Assessment of left ventricular ejection fraction in patients eligible for ICD therapy: Discrepancy between cardiac magnetic resonance imaging and 2D echocardiography

Abstract

ObjectiveImplantable cardioverter defibrillators (ICD) and cardiac resynchronisation therapy (CRT) have substantially improved the survival of patients with cardiomyopathy. Eligibility for this therapy requires a left ventricular ejection fraction (LVEF) <35 %. This is largely based on studies using echocardiography. Cardiac magnetic resonance imaging (CMR) is increasingly utilised for LVEF assessment, but several studies have shown differences between LVEF assessed by CMR and echocardiography. The present study compared LVEF assessment by CMR and echocardiography in a heart failure population and evaluated effects on eligibility for device therapy.Methods152 patients (106 male, mean age 65.5 ± 9.9 years) referred for device therapy were included. During evaluation of eligibility they underwent both CMR and echocardiographic LVEF assessment. CMR volumes were computed from a stack of short-axis images. Echocardiographic volumes were computed using Simpson’s biplane method.ResultsThe study population demonstrated an underestimation of end-diastolic volume (EDV) and end-systolic volume (ESV) by echocardiography of 71 ± 53 ml (mean ± SD) and 70 ± 49 ml, respectively. This resulted in an overestimation of LVEF of 6.6 ± 8.3 % by echocardiography compared with CMR (echocardiographic LVEF 31.5 ± 8.7 % and CMR LVEF 24.9 ± 9.6 %). 28 % of patients had opposing outcomes of eligibility for cardiac device therapy depending on the imaging modality used.ConclusionWe found EDV and ESV to be underestimated by echocardiography, and LVEF assessed by CMR to be significantly smaller than by echocardiography. Applying an LVEF cut-off value of 35 %, CMR would significantly increase the number of patients eligible for device implantation. Therefore, LVEF cut-off values might need reassessment when using CMR.

Impact of contrast echocardiography on accurate discrimination of specific degree of left ventricular systolic dysfunction and comparison with cardiac magnetic resonance imaging

“…Echocardiography is the single most commonly used diagnostic test in the evaluation LVEF in patients with heart failure. Most previous studies reported an overestimation of LVEF by non‐contrast echocardiography compared with CMR, and this discrepancy increased with larger LV volumes and lower LVEF . There was no significant difference in LVEF between the two imaging modalities in our study which could be explained by the fact that only 35% of the patients had severely reduced LVEF.…”

“…The use of CMR may affect cardiac device eligibility in particular in patients with borderline LVEF that is ±5% within the cutoff value. Previous studies comparing non‐contrast echocardiography and CMR demonstrated that use of CMR led to reclassification for cardiac device eligibility in up to 41% of the patients . The present study showed that only 1 (6%) patient with optimal images on non‐contrast echocardiography was reclassified for device eligibility by CMR.…”

“…Previous studies comparing noncontrast echocardiography and CMR demonstrated that use of CMR led to reclassification for cardiac device eligibility in up to 41% of the patients. 16,19,[28][29][30] The present study showed that only 1 (6%) patient with optimal images on non-contrast echocardiography was reclassified for device eligibility by CMR. On the other hand, CMR use led to device eligibility reclassification in 9 (23%) of patients with suboptimal non-contrast echocardiography images.…”

Prognostic Benefit of Cardiac Magnetic Resonance Over Transthoracic Echocardiography for the Assessment of Ischemic and Nonischemic Dilated Cardiomyopathy Patients Referred for the Evaluation of Primary Prevention Implantable Cardioverter–Defibrillator Therapy

“…22,23 CMR imaging is a standardized technique that, thanks to high spatial resolution and independence from geometric assumptions, represents the reference standard for LV volumes and LVEF measurement. 24,25 Indeed, a significant discrepancy between CMR and TTE has been demonstrated, ranging from 7% LVEF overestimation to 4% underestimation with the latter imaging technique 26,27 with the majority of studies indicating an overestimation of LVEF assessment by TTE. 21 In addition, CMR has proven to have high diagnostic and prognostic value in cardiomyopathy evaluation apart from the pure LVEF estimation, thanks to LGE technique.…”

Cardiac sympathetic activity in chronic heart failure: cardiac 123I-mIBG scintigraphy to improve patient selection for ICD implantation

“…However LVEF assessed by cardiovascular magnetic resonance imaging (CMR) is significantly lower compared with echocardiography [14]. Therefore CMR would significantly increase the number of CHF patients eligible for CRT or ICD implantation.…”