Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography

Current therapeutics and practical management strategies for pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) develops from an abnormal interaction between the endothelium and smooth muscle cells in the pulmonary vasculature and is characterized by a progressive rise in pulmonary vascular resistance resulting from vascular remodeling, vasoconstriction, and cellular proliferation. Currently, 3 classes of drugs are approved for the treatment of PAH based on results from small short-term clinical trials-prostacyclin analogues, endothelin receptor antagonists, and phosphodiesterase type 5 inhibitors. The pharmacologic management of PAH is rapidly evolving as newer therapeutic targets that stabilize or reverse pulmonary vascular disease and target right ventricular function are being sought and as clinical practice patterns shift in favor of earlier diagnosis and aggressive treatment. This manuscript will review the practical management aspects of currently approved PAH treatments and briefly discuss combination therapy and novel pharmacologic targets. In addition, the treatment of acute right ventricular failure and evidence (or lack thereof) for therapies in non-PAH pulmonary hypertension, such as pulmonary hypertension from left side of the heart disease, are addressed.

Favorable short-term outcome of transplanted hearts selected from marginal donors by pharmacological stress echocardiography

BACKGROUND

Because of the shortage of donor hearts, the criteria for acceptance have been considerably expanded. Abnormal results on pharmacologic stress echocardiography are associated with significant coronary artery disease and/or occult cardiomyopathy on verification by cardiac autopsy. The aim of this study was to establish the feasibility of an approach based on pharmacologic stress echocardiography as a gatekeeper for extended heart donor criteria.

METHODS

From April 2005 to April 2010, 39 "marginal" candidate donors (mean age, 56 ± 6 years; 21 men) were initially enrolled. After legal declaration of brain death, marginal donors underwent rest echocardiography, and if the results were normal, dipyridamole (0.84 mg/kg over 6 min, n = 25) or dobutamine (up to 40 μg/kg/min, n = 3) stress echocardiography.

RESULTS

A total of 19 eligible hearts were found with normal findings. Of these, three were not transplanted because of the lack of a matching recipient, and verification by cardiac autopsy showed absence of significant coronary artery disease or cardiomyopathy abnormalities. The remaining 16 eligible hearts were uneventfully transplanted in marginal emergency recipients. All showed normal (n = 14) or nearly normal (minor single-vessel disease in two) angiographic, intravascular ultrasound, hemodynamic and ventriculographic findings at 1 month. At follow-up (median, 14 months; interquartile range, 4-31 months), 14 patients survived and two had died, one at 2 months from general sepsis and one at 32 months from allograft vasculopathy in recurrent multiple myeloma.

CONCLUSIONS

Pharmacologic stress echocardiography can safely be performed in candidate heart donors with brain death and shows potential for extending donor criteria in heart transplantation.

Current and evolving echocardiographic techniques for the quantitative evaluation of cardiac mechanics: ASE/EAE consensus statement on methodology and indications endorsed by the Japanese Society of Echocardiography

Echocardiographic imaging is ideally suited for the evaluation of cardiac mechanics because of its intrinsically dynamic nature. Because for decades, echocardiography has been the only imaging modality that allows dynamic imaging of the heart, it is only natural that new, increasingly automated techniques for sophisticated analysis of cardiac mechanics have been driven by researchers and manufacturers of ultrasound imaging equipment. Several such techniques have emerged over the past decades to address the issue of reader's experience and inter-measurement variability in interpretation. Some were widely embraced by echocardiographers around the world and became part of the clinical routine, whereas others remained limited to research and exploration of new clinical applications. Two such techniques have dominated the research arena of echocardiography: (1) Doppler-based tissue velocity measurements, frequently referred to as tissue Doppler or myocardial Doppler, and (2) speckle tracking on the basis of displacement measurements. Both types of measurements lend themselves to the derivation of multiple parameters of myocardial function. The goal of this document is to focus on the currently available techniques that allow quantitative assessment of myocardial function via image-based analysis of local myocardial dynamics, including Doppler tissue imaging and speckle-tracking echocardiography, as well as integrated back- scatter analysis. This document describes the current and potential clinical applications of these techniques and their strengths and weaknesses, briefly surveys a selection of the relevant published literature while highlighting normal and abnormal findings in the context of different cardiovascular pathologies, and summarizes the unresolved issues, future research priorities, and recommended indications for clinical use.

