Head-to-head comparison of indices of left ventricular contractile reserve assessed by high-dose dobutamine stress echocardiography in idiopathic dilated cardiomyopathy: five-year follow up

Noninvasive echocardiographic cardiac power output predicts mortality in cardiac intensive care unit patients

BACKGROUND

Low cardiac power output (CPO), measured invasively, can identify critically ill patients at increased risk of adverse outcomes, including mortality. We sought to determine whether non-invasive, echocardiographic CPO measurement was associated with mortality in cardiac intensive care unit (CICU) patients.

METHODS

Patients admitted to CICU between 2007 and 2018 with echocardiography performed within one day (before or after) admission and who had available data necessary for calculation of CPO were evaluated. Multivariable logistic regression determined the relationship between CPO and adjusted hospital mortality.

RESULTS

A total of 5,585 patients (age of 68.3 ± 14.8 years, 36.7% female) were evaluated with admission diagnoses including acute coronary syndrome (ACS) in 56.7%, heart failure (HF) in 50.1%, cardiac arrest (CA) in 12.2%, shock in 15.5%, and cardiogenic shock (CS) in 12.8%. The mean left ventricular ejection fraction (LVEF) was 47.3 ± 16.2%, and the mean CPO was 1.04 ± 0.37 W. There were 419 in-hospital deaths (7.5%). CPO was inversely associated with the risk of hospital mortality, an association that was consistent among patients with ACS, HF, and CS. On multivariable analysis, higher CPO was associated with reduced hospital mortality (OR 0.960 per 0.1 W, 95CI 0.0.926-0.996, P = .03). Hospital mortality was particularly high in patients with low CPO coupled with reduced LVEF, increased vasopressor requirements, or higher admission lactate.

CONCLUSIONS

Echocardiographic CPO was inversely associated with hospital mortality in unselected CICU patients, particularly among patients with increased lactate and vasopressor requirements. Routine calculation and reporting of CPO should be considered for echocardiograms performed in CICU patients.

Left ventricular contractile reserve as a determinant of adverse clinical outcomes: a systematic review

An abnormal left ventricular contractile reserve is often seen in patients undergoing stress echocardiogram and may indicate the presence of obstructive coronary artery disease. The techniques and indexes used to identify abnormal left ventricular contractile response and its prognostic value in the absence of known causes has not been well studied. To describe the characteristics and clinical outcomes associated with an abnormal left ventricular contractile response, we performed a systematic review that identified 27 eligible studies. A diverse range of indices were utilised to measure left ventricular contractile reserve, most commonly Δleft ventricular ejection fraction in 11 studies. Dobutamine stress echocardiogram was the most commonly performed modality (19 studies) followed by exercise stress echocardiogram (4 studies), dipyridamole stress echocardiogram (2 studies), invasive hemodynamic measurement (1 study) and dobutamine stress magnetic resonance imaging (1 study). All but one study demonstrated a significant association between the absence of left ventricular contractile reserve and increased rate of cardiovascular events, cardiac death and all-cause mortality.

Differentiation between athlete’s heart and dilated cardiomyopathy in athletic individuals

Objective

Distinguishing early dilated cardiomyopathy (DCM) from physiological left ventricular (LV) dilatation with LV ejection fraction <55% in athletes (grey zone) is challenging. We evaluated the role of a cascade of investigations to differentiate these two entities.

Methods

Thirty-five asymptomatic active males with DCM, 25 male athletes in the ‘grey zone’ and 24 male athletes with normal LV ejection fraction underwent N-terminal pro-brain natriuretic peptide (NT-proBNP) measurement, ECG and exercise echocardiography. Grey-zone athletes and patients with DCM underwent cardiovascular magnetic resonance (CMR) and Holter monitoring.

