A Practical Approach to Echocardiographic Imaging in Patients With Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is frequently unrecognized or misdiagnosed. The recently published consensus recommendations from the American Society of Echocardiography provided recommendations for the utilization of multimodality imaging in the care of patients with HCM. This document provides an additional practical framework for optimal image and measurement acquisition and guidance on how to tailor the echocardiography examination for individuals with HCM. It also provides resources for physicians and sonographers to use to develop HCM imaging protocols.

Multimodality Cardiac Imaging, Cardiac Symptoms, and Clinical Outcomes in Patients Who Recovered from Mild COVID-19

Background Many patients have persistent cardiac symptoms after mild COVID-19. However, studies assessing the relationship between symptoms and cardiac imaging are limited. Purpose To assess the relationship between multi-modality cardiac imaging parameters, symptoms, and clinical outcomes in patients recovered from mild COVID-19 compared to COVID-19 negative controls. Materials and Methods Patients who underwent PCR testing for SARS-CoV-2 between August 2020 and January 2022 were invited to participate in this prospective, single-center study. Participants underwent cardiac MRI, echocardiography, and assessment of cardiac symptoms at 3-6 months after SARS-CoV-2 testing. Cardiac symptoms and outcomes were also evaluated at 12-18 months. Statistical analysis included Fisher's exact test and logistic regression. Results This study included 122 participants who recovered from COVID-19 ([COVID+] mean age, 42 years ± 13 [SD]; 73 females) and 22 COVID-19 negative controls (mean age, 46 years ± 16 [SD]; 13 females). At 3-6 months, 20% (24/122) and 44% (54/122) of COVID+ participants had at least one abnormality on echocardiography and cardiac MRI, respectively, which did not differ compared to controls (23% [5/22]; P = .77 and 41% [9/22]; P = .82, respectively). However, COVID+ participants more frequently reported cardiac symptoms at 3-6 months compared to controls (48% [58/122] vs. 23% [4/22]; P = .04). An increase in native T1 (10 ms) was associated with increased odds of cardiac symptoms at 3-6 months (OR, 1.09 [95% CI: 1.00, 1.19]; P = .046) and 12-18 months (OR, 1.14 [95% CI: 1.01, 1.28]; P = .028). No major adverse cardiac events occurred during follow-up. Conclusion Patients recovered from mild COVID-19 reported increased cardiac symptoms 3-6 months after diagnosis compared to controls, but the prevalence of abnormalities on echocardiography and cardiac MRI did not differ between groups. Elevated native T1 was associated with cardiac symptoms 3-6 months and 12-18 months after mild COVID-19.

Stimulator of interferon genes is required for Toll-Like Receptor-8 induced interferon response

The innate immune system is equipped with multiple receptors to detect microbial nucleic acids and induce type I interferon (IFN) to restrict viral replication. When dysregulated these receptor pathways induce inflammation in response to host nucleic acids and promote development and persistence of autoimmune diseases like Systemic Lupus Erythematosus (SLE). IFN production is regulated by the Interferon Regulatory Factor (IRF) transcription factor family of proteins that function downstream of several innate immune receptors such as Toll-like receptors (TLRs) and Stimulator of Interferon Genes (STING). Although both TLRs and STING activate the same downstream molecules, the pathway by which TLRs and STING activate IFN response are thought to be independent. Here we show that STING plays a previously undescribed role in human TLR8 signaling. Stimulation with the TLR8 ligands induced IFN secretion in primary human monocytes, and inhibition of STING reduced IFN secretion from primary monocytes from 8 healthy donors. We demonstrate that TLR8-induced IRF activity was reduced by STING inhibitors. Moreover, TLR8-induced IRF activity was blocked by inhibition or loss of IKKε, but not TBK1. Bulk RNA transcriptomic analysis supported a model where TLR8 induces transcriptional responses associated with SLE that can be downregulated by inhibition of STING. These data demonstrate that STING is required for full TLR8-to-IRF signaling and provide evidence for a new framework of crosstalk between cytosolic and endosomal innate immune receptors, which could be leveraged to treat IFN driven autoimmune diseases.

Background

High levels of type I interferon (IFN) is characteristic of multiple autoimmune diseases, and while TLR8 is associated with autoimmune disease and IFN production, the mechanisms of TLR8-induced IFN production are not fully understood.

Results

STING is phosphorylated following TLR8 signaling, which is selectively required for the IRF arm of TLR8 signaling and for TLR8-induced IFN production in primary human monocytes.

Conclusion

STING plays a previously unappreciated role in TLR8-induced IFN production.

Significance

Nucleic acid-sensing TLRs contribute to development and progression of autoimmune disease including interferonopathies, and we show a novel role for STING in TLR-induced IFN production that could be a therapeutic target.

Interpretable machine learning for automated left ventricular scar quantification in hypertrophic cardiomyopathy patients

Scar quantification on cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) images is important in risk stratifying patients with hypertrophic cardiomyopathy (HCM) due to the importance of scar burden in predicting clinical outcomes. We aimed to develop a machine learning (ML) model that contours left ventricular (LV) endo- and epicardial borders and quantifies CMR LGE images from HCM patients.We retrospectively studied 2557 unprocessed images from 307 HCM patients followed at the University Health Network (Canada) and Tufts Medical Center (USA). LGE images were manually segmented by two experts using two different software packages. Using 6SD LGE intensity cutoff as the gold standard, a 2-dimensional convolutional neural network (CNN) was trained on 80% and tested on the remaining 20% of the data. Model performance was evaluated using the Dice Similarity Coefficient (DSC), Bland-Altman, and Pearson's correlation. The 6SD model DSC scores were good to excellent at 0.91 ± 0.04, 0.83 ± 0.03, and 0.64 ± 0.09 for the LV endocardium, epicardium, and scar segmentation, respectively. The bias and limits of agreement for the percentage of LGE to LV mass were low (-0.53 ± 2.71%), and correlation high (r = 0.92). This fully automated interpretable ML algorithm allows rapid and accurate scar quantification from CMR LGE images. This program does not require manual image pre-processing, and was trained with multiple experts and software, increasing its generalizability.