A hemodynamic study of pulmonary hypertension in sickle cell disease

BACKGROUND

The prevalence and characteristics of pulmonary hypertension in adults with sickle cell disease have not been clearly established.

METHODS

In this prospective study, we evaluated 398 outpatients with sickle cell disease (mean age, 34 years) at referral centers in France. All patients underwent Doppler echocardiography, with measurement of tricuspid-valve regurgitant jet velocity. Right heart catheterization was performed in 96 patients in whom pulmonary hypertension was suspected on the basis of a tricuspid regurgitant jet velocity of at least 2.5 m per second. Pulmonary hypertension was defined as a mean pulmonary arterial pressure of at least 25 mm Hg.

RESULTS

The prevalence of a tricuspid regurgitant jet velocity of at least 2.5 m per second was 27%. In contrast, the prevalence of pulmonary hypertension as confirmed on catheterization was 6%. The positive predictive value of echocardiography for the detection of pulmonary hypertension was 25%. Among the 24 patients with confirmed pulmonary hypertension, the pulmonary-capillary wedge pressure was 15 mm Hg or less (indicating precapillary pulmonary hypertension) in 11 patients. Patients with confirmed pulmonary hypertension were older and had poorer functional capacity and higher levels of N-terminal pro-brain natriuretic peptide than other patients. In contrast, patients who had a tricuspid regurgitant jet velocity of at least 2.5 m per second without pulmonary hypertension and patients with a tricuspid regurgitant jet velocity of less than 2.5 m per second had similar clinical characteristics.

CONCLUSIONS

In this study of adults with sickle cell disease, the prevalence of pulmonary hypertension as confirmed on right heart catheterization was 6%. Echocardiographic evaluation alone had a low positive predictive value for pulmonary hypertension. (Funded by the French Ministry of Health and Assistance Publique-Hôpitaux de Paris; ClinicalTrials.gov number, NCT00434902.).

Range of right heart measurements in top-level athletes: the training impact

OBJECTIVES

To explore the full range of right heart dimensions and the impact of long-term intensive training in athletes.

BACKGROUND

Although echocardiography has been widely used to distinguish the athlete's heart from pathologic left ventricular (LV) hypertrophy, only few reports have described right ventricular (RV) and right atrial (RA) adaptations to extensive physical exercise.

METHODS

650 top-level athletes [395 endurance- (ATE) and 255 strength-trained (ATS); 410 males (63.1%); mean age 28.4 ± 10.1; 18-40 years] and 230 healthy age- and sex-comparable controls underwent a transthoracic echocardiographic exam. Along with left heart parameters, right heart measurements included: RV end-diastolic diameters at the basal and mid-cavity level; RV base-to-apex length; RV proximal and distal outflow tract diameters; RA long and short diameters; and RA area. Tricuspid annular plane systolic excursion and RV tissue Doppler systolic peak velocity were assessed as indexes of RV systolic function. Pulmonary artery systolic pressure (PASP) was estimated from the peak tricuspid regurgitant velocity.

RESULTS

ATS showed increased sum of wall thickness and relative wall thickness, whereas left atrial volume, LV end-diastolic volume, LV stroke volume and PASP were significantly higher in ATE. RV and RA measurements were all significantly greater in ATE than in ATS and controls. ATE also showed improved early diastolic RV function, whereas RV systolic indexes were comparable among groups. On multivariate analysis, type and duration of training (p<0.01), PASP (p<0.01) and LV stroke volume (p<0.001) were the only independent predictors of the main RV and RA dimensions in athletes.

