CinE caRdiac magneTic resonAnce to predIct veNTricular arrhYthmia (CERTAINTY).

Better models to identify individuals at low risk of ventricular arrhythmia (VA) are needed for implantable cardioverter-defibrillator (ICD) candidates to mitigate the risk of ICD-related complications. We designed the CERTAINTY study (CinE caRdiac magneTic resonAnce to predIct veNTricular arrhYthmia) with deep learning for VA risk prediction from cine cardiac magnetic resonance (CMR). Using a training cohort of primary prevention ICD recipients (n = 350, 97 women, median age 59 years, 178 ischemic cardiomyopathy) who underwent CMR immediately prior to ICD implantation, we developed two neural networks: Cine Fingerprint Extractor and Risk Predictor. The former extracts cardiac structure and function features from cine CMR in a form of cine fingerprint in a fully unsupervised fashion, and the latter takes in the cine fingerprint and outputs disease outcomes as a cine risk score. Patients with VA (n = 96) had a significantly higher cine risk score than those without VA. Multivariate analysis showed that the cine risk score was significantly associated with VA after adjusting for clinical characteristics, cardiac structure and function including CMR-derived scar extent. These findings indicate that non-contrast, cine CMR inherently contains features to improve VA risk prediction in primary prevention ICD candidates. We solicit participation from multiple centers for external validation.

Right ventricular function as assessed by cardiac magnetic resonance imaging-derived strain parameters compared to high-fidelity micromanometer catheter measurements.

Right ventricular function has prognostic significance in patients with pulmonary hypertension. We evaluated whether cardiac magnetic resonance-derived strain and strain rate parameters could reliably reflect right ventricular systolic and diastolic function in precapillary pulmonary hypertension. End-systolic elastance and the time constant of right ventricular relaxation tau, both derived from invasive high-fidelity micromanometer catheter measurements, were used as gold standards for assessing systolic and diastolic right ventricular function, respectively. Nineteen consecutive precapillary pulmonary hypertension patients underwent cardiac magnetic resonance and right heart catheterization prospectively. Cardiac magnetic resonance data were compared with those of 19 control subjects. In pulmonary hypertension patients, associations between strain- and strain rate-related parameters and invasive hemodynamic parameters were evaluated. Longitudinal peak systolic strain, strain rate, and early diastolic strain rate were lower in PAH patients than in controls; peak atrial-diastolic strain rate was higher in pulmonary hypertension patients. Similarly, circumferential peak systolic strain rate was lower and peak atrial-diastolic strain rate was higher in pulmonary hypertension. In pulmonary hypertension, no correlations existed between cardiac magnetic resonance-derived and hemodynamically derived measures of systolic right ventricular function. Regarding diastolic parameters, tau was significantly correlated with peak longitudinal atrial-diastolic strain rate (r = -0.61), deceleration time (r = 0.75), longitudinal systolic to diastolic time ratio (r = 0.59), early diastolic strain rate (r = -0.5), circumferential peak atrial-diastolic strain rate (r = -0.52), and deceleration time (r = 0.62). Strain analysis of the right ventricular diastolic phase is a reliable non-invasive method for detecting right ventricular diastolic dysfunction in PAH.

Cardiac MRI structural and functional predictors of left ventricular ejection fraction recovery following PVC catheter ablation.

Frequent premature ventricular contractions (PVCs) can induce cardiomyopathy (PVC CM). We sought to use cardiac magnetic resonance imaging (CMR) to quantify changes in cardiac structure and function of cardiomyopathy patients following catheter ablation for PVCs. Patients undergoing PVC ablation at the Johns Hopkins Hospital with pre-procedural CMR from 2010 to 2018 were included in this study. CMR Images were analyzed to collect information on cardiac structure and function as well as to quantify scar. Of the total 51 included patients, PVC CM (LVEF < 45%) was observed in 51% (n = 29). Of these, 19 had post-ablation ejection fractions quantified, with 78.9% (n = 15) recovering function. Global longitudinal strain was significantly correlated with LVEF (OR 1.831, p < 0.01) but did not predict recovery of function. RV origin of PVCs was more common in the preserved LVEF group but was also significantly correlated with persistently reduced EF post-ablation in the PVC CM group. Scar burden was not correlated with either cardiac function or post-ablation recovery of function. In this cohort, there were no significant CMR findings to predict subsequent recovery of EF after ablation among those with PVC CM. PVC origin in the RV was associated with persistently reduced LVEF after ablation.

