Dobutamine Echocardiography Research Articles

The use of artificial intelligence for predicting postinfarction myocardial viability in echocardiographic images.

Evaluation of standard echocardiographic examination with artificial intelligence may help in the diagnosis of myocardial viability and function recovery after acute coronary syndrome. Sixty-one consecutive patients with acute coronary syndrome were enrolled in the present study (43 men, mean age 61 ± 9 years). All patients underwent percutaneous coronary intervention (PCI). 533 segments of the heart echo images were used. After 12 ± 1 months of follow-up, patients had an echocardiographic evaluation. After PCI each patient underwent cardiac magnetic resonance (CMR) with late enhancement and low-dose dobutamine echocardiographic examination. For texture analysis, custom software was used (MaZda 5.20, Institute of Electronics).Linear and non-linear (neural network) discriminative analyses were performed to identify the optimal analytic method correlating with CMR regarding the necrosis extent and viability prediction after follow-up. Texture parameters were analyzed using machine learning techniques: Artificial Neural Networks, Namely Multilayer Perceptron, Nonlinear Discriminant Analysis, Support Vector Machine, and Adaboost algorithm. The mean concordance between the CMR definition of viability and three classification models in Artificial Neural Networks varied from 42% to 76%. Echo-based detection of non-viable tissue was more sensitive in the segments with the highest relative transmural scar thickness: 51-75% and 76-99%. The best results have been obtained for images with contrast for red and grey components (74% of proper classification). In dobutamine echocardiography, the results of appropriate prediction were 67% for monochromatic images. Detection and semi-quantification of scar transmurality are feasible in echocardiographic images analyzed with artificial intelligence. Selected analytic methods yielded similar accuracy, and contrast enhancement contributed to the prediction accuracy of myocardial viability after myocardial infarction in 12 months of follow-up.

Diagnostic Accuracy of Combined Dobutamine Echocardiography and Electrocardiography in Patients with Suspected Chronic Coronary Syndrome

Diagnostic Accuracy of Combined Dobutamine Echocardiography and Electrocardiography in Patients with Suspected Chronic Coronary Syndrome

The association of catestatin and endocan with the effects of cardiac shock wave therapy: Biomarker sub-study of the randomized, sham procedure-controlled trial.

Cardiac shock-wave therapy (CSWT) is a non-invasive regenerative treatment method based on low-frequency ultrasound waves, which stimulate angiogenesis. Current data about the effects of revascularization procedures on angiogenesis biomarkers is limited. Recently, an association of catestatin and endocan with coronary collateral development was shown in several trials. In this study, we aimed to evaluate the impact of CSWT on the dynamics of catestatin and endocan levels and to assess their correlation with parameters of myocardial perfusion and function. Prospective, randomized, triple-blind, sham procedure-controlled study enrolled 72 adult subjects who complied with defined inclusion criteria (NCT02339454). We measured biomarkers in 48 patients with stable angina (24 patients of CSWT group, 24 patients of sham-procedure group). Additionally, patients were divided into responders and non-responders according to improvement in myocardial perfusion and/or contractility assessed by myocardial scintigraphy and dobutamine echocardiography (30 and 13 patients, respectively). The blood samples were collected at baseline, after the last treatment procedure (9th treatment week) and at 6-month follow-up to evaluate biomarkers concentration and stored at -80° until analysis. Serum catestatin and endocan levels were determined by commercially available ELISA kits. Serum catestatin concentration significantly increased in all patients. While endocan levels significantly decreased in the responders sub-group. The increase in catestatin levels at 9th week and 6 months was positively associated with improvement in summed difference score (rho = 0.356, p = 0.028) and wall motion score, WMS (rho = 0.397, p = 0.009) at 6 months in the whole study population. Meanwhile, the decrease in endocan levels over 6 months was positively correlated with improvement in WMS at 3- and 6- months (r = 0.378, p = 0.015 and r = 0.311, p = 0.045, respectively). ROC analysis revealed that a change at 6 months in catestatin and endocan levels significantly predicted improvement in myocardial perfusion and contractile function with 68.9% sensitivity and 75.0% specificity (p = 0.039) and 51.7% sensitivity, and 91.7% specificity (p = 0.017), respectively. Baseline endocan concentration and its change at 6 months predicted response to CSWT with 68.8% sensitivity and 83.3% specificity (p = 0.039) and 81.3% sensitivity and 100% specificity (p < 0.0001), respectively. This study demonstrates the association of increase in catestatin and decrease in endocan levels with the improvement of myocardial perfusion and contractile function. The potential predictive value of catestatin and endocan dynamics for the response to regenerative therapy is shown.