CONCLUSIONS

This study delineates the upper limits of RV and RA dimensions in highly-trained athletes. Right heart measurements were all significantly greater in elite endurance-trained athletes than in age- and sex-matched strength athletes and controls. This should be considered as a "physiologic phenomenon" when evaluating athletes for sports eligibility.

Phase II trials in heart failure: the role of cardiovascular imaging

The development of new therapies for heart failure (HF), especially acute HF, has proven to be quite challenging; and therapies evaluated in HF have greatly outnumbered treatments that are eventually successful in obtaining regulatory approval. Thus, the development of therapies for HF remains a vexing problem for pharmaceutical and device companies, clinical trialists, and health care professionals. Nowhere is this more apparent than in the phase II HF clinical trial, in which the goal is to determine whether an investigational agent should move forward to a phase III trial. Recent advancements in noninvasive cardiovascular imaging have allowed a new era of comprehensive phenotyping of cardiac structure and function in phase II HF trials. Besides using imaging parameters to predict success of subsequent phase III outcome studies, it is essential to also use imaging in phase II HF trials in a way that increases understanding of drug or device mechanism. Determination of the patients who would benefit most from a particular drug or device could decrease heterogeneity of phase III trial participants and lead to more successful HF clinical trials. In this review, we outline advantages and disadvantages of imaging various aspects of cardiac structure and function that are potential targets for therapy in HF, compare and contrast imaging modalities, provide practical advice for the use of cardiovascular imaging in drug development, and conclude with some novel uses of cardiac imaging in phase II HF trials.

Combining tricuspid valve repair with double lung transplantation in patients with severe pulmonary hypertension, tricuspid regurgitation, and right ventricular dysfunction

BACKGROUND

Concomitant tricuspid valve repair (TVR) and double lung transplantation (DLTx) has been a surgical option at our institution since 2004 in an attempt to improve the outcome of DLTx for end-stage pulmonary hypertension, severe tricuspid regurgitation, and right ventricle (RV) dysfunction. This study is a review of that single institutional experience.

METHODS

Consecutive cases of concomitant TVR and DLTx performed between 2004 and 2009 (TVR group, n = 20) were retrospectively compared with cases of DLTx alone for severe pulmonary hypertension without TVR (non-TVR group, n = 58).

RESULTS

There was one in-hospital death in the TVR group. The 90-day and 1- and 3-year survival rates for the TVR group were 90%, 75%, and 65%, respectively, which were not significantly different from those for the non-TVR group. The TVR group required less inotropic support and less prolonged mechanical ventilation in the ICU. Follow-up echocardiography demonstrated immediate elimination of both volume and pressure overload in the RV and tricuspid regurgitation in the TVR group. Notably, there was a significantly lower incidence of primary graft dysfunction following transplantation in the TVR group (P < .05). Pulmonary functional improvement shown by an FEV(1) increase after 6 months was also significantly better in the TVR group (40% vs 20%, P < .05).

CONCLUSIONS

Combined TVR and DLTx procedures were successfully performed without an increase in morbidity or mortality and contributed to decreased primary graft dysfunction. In our experience, this combined operative approach achieves clinical outcomes equal or superior to the outcomes seen in DLTx patients without RV dysfunction and severe tricuspid regurgitation.

Current and evolving echocardiographic techniques for the quantitative evaluation of cardiac mechanics: ASE/EAE consensus statement on methodology and indications endorsed by the Japanese Society of Echocardiography

Echocardiographic imaging is ideally suited for the evaluation of cardiac mechanics because of its intrinsically dynamic nature. Because for decades, echocardiography has been the only imaging modality that allows dynamic imaging of the heart, it is only natural that new, increasingly automated techniques for sophisticated analysis of cardiac mechanics have been driven by researchers and manufacturers of ultrasound imaging equipment.Several such technique shave emerged over the past decades to address the issue of reader's experience and inter measurement variability in interpretation.Some were widely embraced by echocardiographers around the world and became part of the clinical routine,whereas others remained limited to research and exploration of new clinical applications.Two such techniques have dominated the research arena of echocardiography: (1) Doppler based tissue velocity measurements,frequently referred to as tissue Doppler or myocardial Doppler, and (2) speckle tracking on the basis of displacement measurements.Both types of measurements lend themselves to the derivation of multiple parameters of myocardial function. The goal of this document is to focus on the currently available techniques that allow quantitative assessment of myocardial function via image-based analysis of local myocardial dynamics, including Doppler tissue imaging and speckle-tracking echocardiography, as well as integrated backscatter analysis. This document describes the current and potential clinical applications of these techniques and their strengths and weaknesses,briefly surveys a selection of the relevant published literature while highlighting normal and abnormal findings in the context of different cardiovascular pathologies, and summarizes the unresolved issues, future research priorities, and recommended indications for clinical use.

