Characterizing advanced heart failure risk and hemodynamic phenotypes using interpretable machine learning.

BACKGROUND: Although previous risk models exist for advanced heart failure with reduced ejection fraction (HFrEF), few integrate invasive hemodynamics or support missing data. This study developed and validated a heart failure (HF) hemodynamic risk and phenotyping score for HFrEF, using Machine Learning (ML). METHODS: Prior to modeling, patients in training and validation HF cohorts were assigned to 1 of 5 risk categories based on the composite endpoint of death, left ventricular assist device (LVAD) implantation or transplantation (DeLvTx), and rehospitalization in 6 months of follow-up using unsupervised clustering. The goal of our novel interpretable ML modeling approach, which is robust to missing data, was to predict this risk category (1, 2, 3, 4, or 5) using either invasive hemodynamics alone or a rich and inclusive feature set that included noninvasive hemodynamics (all features). The models were trained using the ESCAPE trial and validated using 4 advanced HF patient cohorts collected from previous trials, then compared with traditional ML models. Prediction accuracy for each of these 5 categories was determined separately for each risk category to generate 5 areas under the curve (AUCs, or C-statistics) for belonging to risk category 1, 2, 3, 4, or 5, respectively. RESULTS: Across all outcomes, our models performed well for predicting the risk category for each patient. Accuracies of 5 separate models predicting a patient's risk category ranged from 0.896 +/- 0.074 to 0.969 +/- 0.081 for the invasive hemodynamics feature set and 0.858 +/- 0.067 to 0.997 +/- 0.070 for the all features feature set. CONCLUSION: Novel interpretable ML models predicted risk categories with a high degree of accuracy. This approach offers a new paradigm for risk stratification that differs from prediction of a binary outcome. Prospective clinical evaluation of this approach is indicated to determine utility for selecting the best treatment approach for patients based on risk and prognosis.

Compensation for respiratory motion-induced signal loss and phase corruption in free-breathing self-navigated cine DENSE using deep learning.

PURPOSE: To introduce a model that describes the effects of rigid translation due to respiratory motion in displacement encoding with stimulated echoes (DENSE) and to use the model to develop a deep convolutional neural network to aid in first-order respiratory motion compensation for self-navigated free-breathing cine DENSE of the heart. METHODS: The motion model includes conventional position shifts of magnetization and further describes the phase shift of the stimulated echo due to breathing. These image-domain effects correspond to linear and constant phase errors, respectively, in k-space. The model was validated using phantom experiments and Bloch-equation simulations and was used along with the simulation of respiratory motion to generate synthetic images with phase-shift artifacts to train a U-Net, DENSE-RESP-NET, to perform motion correction. DENSE-RESP-NET-corrected self-navigated free-breathing DENSE was evaluated in human subjects through comparisons with signal averaging, uncorrected self-navigated free-breathing DENSE, and breath-hold DENSE. RESULTS: Phantom experiments and Bloch-equation simulations showed that breathing-induced constant phase errors in segmented DENSE leads to signal loss in magnitude images and phase corruption in phase images of the stimulated echo, and that these artifacts can be corrected using the known respiratory motion and the model. For self-navigated free-breathing DENSE where the respiratory motion is not known, DENSE-RESP-NET corrected the signal loss and phase-corruption artifacts and provided reliable strain measurements for systolic and diastolic parameters. CONCLUSION: DENSE-RESP-NET is an effective method to correct for breathing-associated constant phase errors. DENSE-RESP-NET used in concert with self-navigation methods provides reliable free-breathing DENSE myocardial strain measurement.

Right atrial structural remodeling predict worse outcomes in transcatheter mitral valve repair.

BACKGROUND: In the current study, we assess the predictive role of right and left atrial volume indices (RAVI and LAVI) as well as the ratio of RAVI/LAVI (RLR) on mortality following transcatheter mitral valve repair (TMVr). METHODS: Transthoracic echocardiograms of 158 patients who underwent TMVr at a single academic medical center from 2011 to 2018 were reviewed retrospectively. RAVI and LAVI were calculated using Simpson's method. Patients were stratified based on etiology of mitral regurgitation (MR). Cox proportional-hazard regression was created utilizing MR type, STS-score, and RLR to assess the independent association of RLR with survival. Kaplan-Meier analysis was used to analyze the association between RAVI and LAVI with all-cause mortality. Hemodynamic values from preprocedural right heart catheterization were also compared between RLR groups. RESULTS: Among 123 patients included (median age 81.3 years; 52.5% female) there were 50 deaths during median follow-up of 3.0 years. Patients with a high RAVI and low LAVI had significantly higher all-cause mortality while patients with high LAVI and low RAVI had significantly improved all-cause mortality compared to other groups (p = 0.0032). RLR was significantly associated with mortality in patients with both functional and degenerative MR (p = 0.0038). Finally, Cox proportion-hazard modeling demonstrated that an elevated RLR above the median value was an independent predictor of all-cause mortality [HR = 2.304; 95% CI = 1.26-4.21, p = 0.006] when MR type and STS score were accounted for. CONCLUSION: Patients with a high RAVI and low LAVI had significantly increased mortality than other groups following TMVr suggesting RA remodeling may predict worse outcomes following the procedure. Concordantly, RLR was predictive of mortality independent of MR type and preprocedural STS-score. These indices may provide additional risk stratification in patients undergoing evaluation for TMVr.