Results

Larger LV cavity dimensions and lower LV ejection fraction were the only differences between grey-zone and control athletes. None of the grey-zone athletes had abnormal NT-proBNP, increased ectopic burden/complex arrhythmias or pathological late gadolinium enhancement on CMR. These features were also absent in 71%, 71% and 50% of patients with DCM, respectively. 95% of grey-zone athletes and 60% of patients with DCM had normal ECG. During exercise echocardiography, 96% grey-zone athletes increased LV ejection fraction by >11% from baseline to peak exercise compared with 23% of patients with DCM (p<0.0001). Peak LV ejection fraction was >63% in 92% grey-zone athletes compared with 17% patients with DCM (p<0.0001). Failure to increase LV ejection fraction >11% from baseline to peak exercise or achieve a peak LV ejection fraction >63% had sensitivity of 77% and 83%, respectively, and specificity of 96% and 92%, respectively, for predicting DCM.

Conclusion

Comprehensive assessment using a cascade of routine investigations revealed that exercise stress echocardiography has the greatest discriminatory value in differentiating between grey-zone athletes and asymptomatic patients with DCM. Our findings require validation in larger studies.

Resting Cardiac Efficiency Affects Survival Following Transcatheter Aortic Valve Replacement

OBJECTIVE

Cardiac power to left ventricular mass (LVM) ratio, also termed cardiac efficiency (CE), reflects the rate of cardiac work delivered to the potential energy stored in LVM. We sought to assess the association between baseline resting CE and survival post transcatheter aortic valve replacement (TAVR).

METHODS

We retrospectively extracted data of patients who received TAVR in the Mayo Clinic Foundation with follow up data available at 1 year. Cardiac output was measured using Doppler echocardiography at baseline. CE was calculated using the formula, (cardiac output × mean arterial blood pressure)/(451 × LVM × 100) W/100 g. Survival score analysis was performed to identify cut off value for CE to identify the maximum difference in mortality in the study cohort. Patients were subsequently divided into 2 groups CE < 0.38 W/100 g and CE ≥ 0.38 W/100 g. Survival was determined using Kaplan-Meier method.

RESULTS

We included 954 patients in the final analysis. CE in group1 vs group 2 was 0.31 ± 0.05 W/100 g vs 0.59 ± 0.18 W/100 g. Patients in group1 were more likely to be male, had a higher prevalence of atrial fibrillation, prior myocardial infarction, mitral and tricuspid regurgitation. They also had a higher STS risk score, NYHA functional class, and lower aortic valve area. The remainder of the baseline characteristics was similar in both groups. A lower CE was associated with higher 1-year mortality following TAVR based on multivariate analysis. (Group1: 22.18% vs Group 2: 9.89%, p < .0001).

CONCLUSION

In our cohort, a low baseline CE (<0.38 W/100 g) conferred higher mortality risk following TAVR.

Contractile reserve and cardiopulmonary exercise parameters in patients with dilated cardiomyopathy, the two dimensions of exercise testing

BACKGROUND

Left ventricular (LV) contractile reserve assessed using imaging and cardiopulmonary exercise testing (CPX) has been shown to predict outcome in patients with dilated cardiomyopathy (DCM). Few clinical studies have, however, analyzed the relationship between them.

METHODS

A cohort of 75 ambulatory patients with DCM underwent stress treadmill echocardiography with CPX. LV contractile reserve was calculated as absolute change (ΔLVEF=LVEF_peak -LVEF_rest ) and percent change (%LVEF=[(LVEF_peak -LVEF_rest )/LVEF_peak) ]×100) in LVEF, circumferential and longitudinal strain (LS). Exercise capacity was measured as peak oxygen uptake (peak VO₂ ) and ventilatory efficiency as the slope of minute ventilation to CO₂ production (VE/VCO₂ slope). Values of contractile reserve were compared to matched controls. We also explored which metric of ventricular response (absolute or percent change) was less dependent on baseline LV function.