Clinical Value of Stress Transaortic Flow Rate During Dobutamine Echocardiography in Reduced Left Ventricular Ejection Fraction, Low-Gradient Aortic Stenosis: A Multicenter Study.

Low rest transaortic flow rate (FR) has been shown previously to predict mortality in low-gradient aortic stenosis. However limited prognostic data exists on stress FR during low-dose dobutamine stress echocardiography. We aimed to assess the value of stress FR for the detection of aortic valve stenosis (AS) severity and the prediction of mortality. This is a multicenter cohort study of patients with reduced left ventricular ejection fraction and low-gradient aortic stenosis (aortic valve area <1 cm2 and mean gradient <40 mm Hg) who underwent low-dose dobutamine stress echocardiography to identify the AS severity and presence of flow reserve. The outcome assessed was all-cause mortality. Of the 287 patients (mean age, 75±10 years; males, 71%; left ventricular ejection fraction, 31±10%) over a mean follow-up of 24±30 months there were 127 (44.3%) deaths and 147 (51.2%) patients underwent aortic valve intervention. Higher stress FR was independently associated with reduced risk of mortality (hazard ratio, 0.97 [95% CI, 0.94-0.99]; P=0.01) after adjusting for age, chronic kidney disease, heart failure symptoms, aortic valve intervention, and rest left ventricular ejection fraction. The minimum cutoff for prediction of mortality was stress FR 210 mL/s. Following adjustment to the same important clinical and echocardiographic parameters, among the three criteria of AS severity during stress, ie, the guideline definition of aortic valve area <1cm2 and aortic valve mean gradient ≥40 mm Hg, or aortic valve mean gradient ≥40 mm Hg, or the novel definition of aortic valve area <1 cm2 at stress FR ≥210 mL/s, only the latter was independently associated with mortality (hazard ratio, 1.72 [95% CI, 1.05-2.82]; P=0.03). Furthermore aortic valve area <1cm2 at stress FR ≥210 mL/s was the only severe aortic stenosis criterion that was associated with improved outcome following aortic valve intervention (P<0.001). Guideline-defined stroke volume flow reserve did not predict mortality. Stress FR during low-dose dobutamine stress echocardiography was useful for the detection of both AS severity and flow reserve and was associated with improved prediction of outcome following aortic valve intervention.

Diagnostic Accuracy of Dobutamine Stress Echocardiography for Detection of Cardiac Allograft Vasculopathy in Orthotopic Heart Transplant Patients.

ObjectiveCardiac allograft vasculopathy is one of the leading causes of late graft failure and subsequent death in orthotopic heart transplant. Although invasive coronary angiography is the gold standard modality for detection of cardiac allograft vasculopathy, dobutamine stress echocardiography has been recently frequently used as an alternative. Our aim was to evaluate the diagnostic performance of dobutamine stress echocardiography for detection of cardiac allograft vasculopathy in transplant patients.MethodsA retrospective analysis was conducted using a total of 150 dobutamine stress echocardiographic exams that were performed on 99 patients in our institution, with paired coronary angiogram and no acute rejection, within a median of 538 [interquartile range 371–816] days. Sensitivity and specificity of dobutamine echocardiography to detect allograft vasculopathy was evaluated. Allograft vasculopathy was defined as Grade 1 or higher based on ISHLT criteria. A positive dobutamine stress echo result was defined by new or worsening wall motion abnormality.ResultsMedian age of the population at transplant was 34 [interquartile range 22–46] years; 76 (77%) patients were male. Allograft vasculopathy was present in 31 (20.6%) out of 150 coronary angiograms. Only 7 (4.6%) of that number were positive on dobutamine stress echocardiography. Sensitivity and specificity for allograft vasculopathy detection was 3% and 94%, respectively. Out of 7 false positive dobutamine stress echocardiograms, two were in patients with myocardial bridging. Two patients with mild acute rejection had both negative dobutamine stress echo.ConclusionsOverall, positivity of dobutamine stress echocardiography in patients after heart transplant is low. It has high specificity, but very low sensitivity for detection of cardiac allograft vasculopathy. Dobutamine stress echocardiography should only be cautiously used as an alternative to coronary angiography.