Systemic arterial pulsatility (SAPi) in advanced heart failure: a novel hemodynamic risk stratification tool.

Systemic arterial pulsatility index (SAPi) is a novel hemodynamic marker for ventriculo-arterial coupling (VAC), as it integrates the contractile properties of the left ventricle with the aortic impendence. SAPi can identify heart failure patients at increased risk for adverse events. Systemic pulsatility decreases as heart failure progresses, and there is a decrease in pulse pressure accompanied by an increase in left ventricular filling pressure. Decreasing SAPi is associated with worse prognosis in advanced heart failure patients.

Academic cardiac electrophysiologists' perspectives on sleep apnea care.

PURPOSE: Obstructive sleep apnea syndrome (OSAS) is an important, modifiable risk factor in the pathophysiology of arrhythmias including atrial fibrillation (AF). The purpose of the study was to evaluate cardiac electrophysiologists' (EPs) perception of OSAS. METHODS: We designed a 27-item online Likert scale-based survey instrument entailing several domains: (1) relevance of OSAS in EP practice, (2) OSAS screening and diagnosis, (3) perception on treatments for OSAS, (4) opinion on the OSAS care model. The survey was distributed to 89 academic EP programs in the USA and Canada. While the survey instrument questions refer to the term sleep apnea (SA), our discussion of the diagnosis, management, and research on the sleep disorder is more accurately described with the term OSAS. RESULTS: A total of 105 cardiac electrophysiologists from 49 institutions responded over a 9-month period. The majority of respondents agreed that sleep apnea (SA) is a major concern in their practice (94%). However, 42% reported insufficient education on SA during training. Many (58%) agreed that they would be comfortable managing SA themselves with proper training and education and 66% agreed cardiac electrophysiologists should become more involved in management. Half of EPs (53%) were not satisfied with the sleep specialist referral process. Additionally, a majority (86%) agreed that trained advanced practice providers should be able to assess and manage SA. Time constraints, lack of knowledge, and the referral process are identified as major barriers to EPs becoming more involved in SA care. CONCLUSIONS: We found that OSAS is widely recognized as a major concern for EP. However, incorporation of OSAS care in training and routine practice lags. Barriers to increased involvement include time constraints and education. This study can serve as an impetus for innovation in the cardiology OSAS care model.

Positional obstructive sleep apnea in patients with atrial fibrillation.

PURPOSE: Obstructive sleep apnea (OSA) is a common, potentially modifiable condition implicated in the pathogenesis of atrial fibrillation (AF). The presence and severity of OSA is largely sleep position-dependent, yet there is high variability in positional dependence among patients with OSA. We investigated the prevalence of positional OSA (POSA) and examined associated factors in patients with AF. METHODS: We recruited an equal number of patients with and without AF who underwent diagnostic polysomnography. Patients included had ≥ 120 min of total sleep time with 30 min of sleep in both supine and lateral positions. POSA was defined as an overall apnea hypopnea index (AHI) ≥ 5/h, supine AHI (sAHI) ≥ 5/h, and sAHI greater than twice the non-supine AHI. POSA prevalence was compared in patients with and without AF adjusting for age, sex, OSA severity, and heart failure. RESULTS: A total of patients (male: 56%, mean age 62 years) were included. POSA prevalence was similar between the two groups (46% vs. 39%; p = 0.33). Obesity and severe OSA (AHI ≥ 30/h) were associated with low likelihood of POSA (OR [CI] of 0.17 [0.09-0.32] and 0.28 [0.12-0.62]). In patients with AF, male sex was associated with a higher likelihood of POSA (OR [CI] of 3.16 [1.06-10.4]). CONCLUSION: POSA is common, affecting more than half of patients with AF, but the prevalence was similar in those without AF. Obesity and more severe OSA are associated with lower odds of POSA. Positional therapy should be considered in patients with mild OSA and POSA.