Automated Quantification of Abnormal QRS Peaks From High-Resolution ECGs Predicts Late Ventricular Arrhythmias in Hypertrophic Cardiomyopathy: A 5-Year Prospective Multicenter Study

Background Patients with hypertrophic cardiomyopathy (HCM) are at risk of ventricular arrhythmia (VA) attributed to abnormal electrical activation arising from myocardial fibrosis and myocyte disarray. We sought to quantify intra-QRS peaks (QRSp) in high-resolution ECGs as a measure of abnormal activation to predict late VA in patients with HCM. Methods and Results Prospectively enrolled patients with HCM (n=143, age 53±14 years) with prophylactic implantable cardioverter-defibrillators had 3-minute, high-resolution (1024 Hz), digital 12-lead ECGs recorded during intrinsic rhythm. For each precordial lead, QRSp was defined as the total number of peaks detected in the QRS complex that deviated from a smoothing filtered version of the QRS. The VA end point was appropriate implantable cardioverter-defibrillator therapy during 5-year prospective follow-up. After 5 years, 21 (16%) patients had VA. Patients who were VA positive had greater QRSp (6.0 [4.0-7.0] versus 4.0 [2.0-5.0]; P<0.01) and lower left ventricular ejection fraction (57±11 versus 62±9; P=0.038) compared with patients who were VA negative, but had similar established HCM risk metrics. Receiver operating characteristic analysis revealed that QRSp discriminated VA (area under the curve=0.76; P<0.001), with a QRSp ≥4 achieving 91% sensitivity and 39% specificity. The annual VA rate was greater in patients with QRSp ≥4 versus QRSp <4 (4.4% versus 0.98%; P=0.012). In multivariable Cox regression, age <50 years (hazard ratio [HR], 2.53; P=0.009) and QRSp (HR per QRS peak, 1.41; P=0.009) predicted VA after adjusting for established HCM risk metrics. In patients aged <50 years, the annual VA rate was 0.0% for QRSp <4 compared with 6.9% for QRSp ≥4 (P=0.012). Conclusions QRSp predicted VA in patients with HCM who were eligible for an implantable cardioverter-defibrillator after adjusting for established HCM risk metrics, such that each additional QRS peak increases VA risk by 40%. QRSp <4 was associated with a <1% annual VA risk in all patients, and no VA risk among those aged <50 years. This novel ECG metric may improve patient selection for prophylactic implantable cardioverter-defibrillator therapy by identifying those with low VA risk. These findings require further validation in a lower risk HCM cohort. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02560844.

Recommendations for Multimodality Cardiovascular Imaging of Patients with Hypertrophic Cardiomyopathy: An Update from the American Society of Echocardiography, in Collaboration with the American Society of Nuclear Cardiology, the Society for Cardiovascular Magnetic Resonance, and the Society of Cardiovascular Computed Tomography

Hypertrophic cardiomyopathy (HCM) is defined by the presence of left ventricular hypertrophy in the absence of other potentially causative cardiac, systemic, syndromic, or metabolic diseases. Symptoms can be related to a range of pathophysiologic mechanisms including left ventricular outflow tract obstruction with or without significant mitral regurgitation, diastolic dysfunction with heart failure with preserved and heart failure with reduced ejection fraction, autonomic dysfunction, ischemia, and arrhythmias. Appropriate understanding and utilization of multimodality imaging is fundamental to accurate diagnosis as well as longitudinal care of patients with HCM. Resting and stress imaging provide comprehensive and complementary information to help clarify mechanism(s) responsible for symptoms such that appropriate and timely treatment strategies may be implemented. Advanced imaging is relied upon to guide certain treatment options including septal reduction therapy and mitral valve repair. Using both clinical and imaging parameters, enhanced algorithms for sudden cardiac death risk stratification facilitate selection of HCM patients most likely to benefit from implantable cardioverter-defibrillators.

A Combined Echocardiography Approach for the Diagnosis of Cancer Therapy-Related Cardiac Dysfunction in Women With Early-Stage Breast Cancer

IMPORTANCE

Diagnosis of cancer therapy-related cardiac dysfunction (CTRCD) remains a challenge. Cardiovascular magnetic resonance (CMR) provides accurate measurement of left ventricular ejection fraction (LVEF), but access to repeated scans is limited.

OBJECTIVE

To develop a diagnostic model for CTRCD using echocardiographic LVEF and strain and biomarkers, with CMR as the reference standard.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective cohort study, patients were recruited from University of Toronto-affiliated hospitals from November 2013 to January 2019 with all cardiac imaging performed at a single tertiary care center. Women with human epidermal growth factor receptor 2 (HER2)-positive early-stage breast cancer were included. The main exclusion criterion was contraindication to CMR. A total of 160 patients were recruited, 136 of whom completed the study.

EXPOSURES

Sequential therapy with anthracyclines and trastuzumab.

MAIN OUTCOMES AND MEASURES

Patients underwent echocardiography, high-sensitivity troponin I (hsTnI), B-type natriuretic peptide (BNP), and CMR studies preanthracycline and postanthracycline every 3 months during and after trastuzumab therapy. Echocardiographic measures included 2-dimensional (2-D) LVEF, 3-D LVEF, peak systolic global longitudinal strain (GLS), and global circumferential strain (GCS). LVEF CTRCD was defined using the Cardiac Review and Evaluation Committee Criteria, GLS or GCS CTRCD as a greater than 15% relative change, and abnormal hsTnI and BNP as greater than 26 pg/mL and ≥ 35 pg/mL, respectively, at any follow-up point. Combinations of echocardiographic measures and biomarkers were examined to diagnose CMR CTRCD using conditional inference tree models.

