Multiparametric Mapping via Cardiovascular Magnetic Resonance in the Risk Stratification of Ventricular Arrhythmias and Sudden Cardiac Death.

Risk stratification for malignant ventricular arrhythmias and sudden cardiac death is a daunting task for physicians in daily practice. Multiparametric mapping sequences obtained via cardiovascular magnetic resonance imaging can improve the risk stratification for malignant ventricular arrhythmias by unveiling the presence of pathophysiological pro-arrhythmogenic processes. However, their employment in clinical practice is still restricted. The present review explores the current evidence supporting the association between mapping abnormalities and the risk of ventricular arrhythmias in several cardiovascular diseases. The key message is that further clinical studies are needed to test the additional value of mapping techniques beyond conventional cardiovascular magnetic resonance imaging for selecting patients eligible for an implantable cardioverter defibrillator.

Predictors of adverse cardiac events of coronary myocardial bridging diagnosed with computed tomography angiography.

AIMS: Myocardial bridging (MB) is a frequent congenital anomaly of the epicardial coronary arteries commonly considered a benign condition. However, in some cases a complex interplay between anatomical, clinical and physiology factors may lead to adverse events, including sudden cardiac death. Coronary CT angiography (CCTA) emerged as the gold standard noninvasive imaging technique for the evaluation of MB. Aim of the study was to evaluate MB prevalence and anatomical features in a large population of patients who underwent CCTA for suspected CAD and to identify potential anatomical and clinical predictors of adverse cardiac events at long-term follow-up. METHODS AND RESULTS: Two-hundred and six patients (mean age 60.3 ± 11.8 years, 128 male) with MB diagnosed at CCTA were considered. A long MB was defined as ≥25 mm of overlying myocardium, whereas a deep MB as ≥2 mm of overlying myocardium. The study endpoint was the sum of the following adverse events: cardiac death, bridge-related acute coronary syndrome, hospitalization for angina or bridge-related ventricular arrhythmias and MB surgical treatment. Of the 206 patients enrolled in the study, 9 were lost to follow-up, whereas 197 (95.6%) had complete follow-up (mean 7.01 ± 3.0 years) and formed the analytic population. Nineteen bridge-related events occurred in 18 patients (acute coronary syndrome in 7, MB surgical treatment in 2 and hospitalization for bridge-related events in 10). Typical angina at the time of diagnosis and long MB resulted as significant independent predictors of adverse outcome. CONCLUSIONS: Typical angina and MB length ≥ 25 mm were independent predictors of cardiac events.

Comparison of Demographic, Clinical, Biochemical, and Imaging Findings in Hypertrophic Cardiomyopathy Prognosis: A Network Meta-Analysis.

BACKGROUND: Despite hypertrophic cardiomyopathy (HCM) being the most common inherited heart disease and conferring increased risk for heart failure (HF) and sudden cardiac death (SCD), risk assessment in HCM patients is still largely unresolved. OBJECTIVES: This study aims to synthesize and compare the prognostic impact of demographic, clinical, biochemical, and imaging findings in patients with HCM. METHODS: The authors searched PubMed, Embase, and Cochrane Library for studies published from 1955 to November 2020, and the endpoints were: 1) all-cause death; 2) an arrhythmic endpoint including SCD, sustained ventricular tachycardia, ventricular fibrillation, or aborted SCD; and 3) a composite endpoint including (1) or (2) plus hospitalization for HF or cardiac transplantation. The authors performed a pairwise meta-analysis obtaining the pooled estimate separately for the association between baseline variables and study endpoints. A random-effects network meta-analysis was subsequently used to comparatively assess the prognostic value of outcome associates. RESULTS: A total of 112 studies with 58,732 HCM patients were included. Among others, increased brain natriuretic peptide/N-terminal pro-B-type natriuretic peptide, late gadolinium enhancement (LGE), positive genotype, impaired global longitudinal strain, and presence of apical aneurysm conferred increased risk for the composite endpoint. At network meta-analysis, LGE showed the highest prognostic value for all endpoints and was superior to all other associates except New York Heart Association functional class >class II. A multiparametric imaging-based model was superior in predicting the composite endpoint compared to a prespecified model based on conventional risk factors. CONCLUSIONS: This network meta-analysis supports the development of multiparametric risk prediction algorithms, including advanced imaging markers additively to conventional risk factors, for refined risk stratification in HCM. (Long-term prognosis of hypertrophic cardiomyopathy according to genetic, clinical, biochemical and imaging findings: a systemic review and meta-analysis; CRD42020185219).