Clinical value of stress transaortic flow rate during dobutamine echocardiography in low-gradient aortic stenosis

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND/INTRODUCTION The clinical value of rest transaortic flow rate (FR) has been shown previously in low-gradient aortic stenosis (LGAS) for the prediction of outcome. However limited data exists on the prognostic value of stress FR in LGAS following low-dose dobutamine stress echocardiography (LDDSE). PURPOSE We aimed to assess the value of stress FR in patients with LGAS in the diagnosis of AS severity and the prediction of mortality. METHODS This is a multi-centre cohort study of patients with low left ventricular ejection fraction (LVEF) and LGAS (aortic valve area –AVA &amp;lt;1cm²) who underwent LDDSE. RESULTS Of the 287 patients (mean age: 75.1 ±10 years, males: 71%) over the mean follow-up of 24 ±30 months there were 127 (44.3%) deaths and 147 (51.2%) patients underwent aortic valve intervention. Lower stress FR was independently associated with increased risk of mortality (HR= 0.99, 95%CI= 0.99-0.999, p= 0.02) after adjusting for age, chronic kidney disease, presence of symptoms (NYHA II-IV), aortic valve intervention, rest LVEF and guideline-defined severe AS (AV mean gradient- AVMG ≥40mmHg with AVA &amp;lt;1cm² at peak stress). The minimum cut-off for prediction of mortality was stress FR 210ml/sec. Among the different criteria of AS severity during stress, i.e. guideline-defined criterion, or stress AVMG ≥40mmHg, or stress AVA &amp;lt;1cm² at stress FR ≥210ml/s, only the latter was independently associated with mortality (HR= 1.81, 95%CI= 1.04-3.2, p= 0.04) (Table 1) and was the parameter of AS severity that predicted improved outcome following aortic valve intervention (p &amp;lt;0.005) (Figure 1). Guideline-defined stroke volume flow reserve did not predict mortality. CONCLUSIONS Assessment of stress FR during LDDSE is important for the detection of both AS severity and flow reserve. Table 1 Multivariable analysis for prediction of all-cause mortality (N = 287) for the different criteria of aortic stenosis HR 95%CI p Age 1 0.98-1.03 0.84 Chronic kidney disease 1..84 1.13-2.99 0.01 Aortic valve intervention 0.37 0.22-0.61 &amp;lt;0.005 Presence of symptoms (NYHA II-IV) 1.87 0.66-5.31 0.24 Rest LVEF (by 1%) increase 0.97 0.95-1 0.06 Stress AVA &amp;lt; 1cm&amp;sup2; with stress AVMG≥40mmHg 1.02 0.31-3.34 0.97 Stress AVMG≥40mmHg 0.57 0.2-1.59 0.28 Stress AVA &amp;lt; 1cm&amp;sup2; at stress FR≥210mmHg 1.81 1.04-3.2 0.04 Abstract Figure 1

Multimodality Imaging of Myocardial Viability

Myocardial viability is an important pathophysiologic concept which may have significant clinical impact in patients with left ventricular dysfunction due to ischemic heart disease. Understanding the imaging modalities used to assess viability, and the clinical implication of their findings, is critical for clinical decision-making in this population. The ability of dobutamine echocardiography, single-photon emission computed tomography, positron emission tomography, and cardiac magnetic resonance imaging to predict functional recovery following revascularization is well-established. Despite different advantages and disadvantages for each imaging modality, each modality has demonstrated reasonable performance characteristics in identifying viable myocardium. Recent data, however, has called into question whether this functional recovery leads to improved clinical outcomes. Although the assessment of viability can be used to aid in clinical decision-making prior to revascularization, its broad application to all patients is limited by a lack of data confirming improvement in clinical outcomes. Thus, viability assessments may be best applied to select patients (such as those with increased surgical risk) and integrated with clinical, laboratory, and imaging data to guide clinical care. Future research efforts should be aimed at establishing the impact of viability on clinical outcomes.

Early Prediction of Myocardial Viability after Acute Myocardial Infarction by Two-Dimensional Speckle Tracking Imaging

Distinguishing the transmural degree of myocardial rot and the level of myocardial suitability in intense myocardial localized necrosis (AMI) is significant clinically. was to survey myocardial suitability utilizing two-dimensional dot following imaging (2D-STI) in patients with AMI. 2D-STI was performed inside three days of medical clinic affirmation and a half year after essential percutaneous coronary intercession (PCI) in 50 patients with AMI, who had a left front plummeting coronary conduit (LAD) offender sore. What's more, 25 patients who had negligible stenotic injuries (< 30% stenosis) on coronary angiography were additionally remembered for the benchmark group. At a half year dobutamine echocardiography was performed for reasonability evaluation in seven sections of the LAD region. As indicated by the recuperation of divider movement variation from the norm, sections were named feasible or non-reasonable. An aggregate of 288 portions were feasible, and 62 were nonviable. There is factual noteworthy distinction between the feasible and nonviable sections in the pinnacle systolic strain and the pinnacle systolic strain rate estimated inside three days from intense myocardial dead tissue. AUC for top systolic strain (0.957, p. <0.001), 95%C.I. (0.937 – 0.976) demonstrated that a cut off degree of <-9 had affectability of 86.11 and particularity 87.1 for expectation of practical myocardium. AUC for top systolic strain rate (0.87, p. <0.001), 95%C.I. (0.809 – 0.931) demonstrated that a cut off degree of <-0.7 had affectability of 91.6 and explicitness 74.19 for forecast of practical myocardium.peak longitudinal Strain and strain rate estimations are attainable, reasonable, quantitative, and quick strategies that can foresee myocardial feasibility with high affectability and particularity.