RESULTS

Among 136 women (mean [SD] age, 51.1 [9.2] years), CMR-identified CTRCD occurred in 37 (27%), and among those with analyzable images, in 30 of 131 (23%) by 2-D LVEF, 27 of 124 (22%) by 3-D LVEF, 53 of 126 (42%) by GLS, 61 of 123 (50%) by GCS, 32 of 136 (24%) by BNP, and 14 of 136 (10%) by hsTnI. In isolation, 3-D LVEF had greater sensitivity and specificity than 2-D LVEF for CMR CTRCD while GLS had greater sensitivity than 2-D or 3-D LVEF. Regression tree analysis identified a sequential algorithm using 3-D LVEF, GLS, and GCS for the optimal diagnosis of CTRCD (area under the receiver operating characteristic curve, 89.3%). The probability of CTRCD when results for all 3 tests were negative was 1.0%. When 3-D LVEF was replaced by 2-D LVEF in the model, the algorithm still performed well; however, its primary value was to rule out CTRCD. Biomarkers did not improve the ability to diagnose CTRCD.

CONCLUSIONS AND RELEVANCE

Using CMR CTRCD as the reference standard, these data suggest that a sequential approach combining echocardiographic 3-D LVEF with 2-D GLS and 2-D GCS may provide a timely diagnosis of CTRCD during routine CTRCD surveillance with greater accuracy than using these measures individually.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02306538.

Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias

Background

Unlike T‐wave alternans (TWA), the relation between QRS alternans (QRSA) and ventricular arrhythmia (VA) risk has not been evaluated in hypertrophic cardiomyopathy (HCM). We assessed microvolt QRSA/TWA in relation to HCM risk factors and late VA outcomes in HCM.

Methods and Results

Prospectively enrolled patients with HCM (n=130) with prophylactic implantable cardioverter‐defibrillators underwent digital 12‐lead ECG recordings during ventricular pacing (100–120 beats/min). QRSA/TWA was quantified using the spectral method. Patients were categorized as QRSA+ and/or TWA+ if sustained alternans was present in ≥2 precordial leads. The VA end point was appropriate implantable cardioverter‐defibrillator therapy over 5 years of follow‐up. QRSA+ and TWA+ occurred together in 28% of patients and alone in 7% and 7% of patients, respectively. QRSA magnitude increased with pacing rate (1.9±0.6 versus 6.2±2.0 µV; P=0.006). Left ventricular thickness was greater in QRSA+ than in QRSA− patients (22±7 versus 20±6 mm; P=0.035). Over 5 years follow‐up, 17% of patients had VA. The annual VA rate was greater in QRSA+ versus QRSA− patients (5.8% versus 2.0%; P=0.006), with the QRSA+/TWA− subgroup having the greatest rate (13.3% versus 2.6%; P<0.001). In those with <2 risk factors, QRSA− patients had a low annual VA rate compared QRSA+ patients (0.58% versus 7.1%; P=0.001). Separate Cox models revealed QRSA+ (hazard ratio [HR], 2.9 [95% CI, 1.2–7.0]; P=0.019) and QRSA+/TWA− (HR, 7.9 [95% CI, 2.9–21.7]; P<0.001) as the most significant VA predictors. TWA and HCM risk factors did not predict VA.

Conclusions

In HCM, microvolt QRSA is a novel, rate‐dependent phenomenon that can exist without TWA and is associated with greater left ventricular thickness. QRSA increases VA risk 3‐fold in all patients, whereas the absence of QRSA confers low VA risk in patients with <2 risk factors.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02560844.

A Diagnostic Dilemma from a Presentation of Shortness of Breath and Chest Pain

INTRODUCTION

A patient presented to hospital with chest pain and shortness of breath on 2 occasions 4 weeks apart. Clinical examination revealed an elevated jugular venous pressure consistent with heart failure or elevated filling pressures.

METHODS

The patient was investigated through various modalities including electrocardiogram (ECG), transthoracic echocardiogram, coronary angiography, MRI, cardiac catheterization, positron emission tomography, and an extensive laboratory workup.

RESULTS

Serial hs TnI measurements consistently revealed grossly elevated troponin I (>10 000 ng/L). In-lab investigation of increased high sensitivity troponin I (hsTnI) showed evidence of falsely increased troponin due to the presence of heterophilic antibodies.

DISCUSSION

This case demonstrates a complex patient presentation and the value of involving the laboratory medicine team when dealing with potentially discrepant results. This is a rare report of grossly elevated troponin due to heterophilic antibodies for high-sensitivity troponin Abbott assay.

Clinical Course and Cardiac Complications of Hospitalized COVID-19 Patients

Purpose

We describe the hospitalization course, cardiac complications and echocardiographic findings in a subset of acutely ill hospitalized patients with COVID-19.

Methods

Patients admitted to a large academic hospital in Ontario, Canada from March-June 2020 with COVID-19 and who had an echocardiogram within 4-weeks of their diagnosis were included in this study. Their demographics, hospitalization details and echocardiographic findings were analyzed.

Results

76 patients are included in our study, 83% of whom required ICU. Mean age was 58.9 years (+/-15.7 years). Cardiovascular comorbidities were common: diabetes (35.5%), hypertension (50%), CKD (11.8%), prior CAD (13.2%) or stroke (11.8%). Median length of admission was 25.5 days (IQR 22days). Overall, in-hospital mortality was high at 35.5%, with increased mortality in the ICU vs. non-ICU group (32.9% vs. 15.4%). A large number of patients required invasive support: intubation (77.6%), Extracorporeal life support (23.7%), or renal replacement therapy (19.7%). Cardiac complications included new AF (13.2%), hemodynamically significant VT (3.9%), moderate or more pericardial effusion (2.6%) and acute stroke (9.2%). Echocardiographic analysis demonstrated that 7.9% of patients developed moderate or more LV dysfunction on visual assessment. RV dysfunction was more common (27.6%) with 11.8% being visually classified as moderate or greater in severity. High sensitivity troponin was elevated in 59.2% of patients and was statistically higher in patients experiencing cardiac complications (Chi-Square 0.005). Although not achieving significance, there was a trend towards elevated troponin and development of moderate or greater LV/RV dysfunction (Chi-square 0.30).

Conclusion

In acute patients hospitalized with COVID-19, there was a high prevalence of cardiovascular co-morbidities. Troponin elevations was common and associated with a significantly increased risk of cardiovascular events and a trend towards moderate or greater ventricular dysfunction.

