strain, strain rate and velocities, and regional longitudinal strain were analyzed and compared with controls.

RESULTS

Median gestational age at echocardiography was 25 + 4 weeks. Fetuses with CoA presented with a narrower, but not shorter, left ventricle when compared with controls (mitral valve diastolic diameter, 5.90 vs 8.50 mm; P = 0.002; left ventricular diastolic length, 16.50 vs 18.50 mm; P = 0.05). Global longitudinal systolic strain (P = 0.004), systolic strain rate (P = 0.01) and diastolic strain rate (P = 0.004) of the left ventricle were significantly lower in fetuses with CoA compared with controls. Similar findings were observed for longitudinal systolic (P = 0.03) and diastolic (P = 0.01) velocities of the left ventricle. Right ventricular parameters were not different between groups.

CONCLUSIONS

Fetuses with CoA have lower left ventricular longitudinal systolic strain, systolic strain rate and diastolic strain rate when compared with gestational age-matched control fetuses. These differences in deformation might explain, at least in part, the cardiac asymmetry observed in fetuses with CoA. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Assessment of Diastolic Function in Congenital Heart Disease

Diastolic function is an important component of left ventricular (LV) function which is often overlooked. It can cause symptoms of heart failure in patients even in the presence of normal systolic function. The parameters used to assess diastolic function often measure flow and are affected by the loading conditions of the heart. The interpretation of diastolic function in the context of congenital heart disease requires some understanding of the effects of the lesions themselves on these parameters. Individual congenital lesions will be discussed in this paper. Recently, load-independent techniques have led to more accurate measurements of ventricular compliance and remodeling in heart disease. The combination of inflow velocities and tissue Doppler measurements can be used to estimate diastolic function and LV filling pressures. This review focuses on diastolic function and assessment in congenital heart disease.

Use of strain and strain rate echocardiographic imaging to predict the progression of mitral stenosis: a 5-year follow-up study the progression of mitral stenosis: a 5-year follow-up study

Objective:

Little information is available about echocardiographic progression of mitral stenosis (MS). The aim of this study was to investigate whether the left ventricular (LV) strain is a favorable method predicting the progression of MS.

Methods:

Forty-eight patients with isolated mild-to-moderate MS were enrolled in this prospective cohort study. LV global longitudinal strain (GLS) and strain rate (GLSR) were measured by two-dimensional echocardiography (2-DE) at the baseline. Mitral valve area (MVA) was evaluated during the 5-year follow-up. The change in MVA from the beginning to the end of the surveillance period was determined as an indicator of progression. Pearson’s correlation test was used, and significant differences between the groups were analyzed using the Student’s t-test or the Mann–Whitney U test. At the end of follow-up, we evaluated the correlation between the change in MVA and both GLS-GLSR. GLS and GLSR are predictive factors for MS progression, whether or not it has been tested according to the receiver operating characteristics curve analysis.

Results:

A meaningful correlation was detected between the change in MVA with both GLS and GLSR (r=0.924 and r=0.980, respectively, p<0.001). The cut-off value for GLS was identified as –16.98 (sensitivity 81%, specificity 96%, p<0.001) and for GLSR as –1.45 (sensitivity 95%, specificity 100%, p<0.001). Patients with MS having a value under (mathematically above) these cut-off values showed more rapid progression.

Conclusion:

The progression of MS can be predicted by GLS and GLSR measurements, which are evaluated via strain echocardiography. (Anatol J Cardiol 2016; 16: 772-7)

The impact of arterial load on left ventricular performance: an invasive haemodynamic study in severe mitral stenosis

KEY POINTS

A hallmark of mitral stenosis (MS) is the markedly altered left ventricular (LV) loading. As most of the methods used to determine LV performance in MS patients are influenced by loading conditions, previous studies have shown conflicting results. The present study calculated LV elastance, which is a robust method to quantify LV function. We demonstrate that LV loading in MS patients is elevated but normalizes after valve repair and might be a result of reflex pathways. Additionally, we show that the LV in MS is less compliant than normal due to a combination of right ventricular loading and the valvular disease itself. Immediately after valve dilatation the increase in blood inflow into the LV results in even greater LV stiffness. Our findings enrich our understanding of heart function in MS patients and provide a simple reproducible way of assessing LV performance in MS.