RESULTS

Patients with DCM had a mean age, rest and peak LVEF of 44±10 years, 42±10% and 50±12%, respectively. Among parameters of contractile reserve, peak cardiac output was the strongest parameter associated with peak VO₂ (r=.63, P<.001). Along with age, sex, and BMI, it explained more than 70% of the variance in peak VO₂ . In contrast, LVEF and LS were only weakly related to peak VO₂ . With regard to ventilatory efficiency, the strongest parameter that emerged was right atrial volume index (r=.36, P<.001). Percent change in LVEF was more independent of baseline function than absolute change.

CONCLUSION

Echocardiographic contractile reserve and CPX provide complementary information. Percent change in contractile reserve was most independent of baseline function, therefore may be preferred when analyzing the ventricular response to exercise.

Endomyocardial radial strain rate imaging during dobutamine stress echocardiography for the evaluation of contractile reserve in patients with dilated cardiomyopathy

PURPOSE

Myocardial contractile reserve is associated with clinical prognosis in patients with dilated cardiomyopathy (DCM). We assessed myocardial contractile reserve using tissue Doppler strain rate imaging with dobutamine stress echocardiography in DCM patients.

METHODS

Simultaneous echocardiography and left ventricular (LV) catheterization during dobutamine stress were performed in 20 patients with DCM, and echocardiography was performed in 31 control subjects. Dobutamine was infused at a starting dose of 5 μg/kg/min for 5 minutes and then at 10 μg/kg/min. Peak endomyocardial radial strain (ɛ) and systolic strain rate (SR_sys ) measured with echocardiography and the maximum first derivative of LV pressure (LV dP/dt_max ) derived from catheterization were used as indices of contractility. Their percentage change from baseline to the dose of 10 μg/kg/min was calculated.

RESULTS

The ɛ and SR_sys were significantly smaller in DCM patients than in controls. The LV dP/dt_max , ɛ, and SR_sys were significantly higher at the dose of 10 μg/kg/min than at baseline. The percentage change in SR_sys was significantly correlated with the percentage change in LV dP/dt_max .

CONCLUSIONS

Strain rate imaging during dobutamine stress in DCM might prove noninvasively informative for the evaluation of myocardial contractile reserve and provide insight into LV systolic dysfunction. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:555-560, 2016.

Prognostic importance of tissue velocity imaging during exercise echocardiography in patients with systolic heart failure

Resting echocardiography measurements are poor predictors of exercise capacity and symptoms in patients with heart failure (HF). Stress echocardiography may provide additional information and can be expressed using left ventricular ejection fraction (LVEF), or diastolic parameters (E/E'), but LVEF has some major limitations. Systolic annular velocity (S') provides a measure of longitudinal systolic function, which is relatively easy to obtain and shows a good relationship with exercise capacity. The objective of this study was to investigate the relationship among S', E/E' and LVEF obtained during stress echocardiography and both mortality and hospitalisation. A secondary objective was to compare S' measured using a simplified two-wall model. A total of 80 patients with stable HF underwent exercise stress echocardiography and simultaneous cardiopulmonary exercise testing. Volumetric and tissue velocity imaging (TVI) measurements were obtained, as was peak oxygen uptake (VO2 peak). Of the total number of patients, 11 died and 22 required cardiac hospitalisation. S' at peak exertion was a powerful predictor for death and hospitalisation. Cut-off points of 5.3 cm/s for death and 5.7 cm/s for hospitalisation provided optimum sensitivity and specificity. This study suggests that, in patients with systolic HF, S' at peak exertion calculated from the averaged spectral TVI systolic velocity of six myocardial segments, or using a simplified measure of two myocardial segments, is a powerful predictor of future events and stronger than LVEF, diastolic velocities at rest or exercise and VO2 peak. Results indicate that measuring S' during exercise echocardiography might play an important role in understanding the likelihood of adverse clinical outcomes in patients with HF.