Association Between Three-Dimensional Left Ventricular Outflow Tract Area and Gradients After Myectomy in Hypertrophic Obstructive Cardiomyopathy

OBJECTIVE

Determine whether the intraoperative three-dimensional left ventricular outflow tract cross-sectional area may be inversely correlated with pressure gradients as a determinant of surgical success after septal myectomy in hypertrophic cardiomyopathy patients.

DESIGN

Perioperative data were obtained by retrospective review.

SETTING

Toronto General Hospital, University of Toronto, Toronto, Canada, a tertiary hospital.

PARTICIPANTS

The study comprised 67 patients with hypertrophic obstructive cardiomyopathy.

INTERVENTIONS

Transthoracic and intraoperative transesophageal echocardiographic assessment of pressure gradients. Transesophageal measurement of the three-dimensional left ventricular outflow tract cross-sectional area.

MEASUREMENTS AND MAIN RESULTS

The smallest left ventricular outflow tract area increased on average 1.883 cm² (98.3%) after septal myectomy. There was a significant correlation between the increase in the area and the transesophageal pressure gradients (r = -0.32; p = 0.01) after myectomy, but none with postoperative transthoracic gradients at rest (r = -0.10; p = 0.42). Postoperative transesophageal and transthoracic gradients were significantly correlated (r = 0.26; p = 0.04). The best risk factors to predict high residual gradients were preoperative transesophageal gradient >97 mmHg, postoperative transesophageal area <3.16 cm², and moderate or more residual transesophageal mitral regurgitation (specificity 89%, 81%, and 78%, respectively).

CONCLUSIONS

Three-dimensional left ventricular outflow tract area measurements with transesophageal echocardiography after myectomy correlated fairly well with postoperative transesophageal pressure gradients. Patients with residual transthoracic elevated gradients after surgery at follow-up had a smaller transesophageal area and higher transesophageal pressure gradients immediately after the procedure. However, transesophageal pressure gradients after myectomy correlated poorly with follow-up transthoracic gradients at rest.

Left Ventricular Mass and Wall Thickness Measurements Using Echocardiography and Cardiac MRI in Patients with Fabry Disease: Clinical Significance of Discrepant Findings

Purpose

To compare transthoracic echocardiography (TTE) and cardiac MRI measurements of left ventricular mass (LVM) and maximum wall thickness (MWT) in patients with Fabry disease and evaluate the clinical significance of discrepancies between modalities.

Materials and Methods

Seventy-eight patients with Fabry disease (mean age, 46 years ± 14 [standard deviation]; 63% female) who underwent TTE and cardiac MRI within a 6-month interval between 2008 and 2018 were included in this retrospective cohort study. The clinical significance of measurement discrepancies was evaluated with respect to diagnosis of left ventricular hypertrophy (LVH), eligibility for disease-specific therapy, and prognosis. Statistical analysis included paired-sample t test, Cox proportional hazard models, Akaike information criterion (AIC), and intraclass correlation coefficients.

Results

LVM indexed to body surface area (LVMI) and MWT were significantly higher at TTE compared with MRI (105 g/m² ± 48 vs 78 g/m² ± 36, P < .001 and 14 mm ± 4 vs 13 mm ± 5, P = .008, respectively). LVH classification was discordant between modalities in 23 patients (29%) (P < .001). Eligibility for disease-specific therapy based on MWT was discordant between modalities in 20 patients (26%) (P < .001). LVMI assessed with MRI was a better predictor of the combined endpoint compared with LVMI assessed with TTE (AIC, 127 vs 131). Interobserver agreement for LVMI and MWT was higher for MRI (intraclass correlation coefficient, 0.951 and 0.912, respectively) compared with TTE (intraclass correlation coefficient, 0.940 and 0.871; respectively).

Conclusion

TTE overestimates LVM and MWT and has lower reproducibility compared with cardiac MRI in Fabry disease. Measurement discrepancies between modalities are clinically significant with respect to diagnosis of LVH, prognosis, and treatment decisions.© RSNA, 2020.

Lung Ultrasound for Cardiologists in the Time of COVID-19

Lung ultrasound (LUS) is a point-of-care ultrasound technique used for its portability, widespread availability, and ability to provide real-time diagnostic information and procedural guidance. LUS outperforms lung auscultation and chest X-ray, and it is an alternative to chest computed tomography in selected cases. Cardiologists may enhance their physical and echocardiographic examination with the addition of LUS. We present a practical guide to LUS, including device selection, scanning, findings, and interpretation. We outline a 3-point scanning protocol using 2-dimensional and M-mode imaging to evaluate the pleural line, pleural space, and parenchyma. We describe LUS findings and interpretation for common causes of respiratory failure. We provide guidance specific of COVID-19, which at the time of writing is a global pandemic. In this context, LUS emerges as a particularly useful tool for the diagnosis and management of patients with cardiopulmonary disease.

P2618Association of left ventricular ejection fraction with mortality and hospitalizations

Background

Although 2-dimensional echocardiography (2DE) is widely used to measure left ventricular ejection fraction (LVEF), the prognostic value of 2DE-derived LVEF has not been clearly demonstrated in a broad range of patients, including those acutely hospitalized as well as ambulatory patients. In particular, the prognostic value of echocardiographic LVEF has not been demonstrated for cardiovascular and heart failure hospitalizations.

Purpose

To determine if greater degrees of LV dysfunction are associated with progressively increasing risks of death or cardiovascular hospitalizations among patients undergoing echocardiography in hospital or outpatient settings.

Methods

We examined quantitative LVEFs from patient-level echocardiographic reports at 3 large hospital laboratories, which were linked to the Canadian Institute for Health Information hospitalization database and to death registries in Ontario, Canada. LVEF was categorized as <25%, 25–35%, 36–45%, or 46–55% (reference). Analyses were performed using cause-specific hazard competing risk models and stratified by: a) outpatient vs. inpatient echocardiogram, and b) if inpatient study, whether the reason for hospitalization was cardiac or noncardiac in nature.

