ECG AI-Guided Screening for Low Ejection Fraction (EAGLE): Rationale and design of a pragmatic cluster randomized trial.

BACKGROUND: A deep learning algorithm to detect low ejection fraction (EF) using routine 12-lead electrocardiogram (ECG) has recently been developed and validated. The algorithm was incorporated into the electronic health record (EHR) to automatically screen for low EF, encouraging clinicians to obtain a confirmatory transthoracic echocardiogram (TTE) for previously undiagnosed patients, thereby facilitating early diagnosis and treatment. OBJECTIVES: To prospectively evaluate a novel artificial intelligence (AI) screening tool for detecting low EF in primary care practices. DESIGN: The EAGLE trial is a pragmatic two-arm cluster randomized trial (NCT04000087) that will randomize >100 clinical teams (i.e., clusters) to either intervention (access to the new AI screening tool) or control (usual care) at 48 primary care practices across Minnesota and Wisconsin. The trial is expected to involve approximately 400 clinicians and 20,000 patients. The primary endpoint is newly discovered EF ≤50%. Eligible patients will include adults who undergo ECG for any reason and have not been previously diagnosed with low EF. Data will be pulled from the EHR, and no contact will be made with patients. A positive deviance qualitative study and a post-implementation survey will be conducted among select clinicians to identify facilitators and barriers to using the new screening report. SUMMARY: This trial will examine the effectiveness of the AI-enabled ECG for detection of asymptomatic low EF in routine primary care practices and will be among the first to prospectively evaluate the value of AI in real-world practice. Its findings will inform future implementation strategies for the translation of other AI-enabled algorithms.

Quantitative Transthoracic Echocardiography of the Response to Dobutamine in Cardiac Surgery Patients With Low Cardiac Output Syndrome.

OBJECTIVE: To quantify the acute effects of dobutamine in postoperative low cardiac output syndrome (LCOS) using transthoracic echocardiographic, hemodynamic, and blood biomarker monitoring and to assess its association with clinical outcomes. DESIGN: Observational prospective study. SETTING: Single university hospital. PARTICIPANTS: Patients undergoing elective cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Echocardiographic parameters, hemodynamic data, and plasma biomarkers were obtained before and early after inotrope initiation. The diagnostic value of transthoracic echocardiographic parameters and their association with clinical outcome were evaluated. Thirty-eight LCOS patients and 12 control patients were included. The left ventricular outflow tract velocity time integral was significantly lower in LCOS patients (11.75 v 19.08 cm; p < 0.001) and showed a marked improvement after dobutamine administration (∼37% increase). Dobutamine improved left and right ventricular function, increased mean arterial pressure and urine output, and lowered lactate levels. The duration of dobutamine support, but not in-hospital mortality, was associated with echocardiographic estimates of cardiac performance early after dobutamine initiation. CONCLUSIONS: Early transthoracic echocardiographic assessment and the acute response to inotropic therapy may provide rapid and highly valuable information in the diagnostic workup and risk evaluation of patients with suspected LCOS after cardiac surgery.

Echodynamics: Interpretation, Limitations, and Clinical Integration!

Echodynamics refers to the use of echocardiography as hemodynamic tool mostly in intensive and acute care settings. It implies a smooth drift from the classic cardiology use to a more critical care adjusted use. A more personalized approach is advocated in critical care, and echo is one way to reach such goal. Correct application necessitates optimum understanding, interpretation, and finally integration into patients' clinical management. As more critical care doctors are advancing from basic focused echo examinations to a more advanced one, this article is trying to underlie many pitfalls of critical care echocardiography in order to guide better practice.

Low Cardiac Output Syndrome After Adult Cardiac Surgery: Predictive Value of Peak Systolic Global Longitudinal Strain.