ABSTRACT

Left ventricular (LV) function in rheumatic mitral stenosis (MS) remains an issue of controversy, due to load dependency of previously employed assessment methods. We investigated LV performance in MS employing relatively load-independent indices robust to the altered loading state. We studied 106 subjects (32 ± 8 years, 72% female) with severe MS (0.8 ± 0.2 cm(2) ) and 40 age-matched controls. MS subjects underwent simultaneous bi-ventricular catheterization and transthoracic echocardiography (TTE) before and immediately after percutaneous transvenous mitral commisurotomy (PTMC). Sphygmomanometric brachial artery pressures and TTE recordings were simultaneously acquired in controls. Single-beat LV elastance (Ees ) was employed for LV contractility measurements. Effective arterial elastance (Ea ) and LV diastolic stiffness were measured. MS patients demonstrated significantly elevated afterload (Ea : 3.0 ± 1.3 vs. 1.5 ± 0.3 mmHg ml(-1) ; P < 0.001) and LV contractility (Ees : 4.1 ± 1.6 vs. 2.4 ± 0.5 mmHg ml(-1) ; P < 0.001) as compared to controls, with higher Ea in subjects with smaller mitral valve area (≤ 0.8 cm(2) ) and pronounced subvalvular fusion. Stroke volume (49 ± 16 to 57 ± 17 ml; P < 0.001) and indexed LV end-diastolic volume (LVEDVindex : 57 ± 16 to 64 ± 16 ml m(-2) ; P < 0.001) increased following PTMC while Ees and Ea returned to more normal levels. Elevated LV stiffness was demonstrated at baseline and increased further following PTMC. Our findings provide evidence of elevated LV contractility, increased arterial load and increased diastolic stiffness in severe MS. Following PTMC, both LV contractility and afterload tend to normalize.

Severity of mitral stenosis and left ventricular mechanics: a speckle tracking study

BACKGROUND

It has been shown that mitral stenosis (MS) impairs left ventricular (LV) systolic function; however, this issue has not been studied comprehensively. We aimed to evaluate the role of 2D strain in the assessment of subclinical LV systolic dysfunction in patients with MS.

METHODS

Seventy-two patients with isolated MS (mild, moderate and severe) and 31 healthy control subjects constituted the study population. 2D echocardiography images were obtained from LV apical 4-chamber (4C), long axis (LAX), and 2-chamber (2C) views. Peak longitudinal strain and strain rate (Sr) were obtained from 4C, LAX, and 2C views. Global strain and Sr were calculated by averaging the three apical views.

RESULTS

There were no significant differences in LV ejection fraction and LV systolic or diastolic dimensions between the groups. Patients with MS had significantly lower LV longitudinal strain and Sr measurements than the control group. In addition, there were no significant differences in MS subgroups with respect to LV strain and Sr measurements.

CONCLUSION

We demonstrated that patients with MS had lower LV functions using 2D strain imaging, and this is independent of the hemodynamic severity of MS. In the detection of subclinical LV dysfunction in patients with MS, 2D strain imaging appears to be useful.

The Fontan circulation: who controls cardiac output?

In a Fontan circuit the mechanisms involved in control of cardiac output at rest and during exercise differ significantly from normal. The classical model presumes an unlimited preload which is not available in the Fontan circuit. This review critically analyses the role of contractility, heart rate, and afterload and highlights the importance of pulmonary vascular resistance (PVR) in determining adequate preload and, therefore, cardiac output in these patients. A conceptual model of the determinants of cardiac output in Fontan patients is presented.

Mitral stenosis

Mitral stenosis is a common disease that causes substantial morbidity worldwide. The disease is most prevalent in developing countries, but is increasingly being identified in an atypical form in developed countries. All treatments that increase valve area improve morbidity. Mortality improves with surgery; the benefit of percutaneous balloon valvuloplasty to mortality might be similar to that of surgery but needs further study. Percutaneous balloon valvuloplasty is the treatment of choice for patients in whom treatment is indicated, except for those with suboptimum valve morphology, and even these patients are sometimes treated with this procedure if surgery is not feasible or if surgical risk is prohibitive. We review the pathology, diagnosis, and treatment options for patients with mitral stenosis.