Results

In the echocardiographic cohort of 27,323 patients (median age 68 [IQR: 58–77], 14,828 women [31.7%]), greater reductions in LVEF were associated with higher rates of all-cause mortality, with adjusted hazard ratios (95% CI) of 1.67 (1.57, 1.77) for LVEF <25%, 1.30 (1.24, 1.36) for LVEF 25–35%, and 1.17 (1.11, 1.23) for LVEF 36–45%, compared to LVEF 46–55% (all p<0.001). The cumulative incidence of cardiovascular death was higher as LVEF progressively worsened (Figure). The rate of heart failure hospitalizations was also increased with hazard ratios of 1.71 (1.59, 1.85) for LVEF <25%, 1.39 (1.31, 1.48) for LVEF 25–35%, and 1.21 (1.13, 1.29) for LVEF 36–45%, compared to LVEF 46–55% (all p<0.001). Cardiovascular hospitalizations were also increased with hazard ratios of 1.35 (1.27, 1.42), 1.21 (1.16, 1.27), and 1.13 (1.07, 1.18) for LVEFs <25%, 25–35%, and 36–45%, respectively (all p<0.001). The risk of mortality and hospitalizations increased comparably with greater reductions in LVEF during both inpatient cardiac or noncardiac admissions (p<0.001).

Cumulative incidence of CV death

Conclusions

Quantitative LVEF assessed by 2DE is potent prognostically and was able to stratify the risk of both death and hospitalization outcomes in a wide range of clinical settings. Patients with reduced LVEF measured on inpatient or outpatient echocardiograms, and even in the context of non-cardiac admission, should be considered an at-risk group in whom quality of care metrics could be evaluated in future studies.

Acknowledgement/Funding

Canadian Institutes of Health Research, Heart and Stroke Foundation, and the Ted Rogers Centre for Heart Research

Dusp6 is a genetic modifier of growth through enhanced ERK activity

Like other single-gene disorders, muscular dystrophy displays a range of phenotypic heterogeneity even with the same primary mutation. Identifying genetic modifiers capable of altering the course of muscular dystrophy is one approach to deciphering gene-gene interactions that can be exploited for therapy development. To this end, we used an intercross strategy in mice to map modifiers of muscular dystrophy. We interrogated genes of interest in an interval on mouse chromosome 10 associated with body mass in muscular dystrophy as skeletal muscle contributes significantly to total body mass. Using whole-genome sequencing of the two parental mouse strains combined with deep RNA sequencing, we identified the Met62Ile substitution in the dual-specificity phosphatase 6 (Dusp6) gene from the DBA/2 J (D2) mouse strain. DUSP6 is a broadly expressed dual-specificity phosphatase protein, which binds and dephosphorylates extracellular-signal-regulated kinase (ERK), leading to decreased ERK activity. We found that the Met62Ile substitution reduced the interaction between DUSP6 and ERK resulting in increased ERK phosphorylation and ERK activity. In dystrophic muscle, DUSP6 Met62Ile is strongly upregulated to counteract its reduced activity. We found that myoblasts from the D2 background were insensitive to a specific small molecule inhibitor of DUSP6, while myoblasts expressing the canonical DUSP6 displayed enhanced proliferation after exposure to DUSP6 inhibition. These data identify DUSP6 as an important regulator of ERK activity in the setting of muscle growth and muscular dystrophy.

Necrotising fasciitis in the North East of Scotland: a 10-year retrospective review

INTRODUCTION

Necrotising fasciitis is a life-threatening rapidly progressing bacterial infection of the skin requiring prompt diagnosis and treatment. Optimum care warrants a combination of surgical debridement, antibiotics and intensive care support. All cases of necrotising fasciitis in 10 years in the North East of Scotland were reviewed to investigate and improve patient care.

METHODS

Cases between August 2006 and February 2016 were reviewed using case notes and electronic hospital records. Data including mode of admission, clinical observations, investigations, operative interventions, microbiological and clinical outcomes was collected and reviewed. Analysis required multidisciplinary input including microbiology, infectious disease, trauma and orthopaedics, plastic surgery and intensive care teams.

RESULTS

A total of 36 cases were identified. The mean laboratory risk indicator for necrotising fasciitis (LRINEC) score was 7 and 86% of patients fulfilled the criteria for necrotising fasciitis. Patients were commonly haemodynamically stable upon admission but deteriorated rapidly; 36% of patients had a temperature of over 37.5 degrees C on initial observations; 29/36 patients were discharged, 6 patients died acutely (acute mortality rate of 17%); 18/31 of cases were polymicrobial with Streptococcus pyogenes, the common organism. Six amputations or disarticulations were performed from a total of 82 operations in this group, with radical debridement the usual primary operation. The mean time to theatre was 3.54 hours. Highly elevated admission respiratory rate (50 breaths/minute) was associated with increased mortality.

CONCLUSIONS

Necrotising fasciitis presents subtly and carries significant morbidity and mortality. A high index of suspicion allows early diagnosis and intervention. We believe that a pan-specialty approach is the cornerstone for good outcomes.

Atrial cardiopathy in patients with embolic strokes of unknown source and other stroke etiologies

Objective

To investigate the prevalence and clinical determinants of atrial cardiopathy in patients with embolic stroke of unknown source (ESUS) and compare with other established stroke etiologies.

Methods

In a cross-sectional study of 846 consecutive patients with ischemic stroke, we compared the prevalence of atrial cardiopathy (defined by p-wave terminal force in V1 >5,000 µV·ms or severe left atrial enlargement) between ESUS patients and patients with large artery atherosclerosis (LAA) and small vessel disease (SVD) strokes. Baseline characteristics were also compared between ESUS and cardioembolic (CE) patients.

Results

Of all, 158 (19%) patients met ESUS diagnostic criteria, while others were classified into LAA (n = 224, 26%), SVD (n = 154, 18%), and CE (n = 310, 37%). The prevalence of atrial cardiopathy was higher in ESUS patients compared to noncardioembolic stroke patients (26.6% vs 12.1% in LAA vs 16.9% in SVD; p = 0.001). ESUS patients were younger, were less hypertensive, and had higher cholesterol and low-density lipoprotein levels, but also had less left ventricular or atrial abnormalities when compared to CE patients.

