Relation of myocardial histomorphometric features and left ventricular contractile reserve assessed by high-dose dobutamine stress echocardiography in patients with idiopathic dilated cardiomyopathy

The additive prognostic value of end-systolic pressure-volume relation by stress CMR in patients with known or suspected coronary artery disease

PURPOSE

The difference between rest and peak stress end-systolic pressure-volume relation (ΔESPVR) is an afterload-independent index of left ventricular (LV) contractility. We assessed the independent prognostic value of ΔESPVR index by dipyridamole stress-cardiovascular magnetic resonance (CMR) in patients with known/suspected coronary artery disease (CAD).

METHODS

We considered 196 consecutive patients (62.74 ± 10.66 years, 49 females). Wall motion and perfusion abnormalities at rest and peak stress were analysed. Replacement myocardial fibrosis was detected by late gadolinium enhancement (LGE) technique. The ESPVR was evaluated at rest and peak stress from raw measurement of systolic arterial pressure and end-systolic volume by biplane Simpson's method.

RESULTS

A reduced ΔESPVR index (≤ 0.02 mmHg/mL/m2) was found in 88 (44.9%) patients and it was associated with a lower LV ejection fraction (EF) and with a higher frequency of abnormal stress CMR and myocardial fibrosis. During a mean follow-up of 53.17 ± 28.21 months, 50 (25.5%) cardiac events were recorded: 5 cardiac deaths, 17 revascularizations, one myocardial infarction, 23 hospitalisations for heart failure or unstable angina, and 4 ventricular arrhythmias. According to Cox regression analysis, diabetes, family history, LVEF, abnormal stress CMR, myocardial fibrosis, and reduced ΔESPVR were significant univariate prognosticators. In the multivariate analysis the independent predictors were ΔESPVR index ≤ 0.02 mmHg/mL/m2 (hazard ratio-HR = 2.58, P = 0.007), myocardial fibrosis (HR = 2.13, P = 0.036), and diabetes (HR = 2.33, P = 0.012).

CONCLUSION

ΔESPVR index by stress-CMR was independently associated with cardiac outcomes in patients with known/suspected CAD, in addition to replacement myocardial fibrosis and diabetes. Thus, the assessment of ΔESPVR index may be included into the standard stress-CMR exam to further stratify the patients.

LVAD as a Bridge to Remission from Advanced Heart Failure: Current Data and Opportunities for Improvement

Left ventricular assist devices (LVADs) are an established treatment modality for advanced heart failure (HF). It has been shown that through volume and pressure unloading they can lead to significant functional and structural cardiac improvement, allowing LVAD support withdrawal in a subset of patients. In the first part of this review, we discuss the historical background, current evidence on the incidence and assessment of LVAD-mediated cardiac recovery, and out-comes including quality of life after LVAD support withdrawal. In the second part, we discuss current and future opportunities to promote LVAD-mediated reverse remodeling and improve our pathophysiological understanding of HF and recovery for the benefit of the greater HF population.

Pressure-volume relationship by pharmacological stress cardiovascular magnetic resonance

The variation between rest and peak stress end-systolic pressure-volume relation (ΔESPVR) is an index of myocardial contractility, easily obtained during routine stress echocardiography and never tested during dipyridamole stress-cardiac magnetic resonance (CMR). We assessed the ΔESPVR index in patients with known/suspected coronary artery disease (CAD) who underwent dipyridamole stress-CMR. One-hundred consecutive patients (24 females, 63.76 ± 10.17 years) were considered. ESPVR index was evaluated at rest and stress from raw measurement of systolic arterial pressure and end-systolic volume by biplane Simpson's method. The ΔESPVR index showed a good inter-operator reproducibility. Mean ΔESPVR index was 0.48 ± 1.45 mmHg/mL/m2. ΔESPVR index was significantly lower in males than in females. ΔESPVR index was not correlated to rest left ventricular end-diastolic volume index or ejection fraction. Forty-six of 85 patients had myocardial fibrosis detected by the late gadolinium enhancement technique and they showed significantly lower ΔESPVR values. An abnormal stress CMR was found in 25 patients and they showed significantly lower ΔESPVR values. During a mean follow-up of 56.34 ± 30.04 months, 24 cardiovascular events occurred. At receiver-operating characteristic curve analysis, a ΔESPVR < 0.02 mmHg/mL/m2 predicted the presence of future cardiac events with a sensitivity of 0.79 and a specificity of 0.68. The noninvasive assessment of the ΔESPVR index during a dipyridamole stress-CMR exam is feasible and reproducible. The ΔESPVR index was independent from rest LV dimensions and function and can be used for a comparative assessment of patients with different diseases. ΔESPVR index by CMR can be a useful and simple marker for additional prognostic stratification.