Assessment of myocardial viability using echocardiographic strain imaging in patients with ST-elevation myocardial infarction: comparison with cardiac PET imaging.

A speckle tracking echocardiographic (STE) strain imaging can predict myocardial viability. The study compared the STE strain imaging using low-dose dobutamine stress with 18fluoro-deoxyglucose positron emission tomographic (18FDG-PET) imaging for the detection of myocardium viability. We studied 57 patients with ST-elevation myocardial infarction (STEMI) having angiographic evidence of total arterial cut off and akinetic myocardium. These patients underwent low-dose dobutamine echocardiography and 18FDG-PET imaging. The STE was used to measure the peak systolic longitudinal and circumferential strain and strain rate at rest and after low-dose dobutamine stress. A total of 298 akinetic segments were evaluated. The viable myocardium showed an increased strain and strain rate values following the dobutamine stress in comparison to the nonviable myocardium. The peak longitudinal strain rate [AUC 0.83 (95% confidence interval (CI) 0.67-0.99], p = 0.001; optimal cutoff - 0.64s-1 for sensitivity 0.87 and specificity 0.81), post-dobutamine peak longitudinal strain rate [AUC 0.94 (95% CI 0.87-1.00), p = 0.001; optimal cutoff - 0.85s-1 for sensitivity 0.89 and specificity 0.77), change in peak longitudinal strain rate [AUC 0.93 (95% CI 0.86-1), p = 0.001; optimal cutoff - 0.2s-1 for sensitivity 0.87 and specificity 0.87] predicted viability. The post-dobutamine peak circumferential strain rate [AUC 0.92 (95% CI 0.81-1.0), p = 0.001; optimal cutoff - 1.1s-1 for sensitivity and specificity 0.86], were predictor of viability. Both resting and post-dobutamine longitudinal and circumferential strain rate had better accuracy for the prediction of viability. The resting and post-dobutamine stress STE strain and strain rate parameters can assess the viability in akinetic segments.

P1303 Pseudo-severe aortic stenosis due to mechanical dyssynchrony in a patient with low contractile reserve

Abstract Introduction Aortic stenosis characterization in patients with low flow – low gradient stenosis (LF-LG) and reduced left ventricular (LV) ejection fraction (EF) is challenging. In this subgroup, pseudo- severe stenosis should be properly identified, as these patients are treated conservatively with heart failure therapy. Its identification relies mainly on preserved contractile reserve seen during dobutamine echocardiography. We present a patient with low contractile reserve and pseudo-severe stenosis due to mechanical dyssynchrony. Case presentation 83-years old patient with ischemic heart disease and chronic kidney disease was admitted to our department due to progressive exertional dyspnea. In 2014 he underwent dual-chamber pacemaker (PM) implantation due to sick sinus syndrome and was programmed to asynchronous pacing mode (VVI mode) in 2016 as atrial electrode dysfunction was observed. Coronary angiogram was normal. Echocardiography showed enlarged left ventricle (LV EDV 180 ml), reduced EF (33%) and signs of mechanical dyssynchrony. Peak aortic valve velocity was 2.5 m/s, mean pressure gradient (MPG) 13 mmHg and AVA 1.0 cm2. Stroke volume was reduced (SVI 28 ml/m2). LF-LG aortic stenosis was suspected. Stress echocardiography using dobutamine at peak infusion of 15 mcg/kg/min showed low contractile reserve (EF 37%, SVI 33 ml/m2) with no significant changes in aortic valve parameters (MPG 29 mmHg, AVA 0.9 cm2). However, significant masurement disparity was noted and at least partly contributed to atrio-ventricular (A-V) and inter-ventricular dyssynchrony because of asynchronous VVI pacing. To overcome A-V and intraventricular dyssynchrony we decided for atrial lead reposition and upgrade to cardiac resynchronization therapy (CRT-P). After six months of CRT, normalization of EF and improvement of exercise capacity were observed. Furthermore, additional evaluation of aortic valve showed only moderate stenosis (peak velocity 2,8 m/s, MPG 18 mmHg and AVA 1.4 cm2). Stroke volume was normal (SVI 48 ml/m2). Consequently, we postponed potential surgical or interventional treatment of the aortic valve. Conclusion Considerable LV mechanical dyssynchrony could interfere with determining the severity of aortic stenosis. As demonstrated in the present case report, special considerations should be taken in patients with notable LV dyssynchrony and low contractile reserve as it may not be overcome with dobutamine stress echocardiography as recommended by the current guidelines.