Contractile reserve assessed by dobutamine test identifies super-responders to cardiac resynchronization therapy

INTRODUCTION

In this study, we sought to determine whether myocardial contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) can identify patients who experience nearly complete normalization of left ventricular (LV) function after the implantation of a cardiac resynchronization therapy (CRT) pacemaker.

MATERIAL AND METHODS

The study group consisted of 55 consecutive patients with non-ischemic dilated cardiomyopathy, LV ejection fraction (LVEF) < 35%, and prolonged QRS complex duration, who were scheduled for CRT pacemaker implantation. The DSE (20 µg/kg/min) was performed in all patients. The CR assessment was based on a change in the wall motion score index (ΔWMSI) and ΔLVEF during DSE. Super-response was defined as an increase in LVEF to > 50% and reduction in left ventricular end-systolic dimension to < 40 mm 12 months following the CRT implantation.

RESULTS

A total of 7 patients (12.7%) were identified as super-responders to CRT. When compared to non-super-responders, these patients had significantly higher values of the dobutamine-induced change in ΔWMSI (1.031 ±0.120 vs. 0.49 ±0.371, p < 0.01), and ΔEF (17.9 ±2.2 vs. 8.8 ±6.2, p < 0.01). Receiver operating characteristic analysis showed that dobutamine-induced changes in ΔWMSI ≥ 0.7 and ≥ 14% for ΔEF are the best discriminators for a super-response. Patients with ΔWMSI ≥ 0.7 and ΔEF ≥ 14% are significantly less often hospitalized (p < 0.01) for worsening of heart failure during 28.5 ±3.0 months of the follow-up.

CONCLUSIONS

Contractile reserve assessed by DSE can identify patients with dilated cardiomyopathy who are likely to experience near normalization of LV function following CRT.

Temporal changes in plasma brain natriuretic peptide levels during exercise stress-echocardiography in patients with dilated cardiomyopathy

The aim of this study was to evaluate temporal changes in brain natriuretic petide (BNP) levels during exercise stress-echocardiography in patients with dilated cardiomyopathy with respect to the left ventricular contractile reserve. We studied 55 consecutive patients with dilated cardiomyopathy (mean age, 55 ± 10 years, 49 (89.1%) male). All patients underwent exercise stress-echocardiography on a treadmill using the modified Bruce protocol. Contractile reserve was assessed by measuring changes in the wall motion score index (ΔWMSI) at rest and and at peak exercise. Levels of BNP were measured at rest, in the first minute, and after 20 minutes following termination of the stress test. Thirty-six patients had preserved left ventricular contractile reserve and 19 patients did not. Patients with preserved left ventricular contractile reserve showed a continuous rise in BNP levels from baseline to peak exercise and to 20 minutes following exertion (83.95 ± 108.51 versus 105.89 ± 116.00 versus 110.95 ± 119.70 ng/L, P < 0.001, respectively). On the other hand, patients without preserved left ventricular contractile reserve showed a decline in BNP levels at peak exercise as compared to baseline (335.49 ± 693.11 versus 320.08 ± 562.60 P = 0.031). ΔBNP was positively correlated with preserved contractile reserve (r = 0.46, P = 0.03) and lower NYHA class (r = -0.65, P = 0.001) in patients in whom baseline LVEF was lower than 20%. Multivariate analysis identified only WMSI at rest (beta -3.365, P = 0.008, 95 CI 0.03 to 0.411) as an independent predictor of left ventricular contractile reserve.The increase in BNP levels during exercise stress-echocardiography is associated with preserved left ventricular contractile reserve in patients with dilated cardiomyopathy.