Echo-derived peak cardiac power output-to-left ventricular mass with cardiopulmonary exercise testing predicts outcome in patients with heart failure and depressed systolic function

AIMS

Peak cardiac power output-to-mass (CPOM) represents a measure of the rate at which cardiac work is delivered respect to the potential energy stored in left ventricular (LV) mass. We studied the value of CPOM and cardiopulmonary exercise test (CPET) in risk stratification of patients with heart failure (HF).

MATERIALS AND RESULTS

We studied 159 patients with chronic HF (mean rest LV ejection fraction 30%) undergoing CPET and exercise stress echocardiography. CPOM was calculated as the product of a constant (K = 2.22 × 10-1) with cardiac output (CO) and the mean blood pressure (MBP), divided by LV mass (M), and expressed in the unit of W/100 g: CPOM = [K × CO (L/min) × MBP (mmHg)]/LVM(g). Patients were followed-up for the primary endpoint, including all-cause death, ventricular assist device implantation, and heart transplantation, and the secondary endpoint that comprised hospitalization for HF. In multivariate Cox regression analyses, peak CPOM was selected as the most powerful independent predictor of both primary and secondary endpoint [hazard ratio (HR) 0.004, 95% confidence interval (CI) 0.004-0.3; P = 0.002 and HR 0.09, 95% CI 0.02-0.55; P = 0.009]. Sixty-month survival free from the combined endpoint was 85% in those exhibiting oxygen consumption (VO2) > 14 mL/min/kg and peak CPOM > 0.6 W/100 g. Peak VO2 ≤ 14 mL/min/kg provided incremental prognostic value over demographic and clinical variables, brain natriuretic peptide, and resting echocardiographic parameters (χ2 from 58 to 64; P = 0.04), that was further increased by peak CPOM ≤ 0.6 W/100 g (χ2 77; P < 0.001).

CONCLUSION

Peak CPOM and peak VO2 showed independent and incremental prognostic values in patients with chronic HF.

Galectin-3 and fibulin-1 in systolic heart failure - relation to glucose metabolism and left ventricular contractile reserve

Background

Heart failure (HF) patients with diabetes (DM) have an adverse prognosis and reduced functional capacity, which could be associated with cardiac fibrosis, increased chamber stiffness and reduced left ventricular (LV) contractile reserve. Galectin-3 (Gal-3) and fibulin-1 are circulating biomarkers potentially reflecting cardiac fibrosis. We hypothesize that plasma levels of Gal-3 and fibulin-1 are elevated in HF patients with DM and are associated with reduced LV contractile reserve in these patients.

Methods

A total of 155 patients with HF with reduced ejection fraction underwent a low-dose dobutamine echocardiography and blood sampling for biomarker measurements. Patients were classified according to history of DM and an oral glucose tolerance test (OGTT) as: normal glucose tolerance (NGT) (n = 70), impaired glucose tolerance (IGT) (n = 25) and DM (n = 60).

Results

Galectin-3 levels were elevated in DM patients as compared to non-diabetic patients (P = 0.02), while higher fibulin-1 levels were observed in HF patients with IGF and DM (P = 0.07). Reduced LV contractile reserve was associated with increasing Gal-3 levels (β = −0.19, P = 0.03) although, this association was attenuated after adjustment for estimated glomerular filtration rate (P = 0.66). Fibulin-1 was not associated with LV contractile reserve (P = 0.71).

Conclusions

Galectin-3 and fibulin-1 levels were elevated in HF patients with impaired glucose metabolism. However, reduced LV contractile reserve among HF patients with DM does not to have an independent impact on plasma Gal-3 and fibulin-1 levels.

Pressure-volume Relationship in the Stress-echocardiography Laboratory: Does (Left Ventricular End-diastolic) Size Matter?