Right atrial speckle tracking analysis as a novel noninvasive method for pulmonary hemodynamics assessment in patients with chronic systolic heart failure

BACKGROUND

The right atrium (RA) plays multiple roles in the cardiac cycle. The reservoir phase of the RA is a dynamic rather than a static phase of cardiac cycle and RA deformation is dependent on pulmonary pressures exerted on the right ventricle and, therefore, backwards on the RA. The purpose of this study was to assess the accuracy and the clinical applicability of the speckle tracking echocardiography (STE) evaluation of the RA in predicting the invasive systolic pulmonary artery pressure (SPAP) in patients with systolic heart failure (HF) undergoing right heart catheterization (RHC).

METHODS

Thirty-one hemodynamically stable, in-clinic HF patients who were undergoing RHC were included. Doppler echocardiography and RHC catheterization were simultaneously performed. Echocardiographic measures and STE where obtained as peak atrial longitudinal strain (PALS), RA strain rate, and time to peak longitudinal strain (TPLS). RA PALS was inversely correlated with invasively assessed SPAP (r =-0.81; P < 0.001) while RA strain directly correlated with SPAP (r = 0.82; P < 0.001). RA PALS and strain rate retained this correlation even after nitroprusside challenge test (r =-0.81; P < 0.001 and r = 0.91; P < 0.001, respectively). Area under the curve optimal cutoffs for predicting the SPAP > 50 mmHg were for RA PALS 10.3% (AUC:0.93, sensitivity: 100%, specificity: 78%).

CONCLUSION

RA STE showed a significant correlation with pulmonary pressure. RA assessment with STE can predict pulmonary artery hypertension in HF patients. This result is consistent with nitroprusside challenge test. Although RA STE is not routinely used, its evaluation may implement right heart evaluation in HF patients.

Preoperative Factors Associated With Adverse Outcome After Tricuspid Valve Replacement

Background—

Preoperative factors associated with increased mortality and worse outcome after tricuspid valve replacement in patients with severe tricuspid regurgitation are poorly understood.

Methods and Results—

We retrospectively analyzed 189 patients (37% men; age, 67.5±11.3 years) who underwent tricuspid valve replacement for severe tricuspid regurgitation. Operative mortality rate was 10%, and was associated with intra-aortic balloon pump (odds ratio, 3.2; 95% confidence interval, 1.9 to 5.6; P <0.0001) or the presence of severe symptoms (New York Heart Association class IV relative to classes II and/or III) at the time of surgery (1.7; 95% confidence interval, 1.05 to 2.8; P =0.02). At the end of follow-up (29.3±27.1 months), 70 patients (37%) died, 6 (3%) needed tricuspid reoperation, and 41 (21.7%) were readmitted for heart failure. Seventy-eight patients (41.3%) were free from cardiovascular events (death, tricuspid reoperation, or heart failure admissions). The only echocardiographic parameter independently associated with adverse outcomes was a decrease in the right index of myocardial performance ratio. All-cause mortality was independently associated with a higher Charlson index (hazard ratio, 1.18; 95% confidence interval, 1.01 to 1.36; P =0.03), shorter right index of myocardial performance ratio (0.91; 95% confidence interval, 0.87 to 0.96; P =0.005), and preoperative New York Heart Association IV class (1.71; 95% confidence interval, 1.3 to 2.2; P <0.0001). In 68 patients with isolated tricuspid valve replacement, the associations between short right index of myocardial performance ratio, high Charlson index, New York Heart Association class IV, and increased mortality remained significant.