Fate of the unligated vertical vein after repair of supracardiac anomalous pulmonary venous connection

OBJECTIVE

To determine the fate of the unligated vertical vein after repair of isolated supracardiac total anomalous pulmonary venous connection (TAPVC).

METHODS

We reviewed the outcome of 28 patients who were diagnosed to have isolated supracardiac TAPVC and determined the fate of the unligated vertical vein.

RESULTS

Of the 28 patients, four died before surgery. The remaining 24 patients underwent surgical correction of TAPVC with (n = 5) or without (n = 19) ligation of vertical vein at a median age of 20 days (range: 1-574 days). There were no significant differences in age, weight, presence of pulmonary venous obstruction, need for preoperative inotropic and ventilatory support, cardiopulmonary bypass duration, postoperative pulmonary hypertensive crisis and requirement of peritoneal dialysis between patients with and those without vertical vein ligation. The in-hospital surgical mortality was 50% (12/24), with 83% (10/12) of deaths occurring before 1990. Patients who died after surgery were significantly younger (median age: 5.5 days vs 37 days, P = 0.005), lighter (3.3 +/- 0.5 kg vs 3.9 +/- 0.6 kg, P = 0.016), more likely to have pulmonary venous obstruction preoperatively (75% vs 12%, P = 0.039) and have undergone surgery before 1990 (83% vs 33%, P = 0.036). The 12 survivors were followed up for a median of 4.7 years (range: 2.3-18.1 years), 10 of whom had their vertical vein unligated. The vertical vein remained patent in five (50%) patients, while stenosis of pulmonary venous anastomosis was only present in one patient. Of these five patients, three had subsequently undergone surgical ligation of the vertical vein to eliminate a large left-to-right shunt.

CONCLUSIONS

Patency of the unligated vertical vein is common after the repair of supracardiac TAPVC, even in the absence of pulmonary venous obstruction. The degree of left-to-right shunt through the patent vertical vein may be so significant as to warrant surgical ligation.

Quantitative assessment of systolic and diastolic ventricular function with tissue Doppler imaging after Fontan type of operation

BACKGROUND

There is evidence that "inappropriate hypertrophy" of the single left ventricle, which occurs as a result of acute preload reduction, leads to adverse consequences on ventricular function. However, a systematic study of the capability of tissue Doppler imaging (TDI) to assess systolic and diastolic ventricular functions after the Fontan procedure is still missing.

METHODS

Twenty-four postoperative patients aged 12-33 years were prospectively evaluated with two-dimensional echocardiography equipped with TDI capabilities. Nineteen age-matched normal subjects were selected as controls. Good-quality echoes for the measurement of ejection fractions were available in 21 patients. Ten patients (group 1) had systolic dysfunction (ejection fraction < 50%), and 11 patients (group 2) had normal systolic function. Peak systolic and diastolic wall velocities were acquired from the two-chamber view in the myocardia and mitral annulus.

RESULTS

Compared with controls, the Fontan patients had a significantly reduced peak systolic velocity at wall and annulus sites. A linear correlation existed between ejection fraction and systolic myocardial velocity from the annular sites. Group 1 patients had lower wall velocities and lower annulus velocities both in systole and diastole. Group 2 patients had preserved systolic velocities but decreased regional and annular early diastolic velocities, suggesting impaired filling. Multiple correlation analysis showed a relation between peak early diastolic mitral velocity and ventricular ejection fraction, mean mitral annular motion at systole, mass/volume ratio, and the number of years post Fontan revision.

CONCLUSIONS

Myocardial velocities recorded after the Fontan operation give insight into systolic and diastolic ventricular functions. The peak systolic mitral annular velocity correlated well with the ventricular ejection fraction. The peak early diastolic velocity and the ratio between the early and late diastolic mitral annular velocity are reduced and reflect diastolic dysfunction even in the presence of normal systolic ejection fraction.