Myocardial contractility in the stress echo lab: from pathophysiological toy to clinical tool

Up-regulation of Ca2+ entry through Ca2+ channels by high rates of beating is involved in the frequency-dependent regulation of contractility: this process is crucial in adaptation to exercise and stress and is universally known as force-frequency relation (FFR). Disturbances in calcium handling play a central role in the disturbed contractile function in myocardial failure. Measurements of twitch tension in isolated left-ventricular strips from explanted cardiomyopathic hearts compared with non-failing hearts show flat or biphasic FFR, while it is up-sloping in normal hearts. Starting in 2003 we introduced the FFR measurement in the stress echo lab using the end-systolic pressure (ESP)/End-systolic volume index (ESVi) ratio (the Suga index) at increasing heart rates. We studied a total of 2,031 patients reported in peer-reviewed journals: 483 during exercise, 34 with pacing, 850 with dobutamine and 664 during dipyridamole stress echo. We demonstrated the feasibility of FFR in the stress echo lab, the clinical usefulness of FFR for diagnosing latent contractile dysfunction in apparently normal hearts, and residual contractile reserve in dilated idiopathic and ischemic cardiomyopathy. In 400 patients with left ventricular dysfunction (ejection fraction 30 ± 9%) with negative stress echocardiography results, event-free survival was higher (p < 0.001) in patients with ΔESPVR (the difference between peak and rest end-systolic pressure-volume ratio, ESPVR) ≥ 0.4 mmHg/mL/m2. The prognostic stratification of patients was better with FFR, beyond the standard LV ejection fraction evaluation, also in the particular settings of severe mitral regurgitation or diabetics without stress-induced ischemia. In the particular setting of selection of heart transplant donors, the stress echo FFR was able to correctly select 34 marginal donor hearts efficiently transplanted in emergency recipients. Starting in 2007, we introduced an operator-independent cutaneous sensor to monitor the FFR: the force is quantified as the sensed pre-ejection myocardial vibration amplitude. We demonstrated that the sensor-derived force changes at increasing heart rates are highly related with both max dP/dt in animal models, and with the stress echo FFR in 220 humans, opening a new window for pervasive cardiac heart failure monitoring in telemedicine systems.

Assessment and Prognostic Relevance of Right Ventricular Contractile Reserve in Patients With Severe Pulmonary Hypertension

Background—

This study sought to analyze a new approach to assess exercise-induced pulmonary artery systolic pressure (PASP) increase by means of stress Doppler echocardiography as a possible measure of right ventricular contractile reserve in patients with severe pulmonary hypertension and right heart failure.

Methods and Results—

In this prospective study, patients with invasively diagnosed pulmonary arterial hypertension or inoperable chronic thromboembolic pulmonary hypertension and impaired right ventricular pump function despite a stable targeted pulmonary arterial hypertension medication underwent a broad panel of noninvasive assessments, including stress echocardiography and cardiopulmonary exercise testing. On the basis of the assumption that exercise-induced PASP is a measure of right ventricular contractile reserve, patients were classified into 2 groups according to an exercise-induced PASP increase above or below the median. Patients were followed up for 3.0±1.8 years. Univariate and multivariate analyses were used for factors predicting survival. Of 124 patients, 66 were below the median exercise-induced PASP increase of 30 mm Hg (low PASP), and 58 patients were above the median (high PASP). These groups were not significantly different in terms of medication and resting hemodynamics. Low PASP was associated with a significantly lower 6-minute walking distance, peak o 2 per kilogram, and 1-, 3-, and 4-year survival rates (92%, 69%, and 48%, respectively, versus 96%, 92%, and 89%). In the multivariate Cox model analysis adjusted for age and sex, PASP increase during exercise and peak o 2 per kilogram remained independent prognostic markers (hazard ratio, 2.56 for peak o 2 per kilogram and 2.84 for PASP increase).

Conclusions—

Exercise-induced PASP increase is of high clinical and prognostic relevance in pulmonary hypertension patients and may indicate right ventricular contractile reserve. Stress Doppler echocardiography may be a useful tool for prognostic assessment in pulmonary hypertension patients.