The prognostic role of right ventricular dysfunction in patients with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) primarily affects the left ventricle (LV) sparing the right ventricle (RV) in vast majority of cases. However, several studies employing CMR have revealed that myocardial hypertrophy may also involve the RV. To assess RV size and function in a large prospectively cohort of HCM patients and to evaluate whether these parameters in association with other MR findings can predict cardiac events. Two participating centers prospectively included patients with known or suspected HCM between 2011 and 2017. CMR studies were performed with three different scanners. Outcome measures were a composite of ventricular arrhythmias, hospitalization for HF and cardiac death. Of 607 consecutive patients with known or suspected HCM, 315 had complete follow-up information (mean 65 ± 20 months). Among them, 115 patients developed major cardiac events (MACE) during follow-up. At CMR evaluation, patients with events had higher left atrium (LA) diameter (41.5 ± 8 mm vs. 37.17 ± 7.6 mm, p < 0.0001), LV mass (156.7 vs. 144 g, p = 0.005) and myocardial LGE (4.3% vs. 1.9%, p = 0.001). Similarly, patients with events had lower RV stroke volume index (42.7 vs. 47.0, p = 0.0003) and higher prevalence of both RV hypertrophy (16.4% vs. 4.7%, p = 0.0005) and reduced RV ejection fraction (12.2% vs. 4.4%, p = 0.006). In the multivariate analysis, LA diameter and RV stroke volume index were the strongest predictors of events (p < 0.001 and p = 0.0006, respectively). Anatomic and functional RV anomalies detected and characterized with CMR may have may have a major role in predicting the prognosis of HCM patients.

Cardiac magnetic resonance features of left dominant arrhythmogenic cardiomyopathy: differential diagnosis with myocarditis.

Cardiac magnetic resonance (CMR) findings suggesting a suspected left-dominant arrhythmogenic cardiomyopathy (LDAC) may be difficult to distinguish from those related to previous myocarditis; however, especially in patients with ventricular arrhythmias (VA) with ECG morphology consistent with a left ventricle (LV) origin differential diagnosis is fundamental. Aim of the study was to identify potential imaging features at CMR specific for LDAC diagnosis. Between January 2011 and December 2019, we enrolled 15 consecutive stable patients with a recent diagnosis of significant VA and ECG morphology consistent with a LV origin, detection of potential LV arrhythmic substrate at CMR and undergoing a clinically-indicated LV endomyocardial biopsy showing tissue abnormalities consistent with the diagnosis of LDAC. From the same CMR-endomyocardial biopsy registry, a second group of 30 consecutive patients who underwent CMR and biopsy with a histological diagnosis of previous myocarditis were identified. (1) Subepicardial LGE at the level of the posterolateral wall of the LV was detected in 13 cases of LDAC vs. 21 cases of myocarditis; (2) fat infiltration, and particularly subepicardial posterolateral fat infiltration, was found in almost all LDAC patients vs. one myocarditis only (p < 0.01). (3) No differences in other CMR findings or in any clinical or echocardiographic parameters were found between patients with a biopsy consistent with LDAC vs. myocarditis. In patients with significant VA and ECG morphology consistent with a LV origin, the presence of morpho-functional involvement of the subepicardial layer of LV posterolateral wall at CMR (LGE, fat infiltration, wall dyskinesis) supports LDAC diagnosis.

Prognostic role of transferrin saturation in heart failure patients.

AIMS: In heart failure (HF) iron deficiency (ID) is frequently observed and represents a major mortality risk factor. Purpose of this study was to evaluate the correlation between mortality and ID in a cohort of 661 consecutive patients hospitalized for HF worsening. METHODS AND RESULTS: Patients were grouped: (i)according to presence(+)/absence(-) of anaemia (A) and ID defined following World Health Organization (WHO) and European Society of Cardiology (ESC)-American College of Cardiology/American Heart Association/HF society of America (ACC/AHA/HFSA) definitions, respectively: Group A-ID- (n = 123), Group A+ID- (n = 80), Group A+ID+ (n = 247), and Group A-ID+ (n = 211); (ii) according to presence of absolute (serum ferritin < 100µg/L) and functional ID [ferritin between 100 and 300µg/L and transferrin saturation (TSAT) < 20%]; and (iii) according to TSAT <20% and ≥20%. Groups were not different for several clinical features but age, gender, kidney function, and chronic obstructive pulmonary disease. Average follow-up was 1.94 year (±420 days). Overall 5 years mortality rate was 29.5%. Only anaemia and functional ID but not ID as defined by guidelines showed an impact on prognosis. Transferrin saturation <20% (n = 360) patients showed worst prognosis compared to TSAT ≥20% (n = 301) patients. In addition, functional ID patients showed worse prognosis compared patients with ferritin <100µg/L and TSAT <20% or ≥20% likely due to more severe chronic inflammatory status [C-reactive protein, 7.4 (interquartile range 2.7-22.6) and 3.2 (1.4-8.7) mg/L, P < 0.0001 respectively]. CONCLUSION: We confirmed that in HF anaemia is associated to a poor prognosis. Moreover, we showed that patients with TSAT <20% had worse prognosis compared to those with TSAT ≥20% but the composite of ferritin between 100 and 300 µg/L and TSAT <20% identifies HF patients with the poorest survival rate.