Effects of percutaneous mitral commissurotomy on longitudinal left ventricular dynamics in mitral stenosis: Quantitative assessment by tissue velocity imaging

OBJECTIVE

We hypothesized that mitral annular velocities would improve immediately after relief of mitral stenosis and that serial assessment could be used as an index for quantifying functional changes after percutaneous mitral commissurotomy (PMC).

METHODS

Longitudinal left ventricular annular velocities were quantified by spectral pulsed wave Doppler tissue velocity imaging in 25 patients (16 women; mean age [+/-SD], 29.2 +/- 8.6 years) who had isolated mitral stenosis and were in sinus rhythm, and were compared with 30 age- and sex-matched control subjects. Echocardiography was performed 1 to 24 hours before PMC and 48 to 72 hours after, and changes in velocities from the lateral and septal corners of the mitral annulus in early diastole, late diastole, isovolumic contraction, and ejection were recorded.

RESULTS

Systolic and diastolic mitral annular velocities were significantly less in patients with mitral stenosis than in control subjects. After PMC, peak annular velocity of systolic excursion in ejection and peak annular velocity in early diastole showed significant improvement. The change in peak annular velocity in early diastole in the lateral wall correlated well with improvement in the mitral valve orifice area by planimetry (ratio of mitral valve orifice area, 1.92 +/- 0.42; ratio of peak annular velocity in early diastole, 1.36 +/- 0.22; r = 0.65; P <.001).

CONCLUSION

Serial evaluation of changes in mitral annular velocities by Doppler tissue imaging aids clinical assessment of immediate improvement in left ventricular function after PMC.

Analysis of the myocardial velocities in patients with mitral stenosis

BACKGROUND

Pure mitral stenosis (MS) affects left-ventricular performance as a result of myocardial and functional factors. We planned this study to evaluate the effect of MS on right- and left-ventricular functions using Doppler tissue imaging (DTI).

METHODS

A total of 46 patients with an established diagnosis of MS (mean age: 41 +/- 11 years), and 40 age-matched healthy individuals (mean age: 40 +/- 9 years) were included in this study. Echocardiography equipped with DTI function was performed on each participant. The mitral valve area was measured. Myocardial velocities were recorded at 4 different sites (septum, lateral, anterior, and inferior) of the left ventricle, and the right-ventricular free wall annulus by DTI. The positive systolic velocity when the mitral and tricuspid ring moved toward the cardiac apex, and 2 negative diastolic velocities when the mitral annulus moved toward the base away from the apex (1 during the early phase of diastole and another in the late phase of diastole [A(m)]) were measured. The early diastolic velocity/A(m) ratio was calculated for each wall. The mean of systolic and diastolic myocardial velocities of the left ventricle was calculated. Patients with pure MS were compared with healthy participants, and the relationship of DTI variables with mitral valve area was evaluated.

RESULTS

The myocardial velocities of the left ventricle indicating left-ventricular function were found to be significantly lower in patients with pure MS. Right-ventricular annulus velocities, on the other hand, were similar in both groups. A significant positive correlation could be established between mitral valve area and mean positive systolic velocity, A(m) of the left ventricle, and right-ventricular A(m) (r = 0.50, P <.001; r = 0.48, P =.001; r = 0.45, P =.002, respectively), whereas a significant negative correlation (r = -0.42, P =.004) was established for right-ventricular early diastolic velocity/A(m) ratio.

CONCLUSION

This first study where pure MS was evaluated by DTI shows that MS affects left-ventricular performance on long axis. The results indicate that the decrease in left-ventricular performance is caused by both functional and myocardial factors.

Outcome following mitral valve replacement in patients with mitral stenosis and moderately reduced left ventricular ejection fraction

BACKGROUND

Some patients with mitral stenosis (MS) have moderately reduced left ventricular (LV) ejection fraction (EF), due to either depressed myocardial contractility or alterations in loading conditions. The effect of moderately reduced LV EF on outcome after mitral valve replacement (MVR) is not known.