Conclusion

The prevalence of atrial cardiopathy was high in ESUS patients compared with patients with nonembolic strokes. Interestingly, ESUS patients were also clinically different from CE patients. While the presence of atrial cardiopathy may reflect a unique mechanism of thromboembolism in ESUS patients, it is still unclear if they may benefit from anticoagulation, or if the presence of atrial cardiopathy in this population could serve as a risk-stratifying marker for stroke recurrence. Further efforts are necessary to provide better characterization of the ESUS population in order to develop better stroke preventive strategies.

Design of the effect of adaptive servo-ventilation on survival and cardiovascular hospital admissions in patients with heart failure and sleep apnoea: the ADVENT-HF trial

INTRODUCTION

Both types of sleep-disordered breathing (SDB), obstructive and central sleep apnoea (OSA and CSA, respectively), are common in patients with heart failure and reduced ejection fraction (HFrEF). In such patients, SDB is associated with increased cardiovascular morbidity and mortality but it remains uncertain whether treating SDB by adaptive servo-ventilation (ASV) in such patients reduces morbidity and mortality.

AIM

ADVENT-HF is designed to assess the effects of treating SDB with ASV on morbidity and mortality in patients with HFrEF.

METHODS

ADVENT-HF is a multicentre, multinational, randomized, parallel-group, open-label trial with blinded assessment of endpoints of standard medical therapy for HFrEF alone vs. with the addition of ASV in patients with HFrEF and SDB. Patients with a history of HFrEF undergo echocardiography and polysomnography. Those with a left ventricular ejection fraction ≤45% and SDB (apnoea-hypopnoea index ≥15) are eligible. SDB is stratified into OSA with ≥50% of events obstructive or CSA with >50% of events central. Those with OSA must not have excessive daytime sleepiness (Epworth score of ≤10). Patients are then randomized to receive or not receive ASV. The primary outcome is the composite of all-cause mortality, cardiovascular hospital admissions, new-onset atrial fibrillation requiring anti-coagulation but not hospitalization, and delivery of an appropriate discharge from an implantable cardioverter-defibrillator not resulting in hospitalization during a maximum follow-up time of 5 years.

CONCLUSION

The ADVENT-HF trial will help to determine whether treating SDB by ASV in patients with HFrEF improves morbidity and mortality.

Distinct Patterns of Hyperpnea During Cheyne-Stokes Respiration: Implication for Cardiac Function in Patients With Heart Failure

STUDY OBJECTIVES

In heart failure (HF), we observed two patterns of hyperpnea during Cheyne-Stokes respiration with central sleep apnea (CSR-CSA): a positive pattern where end-expiratory lung volume remains at or above functional residual capacity, and a negative pattern where it falls below functional residual capacity. We hypothesized the negative pattern is associated with worse HF.

METHODS

Patients with HF underwent polysomnography. During CSR-CSA, hyperpnea, apnea-hyperpnea cycle, and lung to finger circulation times (LFCT) were measured. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentration and left ventricular ejection fraction (LVEF) were assessed.

RESULTS

Of 33 patients with CSR-CSA (31 men, mean age 68 years), 9 had a negative hyperpnea pattern. There was no difference in age, body mass index, and apnea-hypopnea index between groups. Patients with a negative pattern had longer hyperpnea time (39.5 ± 6.4 versus 25.8 ± 5.9 seconds, P < .01), longer cycle time (67.8 ± 15.9 versus 51.7 ± 9.9 seconds, P < .01), higher NT-proBNP concentrations (2740 [6769] versus 570 [864] pg/ml, P = .01), and worse New York Heart Association class (P = .02) than those with a positive pattern. LFCT and LVEF did not differ between groups.

CONCLUSIONS

Patients with HF and a negative CSR-CSA pattern have evidence of worse cardiac function than those with a positive pattern. Greater positive expiratory pressure during hyperpnea is likely generated during the negative pattern and might support stroke volume in patients with worse cardiac function.

COMMENTARY

A commentary on this article appears in this issue on page 1227.

CLINICAL TRIAL REGISTRATION

The trial is registered with Current Controlled Trials (www.controlled-trials.com; ISRCTN67500535) and Clinical Trials (www.clinicaltrials.gov; NCT01128816).

Isolated septal myectomy for hypertrophic obstructive cardiomyopathy: an update on the Toronto General Hospital experience

BACKGROUND

Isolated septal myectomy is considered the gold standard for refractory left ventricular outflow tract (LVOT) obstruction at centers with dedicated hypertrophic obstructive cardiomyopathy (HOCM) surgeons. In this paper, we provide an update on the Toronto General Hospital (TGH) experience for isolated septal myectomy and comment on the safety and efficacy of myectomy in patients with thin basal septal thickness at our institution.

METHODS

We retrospectively reviewed all patients undergoing surgical myectomy at our institution from January 2012 to August 2016. We analyzed patient characteristics, intraoperative variables, pre- and post-procedural echocardiographic parameters, and key outcomes including post-operative stroke, renal failure, iatrogenic ventricular septal defect (VSD), post-procedure insertion of permanent pacemaker, and mortality.

RESULTS

At our institution, 150 isolated septal myectomy surgeries were performed over the study period. Preoperative echocardiography demonstrated an average basal septal thickness of 2.10±0.43 cm with a resting gradient of 67±37 mmHg and a provoked gradient of 89±40 mmHg. Fifty percent of patients had significant systolic anterior motion (SAM) of their mitral valve and 53% had associated moderate to severe mitral regurgitation (MR). Of note, 24% of patients had a thin septum of ≤1.7 cm. Discharge echocardiograms demonstrated significant septal reduction to an average basal septal thickness of 1.04±0.26 (P<0.05), with negligible resting and provokable LVOT gradients. At the time of discharge, none of the patients had significant SAM and only 5.3% of patients had residual greater than mild MR. Patients undergoing isolated myectomy with a thin basal septum had similar outcomes to those with a >1.7 cm septal thickness. In our contemporary cohort, there were no iatrogenic VSDs, 5.3% of patients required a permanent pacemaker and there was one early death.