Conclusions—

Tricuspid valve replacement for severe tricuspid regurgitation can be performed with an acceptable operative mortality if patients undergo surgery before the onset of advanced heart failure symptoms. Late mortality is associated with a high preoperative Charlson index, short right index of myocardial performance ratio, and advanced New York Heart Association class.

Predictive value of predischarge spectral tissue doppler echocardiography and n-terminal pro-B-type natriuretic peptide in patients hospitalized with acute heart failure

BACKGROUND

Admission for an acute heart failure (HF) confers an extremely poor prognosis. We aimed at finding out whether simultaneous assessment of multiple plasma-based biomarkers and Doppler echocardiography could provide complementary information and thus enable clinicians to stratify risk more effectively among patients hospitalized with acute HF; hence, untoward events after discharge avoided.

METHODS

A comprehensive echocardiographic study and measurements of cardiac troponin I (cTnI), N-terminal pro-B-type natriuretic protein (NT-proBNP), and high-sensitivity C-reactive protein (hsCRP) were conducted in 87 patients with symptomatic de novo acute HF or decompensation of chronic HF. Major adverse cardiac events (MACE) regarding cardiac death or hospitalization with worsening HF during a median follow-up period of 191 days were determined.

RESULTS

According to the univariate analysis, echocardiographic variables left atrial volume, left atrial volume index, pulmonary artery systolic pressure, E/E' ratio, and the concentrations of NT-proBNP were significantly related to clinical outcomes (all P-values < 0.05). Cox proportional hazard analysis identified two independent prognostic predictors of MACE: E/E' ratio and NT-proBNP. Moreover, the combining of plasma level of NT-proBNP with E/E' ratio provided independent and additional prognostic value in identifying high-risk acute HF patients.

CONCLUSIONS

These findings reinforce the necessity of combining the heart hemodynamic variable E/E' ratio and plasma-based neurohormonal biomarker NT-proBNP when clinicians attempt to define the individual risk of patients hospitalized with acute HF.

Emergency department diagnosis of atrial and ventricular septal defects, bicuspid aortic valve and pulmonary hypertension

Introduction

A 41-year-old Cuban man with Down syndrome and mental retardation was brought to the Emergency Department for episodes of worsening shortness of breath over one day. Bedside color Doppler ultrasound subcostal and apical four-chamber examination of the heart revealed atrial and ventricular septal defects with left-to-right shunting of blood. A right ventricular outflow tract view revealed a bicuspid aortic valve, and continuous wave Doppler ultrasound in the right ventricular inflow tract view revealed tricuspid regurgitation and pulmonary hypertension.

Conclusion

Bedside echocardiography with color Doppler and continuous wave Doppler imaging can assist the emergency physician and the critical care physician in the diagnosis of ASD, VSD, bicuspid aortic valve, and pulmonary hypertension in the Down syndrome patient who is short of breath.

Associations between cardiovascular parameters and uteroplacental Doppler (blood) flow patterns during pregnancy in women with congenital heart disease: Rationale and design of the Zwangerschap bij Aangeboren Hartafwijking (ZAHARA) II study

BACKGROUND

Previous research has shown that women with congenital heart disease (CHD) are more susceptible to cardiovascular, obstetric, and offspring events. The causative pathophysiologic mechanisms are incompletely understood. Inadequate uteroplacental circulation is an important denominator in adverse obstetric events and offspring outcome. The relation between cardiac function and uteroplacental perfusion has not been investigated in women with CHD. Moreover, the effects of physiologic changes on pregnancy-related events are unknown. In addition, long-term effects of pregnancy on cardiac function and exercise capacity are scarce.