METHODS

We studied 16 consecutive patients with LV EF < or = 0.50 and MS without significant mitral regurgitation or other valvular or coronary artery disease (Group I). We selected four controls with LV EF >0.50 for each patient, matched for time of surgery (Group II, n=64). Mean EF in Groups I and II was 0.45 and 0.66, respectively. We compared short- and long-term outcome between the two groups.

RESULTS

There were no perioperative deaths. Group I patients had a higher incidence of in-hospital postoperative heart failure (25% vs. 6%, P=0.02). Mean follow-up was 9 years in both groups. Mean New York Heart Association class improved from 2.4 to 1.7 in both groups. Group I patients had a higher incidence of heart failure deaths (13% vs. 2%, P=0.03) and admissions (40% vs. 13%, P=0.01). There were, however, no differences between Groups I and II in overall mortality (27% vs. 21%), rate of cardiac admissions (69% vs. 53%), or mean Specific Activity Scale Score (2.5 vs. 2.5).

CONCLUSIONS

Although patients with MS and moderately reduced LV EF are at higher risk for heart failure after MVR, overall mortality is not different from that of patients with normal EF. Moderate depression of LV EF should not be a contraindication to MVR for MS.

Acute effects of 17beta-estradiol on ventricular and vascular hemodynamics in postmenopausal women

Because premenopausal women have lower cardiovascular morbidity than postmenopausal women, it has been proposed that estrogen may have a protective role. Estrogen is involved in smooth muscle relaxation both through its specific receptor as well as through calcium channel blockade. This study examined the acute effect of estradiol on invasive cardiovascular hemodynamics in 18 postmenopausal women (age 62.6 +/- 7.6 years, means +/- SD). The effect of estradiol on left ventricular chamber performance was studied in 9 women using simultaneous left ventricular pressure-volume recordings. In a further group of 9 women, the acute effect of estradiol on arterial function was assessed using input impedance (derived from simultaneous aortic pressure and flow recordings), pressure waveform analysis, and pulse wave velocity. After 2 mg micronized 17beta-estradiol was administered, serum estradiol levels increased from 50.9 +/- 21.9 to 3,190 +/- 2,216 pmol/l, P < 0.0001. There was no effect of estradiol on either left ventricular inotropic or lusitropic function. There was no acute effect of estradiol on arterial impedance, reflection coefficient, augmentation index, or pulse wave velocity. There was a trend to decreased heart rate and cardiac output in both groups of 9 women. Because heart rate and cardiac output were common to both hemodynamic data sets, results for these parameters were pooled. Across all 18 women, there was a small but significant decrease in heart rate (69.2 +/- 10.4 vs. 67.2 +/- 9.9 beats/min, P = 0.02), as well as a significant decrease in cardiac output (4.82 +/- 1.77 vs. 4.17 +/- 1.56 l/min, P = 0.002). Despite achieving supraphysiological serum levels, this study found no significant effect of acute 17beta-estradiol on ventricular or large artery function.

Serial assessment of left ventricular diastolic function after Fontan procedure

OBJECTIVE

To assess longitudinal changes in systemic ventricular diastolic function late after the Fontan procedure.

DESIGN AND PATIENTS

Prospective study of 13 patients at 2.8 (2.0) years (early) and again at 11.4 (2.0) years (late) after the Fontan procedure by Doppler echocardiography with simultaneous ECG, phonocardiogram, and respirometer.

SETTING

Tertiary paediatric cardiac centre.

RESULTS

The isovolumic relaxation time (IVRT) was significantly longer, and E wave deceleration time, E and A wave velocities, and E:A velocity ratio were reduced compared to normal both early and late after the procedure. The mean (SD) z score of IVRT decreased significantly from +2.50 (1.00) to +1.24 (0.80) (p = 0.002), and the z score of the E wave deceleration time decreased from -1.69 (1.31) to -2.40 (1.47) (p = 0.03) during follow up. The A wave deceleration time also tended to decrease (early 80 (12) ms v late 73 (11) ms, p = 0.13) with increased follow up. There were no changes of the E and A wave velocities and E:A velocity ratio. The E wave velocity was inversely related to IVRT both early (r = -0.82, p = 0.001) and late (r = -0.59, p = 0.034) after the operation. The prevalence of diastolic flow during isovolumic relaxation decreased from 85% (11/13) to 38% (5/13) (p = 0.04), while that of mid diastolic flow increased from 23% (3/13) to 77% (10/13) (p = 0.02) between the two assessments.

