The spectrum of functional responses during ABCDE stress echocardiography

Background

The new methodological standard in stress echo (SE) is the comprehensive approach with ABCDE protocol: step A for regional wall motion abnormalities (RWMA); step B for B-lines by lung ultrasound; step C for left ventricular contractile reserve (LVCR); step D for Doppler-based coronary flow velocity reserve (CFVR) in left anterior descending coronary artery; and step E for imaging-independent EKG-based heart rate reserve (HRR).

Purpose

To assess the feasibility of ABCDE-SE in a prospective, large scale, multicenter, international, effectiveness study.

Methods

From September 2016 to December 2019, we enrolled 4,585 all-comers patients (age 63±11 years, 2,566 males, 56%; ejection fraction 61±9%) with known or suspected chronic coronary artery disease referred to clinically-driven SE with exercise (n=1,774, 38.7%), dipyridamole (n=2,403, 52.4%), dobutamine (n=375, 8.2%) or adenosine (n=33, 0.7%). Recruitment involved 13-certified laboratories of 7 countries. All patients underwent ABCDE-SE. The same transducer was used for cardiac and lung scan. Criteria for abnormal response were: stress-induced changes in RWMA in 2 contiguous segments for step A; stress-rest increase in B-lines ≥2 for step B (4-site simplified scan, each site scored from 0= A-lines or black lung to 10= white lung for coalescing B-lines); LVCR ≤2.0 for exercise and dobutamine (≤1.1 for vasodilators) for step C; CFVR in LAD ≤2.0 for step D; HRR (peak/rest heart rate) ≤1.80 for exercise and dobutamine (≤1.22 for vasodilators) for step E.

Results

Success rate was 98%, 100%, 99%, 86% and 100% for A, B, C, D and E steps, respectively. The positivity rate was 19% for A, 27% for B, 35% for C, 27% for D and 37% for E. All 5 parameters were normal in 1,496 patients (32.6%), all 5 were abnormal in 183 patients (4.0%). Most patients had abnormal response of 1 (n=1,356, 29.6%), 2 (n=788, 17.2%), 3 (n=477, 9.7%) or 4 (n=315, 6.9%) criteria (see Figure).

Conclusions

ABCDE-SE is extremely feasible, user-friendly, with minimal increase in imaging and off-line analysis time. It allows a comprehensive and personalized functional stratification assessing different vulnerabilities: epicardial coronary artery stenosis (step A), pulmonary congestion (step B), global myocardial dysfunction (step C), coronary microcirculatory dysfunction (step D), and cardiac autonomic nervous system imbalance (step E). The SE response is not only black and white with step A but can be effectively titrated from benign green code (all steps negative) to more functionally malignant red code (at least 3 steps positive).

Figure 1

Funding Acknowledgement

Type of funding source: None

Left atrial volume stress echocardiography in chronic coronary syndromes

Background

An enlarged left atrial volume index (LAVI) at rest mirrors increased LA pressure and/or impairment of LA function. A cardiovascular stress may acutely modify LAVI within minutes.

Purpose

To assess the feasibility and functional correlates of LAVI-stress echocardiography (SE)

Methods

Out of 514 subjects referred to 10 quality-controlled labs, LAVI-SE was completed in 490 (359 male, age 67±12 yrs, ejection fraction 60±10%) with suspected or known chronic coronary syndromes (n=462) or asymptomatic controls (n=28). The utilized stress was exercise in 177, vasodilator in 167, dobutamine in 146. LAVI was measured with the biplane disk summation method. SE was performed with the ABCDE protocol. In a single center sub-study in 50 subjects, including 28 controls and 22 patients, also peak longitudinal atrial strain (PALS, %) was measured as an index of LA reservoir function.

Results

The intra-observer and inter-observer LAVI variability were 5% and 8%, respectively. Δ-LAVI changes (stress-rest) were negatively correlated with resting LAVI (r=−0.271, p<0.001), heart rate reserve (r=−0.239, p<0.001), and Δ-PALS (n=50, r=−0.374, p=0.007).LAVI-dilators were defined as those with stress-rest increase ≥6.8 ml/m2, a cutoff derived from a calculated reference change value above the biological, analytical and observer variability of LAVI. LAVI dilation (see figure) occurred in 56 patients (11%). At multivariable logistic regression analysis, B-lines ≥2 (OR: 2.586, 95% CI =1.1293–5.169, p=0.007) and abnormal left ventricular contractile reserve (OR: 2.207, 95% CI=1.111–4.386, p=0.024) were associated with LAVI dilation.