References Values for Left Atrial Volumes, Emptying Fractions, Strains, and Strain Rates and Their Determinants by Age, Gender, and Ethnicity: The Multiethnic Study of Atherosclerosis (MESA).

RATIONALE AND OBJECTIVES: Left Atrial (LA) adverse remodeling is an important predictor of morbidity and mortality in several cardiovascular (CV) diseases. Our goals were to quantify and provide reference ranges for LA structure and function using feature tracking cine cardiac magnetic resonance. MATERIALS AND METHODS: 2526 participants of the Multiethnic Study of Atherosclerosis study who had feature tracking cine cardiac magnetic resonance derived LA data and were free of atrial fibrillation/flutter and prior CV events at year five follow-up examination (2010-2012) were included in this study. LA phasic indexed volumes: maximum (LAVi max), minimum (LAVi min), and preatrial contraction (LAVi preA); LA empty fractions: total, passive, and active (LAtEF, LApEF, and LAaEF); LA longitudinal strain: maximum and preatrial contraction (S max and S preA); and LA longitudinal strain rate: systolic (SR max) and early/late diastolic (SR e and SR a) were measured. Age, gender, and race/ethnicity-specific reference ranges were identified. Also, reference values in a select subgroup of healthy participants free of traditional CV risk factors at the time of exam date were reported. RESULTS: The mean ± SD for LAVi max, LAVi min, LAVi preA, S max, SR e, and SR a were in the 45-65-year-old participants: (33.8 ± 10 mL/m2), (14.5 ± 6.4 mL/m2), (24.8 ± 8.2 mL/m2), (34.6 ± 13.8 %), (-1.4 ± 0.7 s-1), (-2.1 ± 1 s-1) and in the ≥ 65-year-old participants: (35 ± 11.5 mL/m2), (16.6 ± 8.3 mL/m2), (27.6 ± 9.9 mL/m2), (31.2 ± 14.3 %), (-1 ± 0.6 s-1), (-2.1 ± 1 s-1) respectively. Younger individuals had Powered by Editorial Manager and ProduXion Manager from Aries Systems Corporation smaller LA volumes and better LA function compared to their older counterparts. Similar findings were observed in Chinese-Americans as compared to Whites. CONCLUSION: This study provides reference values of LA structure and function parameters from a healthy multiethnic community-based population aged 53-94 years evaluated by FTMRI.

Left Atrial Structure in Relationship to Age, Sex, Ethnicity, and Cardiovascular Risk Factors: MESA (Multi-Ethnic Study of Atherosclerosis).

BACKGROUND: Left atrial (LA) size is a marker of diastolic function and is associated with atrial fibrillation and cardiovascular outcomes. However, there are no large population studies measuring LA structure. The relationship of demographics and cardiovascular risk factors to LA size is largely unknown. This study aimed to determine associations of LA size with demographic factors, cardiac structure and function, and cardiovascular risk factors. METHODS AND RESULTS: LA volume indexed to body surface area was measured by cardiovascular magnetic resonance steady-state free precession and fast gradient echo cine long- and short-axis images in 2576 asymptomatic participants of MESA ([Multi-Ethnic Study of Atherosclerosis] 68.7 years, 53.0% women, white 42.2%, Chinese American 12.0%, black 24.5%, and Hispanic 21.2%) using biplane and short-axis images. The mean LA volume index was 36.5±11.4 mL/m2 in the entire cohort and 35.5±10.1 mL/m2 in subjects free of cardiovascular risk factors (n=283). Multivariable analysis included adjustment for demographics, ethnicity, cardiovascular risk factors, serological studies, socioeconomic status, left ventricular structure, and medications. In the adjusted analysis, age (ß=0.2 mL/m2 per year, P<0.0001), male sex (ß=-4.2 mL/m2, P<0.0001), obesity (ß=1.3 mL/m2, P<0.01), end-diastolic volume index (ß=0.4 mL/m2, P<0.0001), Chinese American (ß=-2.6 mL/m2, P<0.0001), and Hispanic (ß=1.1 mL/m2, P<0.05) ethnicities were associated with LA volume index. Diabetes mellitus and smoking were not associated with LA volume index. LA volumes measured by steady-state free precession were 3% larger than by fast gradient echo cine cardiovascular magnetic resonance (P<0.001). CONCLUSIONS: Age, sex, ethnicity and left ventricular structural parameters were associated with LA size. Importantly, the study provides reference values of normal LA volume index.