Multi-Modality Imaging in Dilated Cardiomyopathy: With a Focus on the Role of Cardiac Magnetic Resonance.

Heart failure (HF) is recognized as a leading cause of morbidity and mortality worldwide. Dilated cardiomyopathy (DCM) is a common phenotype in patients presenting with HF. Timely diagnosis, appropriate identification of the underlying cause, individualized risk stratification, and prediction of clinical response to treatment have improved the prognosis of DCM over the last few decades. In this article, we reviewed the current evidence on available imaging techniques used for DCM patients. In this direction, we evaluated appropriate scenarios for the implementation of echocardiography, nuclear imaging, and cardiac computed tomography, and we focused on the primordial role that cardiac magnetic resonance (CMR) holds in the diagnosis, prognosis, and tailoring of therapeutic options in this population of special clinical interest. We explored the predictive value of CMR toward left ventricular reverse remodeling and prediction of sudden cardiac death, thus guiding the decisions for device therapy. Principles underpinning the use of state-of-the-art CMR techniques such as parametric mapping and feature-tracking strain analysis are also provided, along with expectations for the anticipated future advances in this field. We also attempted to correlate the evidence with clinical practice, with the intent to address questions on selecting the optimal imaging method for different indications and clinical needs. Overall, we recommend a comprehensive assessment of DCM patients at baseline and at follow-up intervals depending on the clinical status, with the addition of CMR as a second-line modality to other imaging techniques. We also provide an algorithm to guide the detailed imaging approach of the patient with DCM. We expect that future guidelines will upgrade their clinical recommendations for the utilization of CMR in DCM, which is expected to further improve the quality of care and the outcomes. This review provides an up-to-date perspective on the imaging of dilated cardiomyopathy patients and will be of clinical value to training doctors and physicians involved in the area of heart failure.

FFRCT and CT perfusion: A review on the evaluation of functional impact of coronary artery stenosis by cardiac CT.

Coronary computed tomography angiography (CCTA) is at the frontline of the diagnostic strategies to detect coronary artery disease (CAD). Anatomical information have proven to be insufficient to detect hemodynamic significant epicardial stenosis. In the present invited review we discuss on FFRCT and stress CTP, emerging technologies for an accurate and comprehensive evaluation of patients with suspected CAD, offering both anatomical (i.e. luminal and plaque) and functional assessment in one single technique.

The usefulness of cardiac CT integrated with FFRCT for planning myocardial revascularization in complex coronary artery disease: a lesson from SYNTAX studies.

After two decades of clinical use, during which coronary CT angiography (CCTA) was considered an appropriate method for the non-invasive assessment of patients with suspected stable coronary artery disease (CAD) and low-to-intermediate pretest likelihood of CAD, a growing body of literature is showing that CCTA may have also a clinical role in patients with high pretest likelihood of CAD, known CAD and complex and diffuse CAD. Particularly, the SYNTAX studies demonstrated the usefulness of CCTA in the field of non-invasive assessment of these patients and planning of interventional and surgical coronary procedures, thanks to its ability to combine, in a single method, precise stenosis quantification, accurate plaque characterization, functional assessment and selection of the revascularization modality for any individual patient and of the vessels that need to be revascularized. Of note, the SYNTAX III Revolution trial showed, in patients with three-vessel CAD, that treatment decision-making between PCI and CABG based on CCTA only has an almost perfect agreement with the treatment decision derived from invasive coronary angiography (ICA). Moreover, the SYNTAX Score II demonstrated a high degree of correlation between the two diagnostic strategies, suggesting the potential feasibility of a treatment decision-making based solely on non-invasive imaging and clinical information. New research prospects have opened up for the future to demonstrate the true feasibility and safety of this innovative approach in the clinical arena.