Conclusion

LAVI-SE is feasible, with high success rate and low variability, in patients with chronic coronary syndromes. A wet (increased B-lines) and weak (reduced LV contractile reserve and LA reservoir function) heart frequently portends LAVI dilation during stress.

Figure 1

Funding Acknowledgement

Type of funding source: None

P971 The echocardiographic phenotype in patients with cardiac amyloidosis and heart failure with preserved ejection fraction

BACKGROUND

New echocardiographic phenotypes of heart failure (HF) are focused on myocardial systolic involvement of the left ventricle (LV), either endocardial and/or transmural.

PURPOSE.

To study the pattern of myocardial involvement in patients (p) with HF with preserved left ventricular ejection fraction (pLVEF) and cardiac amyloidosis (CA).

METHODS.

Comparative study of 16 p with CA and HF with pLVEF, considering as cut point LVEF > 50%, in NYHA class ≥ II / IV, and a control group of 16 healthy people. Longitudinal Strain (LS) and Circumferential Strain (CS) were calculated using 2D speckle-tracking echocardiography, along with Mitral Annulus Plane Systolic Excursion (MAPSE) and Base-Apex distance (B-A). Also, the following indexes were calculated: Twist (apical rotation + basal rotation, º); Classic Torsion (TorC): (twist/B-A, º/cm); Torsion Index (Tor.I): (twist/MAPSE, º/cm) and Deformation Index (Def.I): (twist/LS, º).

We suggest the introduction of these dynamic torsion indexes as Tor.I and Def.I that include twist per unit of longitudinal systolic shortening of the LV instead of using TorC which is the normalisation of twist to the end-diastolic longitudinal diameter of the LV.

RESULTS

There were no differences of age between the groups (68.2 ± 11.5 vs 63.7 ± 2.8 years, p = 0.14). Global values of LS and CS were lower in p with CA indicating endocardial and transmural deterioration during systole, while TorC and Twist of the LV remained conserved in p with CA.

However, there is an increase of dynamic torsion parameters such as Tor.I and Def.I that show an increased Twist per unit of longitudinal shortening of the LV in the CA group (Table).

CONCLUSIONS

In p with CA and HF with pLVEF, the impairment of LS and CS indicates endocardial and transmural systolic dysfunction. In these conditions, LVEF would be preserved at the expense of a greater dynamic torsion of the LV.

Table LS (%) CS (%) Twist (º) TorC (º/cm) Tor.I (º/cm) Def.I (º/%) CA pLVEF (n = 16) -11.7 ± 4.2 17.2 ± 4.8 19.8 ± 8.3 2.5 ± 1.1 27.7 ± 13.5 -1.8 ± 0.9 Control Group (n = 15) -20.6 ± 2.5 22.7 ± 4.9 21.7 ± 6.1 2.7 ± 0.8 16.4 ± 4.7 -1.0 ± 0.3 p < 0.001 < 0.01 0.46 0.46 < 0.01 < 0.01 Dynamic Torsion Indexes and Classic Torion Parameters in pLVEF CA patients vs Control group.

P1792 Coronary flow velocity reserve and prognosis during stress echocardiography

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

Stress echocardiography (SE) based on regional wall motion abnormalities (RWMA) has established risk stratification capabilities, further enhanced by assessment of coronary flow velocity reserve (CFVR) on mid-distal left anterior descending coronary artery which assesses not only epicardial coronary artery stenosis but also coronary microcirculation.

Aim

To assess the value of CFVR in predicting outcome

Methods

From September 2016 to December 2018, we enrolled 1848 patients (age 63 ± 11 years; 1121 males, 60%) with known or suspected coronary artery disease and/or heart failure evaluated with SE (exercise in 631, dipyridamole in 1184, adenosine in 10, dobutamine in 43) in 9 quality-controlled centers of 6 countries. CFVR was measured from pulsed wave Doppler as peak/rest ratio of peak diastolic flow. All patients were followed-up for a median of 16 months.