Coexistence of aortic valve stenosis and cardiac amyloidosis: echocardiographic and clinical significance

BackgroundLeft ventricular hypertrophy and diastolic dysfunction are common echocardiographic features of both aortic valve stenosis (AS) and cardiac amyloidosis (CA). These two different entities therefore may mask each other. From recent years, there is a growing body of evidence about the relatively high incidence of wild-type transthyretin (wtTTR) amyloidosis in AS, but there are scarce data on the prevalence of AS in CA, particularly in AL-type amyloidosis. The echocardiographic approach to these patients is not obvious, and not evidence based. We aimed to study the prevalence, severity, and type of AS in patients with CA and also to evaluate the potential of echocardiography in the diagnostic process.MethodsBetween January 2009 and January 2019, we retrospectively analyzed the clinical and echocardiographic data, and the echocardiographic work up of 55 consecutive CA patients.Results80% of our CA patients had AL amyloidosis. We identified 5 patients (9%) with moderate to severe AS: two with moderate AS and three with low-flow, low-grade AS (LFLG AS). Further analysis of the latter three patients with dobutamine stress echocardiography revealed pseudo-severe LFLG AS in two, and true-severe AS in one patient.ConclusionThe prevalence of moderate to severe AS is 9% in our population of CA patients, the majority of whom have AL amyloidosis. Dobutamine echocardiography seems to be appropriate for the further characterization of patients with LFLG AS, even with normal ejection fraction.

Dobutamine echocardiography for assessment of viability in the current era.

Studies from the 1990s and early 2000s documented the utility of dobutamine echocardiography for the prediction of functional recovery and prognosis with revascularization. The results of The Surgical Treatment of Ischemic Heart Failure (STICH) trial called into question the value of viability assessment using dobutamine echocardiography. The purpose of this review is to re-examine the literature on dobutamine echocardiography, put into context the STICH results, and provide insight into the current role of dobutamine echocardiography viability testing. In contrast to the results of previous nonrandomized trials, the STICH trial showed that patients with viability defined by nuclear perfusion imaging or dobutamine echocardiography did not have improved survival with CABG compared with optimal medical therapy. Viability by dobutamine echocardiography was defined as the presence of contractile reserve in at least five segments with baseline dysfunction. The results of dobutamine echocardiography studies published before and after initiation of the STICH trial suggest that the definition of viability utilized in that trial may be suboptimal for assessment of improvement in global function and prognosis in patients undergoing revascularization. Assessment of global contractile reserve using wall motion score (WMS) or ejection fraction may be superior to utilization of a binary definition of viability confined to assessment of contractile reserve in a fixed number of segments because these indices provide information on both the magnitude and extent of contractile reserve of the entire left ventricle (LV). Assessment of WMS or ejection fraction with dobutamine echocardiography may be the optimal means of evaluating the impact of viability on prognosis.Video abstract http://links.lww.com/HCO/A56.

Myocardial Viability and Long-Term Outcomes in Ischemic Cardiomyopathy

BackgroundThe role of assessment of myocardial viability in identifying patients with ischemic cardiomyopathy who might benefit from surgical revascularization remains controversial. Furthermore, although improvement in left ventricular function is one of the goals of revascularization, its relationship to subsequent outcomes is unclear.MethodsAmong 601 patients who had coronary artery disease that was amenable to coronary-artery bypass grafting (CABG) and who had a left ventricular ejection fraction of 35% or lower, we prospectively assessed myocardial viability using single-photon-emission computed tomography, dobutamine echocardiography, or both. Patients were randomly assigned to undergo CABG and receive medical therapy or to receive medical therapy alone. Left ventricular ejection fraction was measured at baseline and after 4 months of follow-up in 318 patients. The primary end point was death from any cause. The median duration of follow-up was 10.4 years.ResultsCABG plus medical therapy was associated with a lower incidence of death from any cause than medical therapy alone (182 deaths among 298 patients in the CABG group vs. 209 deaths among 303 patients in the medical-therapy group; adjusted hazard ratio, 0.73; 95% confidence interval, 0.60 to 0.90). However, no significant interaction was observed between the presence or absence of myocardial viability and the beneficial effect of CABG plus medical therapy over medical therapy alone (P=0.34 for interaction). An increase in left ventricular ejection fraction was observed only among patients with myocardial viability, irrespective of treatment assignment. There was no association between changes in left ventricular ejection fraction and subsequent death.ConclusionsThe findings of this study do not support the concept that myocardial viability is associated with a long-term benefit of CABG in patients with ischemic cardiomyopathy. The presence of viable myocardium was associated with improvement in left ventricular systolic function, irrespective of treatment, but such improvement was not related to long-term survival. (Funded by the National Institutes of Health; STICH ClinicalTrials.gov number, NCT00023595.)