INTRODUCTION AND OBJECTIVES

The variation between rest and peak stress end-systolic pressure-volume relation is an afterload-independent index of left ventricular contractility. Whether and to what extent it depends on end-diastolic volume remains unclear. The aim of this study was to assess the dependence of the delta rest-stress end-systolic pressure-volume relation on end-diastolic volume in patients with negative stress echo and all ranges of resting left ventricular function.

METHODS

We analyzed interpretable data obtained in 891 patients (593 men, age 63 ± 12 years) with ejection fraction 47% ± 12%: 338 were normal or near-normal or hypertensive; 229 patients had coronary artery disease; and 324 patients had ischemic or nonischemic dilated cardiomyopathy. They were studied with exercise (n = 172), dipyridamole (n = 482) or dobutamine (n = 237) stress echocardiography. The end-systolic pressure-volume relation was evaluated at rest and peak stress from raw measurement of systolic arterial pressure by cuff sphygmomanometer and end-systolic volume by biplane Simpson rule 2-dimensional echocardiography.

RESULTS

Absolute values of delta rest-stress end-systolic pressure-volume relation were higher for exercise and dobutamine than for dipyridamole. In the overall population, an inverse relationship between end-systolic pressure-volume relation and end-diastolic volume was present at rest (r² = 0.69, P < .001) and peak stress (r² = 0.56, P < .001), but was absent if the delta rest-stress end-systolic pressure-volume relation was considered (r² = 0.13).

CONCLUSIONS

Left ventricular end-diastolic volume does not affect the rest-stress changes in end-systolic pressure-volume relation in either normal or abnormal left ventricles during physical or pharmacological stress.

Strain-time curve analysis by speckle tracking echocardiography in cardiac resynchronization therapy: Insight into the pathophysiology of responders vs. non-responders

Background

Patients with non-ischemic heart failure etiology and left bundle branch block (LBBB) show better response to cardiac resynchronization therapy (CRT). While these patients have the most pronounced left ventricular (LV) dyssynchrony, LV dyssynchrony assessment often fails to predict outcome. We hypothesized that patients with favorable outcome from CRT can be identified by a characteristic strain distribution pattern.

Methods

From 313 patients who underwent CRT between 2003 and 2006, we identified 10 patients who were CRT non-responders (no LV end-systolic volume [LVESV] reduction) with non-ischemic cardiomyopathy and LBBB and compared with randomly selected CRT responders (n = 10; LVESV reduction ≥15 %). Longitudinal strain (ε_long) data were obtained by speckle tracking echocardiography before and after (9 ± 5 months) CRT implantation and standardized segmental ε_long-time curves were obtained by averaging individual patients.

Results

In responders, ejection fraction (EF) increased from 25 ± 9 to 40 ± 11 % (p = 0.002), while in non-responders, EF was unchanged (20 ± 8 to 21 ± 5 %, p = 0.57). Global ε_long was significantly lower in non-responders at pre CRT (p = 0.02) and only improved in responders (p = 0.04) after CRT. Pre CRT septal ε_long -time curves in both groups showed early septal contraction with mid-systolic decrease, while lateral ε_long showed early stretch followed by vigorous mid to late contraction. Restoration of contraction synchrony was observed in both groups, though non-responder remained low amplitude of ε_long.

Conclusions

CRT non-responders with LBBB and non-ischemic etiology showed a similar improvement of ε_long pattern with responders after CRT implantation, while amplitude of ε_long remained unchanged. Lower ε_long in the non-responders may account for their poor response to CRT.

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.

End-systolic elastance and ventricular-arterial coupling reserve predict cardiac events in patients with negative stress echocardiography