BACKGROUND: Peak systolic global longitudinal strain (GLS) is increasingly used to quantify left ventricular systolic function. The primary objective of this study was to assess whether GLS obtained during intraoperative transesophageal echocardiogram, performed before cardiopulmonary bypass, improves the prediction of postoperative low cardiac output syndrome (LCOS) after adult cardiac surgery. METHODS: GLS from 275 patients undergoing on-pump cardiac surgery was calculated retrospectively using two-dimensional- speckle tracking echocardiography (aCMQ module from Qlab software version 10.5, Philips Medical, Brussels, Belgium). LCOS was defined as the need for inotropic or mechanical circulatory support for >24 hours postoperatively. Patient and procedure characteristics associated with LCOS at the univariable level (P ≤ .05) were entered into a forward stepwise logistic regression to create a first predictive model. A second model was created by adding GLS. The 2 models were compared using the likelihood-ratio test, the area under the receiver operating characteristic (ROC) curve, and the integrated discrimination index. The optimal cutoff value of GLS associated with LCOS was determined by maximizing the Youden index of the ROC curve. Secondary outcomes included time until complete weaning from inotropes, discharge from the intensive care unit and from the hospital, and 30-day mortality. RESULTS: GLS was significantly associated with LCOS (P < .001) at the univariable level. Predictors of LCOS retained in the first model were cardiopulmonary bypass duration, decreased left ventricular ejection fraction, mitral valve surgery, and New York Heart Association functional class III or IV. Adding the GLS value improved the prediction of LCOS (P = .02). However, the area under the ROC curve did not differ between the 2 models (0.83; 95% confidence interval [CI], 0.77-0.99 vs 0.84; 95% CI, 0.79-0.90; P = .15). The integrated discrimination index associated with addition of GLS was 0.02 (P = .046), meaning that the difference in predicted risk between patients with and without LCOS increased by 2% after adding GLS. A GLS cutoff value of -17% (95% CI, -18.8% to -15.3%) was found to best identify LCOS. After adjusting for covariates included in model 1, a lower GLS value was significantly associated with a lower cumulative probability of weaning from inotropes postoperatively (hazard ratio, 0.90; 95% CI, 0.82-0.97; P = .01). No association was found between GLS and other secondary outcome measures. CONCLUSIONS: GLS is an independent predictor of LCOS after on-pump cardiac surgery. Its incremental value over other established risk factors for postoperative LCOS is, however, limited.

Myocardial Protection by Glucose-Insulin-Potassium in Moderate- to High-Risk Patients Undergoing Elective On-Pump Cardiac Surgery: A Randomized Controlled Trial.

BACKGROUND: Low cardiac output syndrome is a main cause of death after cardiac surgery. We sought to assess the impact of glucose-insulin-potassium (GIK) to enhance myocardial protection in moderate- to high-risk patients undergoing on-pump heart surgery. METHODS: A randomized controlled trial was performed in adult patients (Bernstein-Parsonnet score >7) scheduled for elective aortic valve replacement and/or coronary artery bypass surgery. Patients were randomized to GIK (20 IU of insulin, 10 mEq of potassium chloride in 50 mL of glucose 40%) or saline infusion given over 60 minutes on anesthetic induction. The primary end point was postcardiotomy ventricular dysfunction (PCVD), defined as new/worsening left ventricular dysfunction requiring inotropic support (≥120 minutes). Secondary end points were the intraoperative changes in left ventricular function as assessed by transoesophageal echocardiography, postoperative troponin levels, cardiovascular and respiratory complications, and intensive care unit and hospital length of stay. RESULTS: From 224 randomized patients, 222 were analyzed (112 and 110 in the placebo and GIK groups, respectively). GIK pretreatment was associated with a reduced occurrence of PCVD (risk ratio [RR], 0.41; 95% confidence interval [CI], 0.25-0.66). In GIK-treated patients, the left systolic ventricular function was better preserved after weaning from bypass, plasma troponin levels were lower on the first postoperative day (2.9 ng·mL(-) [interquartile range {IQR}, 1.5-6.6] vs 4.3 ng·mL(-) [IQR, 2.4-8.2]), and cardiovascular (RR, 0.69; 95% CI, 0.50-0.89) and respiratory complications (RR, 0.5; 95% CI, 0.38-0.74) were reduced, along with a shorter length of stay in intensive care unit (3 days [IQR, 2-4] vs 3.5 days [IQR, 2-7]) and in hospital (14 days [IQR, 11-18.5] vs 16 days [IQR, 12.5-23.5]), compared with placebo-treated patients. CONCLUSIONS: GIK pretreatment was shown to attenuate PCVD and to improve clinical outcome in moderate- to high-risk patients undergoing on-pump cardiac surgery.

Multisite Tissue Oxygenation Monitoring Indicates Organ-Specific Flow Distribution and Oxygen Delivery Related to Low Cardiac Output in Preterm Infants With Clinical Sepsis.