Comparison of Contrast Enhanced Low-Dose Dobutamine Stress Echocardiography with 99mTc-Sestamibi Single-Photon Emission Computed Tomography in Assessment of Myocardial Viability.

INTRODUCTION:Dobutamine stress echocardiography (DSE) and myocardial perfusion scan are the commonly used modalities to detect viable myocardium. DSE is comparatively cheaper and widely available but has a lower sensitivity.AIM:We aimed to compare contrast-enhanced low-dose dobutamine echocardiography (LDDE) and gated 99mTc-sestamibi myocardial perfusion scan (MPS) for the degree of agreement in the detection of myocardial viability.METHODS:We studied 850 left ventricular segments from 50 patients (42 men, mean age 55.5 years), with coronary artery disease and left ventricular systolic dysfunction (ejection fraction < 40%), using contrast-enhanced LDDE and 99mTc-Sestamibi gated SPECT. Segments were assessed for the presence of viability by both techniques and head to head comparisons were made.RESULTS:Adequate visualisation increased from 80% in unenhanced segments to 96% in contrast-enhanced segments. Of the total 850 segments studied, 290 segments (34.1%) had abnormal contraction (dysfunctional). Among these, 138 were hypokinetic (16.2% of total), 144 were severely hypokinetic or akinetic (16.9% of total), and 8 segments were dyskinetic or aneurismal (0.9% of total). Among 151 segments considered viable by technetium, 137 (90.7%) showed contractile improvement with dobutamine; in contrast, only 8 of the 139 segments (5.7%) considered nonviable by technetium had a positive dobutamine response. The per cent of agreement between technetium uptake and a positive response to dobutamine was 78.6% with kappa = 0.63, suggestive of a substantial degree of agreement between the two modalities.CONCLUSION:Use of contrast-enhanced LDDE significantly increased the adequate endocardial border visualisation. Furthermore, this study showed a strong degree of agreement between the modalities in the detection of viable segments. So, contrast-enhanced LDDE appears to be a safe and comparable alternative to MPS in myocardial viability assessment.

Regulator of G protein Signaling 2 and 5 Coordinate Their Activity to Control Cardiac Contractility

Fine‐tuning of signaling via heterotrimeric G proteins by regulators of G protein signaling (RGS) proteins is critical to maintaining physiological homeostasis. Abnormal G protein signaling due to the loss of G protein regulation by RGS proteins is implicated in several diseases including cardiovascular disorders such as hypertension, cardiac hypertrophy, and heart failure. RGS proteins act as GTPase activating proteins (GAPs) to control the kinetics and amplitude of G protein signaling. Multiple RGS proteins are prominently expressed in the cardiovascular system; however, whether their activities/functions are coordinated to control G protein signaling and cardiovascular function is unknown. Here, we generated mice concurrently lacking RGS2 and 5 (Rgs2/5 dbKO) to determine how the dual absence of potent GAPs for Gq/11 and Gi/oclass G proteins affects cardiovascular function. Blood pressure and heart rate were monitored in conscious, freely moving mice via radiotelemetry. Surgical implantation of the radiotelemetry device induced marked systolic blood pressure increase in Rgs2/5 dbKO mice (WT: 140 ± 6 vs. dbKO: 170 ± 2 mmHg; p&lt;0.01) at baseline, which gradually declined but remained elevated in Rgs2/5 dbKO relative to wild type (WT) mice, several days later. Whereas all WT mice survived the surgery, ~70–80% of male Rgs2/5 dbKO mice surprisingly died 72–96 hr post‐surgery. When subjected to cardiac stress test using acute dobutamine infusion and echocardiography or the invasive pressure‐volume loop analysis of cardiac function, male Rgs2/5 dbKO mice showed hypocontractile response and decreased ejection fraction relative to WT mice. Freshly isolated ventricular cardiomyocytes from male Rgs2/5 dbKO mice showed decreased fractional shortening (WT: 16.1 ± 4.3 vs. dbKO: 7.4 ± 1.1 %; p&lt;0.01) but high calcium transients (WT: 117 ± 20 vs. dbKO: 198 ± 50 au; p=0.07) at baseline, and application of electrical field stimulation or low concentration of the non‐selective β‐adrenergic receptor agonist, isoproterenol (ISO), triggered premature calcium transients, tachyarrhythmia and death of cells from Rgs2/5 dbKO mice. Interestingly, cells from mice harboring just one copy of Rgs2 (Rgs2+/−, Rgs5−/−) but not Rgs5 (Rgs2−/−, Rgs5+/−) were resistant to low‐dose ISO‐induced arrhythmia. These results together suggest that RGS2 and 5 coordinate their activity to control cardiomyocyte excitation‐contraction coupling and normal cardiac rhythm.Support or Funding InformationNIH – NHLBI (1R01 HL139754‐01) and AHA Scientist Development Grant (16SDG27260276)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Can stress echocardiography identify patients who will benefit from percutaneous mitral valve repair?