Background. A maximal negative stress echo identifies a low-risk subset for coronary events. However, the potentially prognostically relevant information on cardiovascular hemodynamics for heart-failure-related events is unsettled. Aim of this study was to assess the prognostic value of stress-induced variation in cardiovascular hemodynamics in patients with negative stress echocardiography. Methods. We enrolled 891 patients (593 males mean age 63 ± 12, ejection fraction 48 ± 17%), with negative (exercise 172, dipyridamole 482, and dobutamine 237) stress echocardiography result. During stress we assessed left ventricular end-systolic elastance index (E_LVI), ventricular arterial coupling (VAC) indexed by the ratio of the E_LVI to arterial elastance index (E_aI), systemic vascular resistance (SVR), and pressure-volume area (PVA). Changes from rest to peak stress (reserve) were tested as predictors of main outcome measures: combined death and heart failure hospitalization. Results. During a median followup of 19 months (interquartile range 8–36), 50 deaths and 84 hospitalization occurred. Receiver-operating-characteristic curves identified as best predictors E_LVI reserve for exercise (AUC = 0.871) and dobutamine (AUC = 0.848) and VAC reserve (AUC = 0.696) for dipyridamole. Conclusions. Patients with negative stress echocardiography may experience an adverse outcome, which can be identified by assessment of E_LVI reserve and VAC reserve during stress echo.

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.

Abnormal glucose metabolism is associated with reduced left ventricular contractile reserve and exercise intolerance in patients with chronic heart failure

AIMS

To investigate the associations between glucose metabolism, left ventricular (LV) contractile reserve, and exercise capacity in patients with chronic systolic heart failure (HF).

METHODS AND RESULTS

From an outpatient HF clinic, 161 patients with systolic HF were included (mean age 70 ± 10 years, 69% male, 59% had ischaemic heart disease, mean LV ejection fraction (LVEF) 37 ± 9%). Thirty-four (21%) patients had known diabetes mellitus (DM). Oral glucose tolerance testing (OGTT) classified patients without a prior DM diagnosis as normal glucose tolerance (NGT), impaired glucose tolerance or new DM. All patients completed low-dose dobutamine echocardiography (LDDE) and 154 patients a 6-min walking distance test (6MWD). Compared with patients with NGT, patients with known DM had lower resting LVEF (33.4 vs. 39.1%, P < 0.05) and higher E/e' (13.9 vs. 11.4, P < 0.05). During LDDE, an increase in LVEF could be observed in all glycemic groups (mean 8.2% absolute increase), but the contractile reserve was lower in patients with known DM (-5.4%, P = 0.001) and new DM (-3.5%, P = 0.035) compared to patients with NGT. 6MWD was lower in known DM (349 m) and new DM (379 m) compared with NGT (467 m) (P < 0.001). Differences in clinical variables, resting echocardiographic parameters or contractile reserve, did not explain the exercise intolerance related to diabetes.

CONCLUSION

Diabetes, known or newly detected by OGTT, is independently associated with reduced LV contractile reserve and exercise intolerance in outpatients with systolic HF. These findings may offer one explanation for the excess mortality related to diabetes in HF.

The concept of ventricular reserve in heart failure and pulmonary hypertension: an old metric that brings us one step closer in our quest for prediction

PURPOSE OF REVIEW

Ventricular reserve is emerging a strong predictor of outcome in heart failure and cardiovascular disease. Ventricular reserve is the term used to describe the extent of increase or change in ventricular function that occurs during exercise or pharmacological stress (typically with dobutamine).

RECENT FINDINGS

The interest in ventricular reserve lies in its ability to assess viability in coronary artery disease, to predict clinical outcome and response to therapy in patients with heart failure and to screen patients for early cardiovascular disease.

SUMMARY

In this paper, we will review the emerging role of ventricular reserve in heart failure and pulmonary hypertension. We will also explore the mechanisms involved in the pathophysiology of impaired ventricular reserve and discuss future directions of research in the field.

Clinical and prognostic role of pressure-volume relationship in the identification of responders to cardiac resynchronization therapy

BACKGROUND

The identification of responders remains challenging in cardiac resynchronization therapy (CRT). Pressure-volume relationship (PVR) is a method to evaluate left ventricular myocardial contractility during stress. The aim of the study was to assess the role of PVR to identify responders to CRT.

METHODS

Seventy-two patients (57% with ischemic etiology) referred to CRT: ejection fraction ≤ 35%, New York Heart Association ≥ III and QRS duration ≥ 120 milliseconds, underwent dobutamine stress echocardiography (up to 40 μg/kg per minute). PVR was defined as systolic cuff pressure/end-systolic volume index difference between rest-peak dobutamine stress echocardiography. Responders were identified by clinical and/or echocardiographic (end-systolic volume decrease ≥ 15%) follow-up criteria. We divided retrospectively the patient population into 2 groups, accordingly to the presence of myocardial contractile reserve that was set at the value of PVR (0.72 mm Hg/mL per square meter) obtained by a receiver operating characteristic analysis.