Coronary perfusion pressure is associated with adverse outcomes in advanced heart failure.

BACKGROUND: Myocardial perfusion is an important determinant of cardiac function. We hypothesized that low coronary perfusion pressure (CPP) would be associated with adverse outcomes in heart failure. Myocardial perfusion impacts the contractile efficiency thus a low CPP would signal low myocardial perfusion in the face of increased cardiac demand as a result of volume overload. METHODS: We analyzed patients with complete hemodynamic data in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness trial using Cox Proportional Hazards regression for the primary outcome of the composite risk of death, heart transplantation, or left ventricular assist device [(LVAD). DT × LVAD] and the secondary outcome of the composite risk of DT × LVAD and heart failure hospitalization (DT × LVADHF). CPP was calculated as the difference between diastolic blood pressure and pulmonary artery wedge pressure. Heart failure categories (ischemic vs non-ischemic) were also stratified based on CPP strata. RESULTS: The 158 patients (56.7 ± 13.6 years, 28.5% female) studied had a median CPP of 40 mmHg (IQR 35-52 mmHg). During 6 months of follow-up, 35 (22.2%) had the composite primary outcome and 109 (69.0%) had the composite secondary outcome. When these outcomes were then stratified based on the median, CPP was associated with these outcomes. Increasing CPP was associated with lower risk of both the primary outcome of DT × LVAD (HR 0.96, 95% CI 0.94-0.99 p = .002) and as well as the secondary outcome of DT × LVADHF (p = .0008) There was significant interaction between CPP and ischemic etiology (p = .04). CONCLUSION: A low coronary artery perfusion pressure below (median) 40mmHg in patients with advanced heart failure undergoing invasive hemodynamic monitoring with a pulmonary artery catheter was associated with adverse outcomes. CPP could useful in guiding risk stratification of advanced heart failure patients and timely evaluation of advanced heart failure therapies.

Relationship of ejection fraction and natriuretic peptide trajectories in heart failure with baseline reduced and mid-range ejection fraction.

BACKGROUND: The prognostic importance of trajectories of neurohormones relative to left ventricular function over time in heart failure with reduced and mid-range EF (HFrEF and HFmrEF) is poorly defined. OBJECTIVE: To evaluate left ventricular ejection fraction (LVEF) and B-type natriuretic peptide (BNP) trajectories in HFrEF and HFmrEF. METHODS: Analyses of LVEF and BNP trajectories after incident HF admissions presenting with abnormal LV systolic function were performed using 3 methods: a Cox proportional hazards model with time-varying covariates, a dual longitudinal-survival model with shared random effects, and an unsupervised analysis to capture 3 discrete trajectories for each parameter. RESULTS: Among 1,158 patients (68.9 ± 13.0 years, 53.3% female), both time-varying LVEF measurements (P=.001) and log-transformed BNP measurements (p-values=2 × 10-16) were independently associated with survival during 6 years after covariate adjustment. In the dual longitudinal/survival model, both LVEF and BNP trajectories again were independently associated with survival (P<.0001 in each model); however, LVEF was more dynamic than BNP (P <.0001 for time covariate in LVEF longitudinal model versus P=.88 for the time covariate in BNP longitudinal model). In the unsupervised analysis, 3 discrete LVEF trajectories (dividing the cohort into approximately thirds) and 3 discrete BNP trajectories were identified. Discrete LVEF and BNP trajectories had independent prognostic value in Kaplan-Meier analyses (P<.0001), and substantial membership variability across BNP and LVEF trajectories was noted. CONCLUSION: Although LVEF trajectories have greater temporal variation, BNP trajectories provide additive prognostication and an even stronger association with survival times in heart failure patients with abnormal LV systolic function.

A Slice-Low-Rank Plus Sparse (slice-L + S) Reconstruction Method for k-t Undersampled Multiband First-Pass Myocardial Perfusion MRI.