State-of-the-art-myocardial perfusion stress testing: Static CT perfusion.

Large multicenter studies and meta-analysis have documented the diagnostic accuracy and the prognostic implications of stress echocardiography, cardiac magnetic resonance and, mainly, nuclear stress tests. However, none of them provides a comprehensive anatomical and functional evaluation within the same study as stress CT perfusion. Myocardial CT perfusion is the only non-invasive modality that allows to quantifying coronary stenosis and determining its functional relevance, constituting a potential "one-stop-shop" method for the diagnosis and global management of patients with known or suspected coronary artery disease. In comparison with the dynamic modality, that requires increased radiation, precise acquisition protocols and dedicated post-processing softwares, static CT perfusion was associated with less radiation exposure, non-inferior diagnostic accuracy, easier interpretation of images and is nowadays more widely available.

Rationale and design of the EPLURIBUS Study (Evidence for a comPrehensive evaLUation of left ventRicle dysfnctIon By a whole-heart coverage cardiac compUted tomography Scanner).

BACKGROUND: Cardiac magnetic resonance (CMR) is the standard of reference for myocardial fibrosis detection by late gadolinium enhancement. Cardiac computed tomography (CCT) is emerging as a promising alternative. The Evidence for a comPrehensive evaLUation of left ventRicle dysfnctIon By a whole-heart coverage cardiac compUted tomography Scanner study will assess the feasibility and diagnostic accuracy of a comprehensive functional and anatomical cardiac evaluation with CCT as compared with CMR and invasive coronary angiography as standard of reference. METHODS: Consecutive patients with a newly diagnosed left ventricle (LV) dysfunction (left ventricular ejection fraction <50%) and a clinical indication to CMR will be screened. Exclusion criteria will be contraindications to contrast agents and impaired renal function. CCT will be performed per protocol within 10 days from CMR. A total of 100 patients will be enrolled within 24 months. We will evaluate with CCT volume and ejection fraction of the LV and right ventricle, presence, extent and pattern of delayed enhancement and cardiac venous system. Moreover, presence and degree of coronary stenoses will be evaluated among patients undergoing invasive coronary angiography in the 6 months following CCT. RESULTS: The primary study endpoints will be: first, to assess the diagnostic performance of CCT vs. CMR to detect the delayed enhancement in a territory-based and patient-based analysis; second, to assess the agreement between CCT and CMR in the discrimination between ischemic vs. nonischemic delayed enhancement patters in a territory-based analysis; third, to assess the correlation between CCT and CMR for LV and right ventricle end-diastolic and end-systolic volumes and ejection fraction measurements. CONCLUSION: The Evidence for a comPrehensive evaLUation of left ventRicle dysfnctIon By a whole-heart coverage cardiac compUted tomography Scanner study will assess the diagnostic performance of CCT using the latest scanner generation for a comprehensive evaluation of patients with new-onset LV dysfunction.

Interpretability of coronary CT angiography performed with a novel whole-heart coverage high-definition CT scanner in 300 consecutive patients with coronary artery bypass grafts.

AIMS: Coronary CT angiography (CCTA) is an accurate non-invasive tool for the evaluation of coronary artery bypass graft (CABG). However, inability to sustain a long breath-hold, high heart rate (HR) and atrial fibrillation may affect image quality. Moreover, radiation exposure is still a matter of some concern. A scanner combining 0.23-mm spatial resolution, new iterative reconstruction and fast gantry rotation time has been recently introduced in the clinical field. The aims of our study were to evaluate interpretability, radiation exposure and diagnostic accuracy of CCTA performed with the latest generation of cardiac-CT scanners compared to invasive coronary angiography (ICA) in the assessment of bypass grafts, and non-grafted and post-anastomotic native coronary arteries. METHODS AND RESULTS: We prospectively enrolled 300 patients undergoing clinically indicated CCTA with a 16-cm z-axis coverage, 256-detector rows, and 0.28-sec gantry rotation time scanner. Coronary artery and graft interpretability, image quality and effective dose (ED) were assessed in all patients and diagnostic accuracy was evaluated in a subgroup of 100 patients who underwent ICA. Mean HR during the scan was 69.6 ±â€¯10.8. Sinus rhythm was present in 118 patients with HR < 75 bpm and in 112 patients with HR ≥ 75 bpm, while 70 patients had atrial fibrillation. CABG interpretability was 100%. Compared to ICA, CCTA was able to correctly detecting occlusions or significant stenoses of all CABG segments. Overall interpretability of native coronary segments was 95.6%. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of coronary arteries were 98.3%, 97.4%, 93.1%, 99.3% and 96.5%, respectively. The diagnostic accuracy in a patient based analysis was 95.2%. Mean ED was 3.14 ±â€¯1.7 mSv. CONCLUSIONS: The novel whole-heart coverage CT scanner allows to evaluating CABG and native coronary arteries with excellent interpretability and low radiation exposure even in the presence of unfavorable heart rhythm.