RESULTS

During a median follow-up of 12 months, 8 patients (11%) died. Patients with lower PVR, showed higher brain natriuretic peptide levels (853 ± 1211 vs 342 ± 239, P = .044) larger left ventricular end-diastolic (196 ± 82 mL vs 152 ± 39 mL, P = .005) and end-systolic (147 ± 66 vs 112 ± 30 mL, P = .006) volumes. Intraventricular dyssynchrony was similar in the 2 groups (88 ± 45 vs 70 ± 32 milliseconds, P = .175). Patients with higher PVR presented a larger incidence of clinical (86% vs 46% P < .001), and echocardiographic responders to CRT (79% vs 40%, P = .002). Event-free survival was significantly better in patients with higher PVR (log rank = 5.78, P = .01).

CONCLUSION

Patients with preserved contractility, assessed by PVR during stress echocardiography show a favor clinical outcome and left ventricular reverse remodeling after CRT. In particular, PVR may have a significant clinical role in patients undergoing CRT, providing critical information for risk stratification.

Identification of responders to cardiac resynchronization therapy by contractile reserve during stress echocardiography

AIMS

The identification of responders to cardiac resynchronization therapy (CRT) remains a challenge. We assessed the role of dyssynchrony (DYS) and contractile reserve (CR) in identifying CRT responders.

METHODS AND RESULTS

Sixty-nine patients (55% with ischaemic aetiology) referred for CRT (ejection fraction < or =35%, New York Heart Association > or =III, and QRS duration > or =120 ms) underwent baseline evaluation of DYS and dobutamine stress-echo [up to 40 microg/kg/min: CR was defined as a wall motion score index (WMSI) variation > or =0.20]. CRT responders were identified by clinical and/or echocardiographic [end-systolic volume (ESV) decrease > or =15%] follow-up criteria. During a median follow-up of 11 months, 46 patients (66%) were classified as clinical responders. Reverse remodelling was found in 34 of the 59 patients (58%) with echocardiographic follow-up. CR was present in 78% of clinical responders (P = 0.001) and in 69% with reverse remodelling (P = 0.005). DYS was equally present in the two groups. Reverse remodelling was correlated with rest-stress changes in ESV (r = 0.439, P = 0.003) and in WMSI (r = 0.450, P = 0.001), but not with DYS. CR (OR = 6.2, 95% CI = 1.4-27.6, P = 0.015) was the best predictor of response to CRT.

CONCLUSION

Patients with CR show a favourable clinical and reverse LV remodelling response to CRT. This finding shifts the focus from electrical (dyssynchrony) to the myocardial substrate of functional response.

Coronary flow reserve in idiopathic dilated cardiomyopathy: relation with left ventricular wall stress, natriuretic peptides, and endothelial dysfunction

Studies have demonstrated impaired coronary blood flow reserve (CBFR) in idiopathic dilated cardiomyopathy (IDCM). It was the aim of this study to examine the potential underlying mechanisms for CBFR reduction in patients with IDCM by Doppler ultrasound techniques. Forty-eight clinically stable patients with heart failure caused by IDCM (New York Heart Association classes 1-3) were evaluated by echocardiographic and Doppler techniques with the assessments of CBFR and brachial artery flow-mediated dilation (FMD). CBFR was estimated as the hyperemic (dipyridamole: 0.84 mg/kg in 10 minutes, intravenously) to resting coronary diastolic peak velocities ratio. N-terminal pro-brain natriuretic peptide (Nt-pro-BNP) plasma levels were measured at the time of the index echocardiogram. Left ventricular (LV) ejection fraction was 30% +/- 8%, and wall motion score index was 2.0 +/- 0.25. The best correlation with CBFR was found with LV wall thickness-to-cavity radius (r = 0.77, P < .0001). A strong correlation of log-transformed Nt-pro-BNP levels was observed with CBFR (r = -0.64; P < .0001). No significant correlation was documented between CBFR and FMD. The stepwise regression model showed that LV wall thickness-to-cavity radius was the strongest independent predictor of CBFR followed by New York Heart Association class and log-transformed Nt-pro-BNP leading to a cumulative R value of 0.82 (P < .0001). The results of the study indicate that by measuring variables related to LV end-diastolic wall stress, such as LV wall thickness-to-cavity radius and plasma Nt-proBNP, it is possible to have information about CBFR in patients with heart failure secondary to IDCM.