Feasibility of semi-quantitative assessment of left ventricular contractile reserve in dilated cardiomyopathy

BACKGROUND

We and others have shown previously that left ventricular (LV) contractile reserve assessed quantitatively by high-dose dobutamine stress-echocardiography (DSE) has prognostic implications in patients with dilated cardiomyopathy.

PURPOSE

To assess the feasibility of semi-quantitative assessment of LV contractile reserve by differently skilled operators in patients with dilated cardiomyopathy.

METHODS

High-dose DSE was performed in 63 consecutive patients, mean age 50 ± 10 years and ejection fraction (EF) 19 ± 8%. LVEF was calculated 1) using Simpson's biplane formula, and 2) semi-quantitatively (5% increments) by novice and experienced echocardiographers, and by a DSE expert. Patients were considered to have preserved LV contractile reserve if LVEF dobutamine-induced change was ≥5%.

RESULTS

Twenty-seven (45.8%) patients died during the 5-year follow-up. The feasibility of the assessment was 89%, 94%, and 98% for novice and experienced readers and DSE expert, respectively. Kaplan-Meier analysis showed that LV contractile reserve assessed semi-quantitatively by DSE expert and experienced reader achieved the best prognostic separation (log rank 19.63 and 18.99, respectively, p < 0.001 for both), followed by quantitative assessment (log rank 9.76, p = 0.0018) and assessment by novice reader (log rank 8.76, p = 0.012). Areas under the curves were similar for quantitative and semi-quantitative assessment of LV contractile reserve.

CONCLUSIONS

Our data indicate that semi-quantitative assessment of LV contractile reserve is feasible by differently skilled operators.

Assessment of cardiac dynamics during stress echocardiography by the peak power output-to-left ventricular mass ratio

Peak cardiac power-to-mass and peak mass-to-power are variables that couple cardiac power output with left ventricular (LV) mass at peak exercise or during maximal inotropic stimulation. Quantitative stress echocardiography enables the calculation of power output according to the formula: 133 × 10–6 × stroke volume per second (ml) × mean blood pressure (BP; mmHg) × heart rate. Power-to-mass may be calculated as LV power output per 100 g of LV mass: 100 g × LV power output divided by LV mass (W/100 g). Conversely, mass-to-power may be estimated by dividing LV mass index by LV power output (g/m2/W). With a little rearrangement of the formulas we can write: power-to-mass (W/100 g) = 0.222 × cardiac output (l/min) × mean BP (mmHg)/LV mass (g) and mass-to-power (g/m2/W) = LV mass index/0.00222 × cardiac output (l/min) × mean BP (mmHg). These parameters reflect the energy delivery of ventricular myocardium with respect to potential energy that is stored in LV mass. The assessment of peak power-to-mass and peak mass-to-power indices may be useful to distinguish compensatory versus maladaptive remodeling in patients with LV dysfunction. When the integrity of myocardial structure is compromised, a disproportion becomes apparent between maximal cardiac power output and LV mass and this leads to either a reduction of peak power-to-mass or an increase of peak mass-to-power. Preliminary reports have demonstrated the usefulness and the prognostic value of peak power-to-mass and peak mass-to-power in patients with LV systolic dysfunction and coronary artery disease.

Peak power output to left ventricular mass: an index to predict ventricular pumping performance and morbidity in advanced heart failure

BACKGROUND

Similar to power-to-weight ratio and weight-to-power ratio, which are measurements of the actual performance of any engine, the ratios of peak power output to left ventricular (LV) mass (peak power/mass) and of peak LV mass to power output (peak mass/power) are indices of LV performance potentially useful in heart failure (HF). This Doppler echocardiographic study was designed to evaluate peak power/mass and peak mass/power in patients with advanced HF compared with healthy subjects and to assess their prognostic value.