PURPOSE: The synergistic use of k-t undersampling and multiband (MB) imaging has the potential to provide extended slice coverage and high spatial resolution for first-pass perfusion MRI. The low-rank plus sparse (L + S) model has shown excellent performance for accelerating single-band (SB) perfusion MRI. METHODS: A MB data consistency method employing ESPIRiT maps and through-plane coil information was developed. This data consistency method was combined with the temporal L + S constraint to form the slice-L + S method. Slice-L + S was compared to SB L + S and the sequential operations of split slice-GRAPPA and SB L + S (seq-SG-L + S) using synthetic data formed from multislice SB images. Prospectively k-t undersampled MB data were also acquired and reconstructed using seq-SG-L + S and slice-L + S. RESULTS: Using synthetic data with total acceleration rates of 6-12, slice-L + S outperformed SB L + S and seq-SG-L + S (N = 7 subjects) with respect to normalized RMSE and the structural similarity index (P < 0.05 for both). For the specific case with MB factor = 3 and rate 3 undersampling, or for SB imaging with rate 9 undersampling (N = 7 subjects), the normalized RMSE values were 0.037 ± 0.007, 0.042 ± 0.005, and 0.031 ± 0.004; and the structural similarity index values were 0.88 ± 0.03, 0.85 ± 0.03, and 0.89 ± 0.02 for SB L + S, seq-SG-L + S, and slice-L + S, respectively (P < 0.05 for both). For prospectively undersampled MB data, slice-L + S provided better image quality than seq-SG-L + S for rate 6 (N = 7) and rate 9 acceleration (N = 7) as scored by blinded experts. CONCLUSION: Slice-L + S outperformed SB-L + S and seq-SG-L + S and provides 9 slice coverage of the left ventricle with a spatial resolution of 1.5 mm × 1.5 mm with good image quality.

Reproducibility of global and segmental myocardial strain using cine DENSE at 3 T: a multicenter cardiovascular magnetic resonance study in healthy subjects and patients with heart disease.

BACKGROUND: While multiple cardiovascular magnetic resonance (CMR) methods provide excellent reproducibility of global circumferential and global longitudinal strain, achieving highly reproducible segmental strain is more challenging. Previous single-center studies have demonstrated excellent reproducibility of displacement encoding with stimulated echoes (DENSE) segmental circumferential strain. The present study evaluated the reproducibility of DENSE for measurement of whole-slice or global circumferential (Ecc), longitudinal (Ell) and radial (Err) strain, torsion, and segmental Ecc at multiple centers. METHODS: Six centers participated and a total of 81 subjects were studied, including 60 healthy subjects and 21 patients with various types of heart disease. CMR utilized 3 T scanners, and cine DENSE images were acquired in three short-axis planes and in the four-chamber long-axis view. During one imaging session, each subject underwent two separate DENSE scans to assess inter-scan reproducibility. Each subject was taken out of the scanner and repositioned between the scans. Intra-user, inter-user-same-site, inter-user-different-site, and inter-user-Human-Deep-Learning (DL) comparisons assessed the reproducibility of different users analyzing the same data. Inter-scan comparisons assessed the reproducibility of DENSE from scan to scan. The reproducibility of whole-slice or global Ecc, Ell and Err, torsion, and segmental Ecc were quantified using Bland-Altman analysis, the coefficient of variation (CV), and the intraclass correlation coefficient (ICC). CV was considered excellent for CV ≤ 10%, good for 10% < CV ≤ 20%, fair for 20% < CV ≤ 40%, and poor for CV > 40. ICC values were considered excellent for ICC > 0.74, good for ICC 0.6 < ICC ≤ 0.74, fair for ICC 0.4 < ICC ≤ 0.59, poor for ICC < 0.4. RESULTS: Based on CV and ICC, segmental Ecc provided excellent intra-user, inter-user-same-site, inter-user-different-site, inter-user-Human-DL reproducibility and good-excellent inter-scan reproducibility. Whole-slice Ecc and global Ell provided excellent intra-user, inter-user-same-site, inter-user-different-site, inter-user-Human-DL and inter-scan reproducibility. The reproducibility of torsion was good-excellent for all comparisons. For whole-slice Err, CV was in the fair-good range, and ICC was in the good-excellent range. CONCLUSIONS: Multicenter data show that 3 T CMR DENSE provides highly reproducible whole-slice and segmental Ecc, global Ell, and torsion measurements in healthy subjects and heart disease patients.

Evaluation of a novel mechanical compression device for hematoma prevention and wound cosmesis after CIED implantation.