Results CFV was 28 ± 10 cm/s at rest and 62 ± 19 cm/s at peak stress (p<.001) with a CFVR of 2.25 ± 0.58. At individual patient analysis, CFVR was abnormal (≤2.0) in 528 (28%) patients: 265 (42%) with exercise, 254 (21%) with vasodilator and 9 (21%) with dobutamine stress. At follow-up, there were 218 events: 22 deaths, 22 non-fatal myocardial infarctions, 62 acute heart failures, and 112 late (> 3 months from SE) myocardial revascularizations. At multivariable analysis, stress-induced RWMA (Hazard Ratio 3.883, 95% Confidence Intervals: 2.379-6.336, p<.0.001) and CFVR (Hazard Ratio 1.590, 95% Confidence Intervals: 1.123-2.275, p<.009) were independent predictors. Kaplan-Meier curves showed progressively worsening event-free survival with progressively lower values of CFVR: see figure

Conclusion In patients referred to SE, CFVR assessing coronary microvascular dysfunction allows a more accurate prediction of outcome than RWMA which only detect epicardial coronary artery stenoses.

Abstract P1792 Figure. CFVR and event-free survival curves

P1401 The prognostic value of the reduction of coronary flow velocity reserve in non-ischemic heart failure patients

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

Coronary microvascular abnormalities determining a reduction of coronary flow velocity reserve (CFVR) have been described in patients (pts) with non-ischemic heart failure (HF).

Aim

To assess the prognostic value of CFVR in HF.

Methods

In a prospective, observational, multicenter study, we recruited 333 pts with angiographically normal coronary arteries: 105 patients with HF and preserved (>50%) ejection fraction (HFpEF); 71 with HF and mid-range (40-50%) ejection fraction (HFmrEF); 157 with HF and reduced (<40%) ejection fraction (HFrEF). All patients underwent vasodilator SE with dipyridamole (0.84 mg/kg) in 10 accredited laboratories of 5 countries (Argentina, Brazil, Italy, Mexico, Serbia). CFVR was calculated as the stress/rest ratio of diastolic peak flow velocity pulsed wave-Doppler assessment of LAD flow. In all patients we also assessed left ventricular contractile reserve (LVCR) based on force (systolic blood pressure/end-systolic volume) Abnormal cutoff values were ≤2.0 for CFVR and ≤1.1 for LVCR. All pts were followed-up.

Results

After a median follow-up time of 15 months, 78 events occurred: 36 hospital admissions for acute decompensated heart failure, 23 deaths, 16 worsening in NYHA functional class, 2 stroke and 1 late revascularization. Event-free survival was best in patients with preserved CFVR and LVCR and worst in pts with reduced CFVR and impaired LVCR, with intermediate values for patients with either one (CFVR or LVCR) abnormal results: see figure. A preserved CFVR was associated with a better 24-month event-free survival than reduced CFVR in a subset analysis in pts with HFpEF (HR = 16.2, 95% CI, 1.8-145.1, p = 0.001) and in HFrEF (HR = 3.06, 95% CI, 1.6-5.6, p < 0.001). A multivariable analysis in the overall group of HF pts identified a reduced CFVR as the only independent predictor of event-free survival (HR = 3.455,95% CI 1.723-6.929).

Conclusions

A reduction in CFVR identifies a high risk subset in HF patients, outlining a shared role of coronary microvascular abnormalities as a marker and potential therapeutic target of HF, independently of underlying EF.

Abstract P1401 Figure. Event-free survival based on CFVR-LVCR

P308 Changes in the echocardiographic phenotype during the evolution of cardiac amyloidosis from preserved to reduced left ventricle ejection fraction

Introduction

Cardiomyopaties like Cardiac Amyloidosis (CA), are an important cause of Heart Failure (HF). They can cause endocardial or transmural involvement. It is possible to characterize the kind of affectation thanks to different phenotypes identified by 2D speckle tracking echocardiography. Purpose: To study the pattern of myocardial involvement in patients (p) affected by CA and HF. Methods: Comparative study of 30 p with CA and HF, in NYHA class ≥II/IV, of which 16 had preseved left ventricle ejection fraction (pLVEF) and 14 had reduced LVEF (rLVEF), considering as cut point a LVEF > 50%. There was a control group (CG) of 16 healthy subjects. Twist, radial strain (RS), circunferential strain (CS) and longitudinal strain (LS) were determined using 2D speckle-tracking echocardiography, along with mitral annulus plane systolic excursion (MAPSE) and basal-apex distance (B-A). The following indexes were calculated: Twist (apical rotation + basal rotation, °); Torsion (twist/B-A, °/cm); Torsion Index (TorI: twist/MAPSE, °/cm), and Deformation Index (DefI:twist/LS,°). The last indexes are dynamic parameters that allow for a more realistic assessment of LV torsion, since they include longitudinal shortening measures such as MAPSE and LS, describing in a more complete and physiological way the global LV systolic movement.