OBJECTIVES: Cardiac output may be compromised in preterm infants with sepsis. Whether low cardiac output is associated with low tissue oxygen supply in these patients is unclear. The aim of the current study was to assess the association between cardiac output, assessed by echocardiography, and tissue oxygenation, measured with multisite near-infrared spectroscopy, in a cohort of preterm infants with clinical sepsis. DESIGN: Prospective observational cohort study. SETTING: Level III neonatal ICU. PATIENTS: Twenty-four preterm infants (gestational age < 32 wk) with clinical sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Clinical and echocardiographic assessment of hemodynamics was performed within 48 hours of sepsis workup and repeated at least 24 hours later. We measured cerebral, renal, and intestinal tissue oxygen saturation using near-infrared spectroscopy during an hour of stable measurements directly preceding or following echocardiography and calculated fractional tissue oxygen extraction in each tissue. We determined Spearman correlation coefficients between fractional tissue oxygen extraction and right ventricular output corrected for patent foramen ovale flow, left ventricular output corrected for ductus arteriosus flow, and superior vena cava flow. Right ventricular output corrected for patent foramen ovale and left ventricular output corrected for ductus arteriosus flow both correlated significantly with intestinal fractional tissue oxygen extraction (ρ, -0.700; p = 0.036 and ρ, -0.604; p = 0.029, respectively). In contrast, no significant correlations were found between cardiac output measurements and cerebral and renal fractional tissue oxygen extraction, respectively. Changes in cardiac output measurements were not associated with observed changes in fractional tissue oxygen extraction values. CONCLUSIONS: Right ventricular output corrected for patent foramen ovale and left ventricular output corrected for ductus arteriosus flow, indicators of systemic blood flow in preterm infants with shunts, were negatively associated with intestinal fractional tissue oxygen extraction, but not with renal and cerebral fractional tissue oxygen extraction. These findings suggest that during low output states due to clinical sepsis intestinal perfusion is most at risk.

Cardiac dysfunction and orthostatic intolerance in patients with myalgic encephalomyelitis and a small left ventricle.

The etiology of chronic fatigue syndrome (CFS) is unknown. Myalgic encephalomyelitis (ME) has been recently postulated to be the cause of CFS. Orthostatic intolerance (OI) has been known as an important symptom in predicting quality of life in CFS patients. Cardiac function may be impaired in patients with ME. The presence or absence of OI was determined both symptomatically and by using a 10-min stand-up test in 40 ME patients. Left ventricular (LV) dimensions and function were determined echocardiographically in the ME patients compared to 40 control subjects. OI was noted in 35 (97%) of the 36 ME patients who could stand up quickly. The mean values for the cardiothoracic ratio, systemic systolic and diastolic pressures, LV end-diastolic diameter (EDD), LV end-systolic diameter, stroke volume index, cardiac index and LV mass index were all significantly smaller in the ME group than in the controls. Both a small LVEDD (<40 mm, 45 vs. 3%) and a low cardiac index (<2 l/ min/mm2, 53 vs. 8%) were significantly more common in the ME group than in the controls. Both heart rate and LV ejection fraction were similar between the groups. In conclusion, a small LV size with a low cardiac output was common in ME patients, in whom OI was extremely common. Cardiac dysfunction with a small heart appears to be related to the symptoms of ME.

[DEFORMITY OF LEFT VENTRICLE WALLS IN PATIENTS WITH AORTAL VALVE STENOSIS].

Parameters of longitudinal deformity of left ventricle walls in patients, suffering aortal valve stenosis (AVS), were analyzed. While the process of heart contraction in norm and in AVS occurs, longitudinal deformity is expressed maximally in its apical divisions. AVS deformity of apical divisions of left ventricle, as well as middle divisions of interventricular septum and lower wall, practically did not differ from such in norm, and deformity of basal divisions of all walls and middle divisions of posterior, lateral and anterior walls of left ventricle was trustworthy less than a norm. Thus, a reduction of the deformity indices in basal divisions of left ventricle and middle segments of its posterior, lateral and anterior walls in patients, suffering AVS with preserved output fraction, precedes the disorders of its hemodynamics and constitutes a predictor for the cardiac output reduction.