BACKGROUND: An important complication of cardiac implantable electronic devices (CIED) implantation is the development of hematoma and device infection. OBJECTIVE: We aimed to evaluate a novel mechanical compression device for hematoma prevention and cosmetic outcomes following CIED implantation. METHODS: An open, prospective, randomized, single-center clinical trial was performed in patients undergoing CIED implantation. Patients were randomized to receive a novel mechanical compression device (PressRite, PR) or to receive the standard of care post device implantation. Skin pliability was measured with a calibrated durometer; the surgical site was evaluated using the Manchester Scar Scale (MSS) by a blinded plastic surgeon and the Patient and Observer Scar Scale (POSAS). Performance of PR was assessed through pressure measurements, standardized scar scales and tolerability. RESULTS: From the total of 114 patients evaluated for enrollment, 105 patients were eligible for analysis. Fifty-one patients were randomized to management group (PR) and 54 to the control group. No patients required early removal or experienced adverse effects from PR application. There were 11 hematomas (14.8% vs. 5.9% in the control and PR group respectively, p = NS). The control group had higher post procedure durometer readings in the surgical site when compared with the PR group (7.50 ± 3.45 vs. 5.37 ± 2.78; p = < .01). There were lower MSS scores in the PR group after 2 weeks (p = .03). CONCLUSION: We have demonstrated the safety of PR application and removal. In addition, PR appears to improve postoperative skin pliability, which could facilitate wound healing.

Systemic arterial pulsatility index (SAPi) predicts adverse outcomes in advanced heart failure patients.

Ventriculo-arterial (VA) coupling has been shown to have physiologic importance in heart failure (HF). We hypothesized that the systemic arterial pulsatility index (SAPi), a measure that integrates pulse pressure and a proxy for left ventricular end-diastolic pressure, would be associated with adverse outcomes in advanced HF. We evaluated the SAPi ([systemic systolic blood pressure-systemic diastolic blood pressure]/pulmonary artery wedge pressure) obtained from the final hemodynamic measurement in patients randomized to therapy guided by a pulmonary arterial catheter (PAC) and with complete data in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial. Cox proportional hazards regression was performed for the outcomes of (a) death, transplant, left ventricular assist device (DTxLVAD) or hospitalization, (DTxLVADHF) and (b) DTxLVAD. Among 142 patients (mean age 56.8 ± 13.3 years, 30.3% female), the median SAPi was 2.57 (IQR 1.63-3.45). Increasing SAPi was associated with significant reductions in DTxLVAD (HR 0.60 per unit increase in SAPi, 95% CI 0.44-0.84) and DTxLVADHF (HR 0.81 per unit increase, 95% CI 0.70-0.95). Patients with a SAPi ≤ 2.57 had a marked increase in both outcomes, including more than twice the risk of DTxLVAD (HR 2.19, 95% CI 1.11-4.30) over 6 months. Among advanced heart failure patients with invasive hemodynamic monitoring in the ESCAPE trial, SAPi was strongly associated with adverse clinical outcomes. These findings support further investigation of the SAPi to guide treatment and prognosis in HF undergoing invasive hemodynamic monitoring.

A systemic congestive index (systemic pulse pressure to central venous pressure ratio) predicts adverse outcomes in patients undergoing valvular heart surgery.

BACKGROUND AND AIMS: Invasive hemodynamics may provide a more nuanced assessment of cardiac function and risk phenotyping in patients undergoing cardiac surgery. The systemic pulse pressure (SPP) to central venous pressure (CVP) ratio represents an integrated index of right and left ventricular function and thus may demonstrate an association with valvular heart surgery outcomes. This study hypothesized that a low SPP/CVP ratio would be associated with mortality in valvular surgery patients. METHODS: This retrospective cohort study examined adult valvular surgery patients with preoperative right heart catheterization from 2007 through 2016 at a single tertiary medical center (n = 215). Associations between the SPP/CVP ratio and mortality were investigated with univariate and multivariate analyses. RESULTS: Among 215 patients (age 69.7 ± 12.4 years; 55.8% male), 61 died (28.4%) over a median follow-up of 5.9 years. A SPP/CVP ratio <7.6 was associated with increased mortality (relative risk 1.70, 95% confidence interval [CI] 1.08-2.67, p = .019) and increased length of stay (11.56 ± 13.73 days vs. 7.93 ± 4.92 days, p = .016). It remained an independent predictor of mortality (adjusted odds ratio 3.99, 95% CI 1.47-11.45, p = .008) after adjusting for CVP, mean pulmonary artery pressure, aortic stenosis, tricuspid regurgitation, smoking status, diabetes mellitus, dialysis, and cross-clamp time. CONCLUSIONS: A low SPP/CVP ratio was associated with worse outcomes in patients undergoing valvular heart surgery. This metric has potential utility in preoperative risk stratification to guide patient selection, prognosis, and surgical outcomes.

Suppression of artifact-generating echoes in cine DENSE using deep learning.