Results

There were differences of age between the three gropus, being older the p with rLVEF and younger the ones in the CG (63,7 ± 2,8; 68,2 ± 11,5; y 73,9 ± 12,9 years respectively). LS and CS were lower in rLVEF group when compared with pLVEF group, as well as in pLVEF group compared with the CG. The p with pLVEF showed increased values of the dynamic torsion parameters (DefI and TorI), indicating a compensatory increase of LV twist that disappears in p with rLVEF. Twist and Torsion are significantly lower only in the rLVEF group (see table).

Conclusions

In both CA groups, LS and CS deterioration indicates endocardial and transmural involvement. The loss of compensation given by the increased LV twist, reflected by DefI and TorI, marks the transition to the deterioration of LVEF.

Results Table LVEF (%) LS (%) CS (%) TWIST (°) Torsion (°/cm) TorI (°/cm) DefI (°/%) Control Group (n = 15) 68.2 ± 6.3 -20.6 ± 2.5 -22.7 ± 4.9 21.7 ± 6.1 2.7± 0.8 16.4 ± 4.7 -1.0 ± 0.3 CA pLVEF (n = 16) 60,6 ± 5.4* -11.7 ± 4.2* -17.2 ± 4.8* 19.8 ± 8.3 2.5± 1.1 27.7 ±13.5* -1.8 ± 0.9* CA rLVEF (n = 14) 37.2 ± 8.8** -8.7 ± 3.2** -13.0 ± 3.4** 8.3 ± 5.6** 1.0 ± 1.7** 13.4 ± 9.6** -1.0 ± 0.7** *:p value <0,01 between CG and pLVEF group; **:p value <0,01 between pLVEF and rLVEF

1675 ABCDE vasodilator stress echocardiography in non-ischemic heart failure

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

ABCDE-stress echocardiography (SE) may explore different aspects in the heterogeneous entity of known or suspected heart failure (HF).

Aim

To assess ABCDE-vasodilator SE in non-ischemic HF

Methods

In a prospective, observational, multicenter study, we recruited 428 patients with angiographically normal coronary arteries: 148 patients with HF and preserved (>50%) ejection fraction (HFpEF, Group 1); 100 with HF and mid-range (40-50%) ejection fraction (HFmrEF, Group 2); 180 with HF and reduced (<40%) ejection fraction (HFrEF, Group 3). A group of 75 healthy asymptomatic patients (30 male, 40%, age 57 ± 14 years) referred to testing for screening was also selected (Controls). All patients underwent vasodilator SE with dipyridamole (0.84 mg/kg) in 14 accredited laboratories of 5 countries (Argentina, Brasil, Russian Federation, Serbia and Italy). The ABCDE-SE protocol was adopted: A for regional wall motion abnormalities; B for B-lines (positivity criterion: stress ≥ rest for ≥ 2 points in a 4-site simplified scan available in 181 pts and 10 controls); C for left ventricular contractile reserve (LVCR) based on force (systolic blood pressure/end-systolic volume, positivity criterion: peak/ rest ≤1.1); D for pulsed wave Doppler-based assessment of coronary flow velocity reserve (CFVR) in left anterior descending coronary artery (positivity criterion: peak/rest ≤2.0); E for EKG-based assessment of heart rate reserve (positivity criterion: peak/rest ≤1.22).

Results

All positivity criteria, except A, were more prevalent (p<.01) in Group 3 compared to Group 2, in Group 2 compared to Group 1, and Group 1 compared to controls: see figure. In particular, a blunted heart rate reserve was found in 4/75 controls (5%), 27/148 pts of Group 1 (18%), 28/100 of Group 2 (28%) and 98/180 of Group 3 (54%).

Conclusions

ABCDE-vasodilator SE can help to identify the profound pathophysiological heterogeneity underlying a similar clinical presentation in patients with known or suspected HF with angiographically normal coronary arteries. These patients rarely show stress-induced regional wall motion abnormalities (A), but may exhibit pulmonary congestion (B), reduced myocardial functional reserve (C), altered coronary microcirculation (D) and cardiac autonomic dysfunction (E).

Abstract 1675 Figure. The positivity rate of ABCDE criteria

P4981The reduction of coronary flow velocity reserve in heart failure with reduced, mid-range or preserved ejection fraction

Background

Coronary microvascular disease has been described in heart failure (HF) in presence of angiographically normal epicardial coronary arteries. The prevalence of a reduction of coronary flow velocity reserve (CFVR) in different types of HF and its link with left ventricular contractile reserve (LVCR) is unclear.