[Assessment of cardiovascular preload and response to volume expansion]. / Valoración de la precarga y la respuesta cardiovascular al aporte de volumen.

Volume expansion is used in patients with hemodynamic insufficiency in an attempt to improve cardiac output. Finding criteria to predict fluid responsiveness would be helpful to guide resuscitation and to avoid excessive volume effects. Static and dynamic indicators have been described to predict fluid responsiveness under certain conditions. In this review we define preload and preload-responsiveness concepts. A description is made of the characteristics of each indicator in patients subjected to mechanical ventilation or with spontaneous breathing.

[Role of echocardiography in the hemodynamic monitorization of critical patients]. / Papel de la ecocardiografía en la monitorización hemodinámica de los pacientes críticos.

The use of echocardiography in intensive care units in shock patients allows us to measure various hemodynamic variables in an accurate and a non-invasive manner. By using echocardiography not only as a diagnostic technique but also as a tool for continuous hemodynamic monitorization, the intensivist can evaluate various aspects of shock states, such as cardiac output and fluid responsiveness, myocardial contractility, intracavitary pressures, heart-lung interaction and biventricular interdependence. However, to date there has been little guidance orienting echocardiographic hemodynamic parameters in the intensive care unit, and intensivists are usually not familiar with this tool. In this review, we describe some of the most important hemodynamic parameters that can be obtained at the patient bedside with transthoracic echocardiography in critically ill patients.

A novel hands-free carotid ultrasound detects low-flow cardiac output in a swine model of pulseless electrical activity arrest.

OBJECTIVE: To determine if a hands-free, noninvasive Doppler ultrasound device can reliably detect low-flow cardiac output by measuring carotid artery blood flow velocities. We compared the ability of observers to detect carotid artery flow velocity differences between pseudo-pulseless electrical activity (PEA) and true-PEA cardiac arrest. METHODS: Five swine were instrumented with aortic (Ao) and right atrial pressure-transducing catheters. The Doppler ultrasound device was adhered to the neck over the carotid artery. Continuous electrocardiogram, pressure readings, and Doppler signal were recorded. Each swine underwent multiple episodes of fibrillation and resuscitation. Episodes of true-PEA and pseudo-PEA were retrospectively identified from all resuscitation attempts by examination of electrocardiogram and Ao waveforms. The sensitivity and specificity of the device to detect pseudo-PEA was obtained using observers blinded to Ao waveform recordings. RESULTS: There was good interobserver reliability related to identification of pseudo- and true-PEA (κ = 0.873). The observers blinded to Ao waveform recordings agreed on 8 of the 9 episodes of pseudo-PEA, whereas 4 false positives of 26 true-PEA events were reported (sensitivity, 0.89; specificity, 0.85). The Doppler device was able to detect carotid flow velocity over a wide range of Ao blood pressures. CONCLUSIONS: This hands-free, noninvasive Doppler ultrasound device can reliably differentiate pseudo-PEA from true-PEA during resuscitation from cardiac arrest, detecting pressure gradient changes of less than 5 mm Hg through to normotension. This device distinguishes conditions of no cardiac output from low cardiac output and may have applications for use during resuscitation from various etiologies of arrest and shock.

Does pre-eclampsia influence fetal cardiovascular function in early-onset intrauterine growth restriction?

OBJECTIVES: Increasing evidence shows that intrauterine growth restriction (IUGR) is associated with fetal cardiac dysfunction. Most studies group IUGR with and without pre-eclampsia (PE) altogether. Our objective was to evaluate whether the association with PE has any impact on cardiac function in IUGR fetuses METHODS: Thirty-one normotensive IUGR cases and 31 IUGR cases with pre-eclampsia (PE + IUGR) below 34 weeks of gestation were included. IUGR was defined as a birth weight below the 10(th) centile together with an umbilical artery pulsatility index above 2 SD. Fetal cardiac function was assessed by measuring ductus venosus pulsatility index, modified myocardial performance index, aortic isthmus blood flow, E/A ratios and cardiac output. The presence of fetal cardiac dysfunction was also assessed by measuring cord blood B-type natriuretic peptide (BNP) levels collected at birth. Echocardiographic data were compared with those in 80 term appropriate-for-gestational age (AGA) fetuses from normotensive mothers. Cord blood BNP levels were compared with those in 40 AGA cases that delivered preterm. RESULTS: All IUGR cases (with or without PE) showed echocardiographic and biochemical signs of cardiac dysfunction compared with AGA cases. However, no differences were observed between IUGR and PE + IUGR cases either in echocardiographic or in biochemical parameters. IUGR cases with or without PE had similar perinatal results. CONCLUSIONS: IUGR fetuses showed echocardiographic and biochemical signs of cardiac dysfunction. Pre-eclampsia per se does not influence cardiac function in IUGR fetuses.