Role of echocardiography in diagnosis and risk stratification in heart failure with left ventricular systolic dysfunction

Heart failure (HF) is a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood. Echocardiography represents the "gold standard" in the assessment of LV systolic dysfunction and in the recognition of systolic heart failure, since dilatation of the LV results in alteration of intracardiac geometry and hemodynamics leading to increased morbidity and mortality. The functional mitral regurgitation is a consequence of adverse LV remodelling that occurs with a structurally normal valve and it is a marker of adverse prognosis. Diastolic dysfunction plays a major role in signs and symptoms of HF and in the risk stratification, and provides prognostic information independently in HF patients and impaired systolic function. Ultrasound lung comets are a simple echographic sign of extravascular lung water, more frequently associated with left ventricular diastolic and/or systolic dysfunction, which can integrate the clinical and pathophysiological information provided by conventional echocardiography and provide a useful information for prognostic stratification of HF patients. Contractile reserve is defined as the difference between values of an index of left ventricular contractility during peak stress and its baseline values and the presence of myocardial viability predicts a favorable outcome. A non-invasive echocardiographic method for the evaluation of force-frequency relationship has been proposed to assess the changes in contractility during stress echo. In conclusion, in HF patients, the evaluation of systolic, diastolic function and myocardial contractile reserve plays a fundamental role in the risk stratification. The highest risk is present in HF patients with a heart that is weak, big, noisy, stiff and wet.

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

OBJECTIVE

To compare head to head the indices of left ventricular contractile reserve assessed by high-dose dobutamine in the five-year prognosis of patients with idiopathic dilated cardiomyopathy.

DESIGN AND SETTING

Prospective study in a tertiary care centre.

PATIENTS

63 consecutive patients with idiopathic dilated cardiomyopathy.

INTERVENTIONS

High-dose dobutamine stress echocardiography was performed in progressive stages lasting 5 min each. Wall motion score index, ejection fraction, cardiac power output and end systolic pressure to volume ratio were evaluated as indices of left ventricular contractility.

MAIN OUTCOME MEASURE

Five-year cardiac mortality.

RESULTS

During the follow up of 59 patients, 27 (45.8%) died of cardiac causes. According to Kaplan-Meier and receiver operating characteristic analyses all indices of contractile reserve differentiated patients with respect to cardiac death. Wall motion score index achieved the best separation (log rank 21.75, p < 0.0001, area under the curve 0.84), followed by change in ejection fraction (log rank 11.25, p = 0.0008, area under the curve 0.79), end systolic pressure to volume ratio (log rank 14.32, p = 0.0002, area under the curve 0.75) and cardiac power output (log rank 9.84, p = 0.0017, area under the curve 0.71). Cox's regression model identified wall motion score index as the only independent predictor of cardiac death.

CONCLUSIONS

These data show that all examined indices of left ventricular contractile reserve are predictive of five-year prognosis, but change in wall motion score index may have the greatest prognostic potential.

Stress-echocardiography in idiopathic dilated cardiomyopathy: instructions for use

A number of studies have suggested that stress-echocardiography may be used for prognostic stratification in patients with idiopathic dilated cardiomyopathy. There is no consensus on which protocol or which measurements of left ventricular contractile reserve to use. The most frequently used protocol is low-dose dobutamine stress-echocardiography, and most commonly used measures of left ventricular systolic performance are ejection fraction, wall motion score index and cardiac power output.Stress-echocardiography has been shown to predict improvement in cardiac function in patients with recently diagnosed dilated cardiomyopathy, as well as to predict which patients will benefit from the treatment with beta-blockers. Most importantly, stress-echocardiography can identify patients with worse prognosis in terms of cardiac death and need for transplantation. Additionally, contractile reserve is closely correlated with maximal oxygen consumption and can even be used for further stratification in patients with maximal oxygen consumption between 10 and 14 ml/kg/min. Future studies are needed for head-to-head comparison of various protocols in an attempt to make standardization in the assessment of patients with dilated cardiomyopathy.