METHODS

Power output was measured at rest and at peak exercise in 75 subjects, 60 patients with advanced HF (LV ejection fraction ≤ 35%) and 15 controls. Peak LV power output (W) was calculated as the maximal product of (133 × 10⁻⁶) × stroke volume (mL) × mean arterial pressure (mm Hg) × heart rate (beats/min). LV mass was assessed using a standard M-mode echocardiographic method.

RESULTS

Peak power/mass was 1.84 ± 0.46 W/100 g and 0.76 ± 0.31 W/100 g, and peak mass/power was 32 ± 10 g/m²/W and 84 ± 38 g/m²/W in controls and in patients with HF, respectively (both P values < .0001). Peak power/mass was a powerful predictor of outcome on multivariate logistic regression analysis (hazard ratio, 0.907; P = .009). On receiver operating characteristic curve analysis, the areas under the curve for HF-related events were greater for peak power/mass (P = .002) and peak mass/power (P = .011) with respect to resting ejection fraction. Comparisons of Cox models showed that peak power/mass added prognostic value to a model that included age, New York Heart Association class, etiology, ejection fraction, and diastolic dysfunction (P < .0001).

CONCLUSION

Peak power/mass is useful to discriminate and risk stratify patients with advanced HF with additional power with respect to ejection fraction.

Usefulness of Tei index in patients with rheumatic mitral regurgitation and apparently normal left ventricular ejection fraction

BACKGROUND AND AIM

Rheumatic mitral regurgitation is rather common in developing countries. It usually progresses insidiously, because the heart compensates for increasing regurgitant volume by left-atrial enlargement, causes left-ventricular overload and dysfunction, and yields poor outcome when it becomes severe. Doppler-echocardiographic methods can be used to quantify the severity of mitral regurgitation. It is known that ejection fraction underestimates the presence of left ventricular dysfunction in these patients. This study aimed to study global cardiac function of these patients by using LV Tei index.

METHODS

One hundred patients with rheumatic mitral regurge predominantly were included (40 males and 60 females; aged 10-24 years, median 20.6 years). All participants were subjected to full echocardiographic study including total isovolumic index (Tei index = isovolumic relaxation time IRT + isovolumic contraction time ICT/ejection time ET) for the left ventricle. Special attention was paid to grading of severity of the mitral regurgitation.

RESULTS

LV ejection fraction was preserved in all cases but, however, the total left isovolumic index was prolonged 0.56 ± 3 in 64 of them (34 females and 30 males) denoting masked LV dysfunction P < .00001. There was a correlation of increasing severity of dysfunction with the degree of mitral regurgitation.

CONCLUSION

Ejection fraction underestimates the presence of left ventricular dysfunction in these patients. However, this was unmasked by the Tei index which could be an additive data for detecting early left ventricular dysfunction.

Right ventricular dysfunction and B-type natriuretic peptide in asymptomatic patients after repair for tetralogy of Fallot

Early detection of right ventricular (RV) dysfunction is essential in the assessment of patients with repaired tetralogy of Fallot (TOF). This study aimed to assess latent RV dysfunction in asymptomatic patients with TOF and to determine the predictive value of B-type natriuretic peptide (BNP). Pressure-volume loops were recorded for 16 young patients (New York Heart Association class 1 or Ross class 0; median age, 14.2 years) using the conductance catheter technique. All the patients had RV dilation secondary to pulmonary regurgitation after surgical repair of TOF. Indexes of RV function were derived at baseline level and during dobutamine infusion. Contractility was calculated by the slope of the end-systolic pressure-volume relation (ESPVR). An increase in ESPVR during dobutamine infusion was considered to indicate contractile reserve as a marker for latent RV dysfunction. The median ESPVR significantly increased from 0.32 mmHg/ml (0.13-0.72 mmHg/ml) at baseline to 0.57 mmHg/ml (0.24-1.55 mmHg/ml) during dobutamine infusion (p = 0.005). However, for five patients, no relevant increase in contractility was found, indicating impaired RV contractile reserve. There was only a weak inverse correlation between impaired contractile reserve and BNP (r = -0.28). Even asymptomatic patients with only a mildly enlarged right ventricle can have impaired RV function. Early RV dysfunction cannot be predicted accurately with BNP.