The aim of the current study was to investigate whether stress echocardiography improves selection of patients who might have clinical benefit from percutaneous mitral valve repair with the MitraClip. In total, 39 patients selected for MitraClip implantation underwent preprocedural low-dose stress (dobutamine or handgrip) echocardiography from which stroke volume, ejection fraction and MR grade were measured. Outcome after MitraClip implantation was determined by New York Heart Association classification and Quality of Life questionnaires. Clinical benefit from MitraClip treatment was defined as survival and NYHA class I–II at 6 months follow-up. In total, 36 patients with a technically successful procedure were included in the analysis (mean age 79 ± 8 years, 47% male, 50% functional MR). Clinical benefit was achieved in 18 patients. All seven patients with MR decreasing during stress remained in NYHA III–IV or died within 6 months, while 62% (18 out of 29) of the patients with stable or increased MR during stress had clinical benefit (p = 0.008). Significant increase in Quality of Life on 4/8 subscales of the RAND Short Form-36 questionnaire was observed: Physical Functioning (p < 0.001), Social Functioning (p < 0.001), Mental Health (p = 0.022) and Vitality (p = 0.026) was seen in patients with an increase in stroke volume during stress echocardiography. Patients with a decreased MR during preprocedural stress echocardiography remained more symptomatic than patients with a stable or increased MR during stress. Stress echocardiography may support patient selection for percutaneous mitral valve repair.

The efficacy of coronary sinus reducer in patients with refractory angina—A systematic review of the literature

The aim of our systematic review was to investigate the efficacy of coronary sinus (CS) reducer device in patients with refractory angina. The CS reducer device provides a therapeutic option for patients with coronary artery disease who are not suitable for revascularization. Two independent investigators (GB and GT) systematically searched the Medline and Cochrane library databases for studies describing the efficacy and safety of the CS reducer in patients with refractory angina from January 1, 2000 until May 12, 2018 using the following terms: "coronary sinus (reducer OR reducing) device." Efficacy was defined as ≥1 unit improvement in the Canadian cardiovascular society (CCS) score. Our search strategy provided six studies (five observational studies and one randomized clinical trial) with 196 patients. The CS reducer device was effective in 146/186 (78.5%) patients. CCS score improved from 3.2 at baseline to 1.9 after 8.6 months of follow-up. The efficacy of CS reducer device was also demonstrated as an improvement in Seattle Angina Questionnaire score, dobutamine echocardiography, thalium single-photon emission computed tomography perfusion studies, 6-min-walk test and myocardial perfusion reserve index. Implantation failed in 4 of 196 (2%) patients and 5 patients (2.5%) had a complication during 30-day follow-up. The CS reducer is a promising treatment option for patients with refractory angina who are not candidates for revascularization. However, larger randomized control trials with long-term follow-up are needed to elucidate its role.

Abstract P184: Coordinated Control of Cardiac Contractility By Multiple RGS Proteins