CONCLUSIONS

Left ventricular diastolic function remains highly abnormal late after the Fontan procedure. The longitudinal changes demonstrated on follow up are compatible with reduction of left ventricular compliance in addition to persisting abnormalities of relaxation.

Distance between mitral anulus and papillary muscles: anatomic study in normal human hearts

BACKGROUND

Preservation of the annulo-papillary muscle continuity in mitral valve replacement is important. Even in patients who require excision of the mitral apparatus, the continuity can be restored. However, there is no guide to the proper length for the resuspension.

METHODS

In 57 normal cadaveric hearts, the distance from the tip of the papillary muscle to its corresponding mitral anulus was directly measured.

RESULTS

The distance from the tip of the anterolateral papillary muscle to the left trigone (10-o'clock position: D10) and to the point between the anterior and the middle scallops of the mural leaflet (8-o'clock position: D8) was 23.5 +/- 3.7 mm and 23.2 +/- 3.6 mm, respectively. The distance from the tip of the posteromedial papillary muscle to the right trigone (2-o'clock position: D2) and to the point between the middle and the posterior scallops of the mural leaflet (4-o'clock position: D4) was 23.5 +/- 4.0 mm and 23.5 +/- 3.9 mm, respectively. There was no statistically significant difference among the 4 distances (P =.96). Each distance was significantly longer than the corresponding chordae tendineae (D10 vs the anterior main chorda: 17.2 +/- 3.9 mm, D8 vs the anterior cleft chorda: 14.5 +/- 3.2 mm, D2 vs the posterior main chorda: 17.9 +/- 4.3 mm, and D4 vs the posterior cleft chorda: 14.9 +/- 3.2 mm, respectively; P =.0001). The mean distance had a significant correlation with the mitral annular diameter (r = 0.31, P =.019).

CONCLUSIONS

In normal hearts, the annulo-papillary muscle distances of the mitral apparatus are similar in 2-, 4-, 8-, and 10-o'clock positions and correlate with the mitral annular diameter.

Hemodynamic correlates of effective arterial elastance in mitral stenosis before and after balloon valvotomy

This study had the purpose of documenting the hemodynamic correlates of effective arterial elastance (Ea; i.e., an accurate estimate of hydraulic load) in mitral stenosis (MS) patients. The main hypothesis tested was that Ea relates to the total vascular resistance (R)-to-pulse interval duration (T) ratio (R/T) in MS patients both before and after successful balloon mitral valvotomy (BMV). High-fidelity aortic pressure recordings were obtained in 10 patients (40 +/- 12 yr) before and 15 min after BMV. Ea value was calculated as the ratio of the steady-state end-systolic aortic pressure (ESAP) to stroke volume (thermodilution). Ea increased after BMV (from 1.55 +/- 0.63 to 1.83 +/- 0.71 mmHg/ml; P < 0.05). Throughout the procedure, there was a strong linear relationship between Ea and R/T: Ea = 1.09R/T - 0.01 mmHg/ml, r = 0.99, P = 0.0001. This ultimately depended on the powerful link between ESAP and mean aortic pressure [MAP; r = 0.99, 95% confidence interval for the difference (MAP - ESAP) from -18.5 to +4.5 mmHg]. Ea was also related to total arterial compliance (area method) and to wave reflections (augmentation index), although to a lesser extent. After BMV, enhanced and anticipated wave reflections were observed, and this was likely to be explained by decreased arterial compliance. The present study indicated that Ea depended mainly on the steady component of hydraulic load (i.e., R) and on heart period (i.e., T) in MS patients.