Plaque quantification by coronary computed tomography angiography using intravascular ultrasound as a reference standard: a comparison between standard and last generation computed tomography scanners.

AIMS: The emerging role of coronary computed tomography angiography (CCTA) as a non-invasive tool for atherosclerosis evaluation is supported by data reporting a good correlation between CCTA and intravascular ultrasound (IVUS) for plaque volume quantification. Aim of the present study was to evaluate whether a last generation CT-scanner may improve coronary plaque volume assessment using IVUS as standard-of-reference. METHODS AND RESULTS: From a registry of 1915 consecutive, all-comers, patients who underwent a clinically indicated IVUS evaluation we enrolled 59 patients who underwent CCTA with a 64-slice CT (Group 1) and 59 patients who underwent CCTA with whole-heart coverage CT scanner (Group 2). Patients who underwent CCTA with unfavourable heart rhythm were not excluded from the analysis. Image quality (4-point Likert scale) focused on plaque analysis was evaluated. Plaque volume quantification by CCTA was compared to IVUS. No difference in clinical characteristics was found between Group 1 and Group 2. Plaque volume quantification by CCTA was considered not feasible in 11 plaques of Group 1 and in 4 plaques of Group 2 (P = 0.09). Higher correlation for plaque volume quantification by CCTA vs. IVUS was demonstrated in Group 2 when compared with Group 1 (r = 0.9888 vs. 0.9499; P < 0.0001). The Bland-Altman analysis showed plaque volume overestimation by CCTA of 11.9 mm3 in Group 1 and 4 mm2 in Group 2 (P < 0.001). Effective radiation dose of CCTA was significantly lower in Group 2 vs. Group 1 (2.7 ± 0.9 vs. 8.1 ± 3.6 mSv, respectively; P < 0.001). CONCLUSIONS: CCTA using a new scanner generation showed to be an accurate non-invasive tool to assess and quantify coronary plaque volume.

Minimally invasive coronary artery bypass: Twenty-year experience.

OBJECTIVE: Minimally invasive direct coronary artery bypass for the left thoracic artery on the left anterior descending artery is a safe and less traumatic surgical technique. We retrospectively evaluated long-term outcomes in a large series of patients undergoing minimally invasive direct coronary artery bypass. METHODS: From 1997 to 2016, 1060 patients underwent minimally invasive direct coronary artery bypass: 646 patients (61%) with isolated proximal left anterior descending disease and 414 patients (39%) with multivessel disease as a part of hybrid coronary revascularization or in association with medical therapy. Long-term follow-up, major cardiac and cerebral adverse events, and freedom from angina were analyzed. RESULTS: Mean age of patients was 71 ± 12.5 years, and median European System for Cardiac Operative Risk Evaluation II was 3.2% (interquartile range, 0.6%-7.8%). Postoperative death occurred in 9 patients (0.8%), and perioperative stroke occurred in 3 patients (0.3%). An angiogram or computed tomography scan was performed and was available in patients within 10 years of follow-up (n = 696), demonstrating a 96.8% graft patency rate. At 13.9 ± 5.6 years of follow-up, no surgical reintervention was performed for left thoracic artery on left anterior descending artery graft failure, but 14 patients underwent left anterior descending or left thoracic artery on left anterior descending artery percutaneous coronary intervention. Kaplan-Meier survival curve shows 87.1% at 5 years (95% confidence interval, 81-92.5), 84.3% at 10 years (95% confidence interval, 77.1-91.4), and 79.8% at 15 years (95% confidence interval, 72.2-87.3). Survival freedom from major adverse events was 87.0% (95% confidence interval, 85.9-88.1) at 5 years and 70.5% (95% confidence interval, 66.4-74.6) at 15 years. CONCLUSIONS: Minimally invasive direct coronary artery bypass can be safely performed with low postoperative mortality and morbidity with excellent short- and long-term survival and freedom from major adverse events and angina with a reduced surgical invasiveness.