Aim

To assess CFVR and LVCR in HF.

Methods

In a prospective, observational, multicenter study, we recruited 380 patients (234 male, 61%, age 66±11 years): 143 (38%) with HF and reduced (<40%) ejection fraction (HFrEF); 98 (26%) with HF and mid-range (40–50%) ejection fraction (HFmrEF); 139 (36%) patients with HF and preserved (>50%) ejection fraction (HFpEF). A control group of 52 asymptomatic patients (23 male, 44%, age 61±14 years) referred to testing for screening was also selected (Controls). All patients underwent dipyridamole (0.84 mg/kg) stress echocardiography in 12 accredited laboratories of 3 countries (Argentina, Brazil and Italy). CFVR was calculated as the stress/rest ratio of diastolic peak flow velocity pulsed-Doppler assessment of left anterior descending (LAD) artery flow. We assessed left ventricular contractile reserve (LVCR) based on global LV Force (systolic blood pressure/end-systolic volume).

Results

Reduced (≤2.0) CFVR was observed in 0/52 controls (0%); 25/139 HFpEF (18%); 28/98 HFmrEF (29%); 78/143 HFrEF (54%, p<0.001 vs all other groups). CFVR was highest in controls (2.80±0.57), lower in HFpEF (2.51±0.57) and HFmrEF (2.26±0.44), lowest in HFrEF (2.04±0.48, p<0.001 vs all other groups). The correlation with LVCR was absent in controls (r=0.098, p=0.491) and HFmrEF (r=0.032, p=0.756), present in HFrEF (r=0.375, p<0.001) and HFpEF (r=0.314, p<0.001).

LVCR vs CFVR

Conclusions

CFVR is frequently abnormal in all types of HF, although more frequently and more profoundly in HFrEF. CFVR mirrors contractile reserve in HFrEF and - less tightly - in HFpEF.

MO-D-BRB-02: The Radiological Physics Center's Quality Audit Program: Where Can We Improve?

PURPOSE

To analyze the findings of the Radiological Physics Center's (RPC) QA audits of institutions participating in NCI sponsored clinical trials.

METHODS

The RPC has developed an extensive Quality Assurance (QA) program over the past 44 years. This program includes on-site dosimetry reviews where measurements on therapy machines are made, records are reviewed and personnel are interviewed. The program's remote audit tools include mailed dosimeters (OSLD/TLD) to verify output calibration, comparison of dosimetry data with RPC 'standard' data, evaluation of benchmark and patient calculations to verify the treatment planning algorithms, review of institution's QA procedures and records, and use of anthropomorphic phantoms to verify tumor dose delivery. The RPC endeavors to assist institutions in finding the origins of any detected discrepancies, and to resolve them.

RESULTS

Ninety percent of institutions receiving dosimetry recommendations has remained level for the past 5 years. The most frequent recommendations were for not performing TG-40 QA tests, wedge factors, small field size output factors and off-axis factors. Since TG-51 was published, the number of beam calibrations audited during visits with ion chambers, that met the RPC's ±3% criterion, decreased initially but has risen to pre-TG-51 levels. The OSLD/TLD program shows that only ∼3% of the beams are outside our ±5% criteria, but these discrepancies are distributed over 12-20% of the institutions. The percent of institutions with ï,³ l beam outside the RPC's criteria is approximately the same whether OSLD/TLD or ion chambers were used. The first time passing rate for the anthropomorphic phantoms is increasing with time. The prostate phantom has the highest pass rate while the spine phantom has the lowest.

CONCLUSIONS

Numerous dosimetry errors continue to be discovered by the RPC's QA program and the RPC continues to play an important role in helping institutions resolve these errors. This work was supported by PHS grants CA10953 and CA081647 awarded by NCI.

Intraneural ganglion of the peroneal nerve: importance of timely diagnosis

Peroneal nerve ganglion cysts typically present because of a palpable mass or symptoms and signs of entrapment neuropathy, including pain, diminished sensation, and motor weakness. Surgical treatment is usually successful when performed early, but, when diagnosis is delayed, intraneural growth and invasion may cause irreversible axonal injury and footdrop. This case report illustrates the importance of timely diagnosis when treating a ganglion of the peroneal nerve and reviews the appropriate workup, differential diagnosis, and treatment.

Fibrolipoma of the median nerve: a case report and review of the literature

A 38 year-old patient presented with right median nerve distribution paresthesias. Electrodiagnostic studies confirmed severe carpal tunnel syndrome. A palmar mass prompted a magnetic resonance imaging scan, which suggested a fibrolipoma of the median nerve. Carpal tunnel release resulted in resolution of preoperative pain and paresthesias. We review the literature dealing with this primary nerve tumor.