Effect of inhaled nitric oxide on normal human left ventricular function

OBJECTIVES

This study determined the effects of inhaled nitric oxide (NO) on load-independent indexes of normal human left ventricular (LV) function.

BACKGROUND

Inhaled NO is a potent and selective pulmonary vasodilator. However, when it is used in patients with congestive heart failure, the decrease in pulmonary vascular resistance (PVR) is often associated with an increase in pulmonary capillary wedge pressure. NO has been shown to have a negative inotropic action, but it is not known whether it affects LV chamber function when delivered by inhalation.

METHODS

Eleven subjects (51 to 69 years old) with normal LV function (mean ejection fraction 72% [range 60% to 80%]) were studied. Four patients had concomitant coronary artery disease. Pressure-volume loop recordings were used to determine end-systolic and end-diastolic pressure-volume and preload recruitable stroke work relations. NO was delivered at 20 ppm for 10 min. In an additional group of patients with normal LV function, PVR (n = 5) and NO metabolites (n = 9) were measured.

RESULTS

There was no effect of inhaled NO on steady state LV pressures, volumes, contractility, contraction duration, active relaxation (time constant of relaxation, peak negative first derivative of left ventricular pressure), diastolic compliance or PVR. NO metabolites (methemoglobin and nitrate) were present in the LV cavity at the same concentration as right atrial venous blood, suggesting inactivation of free NO before arrival in the LV chamber. This study had a power of 0.995 to detect a 5% change in contractility (slope of preload recruitable stroke work relation) for alpha = 0.05, based on the multiple linear regression model used.

CONCLUSIONS

These results indicate that 20 ppm of inhaled NO does not have significant effects on normal LV function. This lack of effect may be due in part to rapid inactivation of free NO in transit to the heart.

Left ventricular filling and ejection fraction after successful percutaneous balloon mitral valvuloplasty

The effect of percutaneous balloon mitral valvuloplasty (PBMV) on left ventricular (LV) filling and ejection fraction (EF) still remains controversial. We evaluated LV filling and EF in 23 patients (19 women and four men, mean age 35.6+/-9.6, range 17-56 years) with mitral stenosis (MS) and sinus rhythm immediately before and after successful PBMV not complicated with significant mitral regurgitation and arrhythmia during left ventriculography. After PBMV mean mitral valve area increased from 1.4+/-0.2 to 2.2+/-0.3 cm2 (P<0.01), mean mitral valve gradient (MVG) decreased from 18.6+/-5.7 to 6.9+/-3.2 mmHg (P<0.01) and mean left atrial pressure (LAP) decreased from 26.0+/-8.2 to 12.3+/-5.2 mmHg (P<0.01). We did not determine any change in EF (before PBMV 61.8+/-9.3% and after PBMV 61.8+/-7.6% (P>0.05)). Heart rate did not change significantly before and after valvuloplasty (P>0.05). Despite the decrease in LAP and MVG, the early diastolic filling fraction of left ventricle did not change (before PBMV 59.5+/-7.5%, after PBMV 57.8+/-8.9% (P>0.05)). Also, we did not determine any increase in LV end diastolic volume index (before PBMV 89.9+/-27.7 cm3/m2 and after PBMV 84.6+/-20.9 cm3/m2 (P>0.05)). However, LV end diastolic pressure increased significantly after PBMV (from 6.6+/-3.0 to 11.3+/-4.9 mmHg (P<0.01)). We conclude that in patients with MS, LV diastolic performance is impaired and LV EF does not change acutely after PBMV.

Percutaneous transvenous mitral commissurotomy for rheumatic mitral stenosis with impaired left ventricular function: an echocardiographic follow-up study