METHODS

Zwangerschap bij Aangeboren Hartafwijking (ZAHARA) II, a prospective multicenter cohort study, investigates changes in and relations between cardiovascular parameters and uteroplacental Doppler flow patterns during pregnancy in women with CHD compared to matched healthy controls. The relation between cardiovascular parameters and uteroplacental Doppler flow patterns and the occurrence of cardiac, obstetric, and offspring events will be investigated. At 20 and 32 weeks of gestation, clinical, neurohumoral, and echocardiographic evaluation and fetal growth together with Doppler flow measurements in fetal and maternal circulation are performed. Maternal evaluation is repeated 1 year postpartum.

IMPLICATIONS

By identifying the factors responsible for pregnancy-related events in women with CHD, risk stratification can be refined, which may lead to better pre-pregnancy counseling and eventually improve treatment of these women.

Serum uric acid levels correlate with filling pressures in systolic heart failure

The authors studied the relationship between liver function tests and serum uric acid level with clinical and hemodynamic profiles in heart failure. Fifty patients (aged 44±15 years; 74.5% men) with an ejection fraction (EF) <35% were enrolled and clinical assessment was performed. Hemodynamic indices (including pulmonary arterial pressure [PAP], pulmonary capillary wedge pressure [PCWP], and cardiac index were studied by standard Edwards Lifesciences Swan-Ganz catheters, and liver function tests and serum uric acid level were measured simultaneously. Fifty age- and sex-matched controls with normal EF were also studied. A total of 73% of patients had ischemic cardiomyopathy. Mean uric acid level was 7.2±3.8 mg/dL and was significantly higher than in the control group (P value<.001). In multivariate analysis, uric acid correlated significantly with PAP (r=.5, P<.001) and PCWP (r=.4, P=.002) and was also associated with clinical signs of rales, edema, paroxysmal nocturnal dyspnea (r=.5, P=.01), and New York Heart Association class (r=.4, P=.005). Uric acid level was also correlated inversely with left ventricular EF (r=.27, P=.006). Elevated uric acid levels in patients with systolic heart failure is associated with impaired clinical and hemodynamic profile and might be used as a noninvasive indicator of elevated left ventricular filling pressures.

Liver diseases in heart failure

Heart failure (HF) is a growing public health concern as a consequence of the ageing of the population and the improved survival of patients with HF. HF is defined as impaired organ perfusion and/or high filling pressure. It is a systemic and chronic disease and as such involves many organs, not least the liver and kidney. The complex vascular system of the liver and its high metabolic activity render it vulnerable to circulation disturbances and trigger many molecular and haemodynamic changes in patients. There are many studies describing the impact of liver disease on patient outcomes. Hepatic dysfunction is commonly seen in HF patients and is closely correlated with a poor outcome. Knowledge about the mechanisms and impacts of liver disease in HF helps us to know the stage of the disease and treat it properly. Moreover, many drugs and toxins that are metabolised in the liver and contribute to drug interactions should also be taken into account when prescribing medication for HF patients. In light of the above-mentioned points, the authors have compiled this review on congestive hepatopathy with the aim of providing physicians and cardiologists with a succinct and useful guide on the role of the liver in HF.

Right ventricular ejection fraction and left ventricular dyssynchrony by 3D echo correlate with functional impairment in patients with dilated cardiomyopathy

BACKGROUND

The aim of the study was to detect if right ventricular (RV) ejection fraction assessed by real-time 3-dimensional echocardiography (RT3DE) could predict patients with dilated cardiomyopathy (DCM) with greater functional impairment in response to cardiopulmonary exercise.