Prognostic value of pharmacological stress echocardiography in patients with known or suspected coronary artery disease: a prospective, large-scale, multicenter, head-to-head comparison between dipyridamole and dobutamine test. Echo-Persantine International Cooperative (EPIC) and Echo-Dobutamine International Cooperative (EDIC) Study Groups

OBJECTIVES

The study compared the prognostic value of dipyridamole and dobutamine stress echocardiography in patients with known or suspected coronary artery disease.

BACKGROUND

Extensive information is available on the relative diagnostic accuracy of the two tests assessed in a head-to-head fashion, whereas comparative data on their prognostic yield are largely preliminary to date.

METHODS

Dipyridamole (up to 0.84 mg/kg over 10 min) atropine (up to 1 mg over 4 min) (DIP) and dobutamine (up to 40 microg/kg/min)-atropine (1 mg over 4 min) (DOB) stress tests were performed in 460 patients with known or suspected coronary artery disease. Patients were followed up for 38+/-21 months.

RESULTS

The DIP was negative in 253 and positive in 207 patients. The DOB was negative in 242 and positive in 218 patients. During the follow-up, there were 80 cardiac events. For all cardiac events, the negative and positive predictive value were 83% and 17% for DOB, 84% and 19% for DIP, respectively (p = NS). Considering only cardiac death, by univariate analysis Wall-Motion Score Index (WMSI) at DIP peak dose (chi-square 13.80, p<0.0002) was the strongest predictor, followed by WMSI DOB (chi2 = 8.02, p<0.004) and WMSI at rest (chi2 = 6.85, p<0.008). By stepwise analysis, WMSI at DIP peak dose was the most important predictor (RR [relative risk] 7.4, p<0.0001).

CONCLUSIONS

In patients at low-to-moderate risk of cardiac events, pharmacological stress echocardiography with either dobutamine or dipyridamole allows effective and grossly comparable, risk stratification on the basis of the presence, severity and extension of the induced ischemia.

Prognostic value of myocardial viability in medically treated patients with global left ventricular dysfunction early after an acute uncomplicated myocardial infarction: a dobutamine stress echocardiographic study

BACKGROUND

Residual viable myocardium identified by dobutamine stress after myocardial infarction may act as an unstable substrate for further events such as subsequent angina and reinfarction. However, in patients with severe global left ventricular dysfunction, viability might be protective rather than detrimental. The aim of this study was to assess the impact on survival of echocardiographically detected viability in medically treated patients with global left ventricular dysfunction evaluated after acute uncomplicated myocardial infarction.

METHODS AND RESULTS

The data bank of the large-scale, prospective, multicenter, observational Echo Dobutamine International Cooperative (EDIC) study was interrogated to select 314 medically treated patients (271 men; age, 58+/-9 years) who underwent low-dose (</=10 microg x kg-1 x min-1) dobutamine for the detection of myocardial viability and high-dose dobutamine for the detection of myocardial ischemia (</=40 microg x kg-1 x min-1 with atropine </=1 mg) performed 12+/-6 days after an acute uncomplicated myocardial infarction and showing a moderate to severe resting left ventricular dysfunction (wall motion score index [WMSI] >1.6). Patients were followed up for 9+/-7 months. Low-dose dobutamine stress echocardiography identified myocardial viability in 130 patients (52%). Dobutamine-atropine stress echocardiography was positive for ischemia in 148 patients (47%) and negative in 166 patients (53%). During the follow-up, there were 12 cardiac deaths (3.8% of the total population). With the use of Cox proportional hazards model, delta low-dose WMSI (the variation between rest WMSI and low-dose WMSI) was shown to exert a protective effect by reducing cardiac death by 0.8 for each decrease in WMSI at low-dose dobutamine (coefficient, -0.2; hazard ratio, 0.8; P<0.03); WMSI at peak stress was the best predictor of cardiac death in this set of patients (hazard ratio, 14.9; P<0.0018).

CONCLUSIONS

In medically treated patients with severe global left ventricular dysfunction early after acute uncomplicated myocardial infarction, the presence of myocardial viability identified as inotropic reserve after low-dose dobutamine is associated with a higher probability of survival. The higher the number of segments showing improvement of function, the better the impact is of myocardial viability on survival. The presence of inducible ischemia in this set of patients is the best predictor of cardiac death.