PURPOSE: To use deep learning for suppression of the artifact-generating T1 -relaxation echo in cine displacement encoding with stimulated echoes (DENSE) for the purpose of reducing the scan time. METHODS: A U-Net was trained to suppress the artifact-generating T1 -relaxation echo using complementary phase-cycled data as the ground truth. A data-augmentation method was developed that generates synthetic DENSE images with arbitrary displacement-encoding frequencies to suppress the T1 -relaxation echo modulated for a range of frequencies. The resulting U-Net (DAS-Net) was compared with k-space zero-filling as an alternative method. Non-phase-cycled DENSE images acquired in shorter breath-holds were processed by DAS-Net and compared with DENSE images acquired with phase cycling for the quantification of myocardial strain. RESULTS: The DAS-Net method effectively suppressed the T1 -relaxation echo and its artifacts, and achieved root Mean Square(RMS) error = 5.5 ± 0.8 and structural similarity index = 0.85 ± 0.02 for DENSE images acquired with a displacement encoding frequency of 0.10 cycles/mm. The DAS-Net method outperformed zero-filling (root Mean Square error = 5.8 ± 1.5 vs 13.5 ± 1.5, DAS-Net vs zero-filling, P < .01; and structural similarity index = 0.83 ± 0.04 vs 0.66 ± 0.03, DAS-Net vs zero-filling, P < .01). Strain data for non-phase-cycled DENSE images with DAS-Net showed close agreement with strain from phase-cycled DENSE. CONCLUSION: The DAS-Net method provides an effective alternative approach for suppression of the artifact-generating T1 -relaxation echo in DENSE MRI, enabling a 42% reduction in scan time compared to DENSE with phase-cycling.

Left atrial thickness and acute thermal injury in patients undergoing ablation for atrial fibrillation: Laser versus radiofrequency energies.

INTRODUCTION: Thermally induced cardiac lesions result in necrosis, edema, and inflammation. This tissue change may be seen with ultrasound. In this study, we sought to use intracardiac echocardiography (ICE) to evaluate pulmonary vein tissue morphology and assess the acute tissue changes that occur following radiofrequency (RF) or laser ablation for atrial fibrillation (AF). METHODS AND RESULTS: Patients with AF underwent pulmonary vein isolation (PVI) using irrigated RF or laser balloon. Pre- and post-ablation ICE imaging was performed from within each pulmonary vein (PV). At least 10 transverse imaging planes per PV were evaluated and each plane was divided into eight segments. The PV/atrial wall thickness and the luminal area were measured at each segment. Twenty-seven patients underwent PVI (15 with laser, 12 with RF). Ninety-eight pulmonary veins were analyzed (58 PVs laser; 40 PVs RF). At baseline, there were no regional differences in PV wall thickness in the right-sided veins. The anterior regions of left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV) were significantly thicker compared with the posterior and inferior regions (p < .01). Post-ablation, PV wall thickness in RF group increased 24.1% interquartile range (IQR) (17.2%-36.7%) compared with 1.2% IQR (0.4%-8.9%) in laser group, p = .004. In all PVs, RF ablation resulted in significantly greater percent increase in wall thickness compared with laser. Additionally, RF resulted in more variable changes in regional PV wall thickness; with more increases in wall thickness in anterior versus posterior LSPV (75.4 ± 58.5% vs. 46.8 ± 55.6%, p < .01), anterior versus posterior right superior pulmonary vein (RSPV) (62.9 ± 63.9% vs. 44.6 ± 51.7%, p < .05), and superior versus inferior RSPV (69.1 ± 45.4% vs. 35.9 ± 45%, p < .05). There were no significant regional differences in PV wall thickness changes for the laser group. CONCLUSIONS: Rotational ICE can be used to measure acute tissue changes with ablation. Regional variability in baseline wall thickness was nonuniformly present in PVs. Acute tissue changes occurred immediately post-ablation. Compared with laser balloon, RF shows markedly more thickening post-ablation with significant regional variations.

Fully-automated global and segmental strain analysis of DENSE cardiovascular magnetic resonance using deep learning for segmentation and phase unwrapping.