Outcomes Among Patients With Heart Failure With Reduced Ejection Fraction Undergoing Transcatheter Aortic Valve Replacement: Minimally Invasive Strategy Versus Conventional Strategy.

OBJECTIVES: To investigate the effect of TAVR technique on in-hospital and 30-day outcomes in patients with aortic stenosis (AS) and reduced ejection fraction (EF). BACKGROUND: Patients with AS and concomitant low EF may be at risk for adverse hemodynamic effects from general anesthesia utilized in transcatheter aortic valve replacement (TAVR) via the conventional strategy (CS). These patients may be better suited for the minimally invasive strategy (MIS), which employs conscious sedation. However, data are lacking that compare MIS to CS in patients with AS and concomitant low EF. METHODS: In this retrospective study, we identified all patients with low EF (<50%) undergoing transfemoral MIS-TAVR vs CS-TAVR between March 2011 and May 2018. Our primary endpoint was defined as the composite of in-hospital mortality and major periprocedural bleeding or vascular complications. RESULTS: Two hundred and seventy patients had EF <50%, while 154 patients had EF ≤35%. Overall, a total of 236 patients were in the MIS group and 34 were in the CS group. Baseline characteristics between the two groups were similar except for Society of Thoracic Surgeons (STS) score (MIS 8.4 ± 5.1 vs CS 11.7 ± 6.8; P<.01). There were no differences between the two groups in incidence of the primary endpoint (MIS 5.5% vs CS 8.8%; odds ratio for MIS, 0.60; 95% confidence interval, 0.16-2.23; P=.45). CONCLUSIONS: In patients with severe AS and reduced EF, MIS was not associated with adverse in-hospital or 30-day clinical outcomes compared with CS. In these patients, MIS may be a suitable alternative to CS without compromising clinical outcomes.

Actual incidence of global left ventricular hypokinesia in adult septic shock.

RATIONALE AND OBJECTIVE: To evaluate the actual incidence of global left ventricular hypokinesia in septic shock. METHOD: All mechanically ventilated patients treated for an episode of septic shock in our unit were studied by transesophageal echocardiography, at least once a day, during the first 3 days of hemodynamic support. In patients who recovered, echocardiography was repeated after weaning from vasoactive agents. Main measurements were obtained from the software of the apparatus. Global left ventricular hypokinesia was defined as a left ventricular ejection fraction of <45%. MEASUREMENTS AND MAIN RESULTS: During a 3-yr period (January 2004 through December 2006), 67 patients free from previous cardiac disease, and who survived for >48 hrs, were repeatedly studied. Global left ventricular hypokinesia was observed in 26 of these 67 patients at admission (primary hypokinesia) and in 14 after 24 or 48 hrs of hemodynamic support by norepinephrine (secondary hypokinesia), leading to an overall hypokinesia rate of 60%. Left ventricular hypokinesia was partially corrected by dobutamine, added to a reduced dosage of norepinephrine, or by epinephrine. This reversible acute left ventricular dysfunction was not associated with a worse prognosis. CONCLUSION: Global left ventricular hypokinesia is very frequent in adult septic shock and could be unmasked, in some patients, by norepinephrine treatment. Left ventricular hypokinesia is usually corrected by addition of an inotropic agent to the hemodynamic support.

Low cardiac output to the placenta: an early hemodynamic adaptive mechanism in intrauterine growth restriction.