Usefulness of dobutamine-induced changes of the two-dimensional longitudinal deformation predict clinical and neurohumoral improvement in men after levosimendan treatment in acutely decompensated chronic heart failure

Levosimendan reduces symptoms and improves hemodynamics in patients with acutely decompensated chronic heart failure (ADCHF). The aim of this study was to investigate (1) the association of changes induced by low-dose dobutamine stress echocardiography in 2-dimensional strain parameters with the corresponding changes in the left ventricular (LV) ejection fraction (EF) and LV outflow tract velocity time integral (VTI) in patients with ADCHF and (2) whether LV contractile reserve assessed by conventional and speckle-tracking echocardiography is associated with clinical and neurohumoral improvement after levosimendan treatment. Twenty-eight consecutive patients with ADCHF (mean age 65 +/- 10 years, mean New York Heart Association class 3.6 +/- 0.3, mean EF 22 +/- 6%) were studied using dobutamine stress echocardiography before 24-hour infusion of levosimendan. The LV EF, VTI, and mean longitudinal, circumferential, and radial strain and strain rate using speckle-tracking imaging were measured. Twenty-one patients (75%) had evidence of contractile reserve (LV EF increase >10% and VTI increase >20% after peak dobutamine dose). Patients with versus without contractile reserve demonstrated greater improvements in New York Heart Association class (mean change -1.0 +/- 0.5 vs -0.5 +/- 0.3, p = 0.01) and reductions in B-type natriuretic peptide levels (-34 +/- 30% vs +4 +/- 31%, p <0.01) 48 hours after treatment. On multivariate analysis, mean longitudinal systolic strain rate reserve (peak longitudinal strain rate minus longitudinal strain rate at rest) was the best predictor of improvement in New York Heart Association class (p = 0.039) and B-type natriuretic peptide level (p = 0.042) after levosimendan among the reserve of LV fractional shortening, the EF, VTI, and longitudinal, circumferential, and radial strain and strain rate. In conclusion, dobutamine-induced changes in longitudinal systolic strain rate are associated with clinical and neurohumoral improvement after levosimendan treatment in patients with ADCHF.

Levosimendan allows detection of contractile reserve in patients with chronic ischaemic left ventricular dysfunction and non-diagnostic dobutamine echocardiography

BACKGROUND

Dobutamine echocardiography is commonly used to detect contractile reserve in ischaemic left ventricular (LV) systolic dysfunction, although its sensitivity and specificity are not optimal. We tested the hypothesis that echocardiography with levosimendan could identify contractile reserve in patients with a non-diagnostic dobutamine test.

METHODS

Twenty-two patients with LV ejection fraction <40% and non-diagnostic dobutamine echocardiography underwent levosimendan challenge (24 microg/kg in 10 min) prior to coronary angioplasty or surgery.

RESULTS

Contractile reserve was identified by levosimendan in 10 patients (Gr. A) but was not seen in 12 patients (Gr. B). With levosimendan, LV ejection fraction increased and wall motion score index decreased significantly in Gr. A, but only slightly in Gr. B. Similarly, mean mitral annular plane excursion and peak systolic mitral annular motion velocity increased significantly in Gr. A only. Six months after revascularisation, contractile reserve was seen in 8/10 Gr. A patients but in only 2/12 Gr. B patients (80% vs 17%, p=0.011). LV ejection fraction, wall motion score index, mean mitral annular plane excursion and peak systolic mitral annular motion velocity were significantly higher in Gr. A than in Gr. B.

CONCLUSION

Levosimendan echocardiography can identify contractile reserve in a sizeable proportion of patients with chronic ischaemic LV dysfunction and a non-diagnostic dobutamine test.