METHODS AND RESULTS

Seventy chronic heart failure patients with DCM (55.5 ± 9.1 years; 48 males; 30 ischemic; New York Heart Association Class III: 48) underwent both left ventricular (LV) and RV analysis by RT3DE. Postprocessing software provided data of RT3DE systolic dyssynchrony index of 16 LV segments (systolic dyssynchrony index [SDI]) and of both LV and RV ejection fraction. Cardiac magnetic resonance was performed in a subgroup of 40 DCM patients to confirm RT3DE measurements. All the patients underwent also bicycle cardiopulmonary exercise test with evaluation of oxygen consumption (VO2) peak% (percentage of the predicted value), VE/VCO2 slope, and circulatory power (CP). Mean LV ejection fraction was 29.8 ± 4.6%. RT3DE LV SDI index was 8.4.4 ± 4.2, and RV ejection fraction was 51.3 ± 4.6%. By cardiopulmonary test, mean VO2 peak was 15.2 ± 4.4 mL·kg·min, and mean CP was 2.1 ± 0.8. By univariable analyses, significant correlations were detectable between SDI index and VO2 peak% (r = -0.56; P < .0001) and peak CP (r = -0.48; P < .0005). Also RV ejection fraction directly correlated with VO2 peak% (r = 0.58; P < .0001) and inversely with VE/VCO2 slope (r = -0.44; P < .001). By multivariable analysis, SDI index (β coefficient = -0.46; P < .001) and 3D RV ejection fraction (β coefficient = 0.42; P < .001) emerged as the only independent determinants of VO2 peak% during cardiopulmonary test.

CONCLUSIONS

Increased LV electromechanical dyssynchrony and impaired RV function in DCM patients are independently associated with worse ability to perform aerobic exercise.

Accuracy of Doppler-echocardiographic mean pulmonary artery pressure for diagnosis of pulmonary hypertension

Background

The validity of Doppler echocardiographic (DE) measurement of systolic pulmonary artery pressure (sPAP) has been questioned. Recent studies suggest that mean pulmonary artery pressure (mPAP) might reflect more accurately the invasive pressures.

Methodology/Principal Findings

241 patients were prospectively studied to evaluate the diagnostic accuracy of mPAP for the diagnosis of PH. Right heart catheterization (RHC) and DE were performed in 164 patients mainly for preoperative evaluation of heart valve dysfunction. The correlation between DE and RHC was better when mPAP (r = 0.93) and not sPAP (r = 0.81) was assessed. Bland-Altman analysis revealed a smaller variation of mPAP than sPAP. The following ROC analysis identified that a mPAP≥25.5 mmHg is useful for the diagnosis of PH. This value was validated in an independent cohort of patients (n = 50) with the suspicion of chronic-thromboembolic pulmonary hypertension. The calculated diagnostic accuracy was 98%, based on excellent sensitivity of 98% and specificity of 100%. The corresponding positive and negative predictive values were 100%, respectively 88%.

Conclusion

mPAP has been found to be highly accurate for the initial diagnosis of PH. A cut-off value of 25.5 mmHg might be helpful to avoid unnecessary RHC and select patients in whom RHC might be beneficial.

WEB downloadable software for training in cardiovascular hemodynamics in the (3-D) stress echo lab

When a physiological (exercise) stress echo is scheduled, interest focuses on wall motion segmental contraction abnormalities to diagnose ischemic response to stress, and on left ventricular ejection fraction to assess contractile reserve. Echocardiographic evaluation of volumes (plus standard assessment of heart rate and blood pressure) is ideally suited for the quantitative and accurate calculation of a set of parameters allowing a complete characterization of cardiovascular hemodynamics (including cardiac output and systemic vascular resistance), left ventricular elastance (mirroring left ventricular contractility, theoretically independent of preload and afterload changes heavily affecting the ejection fraction), arterial elastance, ventricular arterial coupling (a central determinant of net cardiovascular performance in normal and pathological conditions), and diastolic function (through the diastolic mean filling rate). All these parameters were previously inaccessible, inaccurate or labor-intensive and now become, at least in principle, available in the stress echocardiography laboratory since all of them need an accurate estimation of left ventricular volumes and stroke volume, easily derived from 3 D echo.

Aims of this paper are: 1) to propose a simple method to assess a set of parameters allowing a complete characterization of cardiovascular hemodynamics in the stress echo lab, from basic measurements to calculations 2) to propose a simple, web-based software program, to learn and training calculations as a phantom of the everyday activity in the busy stress echo lab 3) to show examples of software testing in a way that proves its value.

The informatics infrastructure is available on the web, linking to http://cctrainer.ifc.cnr.it

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.