OBJECTIVE: A low combined cardiac output (CCO) to the placenta (placenta/CCO fraction) has been reported in growth-restricted (IUGR) fetuses, but the temporal sequence of these modifications in relation to other changes in the fetal circulation is unknown. The aim of this study was to evaluate the placenta/CCO fraction in relation to other hemodynamic changes in fetuses at risk of developing IUGR. METHODS: We studied 340 singleton nulliparous pregnancies characterized at 20-24 weeks by abnormal uterine artery pulsatility index (PI) values (> 95(th) centile). At this gestational age we measured fetal biometry and Doppler waveforms from the umbilical artery (UA), middle cerebral artery (MCA), ductus venosus (DV), umbilical vein (UV) and outflow tracts of both ventricles. The diameters of the semilunar valves and UV were measured and CCO (left cardiac + right cardiac outputs) and UV blood flow were calculated. The placenta/CCO fraction was calculated as UV flow as a percentage of CCO. RESULTS: There were 283 pregnancies with birth weight >or= 10(th) centile and normal UA-PI throughout gestation (Group A), 34 with birth weight < 10(th) centile and normal UA-PI throughout gestation (Group B) and 23 with birth weight < 10(th) centile and abnormal UA-PI developing later in gestation (Group C). At 20-24 weeks there were no differences among the three groups in fetal biometric parameters, PI values from the UA, MCA and DV, and CCO. UV flow and placenta/CCO fraction were significantly lower in Group C compared with Group A (UV flow delta value = - 1.439, P < 0.0001; placenta/CCO fraction delta value = - 1.74, P < 0.0001) but not in Group B. CONCLUSIONS: Our data suggest that, in fetuses developing IUGR secondary to placental compromise, UV flow and placental/CCO fraction are already reduced by 20-24 weeks, and that this reduction occurs earlier than do modifications in fetal size and arterial and venous PI values.

Prolonged central circulation transit time in patients with HFpEF and HFrEF by magnetic resonance imaging.

Aims: Prolonged central circulation transit time (TT) has long been associated with heart failure (HF) and left ventricular (LV) dysfunction. In this study, we assessed the central circulation TT using cardiovascular magnetic resonance imaging (CMR) in patients with HF of preserved ejection fraction (HFpEF) and of reduced EF (HFrEF) and investigated its relation to haemodynamics. Methods and results: Fifty eight prospectively recruited volunteers underwent CMR. TT was taken as the time between the peaks of time-intensity curves from first pass perfusion images and normalized to cardiac cycle length intervals. Left ventricular ejection fraction was 55 ± 3%, 57 ± 7%, and 28 ± 10% in control (N = 10), HFpEF (N = 20), and HFrEF (N = 28), respectively (P < 0.001). Global central TT from right atrium to ascending aorta was significantly prolonged in patients with HFrEF [17 ± 5 cardiac cycles (cc)] and HFpEF (12 ± 3 cc) when compared to the normal controls (8 ± 1 cc) (P < 0.001). Regional TT was also prolonged in HF patients between right atrium and pulmonary artery (PA), PA and left atrium (LA), and LA and ascending aorta (all P-value < 0.001) with the longest delay seen between PA and LA. Among 48 HF patients, 28 underwent same day cardiac catheterization. Multivariate regression analysis suggested while reduced left and right ventricular EF were the strongest correlates for HFrEF increased pulmonary capillary wedge (PCWP) and reduced PA oxygen saturation were the strongest correlates for HFpEF. Conclusions: Global and regional central TT can be assessed in the first pass perfusion imaging. Prolonged normalized global TT correlates with reduced EF in HFrEF and increased PCWP in HFpEF.

Synergistic prognostic implications of left ventricular mechanical dyssynchrony and impaired cardiac sympathetic nerve activity in heart failure patients with reduced left ventricular ejection fraction.