BACKGROUND: Cardiovascular magnetic resonance (CMR) cine displacement encoding with stimulated echoes (DENSE) measures heart motion by encoding myocardial displacement into the signal phase, facilitating high accuracy and reproducibility of global and segmental myocardial strain and providing benefits in clinical performance. While conventional methods for strain analysis of DENSE images are faster than those for myocardial tagging, they still require manual user assistance. The present study developed and evaluated deep learning methods for fully-automatic DENSE strain analysis. METHODS: Convolutional neural networks (CNNs) were developed and trained to (a) identify the left-ventricular (LV) epicardial and endocardial borders, (b) identify the anterior right-ventricular (RV)-LV insertion point, and (c) perform phase unwrapping. Subsequent conventional automatic steps were employed to compute strain. The networks were trained using 12,415 short-axis DENSE images from 45 healthy subjects and 19 heart disease patients and were tested using 10,510 images from 25 healthy subjects and 19 patients. Each individual CNN was evaluated, and the end-to-end fully-automatic deep learning pipeline was compared to conventional user-assisted DENSE analysis using linear correlation and Bland Altman analysis of circumferential strain. RESULTS: LV myocardial segmentation U-Nets achieved a DICE similarity coefficient of 0.87 ± 0.04, a Hausdorff distance of 2.7 ± 1.0 pixels, and a mean surface distance of 0.41 ± 0.29 pixels in comparison with manual LV myocardial segmentation by an expert. The anterior RV-LV insertion point was detected within 1.38 ± 0.9 pixels compared to manually annotated data. The phase-unwrapping U-Net had similar or lower mean squared error vs. ground-truth data compared to the conventional path-following method for images with typical signal-to-noise ratio (SNR) or low SNR (p < 0.05), respectively. Bland-Altman analyses showed biases of 0.00 ± 0.03 and limits of agreement of - 0.04 to 0.05 or better for deep learning-based fully-automatic global and segmental end-systolic circumferential strain vs. conventional user-assisted methods. CONCLUSIONS: Deep learning enables fully-automatic global and segmental circumferential strain analysis of DENSE CMR providing excellent agreement with conventional user-assisted methods. Deep learning-based automatic strain analysis may facilitate greater clinical use of DENSE for the quantification of global and segmental strain in patients with cardiac disease.

MAGGIC, STS, and EuroSCORE II Risk Score Comparison After Aortic and Mitral Valve Surgery.

OBJECTIVES: To compare the Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) risk score with the established Society of Thoracic Surgeons (STS) and EuroSCORE II risk prediction models regarding mortality discrimination after aortic and mitral valve surgery. DESIGN: Retrospective cohort study. SETTING: Single tertiary academic medical center. PARTICIPANTS: A total of 259 patients who underwent open aortic valve replacement or open mitral valve repair/replacement from 2009-2014. INTERVENTIONS: Retrospective chart review. MEASUREMENTS AND MAIN RESULTS: MAGGIC, STS, and EuroSCORE II risk scores for each patient were studied using binary logistic regression and receiver operating characteristic analysis for the primary endpoint of one-year mortality and secondary endpoint of 30-day mortality. One-year mortality C-statistics were similar across risk scores (STS 0.709, 95% confidence interval [CI] 0.578-0.841; MAGGIC 0.673, 95% CI 0.547-0.799; EuroSCORE II 0.642, 95% CI 0.521-0.762; p = 0.56 between STS and MAGGIC; p = 0.20 between STS and EuroSCORE II; and p = 0.69 between MAGGIC and EuroSCORE II). Thirty-day mortality C-statistics also were similar between STS (0.797, 95% CI 0.655-0.939; p < 0.0001 v null hypothesis), MAGGIC (0.721, 95% CI 0.581-0.860; p = 0.33 v STS), and EuroSCORE II (0.688, 95% CI 0.557-0.818; p = 0.06 v STS; p = 0.68 v MAGGIC). CONCLUSIONS: The MAGGIC risk score performs similarly to STS and EuroSCORE II risk models in mortality discrimination after aortic and mitral valve surgery, albeit in a small sample size. This finding has important implications in establishing MAGGIC as a viable prognostic model in this population subset, with fewer variables and ease of use representing key advantages over STS and EuroSCORE II.

Pulmonary Artery Proportional Pulse Pressure (PAPP) Index Identifies Patients With Improved Survival From the CardioMEMS Implantable Pulmonary Artery Pressure Monitor.