Signaling via heterotrimeric G proteins is critical to maintaining cardiovascular homeostasis. Abnormal G protein signaling due to the loss of G protein regulation by proteins such as regulators of G protein signaling (RGS) proteins is implicated in several cardiovascular disorders such as hypertension, cardiac hypertrophy, and heart failure. RGS act as GTPase activating proteins (GAPs) to control the kinetics and amplitude of G protein signaling. Multiple RGS proteins are prominently expressed in the cardiovascular system; however, it is unknown whether their activities/functions are coordinated to control G protein signaling and cardiovascular function. This study used mice concurrently lacking RGS2 and 5 ( Rgs2/5 dbKO) to determine how the dual loss of potent GAPs for Gq/11 and Gi/o class G proteins affects cardiovascular function. Blood pressure and heart rate in conscious, freely moving mice were monitored via radiotelemetry. Surgical implantation of the radiotelemetry device induced marked systolic blood pressure increase in Rgs2/5 dbKO mice (WT: 140 ± 6 vs. dbKO: 170 ± 2 mmHg; p &lt;0.01) at baseline, which gradually declined but remained elevated above wild type (WT) control level several days later. Whereas all WT mice survived the surgery, ~70-80% of male Rgs2/5 dbKO mice died 72-96 hr post-surgery. When subjected to cardiac stress test using acute dobutamine infusion and echocardiography, male Rgs2/5 dbko mice showed hypocontractile response relative to WT mice. Freshly isolated ventricular cardiomyocytes from male Rgs2/5 dbKO mice showed decreased fractional shortening (WT: 16.1 ± 4.3 vs. dbKO: 7.4 ± 1.1 %; p &lt;0.01) but high calcium transients (WT: 117 ± 20 vs. dbKO: 198 ± 50 au; p =0.07) at baseline, and application of electrical field stimulation or the non-selective β-adrenergic receptor agonist, isoproterenol (ISO), triggered premature calcium transients, tachyarrhythmia and death of cells from Rgs2/5 dbKO mice. Interestingly, cells from mice harboring just one copy of Rgs2 ( Rgs2+/-,Rgs5-/- ) but not Rgs5 ( Rgs2-/-,Rgs5+/- ) were resistant to low-dose ISO-induced arrhythmia. These results together suggest that RGS2 and 5 coordinate their activity to control cardiomyocyte excitation-contraction coupling and normal cardiac rhythm.

Coronary Sinus Reducer implantation improves symptoms, ischaemia and physical capacity in patients with refractory angina unsuitable for myocardial revascularisation: a single-centre experience.

The aim of this study was to evaluate the clinical efficacy of Coronary Sinus Reducer implantation in alleviating angina symptoms and improving objective ischaemia parameters and indices of physical capacity. Patients with refractory angina (Canadian Cardiovascular Society [CCS] class 3-4) were treated with the Reducer. Baseline and follow-up evaluation consisted of clinical assessment including completion of the Seattle Angina Questionnaire (SAQ) and CCS class evaluation, and objective assessment by treadmill exercise test, dobutamine echocardiography and six-minute walk test (6MWT). Overall, 48 patients (40 male) were enrolled. No periprocedural or long-term adverse events were recorded. CCS class diminished from a mean of 3.4±0.5 at baseline to 2.0±1 (p<0.001), and all domains of the SAQ improved significantly following Reducer implantation. Mean exercise duration increased from 03:43±01:30 to 04:36±02:18 min:sec (p=0.025) and 6MWT distance increased from 299.9±97.9 m to 352.9±75.3 m (p=0.002). Ejection fraction (EF%) at stress increased from 51.0±10 to 56.5±10 (p=0.004), and wall motion score index improved from 1.58±0.4 to 1.37±0.3 (p=0.004). Reducer implantation for the treatment of refractory angina is a simple and safe procedure which significantly alleviates symptoms of angina and improves objective ischaemia parameters and indices of physical function.

Left atrial function: Correlation with left ventricular function and contractile reserve in patients with hypertension.

Alterations in left atrial (LA) and left ventricular (LV) function have been documented in hypertensive patients. However, the correlation of LA with LV functional changes has not been established. Using normotensive controls, we examined LA functional changes in hypertensive patients by strain deformation analysis, and their relationship to LV functional changes including contractile reserve (CR). One hundred and sixteen patients (61 men, aged 57.6±9.1years, 67 with hypertension) underwent dobutamine echocardiography. Patients with significant coronary or valvular disease, previous myocardial infarction or coronary revascularization, and diabetes were excluded. LA reservoir (Ɛs), conduit (Ɛe), and atrial contractile (Ɛa) strain were measured at rest. LV global longitudinal strain (GLS) and ejection fraction (LVEF) were measured at rest and at low-dose dobutamine. LV CR was calculated as the difference in GLS and LVEF between the low dose and their corresponding resting values. Hypertensive patients, compared with controls, had significantly impaired LA Ɛs (30.7±3.9% vs 42.4±4.9%), Ɛe (16.2±4.1% vs 22.5±5.5%), and Ɛa (14.5±4.1% vs 19.9±5.0%, all P<.001) strain. All LA phasic strain correlated with LV GLS at rest, at low-dose dobutamine, and LV CR. There was no correlation between LA strain and LVEF or LV CR assessed by LVEF. LV GLS and LAVImax were the strongest independent determinants for LA Ɛs/Ɛe and LA Ɛa, respectively. Compared to controls, hypertensive patients had impaired LA strain, which correlated with LV GLS and CR. LV GLS and LAVImax were the strongest independent determinants for LA Ɛs/Ɛe and LA Ɛa, respectively, independent of BP and LVMi.