Aims: Impairment of cardiac sympathetic innervation is a potent prognostic marker in heart failure, while left ventricular mechanical dyssynchrony (LVMD) has recently been noted as a novel prognosis determinant in heart failure patients with reduced LV ejection fraction (HFrEF). This study was designed to determine the correlation between cardiac sympathetic innervation quantified by metaiodobenzylguanidine (MIBG) activity and LVMD measured by electrocardiogram-gated myocardial perfusion imaging and to evaluate their incremental prognostic values in HFrEF patients. Methods and results: A total of 570 consecutive HFrEF patients were followed up for 19.6 months with a primary endpoint of lethal cardiac events (CE) such as sudden cardiac death, death due to pump failure and appropriate ICD shock against life-threatening ventricular tachyarrhythmias. Cardiac sympathetic function and innervation were quantified as heart-to-mediastinum ratio (HMR) and washout kinetics of cardiac MIBG activity. LVMD was assessed by a standard deviation (SD) of systolic phase angle in gated myocardial perfusion imaging. Patients with CE (n = 166, 29%) had a significantly lower HMR and a significantly greater phase SD than did non-CE patients: 1.46 ± 0.28 vs. 1.63 ± 0.29, P < 0.0001 and 39.1 ± 11.6 vs. 33.1 ± 10.1, P < 0.0001, respectively. Compared to the single use of optimal cut-offs of late HMR (1.54) and phase SD (38), their combination more precisely discriminated high-risk or low-risk patients from others with log rank values from 7.78 to 65.2 (P = 0.0053 to P ≤ 0.0001). Among significant univariate variables, multivariate Cox proportional hazards model identified NYHA functional class, estimated glomerular filtration rate (eGFR), HMR 1.54 and phase SD 60 as significant determinants of CE with hazard ratios of 3.108 (95% CI, 2.472-3.910; P < 0.0001), 0.988 (95% CI, 0.981-0.996; P = 0.0021), 0.257 (95% CI, 0.128-0.498; P < 0.0001) and 1.019 (95% CI, 1.019-1.037; P = 0.0228), respectively. By combining the four independent determinants, the prognostic powers synergistically (P < 0.0001) increased maximally to 263.8. Conclusions: Left ventricular mechanical dyssynchrony and impairment of cardiac sympathetic innervation are synergistically related to lethal cardiac events, contributing to better stratification of lethal cardiac event-risks and probably to optimization of therapeutic strategy in patients with HFrEF.

Independent prognostic value of left ventricular contractile reserve and chronotropic response in patients with reduced left ventricular ejection fraction undergoing vasodilator stress myocardial perfusion imaging with Rb-82 positron emission tomography.

Objectives: We evaluated the prognostic value of heart rate reserve (ΔHR) and left ventricular ejection fraction reserve (ΔLVEF) among patients with systolic dysfunction. Background: Inadequate ΔHR (maximal stress HR - resting HR) and ΔLVEF (LVEF at stress - LVEF at rest) in response to stress are associated with adverse cardiac events. However, the significance of an abnormal ΔHR and ΔLVEF in patients with systolic dysfunction has not been described. Methods and results: We performed a retrospective analysis of patients with rest LVEF < 45% who underwent dipyridamole stress-rest gated Rb-82 PET myocardial perfusion imaging (PET-MPI) at the Cleveland Clinic between 2006 and 2009. Stress LVEF and volumes were calculated using commercially available software (4DM). A Cox proportional hazards model (CPH) was used to examine the association between ΔLVEF, ΔHR, and all-cause death (ACD). Among 461 patients (mean age 65.7 ± 11.3 years, 82% men) 167 experienced ACD (median follow-up 1045 days). Survival was reduced among patients with ΔHR < 0 (1090 vs. 1300 days, P = 0.04) and ΔLVEF < 0 (1002 vs. 1057 days, P = 0.03). In a CPH after adjusting for confounding variables, ΔHR ≤ 0 and ΔLVEF ≤ 0 were associated with reduced survival (hazard ratio 0.93, P < 0.01 and 0.84, P = 0.01, respectively) with an interaction between age and ΔHR (χ2 = 8.1, P < 0.01). Our model predicts that the magnitude of ΔHR is associated with improved survival among younger patients. For any given ΔLVEF the magnitude of ΔHR has a greater positive effect on survival among younger patients. Conclusion: Both ΔHR and ΔLVEF during pharmacologic stress PET-MPI provide incremental value in predicting ACD among patients with systolic dysfunction.

Perioperative management of critical right ventricular inflow obstruction from right atrial rhabdomyoma.

Rhabdomyoma is the most common cardiac tumor in infancy and commonly located in the ventricles causing outflow obstruction or arrhythmias. We report a rare pediatric (7 month old) case of a right atrial rhabdomyoma presenting with severe cyanosis and low cardiac output from significant tricuspid inflow obstruction with right to left shunt across a stretched patent foramen ovale. We present an emergency cardiac surgery for right atrial tumor resection, and the management of separating the patient with failing right ventricle from cardiopulmonary bypass using a Glenn shunt, since extracorporeal membrane oxygenation (ECMO) or nitric oxide was not available.