Qualitative and quantitative evaluation of a new wearable device for ECG and respiratory Holter monitoring.

BACKGROUND: Recent advances in wearable technology make continuous cardiorespiratory monitoring possible, with potential applications in assessment of cardiopulmonary patients, healthy subjects and athletes. The aim of the present study was to qualitatively and quantitatively evaluate a new wearable device (Learn Inspire Free Entertain = L.I.F.E.) by embedding in a compression shirt a 12­lead ECG system and 5 respiratory sensors. METHODS: Thirty cardiorespiratory patients and ten healthy subjects were studied for 24 h during their usual life activities. In 8 healthy subjects, simultaneous measurements of the device and of an ergo-spirometer were performed during different levels of ventilation in five different body positions. The quality of ECG signals in terms of measurability of heart rate, P wave, QRS complex and ST segment, was analyzed by four expert cardiologists/respiratory physiologists using an arbitrary 1-5 scale. The sum of the respiratory signals was used to calculate the respiratory rate, inspiratory time and relative changes of tidal volume. These parameters were compared to ergo-spirometer measurements. RESULTS: Median quality value was >3 for heart rate, QRS complex, ST segment and P wave (except in L3, aVL, aVF, V1 and V2 leads). Median quality of respiratory traces was >4 in patients and between 3 and 4 in healthy subjects. The respiratory monitoring of respiratory rate and inspiratory time was accurate in all body positions. Tidal volumes were underestimated due to a high level of ventilation. CONCLUSIONS: The L.I.F.E. device provides an accurate continuous monitoring of cardiorespiratory signals during the 24 h both in normal subjects and cardiorespiratory patients.

Rescue Leadless Pacemaker Implantation in a Pacemaker-Dependent Patient with Congenital Heart Disease and no Alternative Routes for Pacing.

Congenital heart disease patients are considered a unique group of patients regarding their high risk of conduction abnormalities , whether de novo or surgically induced , and the challenges in both implantation and management of device related complications. We present a case of a pacemaker-dependent patient with congenital heart disease who experienced complications of both previous epicardial and transvenous pacing which rendered her a non-suitable candidate of both routes.

Lvad pump speed increase is associated with increased peak exercise cardiac output and vo2, postponed anaerobic threshold and improved ventilatory efficiency.

BACKGROUNDS: Peak exercise cardiac output (CO) increase is associated with an increase of peak oxygen uptake (VO2), provided that arteriovenous O2 difference [Δ(Ca-Cv)O2] does not decrease. At anaerobic threshold, VO2, is related to CO. We tested the hypothesis that, in heart failure (HF) patients with left ventricular assistance device (LVAD), an acute increase of CO obtained through changes in LVAD pump speed is associated with peak exercise and anaerobic threshold VO2 increase. METHODS: Fifteen of 20 patients bearing LVAD (Jarvik 2000) enrolled in the study successfully performed peak exercise evaluation. All patients had severe HF as shown by clinical evaluation, laboratory tests, echocardiography, spirometry with alveolar-capillary diffusion, and maximal cardiopulmonary exercise testing (CPET). CPETs with non-invasive CO measurements at rest and peak exercise were done on 2days at LVAD pump speed set randomly at 2 and 4. RESULTS: Increasing LVAD pump speed from 2 to 4 increased CO from 3.4±0.9 to 3.8±1.0L/min (ΔCO 0.4±0.6L/min, p=0.04) and from 5.3±1.3 to 5.9±1.4L/min (ΔCO 0.6±0.7L/min, p<0.01) at rest and peak exercise, respectively. Similarly, VO2 increased from 788±169 to 841±152mL/min (ΔVO2 52±76mL/min, p=0.01) and from 568±116 to 619±124mL/min (ΔVO2 69±96mL/min, p=0.02) at peak exercise and at anaerobic threshold, respectively. Δ(Ca-Cv)O2 did not change significantly, while ventilatory efficiency improved (VE/VCO2 slope from 39.9±5.4 to 34.9±8.3, ΔVE/VCO2 -5.0±6.4, p<0.01). CONCLUSIONS: In HF, an increase in CO with a higher LVAD pump speed is associated with increased peak VO2, postponed anaerobic threshold, and improved ventilatory efficiency.