Prognostic value of cardiovascular magnetic resonance left ventricular volumetry and geometry in patients receiving an implantable cardioverter defibrillator

Abstract

Background Current indications for implantable cardioverter defibrillator (ICD) implantation for sudden cardiac death prevention rely primarily on left ventricular (LV) ejection fraction (LVEF). Currently, two different contouring methods by cardiovascular magnetic resonance (CMR) are used for LVEF calculation. We evaluated the comparative prognostic value of these two methods in the ICD population, and if measures of LV geometry added predictive value. Methods In this retrospective, 2-center observational cohort study, patients underwent CMR prior to ICD implantation for primary or secondary prevention from January 2005 to December 2018. Two readers, blinded to all clinical and outcome data assessed CMR studies by: (a) including the LV trabeculae and papillary muscles (TPM) (trabeculated endocardial contours), and (b) excluding LV TPM (rounded endocardial contours) from the total LV mass for calculation of LVEF, LV volumes and mass. LV sphericity and sphere-volume indices were also calculated. The primary outcome was a composite of appropriate ICD shocks or death. Results Of the 372 consecutive eligible patients, 129 patients (34.7%) had appropriate ICD shock, and 65 (17.5%) died over a median duration follow-up of 61 months (IQR 38–103). LVEF was higher when including TPM versus excluding TPM (36% vs. 31%, p < 0.001). The rate of appropriate ICD shock or all-cause death was higher among patients with lower LVEF both including and excluding TPM (p for trend = 0.019 and 0.004, respectively). In multivariable models adjusting for age, primary prevention, ischemic heart disease and late gadolinium enhancement, both LVEF (HR per 10% including TPM 0.814 [95%CI 0.688–0.962] p = 0.016, vs. HR per 10% excluding TPM 0.780 [95%CI 0.639–0.951] p = 0.014) and LV mass index (HR per 10 g/m2 including TPM 1.099 [95%CI 1.027–1.175] p = 0.006; HR per 10 g/m2 excluding TPM 1.126 [95%CI 1.032–1.228] p = 0.008) had independent prognostic value. Higher LV end-systolic volumes and LV sphericity were significantly associated with increased mortality but showed no added prognostic value. Conclusion Both CMR post-processing methods showed similar prognostic value and can be used for LVEF assessment. LVEF and indexed LV mass are independent predictors for appropriate ICD shocks and all-cause mortality in the ICD population.

Pediatric Cardiac Magnetic Resonance Reference Values for Biventricular Volumes Derived From Different Contouring Techniques

“…With regard to the available pediatric normal values, studies using a simple approach by including trabeculations into the blood pool are lacking. We therefore tried to close this gap and also confirmed that the two contouring methods give significantly different results for biventricular volumes and EF 3,17–19 . Another reason for providing additional normal values for a simple approach is that from our experience until recently, software tools for semi‐automatic or automatic contour delineation in children especially with congenital heart disease commonly did not work as well as in adults.…”

“…Previous studies on ventricular MRI normal values in children have used different approaches and contouring methods 3,5–7,16 . However, it has been shown in several studies that results from varying contouring methods can give different volumetric results 16–19 . Therefore, the decision about the best matching normal values should take postprocessing methods into account 2 .…”

“…Nevertheless, there is still discussion about excluding papillary muscles and trabeculations from the ventricular volume and until now, both methods have been acceptable 2 . As suggested by Urzua Fresna et al, it is therefore probably best to use the institution's most reproducible contouring method 17 . It must also be mentioned that different software venders have different segmentation tools and that this can particularly impact volumetric results when myocardial trabeculations and papillary muscles are included into the blood pool.…”

Meta-Analysis of Normal Reference Values for Right and Left Ventricular Quantification by Cardiovascular Magnetic Resonance

“…When including the PMT in the LV mass (as opposed to the LV cavity), mean left ventricular mass index and left ventricular ejection fraction were higher by +8 g/m 2 and +2% in our meta-analysis, similar to +6 g/m 2 and +2.6% in the study by Riffel et al 7 of healthy volunteers; mean left ventricular end-diastolic volume index and left ventricular end-systolic volume index were lower by −8 and −4 mL/m 2 , similar to −6 and −4 mL/m 2 . While these differences are modest in normal hearts, clinicians should be aware that they are amplified in cardiomyopathic hearts; mean left ventricular mass index and left ventricular ejection fraction were higher by +20 g/m 2 and +5% in a study of mostly dilated cardiomyopathies 13 and by +26 g/m 2 and +9% in studies of hypertrophic cardiomyopathies. 14,15 Accordingly, PMT mass accounts for 9% of the total myocardial mass in normal hearts but up to 21% in cardiomyopathic hearts, with PMT mass increasing in proportion to LV cavity dilation and, to a lesser extent, LV pressure overload.…”

Diabetes mellitus is associated with more adverse non-hemodynamic left ventricular remodeling and less recovery in patients with primary aldosteronism

“…In addition, LV regression is independently associated with prevention of heart failure. [63][64][65][66] Inappropriate LVM has also been associated with an increased risk of cardiovascular events and mortality. 67 In this study, we aimed to investigate the impact of DM on LV remodeling.…”