Sixty consecutive patients of rheumatic mitral stenosis who underwent percutaneous transvenous mitral commissurotomy were evaluated and followed up for 3 months in order to study the effect of the procedure on left ventricular ejection fraction and to elucidate the pathophysiology of impaired left ventricular function. The response in 16 patients (26.7%) with left ventricular dysfunction (ejection fraction less than 50%) was compared to that in 44 patients with normal left ventricular ejection fraction. Patients with left ventricular dysfunction had relatively larger left ventricular end-diastolic (84 +/- 15 vs. 76 +/- 14 ml) and end-systolic (45 +/- 11.5 vs. 35 +/- 12 ml) volumes. Percutaneous transvenous mitral commissurotomy was successful in all patients. Mitral valve area increased in all patients, from 0.8 +/- 0.2 cm2 to 1.82 +/- 0.37 cm2. After commissurotomy there was a trend towards increase of the left ventricle end-diastolic volumes in both groups of patients. Left ventricular ejection fraction also marginally increased in both groups. A reduced left ventricular compliance due to thickened and fibrotic mitral valve apparatus and excessive afterload due to increased systemic vascular resistance because of low output are possible mechanisms for left ventricular dysfunction in patients with mitral stenosis.

Severely symptomatic mitral stenosis with a low gradient: a case for low-technology medicine

We have observed a group of patients with mitral valve disease and severe symptoms but also with low transmitral gradients and normal cardiac outputs who defy the traditional hemodynamic explanation of mitral stenosis. We performed a 10-year retrospective chart review of all mitral valve replacements at our institution to further characterize this population. The study group consisted of 16 of 132 patients (12%) with symptomatically severe (New York Heart Association [NYHA] class 3.3 +/- 0.5) mitral stenosis but a low (< 10 mm Hg) transmitral gradient, a normal cardiac output (4.8 +/- 1.2 L/min), and a preserved valve area (1.6 +/- 0.4 cm2). Sixteen patients were randomly chosen from the remaining group to serve as a comparison population. Study patients were noted to have less atrial fibrillation, lower wedge and mean pulmonary artery pressures, and a higher incidence of subvalvular disease identified at the time of surgery than did the comparison population. Left ventricular end-diastolic pressure and cardiac output did not differ. Study patients did well with surgery and reported an excellent functional benefit. We believe that this subgroup of patients with mitral valve disease is important, may be missed by using conventional criteria of valve area to determine timing of surgical intervention, and may have their symptoms primarily because of subvalvular disease. Further and perhaps most important, this group illustrates the ongoing need for careful clinical assessment skills and judgement in the face of ever-increasing technology.

Transesophageal echocardiographic evaluation of native valvular disease and repair

Surgery for valvular heart disease corrects systolic or diastolic dysfunction of the mitral, aortic, or tricuspid valves. The intraoperative echocardiographic assessment of the native heart valve is aimed at defining the pathology of valve disease, determining the mechanism of valve dysfunction, and quantitating the degree (grade) of valvular stenosis or insufficiency.

Acute changes in left ventricular function after percutaneous transluminal mitral valvuloplasty

Percutaneous balloon mitral valvuloplasty (PBMV) has been shown to induce an immediate increase in the left ventricular end-diastolic volume, which increase, in turn, has been attributed to an increase in left ventricular compliance. We studied 51 patients, 41 women and 10 men, who underwent PBMV, and were in sinus rhythm before and after the procedure. Heart rate did not vary significantly. There were increases in left ventricular end-diastolic volume (97.5 +/- 25.6 vs 112.7 +/- 25.7 ml/m2, P < 0.001), left ventricular end-diastolic pressure (8.7 +/- 3.0 vs 9.7 +/- 4.3 mmHg, P = 0.04), and both left ventricular systolic pressure and stress (118 +/- 20.5 vs 123 +/- 23.2 mmHg and 468 +/- 129 vs 580 +/- 164 mmHg; P = 0.04 and P < 0.001, respectively). The elastic stiffness constant did not vary (16.2 +/- 1.9 vs 15.7 +/- 1.9 (dimensionless units), P = 0.2). The increase in volume seemed to be particularly important when the ventricle appeared to be "shrunken" before PBMV. This increase was still present after a 1 year follow up. Thus, PBMV determines an increase in both end-diastolic volume and pressure, so that the left ventricle appears to move along a single pressure-volume curve. This enlargement evokes the Frank Starling mechanism, and improves systolic performance. Since it is still evident after a 1 year follow up, some concern may arise when a simultaneous volume overload is present, as in aortic insufficiency.