BACKGROUND: Pulmonary artery proportional pulse pressure (PAPP) was recently shown to have prognostic value in heart failure (HF) with reduced ejection fraction (HFrEF) and pulmonary hypertension. We tested the hypothesis that PAPP would be predictive of adverse outcomes in patients with implantable pulmonary artery pressure monitor (CardioMEMS™ HF System, St. Jude Medical [now Abbott], Atlanta, GA, USA). METHODS: Survival analysis with Cox proportional hazards regression was used to evaluate all-cause deaths and HF hospitalisation (HFH) in CHAMPION trial1 patients who received treatment with the CardioMEMS device based on the PAPP. RESULTS: Among 550 randomised patients, 274 had PAPP ≤ the median value of 0.583 while 276 had PAPP>0.583. Patients with PAPP≤0.583 (versus PAPP>0.583) had an increased risk of HFH (HR 1.40, 95% CI 1.16-1.68, p=0.0004) and experienced a significant 46% reduction in annualised risk of death with CardioMEMS treatment (HR 0.54, 95% CI 0.31-0.92) during 2-3 years of follow-up. This survival benefit was attributable to the treatment benefit in patients with HFrEF and PAPP≤0.583 (HR 0.50, 95% CI 0.28-0.90, p<0.05). Patients with PAPP>0.583 or HF with preserved EF (HFpEF) had no significant survival benefit with treatment (p>0.05). CONCLUSION: Lower PAPP in HFrEF patients with CardioMEMS constitutes a higher mortality risk status. More studies are needed to understand clinical applications of PAPP in implantable pulmonary artery pressure monitors.

Modeling defibrillation benefit for survival among cardiac resynchronization therapy defibrillator recipients.

BACKGROUND: Patients with heart failure having a low expected probability of arrhythmic death may not benefit from implantable cardioverter defibrillators (ICDs). OBJECTIVE: The objective was to validate models to identify cardiac resynchronization therapy (CRT) candidates who may not require CRT devices with ICD functionality. METHODS: Heart failure (HF) patients with CRT-Ds and non-CRT ICDs from the National Cardiovascular Data Registry and others with no device from 3 separate registries and 3 heart failure trials were analyzed using multivariable Cox proportional hazards regression for survival with the Seattle Heart Failure Model (SHFM; estimates overall mortality) and the Seattle Proportional Risk Model (SPRM; estimates proportional risk of arrhythmic death). RESULTS: Among 60,185 patients (age 68.6 ±â€¯11.3 years, 31.9% female) meeting CRT-D criteria, 38,348 had CRT-Ds, 11,389 had non-CRT ICDs, and 10,448 had no device. CRT-D patients had a prominent adjusted survival benefit (HR 0.52, 95% CI 0.50-0.55, P < .0001 versus no device). CRT-D patients with SHFM-predicted 4-year survival ≥81% (median) and a low SPRM-predicted probability of an arrhythmic mode of death ≤42% (median) had an absolute adjusted risk reduction attributable to ICD functionality of just 0.95%/year with the majority of survival benefit (70%) attributable to CRT pacing. In contrast, CRT-D patients with SHFM-predicted survival median had substantially more ICD-attributable benefit (absolute risk reduction of 2.6%/year combined; P < .0001). CONCLUSIONS: The SPRM and SHFM identified a quarter of real-world, primary prevention CRT-D patients with minimal benefit from ICD functionality. Further studies to evaluate CRT pacemakers in these low-risk CRT candidates are indicated.

Electrocardiographic left atrial abnormality in patients presenting with ischemic stroke.

BACKGROUND: P wave indices represent electrocardiographic marker of left atrial pathology. We hypothesized that P wave would be more abnormal in patients presenting with ischemic stroke than a comparable group without ischemic stroke. METHODS: We compared P wave terminal force in V1 (PTFV1) between patients admitted with ischemic stroke (case) and patients followed in cardiology clinic (control) at a single medical center. Using logistic regression models, we tested for an association between abnormal PTFV1 (> 4000 µV ms) and ischemic stroke. We also defined several optimal cut-off values of PTFV1 using a LOESS plot and estimated odds ratio of ischemic stroke when moving from one cut-point level to the next higher-level. RESULTS: A total of 297 patients (case 147, control 150) were included. PTFV1 was higher in patients with vs. those without ischemic stroke (median 4620 vs 3994 µV ms; p=0.006). PTFV1 was similar between cardioembolic/cryptogenic and other stroke subtypes. In multivariable analyses adjusting for sex, obesity, age, and hypertension, the association between abnormal PTFV1 and ischemic stroke ceased to be significant (OR 1.53 [0.95, 2.50], p=0.083). Increase to the next cutoff level of PTFV1 (900, 2000, 3000, 4000, 5000, and 6000 µV ms) was associated with 18% increase in odds of having ischemic stroke (vs. no ischemic stroke) (OR 1.18 [1.02, 1.36], p=0.026). CONCLUSION: Patients presenting with acute ischemic stroke are more likely to have abnormal PTFV1. These findings from a real-world clinical setting support the results of cohort studies that left atrial pathology manifested as abnormal PTFV1 is associated with ischemic stroke.