CONCLUSIONS

Our cohort demonstrates that isolated septal myectomy remains a safe and effective operation that can achieve excellent results, irrespective of basal septal thickness, when done by experienced surgeons in a dedicated hypertrophic cardiomyopathy (HCM) center.

Rapid Device-Detected Nonsustained Ventricular Tachycardia in the Risk Stratification of Hypertrophic Cardiomyopathy

BACKGROUND

Nonsustained ventricular tachycardia (NSVT) detected by ambulatory Holter (Holter NSVT) is a major risk factor for sudden cardiac death in hypertrophic cardiomyopathy (HCM). We hypothesized that the prognostic utility of Holter NSVT in HCM would improve with prolonged monitoring and a higher heart rate cut-off for detection.

METHODS

We enrolled 60 patients (44 ± 14 years) with HCM, who had a prophylactic implantable cardioverter defibrillator (ICD). Positive Holter NSVT (prior to implant) was defined as ≥3 beats at ≥120 beats per minute (bpm). We assessed the prevalence of rapid NSVT (RNSVT) detected by their ICD within 12 months of its implant, defined as 4-16 beats at ≥150-200 bpm. The primary outcome was appropriate ICD therapy (antitachycardia pacing and shocks) for sustained ventricular arrhythmia (VA).

RESULTS

Holter NSVT was detected in 34 patients. RNSVT occurred in 21 (35%) patients of whom five did not have Holter NSVT. Over a median follow-up of 61 (interquartile range 29, 129) months after ICD implant, nine patients had VA. RNSVT, but not Holter NSVT, was significantly associated with VA (hazard ratio 6.2, 95% confidence interval [1.3-30], P = 0.01) by multivariable Cox regression analysis that included conventional risk factors. Receiver operating characteristic analysis for RNSVT (area under curve 0.80, P = 0.005) showed that the occurrence of ≥2 episodes of RNSVT discriminated patients for VA optimally (sensitivity 78%, specificity 84%, positive predictive value 47%, negative predictive value 96%).

CONCLUSIONS

In this pilot study, RNSVT detected by continuous monitoring independently predicted VA in HCM and offered superior discrimination of VA risk compared to conventional risk factors, including Holter NSVT. Future studies are needed to validate these findings in a larger, unselected HCM cohort.

Abstract P2-06-01: Characterisation of C11orf67, an oncogenic driver in a new subtype of aggressive endocrine receptor positive breast cancer

The recent integration of both genomic and transcriptomic datasets have added a further dimension to the landscape of breast cancer (BrCa) subtyping, defining novel functional subgroups with distinctive oncogenic drivers that carry important implications for therapy. This integrative clustering has unveiled a novel subtype of hormone receptor positive (HR+) BrCa associated with high proliferation and very poor survival characterised by copy number amplification and overexpression of a cluster of candidate oncogenic drivers at the 11q13.5-14 locus (1). At the heart of this amplicon we have demonstrated the selective overexpression of C11orf67/AAMDC (Adipogenesis associated Mth938 domain containing) which encodes a hypothetical protein of 122 aa with unknown function. In a pilot tissue microarray of 75 BrCa cases C11orf67 amplification and expression were significantly correlated with hormone receptor positivity. These positive cases also demonstrated high risk features with 75% demonstrating lymph node involvement.

In functional elucidation studies knockdown of C11orf67 in the highly expressing T47D cell line lead to decreased cell proliferation, cell migration, anchorage independent cell growth and induction of senescence. T47D xenografts with stable shRNA-induced C11orf67 knockdowns introduced into BALB/c mice showed significantly lower tumour volumes relative to T47D with empty vector. A genome wide analysis of these T47D-C11orf67 shRNA cells compared to T47D-empty vector cells using the Illumina HumanHT-12 platform demonstrated 40 differentially expressed genes. Network analysis revealed a proliferation node, enriched in cell cycle proteins, and a metabolic node comprising several biosynthetic enzymes such as MTHFD1L involved in one-carbon folate metabolism. Supporting this link and pointing to potential utility in chemotherapy selection, induction of ectopic C11orf67 expression in MCF7 cells increased sensitivity to fluorouracil and methotrexate but not to paclitaxel.

Investigating potential novel binding partners and effectors, in yeast two hybrid screening C11orf67 was a found to associate strongly with RABGAP1L, a protein involved in controlling GTPase signalling, protein trafficking, and autophagy.

Exploring the molecular cues that control C11orf67 expression, our data suggest the locus is regulated by transcription factors associated with high proliferation and metabolic control, notably Myc and NFkB, as well as HRs. E2 lead to a significant down-regulation of C11orf67 in T47D cells, which was reversed by the antiestrogen drug tamoxifen, whereas PG significantly increased C11orf67 levels. In keeping with this MCF7 cells ectopically expressing C11orf67 were resistant to the anti-proliferative effects of tamoxifen compared to the parent cell line.

These observations endorse C11orf67 as a novel oncogenic driver with exciting therapeutic potential, which could serve to distinguish the HR+ tumours at high risk of relapse and guide both the selection of current chemotherapeutical and endocrine treatments as well as the design of future precision therapeutics, notably anti-folate/one carbon drugs and novel endocrine agents.

References

1. Curtis et al. Nature. 2012 Jun 21;486 (7403):346-52.

Citation Format: Redfern A, Rashwan R, Sorolla A, Ratajska M, Kardas I, Kuzniacka A, Parry J, Curtis C, Woo A, Sgro A, Biernat W. Characterisation of C11orf67, an oncogenic driver in a new subtype of aggressive endocrine receptor positive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-06-01.

Impact of Prosthesis-Patient Mismatch on Left Ventricular Myocardial Mechanics After Transcatheter Aortic Valve Replacement

Background

The aim of this study was to compare left ventricular (LV) remodeling using myocardial strain between patients with severe aortic stenosis (AS) treated with transcatheter aortic valve replacement (TAVR) with and without prosthesis‐patient mismatch (PPM).

Methods and Results

In a retrospective study, speckle‐tracking echocardiography was used to measure global longitudinal strain (GLS) and strain rate (GLSR), circumferential strain, and rotation before and at mid‐term follow‐up post‐TAVR. Moderate and severe PPM were defined as an effective orifice area ≤0.85 and <0.65 cm²/m², respectively. A total of 102 patients (median age, 83 years [77–88]) with severe AS were included. At 6±3 months post‐TAVR, moderate and severe PPM were found in 32 (31%) and 9 (9%) patients. Patients without PPM had a significant regression in LV mass (from 134±41 to 119±38 g/m²; P=0.001) at follow‐up whereas those with PPM did not. There was a significant improvement in LV GLS (−12.8±4.0 to −14.3±4.3%; P=0.01), GLSR (−0.61±0.20 to −0.73±0.25 second⁻¹; P<0.001), and early diastolic strain rate (0.52±0.20 to 0.64±0.20 second⁻¹; P<0.001) in patients without PPM, but not in those with PPM. After adjustment for pre‐TAVR ejection fraction and post‐TAVR aortic regurgitation, patients without PPM had greater improvement in LV longitudinal strain parameters compared to those with PPM. After a median follow‐up of 46.1 months (interquartile range, 35.4–60.8), there was no difference in survival between patients with and without PPM.

Conclusions

TAVR was associated with an incidence of PPM of 40%. Greater reverse LV remodeling using myocardial strain was evident in patients without PPM compared to PPM. Presence of PPM was not associated with mortality.

Genotype-Positive Status in Patients With Hypertrophic Cardiomyopathy Is Associated With Higher Rates of Heart Failure Events

Background—

The aim of the study was to clarify the relationship between genotype status and major cardiovascular outcomes in a large cohort of patients with hypertrophic cardiomyopathy.

Methods and Results—

Genetic testing was performed in 558 consecutive proband patients with hypertrophic cardiomyopathy. Baseline and follow-up (mean follow-up 6.3 years) clinical and echocardiographic data were obtained. Pathogenic mutations were identified in 198 (35.4%) patients. Genotype-positive patients were more likely to be women (44% versus 30%; P =0.001), younger (39 versus 48 years; P <0.001), and have a family history of hypertrophic cardiomyopathy (53% versus 20%; P <0.001), as well as family history of sudden cardiac death (17% versus 7%; P =0.002). There were no significant differences in the rates of atrial fibrillation, stroke, or septal reduction procedures. Multivariable analysis demonstrated that genotype-positive status was an independent risk factor for the development of combined heart failure end points (decline in left ventricular ejection fraction to <50%, New York Heart Association III or IV in the absence of obstruction, heart failure–related hospital admission, transplantation, and heart failure–related death; hazards ratio, 4.51; confidence interval, 2.09–9.31; P <0.001). No difference was seen in heart failure events between the myosin heavy chain and myosin-binding protein C genotype-positive patients.

Conclusions—

The presence of a pathogenic sarcomere mutation in patients with hypertrophic cardiomyopathy was associated with an increase in heart failure events, with no differences in event rates seen between myosin heavy chain and myosin-binding protein C genotype-positive patients. The presence of a disease-causing mutation seems more clinically relevant than the specific mutation itself.

Use of myocardial strain imaging by echocardiography for the early detection of cardiotoxicity in patients during and after cancer chemotherapy: a systematic review

The literature exploring the utility of advanced echocardiographic techniques (such as deformation imaging) in the diagnosis and prognostication of patients receiving potentially cardiotoxic cancer therapy has involved relatively small trials in the research setting. In this systematic review of the current literature, we describe echocardiographic myocardial deformation parameters in 1,504 patients during or after cancer chemotherapy for 3 clinically-relevant scenarios. The systematic review was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using the EMBASE (1974 to November 2013) and MEDLINE (1946 to November 2013) databases. All studies of early myocardial changes with chemotherapy demonstrate that alterations of myocardial deformation precede significant change in left ventricular ejection fraction (LVEF). Using tissue Doppler-based strain imaging, peak systolic longitudinal strain rate has most consistently detected early myocardial changes during therapy, whereas with speckle tracking echocardiography (STE), peak systolic global longitudinal strain (GLS) appears to be the best measure. A 10% to 15% early reduction in GLS by STE during therapy appears to be the most useful parameter for the prediction of cardiotoxicity, defined as a drop in LVEF or heart failure. In late survivors of cancer, measures of global radial and circumferential strain are consistently abnormal, even in the context of normal LVEF, but their clinical value in predicting subsequent ventricular dysfunction or heart failure has not been explored. Thus, this systematic review confirms the value of echocardiographic myocardial deformation parameters for the early detection of myocardial changes and prediction of cardiotoxicity in patients receiving cancer therapy.

The Ross procedure: outcomes at 20 years

OBJECTIVES

Our study examines the outcomes of the Ross procedure in a cohort of 212 patients prospectively followed with clinical and echocardiographic assessments.

METHODS

Patients' mean age was 34 ± 9 years; 66% were men and 82% had congenital aortic valve disease. The median follow-up was 13.8 years. Patients who had reoperations continued to be followed and entered into the survival analysis.

RESULTS

There was 1 operative death as well as 9 late deaths (3 in patients who no longer had the Ross). Survival at 20 years was 93.6% and similar to the general population matched for age and sex. Fifteen patients required reoperations on the pulmonary autograft (4 repairs and 11 replacements), 8 on the pulmonary homograft, and 4 other cardiac procedures. At 20 years the freedom from reoperation on the pulmonary autograft was 81.8% and on the pulmonary homograft was 92.7%, and in both was 79.9%. Preoperative aortic insufficiency, aortic annulus diameter ≥15 mm/m(2), and being a man were associated with increased risk of reoperation on the pulmonary autograft. Twenty-six patients developed aortic insufficiency greater than mild and 25 patients developed pulmonary homograft dysfunction (defined as moderate or severe insufficiency and/or peak systolic gradient of >40 mm Hg). At 20 years the freedom from aortic insufficiency was 62.6% and freedom from pulmonary valve dysfunction was 53.5%.

CONCLUSIONS

Survival after the Ross procedure in this cohort was similar to the general population. Dilated aortic annulus and aortic insufficiency were associated with increased risk of developing aortic insufficiency. Pulmonary homograft dysfunction was common at 20 years.