Magnetic resonance imaging abnormalities in the basal interventricular septum of patients with left ventricular outflow tract arrhythmias

Abstract

Introduction: Concealed structural abnormalities were detected by delayed enhancementmagnetic resonance imaging (DE-MRI) in patients with apparently idiopathic tachycardia of left ventricular (LV) origin. Basal septal fibrosis was evaluated as a potential arrhythmia substrate in patients with left ventricular outflow tract (LVOT) arrhythmias. Methods and Results: A total of 22 patients with LVOT arrhythmias, including frequent monomorphic premature ventricular complexes (PVCs) in 15 patients and ventricular tachycardia (VT) in 7 patients, underwent catheter ablation and DE-MRI. A total of 19 patients with frequent PVCs and 17 patients with idiopathic VT of other origin served as a control group. Basal septal intramural fibrosis as thin strip-shaped intramyocardial DE or as marked intramyocardial DE involving >25% of wall thickness was detected more frequently in patients with LVOT arrhythmias (41% and 32%) than in patients with non LVOT arrhythmias (14% and 3%). After successful ablation, 4/16 patients with basal septal intramural fibrosis and LVOT PVCs (n = 3) or LVOT VT (n = 1) compared with no patient without basal septal fibrosis experienced episodes of sustained VT with similar or different QRS morphology resulting in ICD therapy in three patients. Follow-up DE-MRI after PVC ablation (17 ± 7 months)revealed an increase in LV ejection fraction from 49 ± 5% to 56 ± 5% (n = 9) but the amount of septal DE remained unchanged.Conclusions: Basal septal intramural fibrosis may serve as the arrhythmia substrate in a substantial part of patients with premature ventricular complexes (PVCs) and VT originating from the LVOT and identifies patients with continued risk for VT recurrence after initially successful ablation of LVOT arrhythmias. K E Y W O R D S delayed enhancement (DE), left ventricular outflow tract (LVOT), magnetic resonance imaging (MRI), premature ventricular contraction (PVC), ventricular tachycardia (VT)

Validation of a clinical model for predicting left versus right ventricular outflow tract origin of idiopathic ventricular arrhythmias

“…Structural heart diseases, which could have potentially served as substrate for VA were not systematically ruled out using cMRI. Recent studies have shown concealed myocardial abnormalities in patients with apparently idiopathic PVC using cMRI data, especially in those with PVCs arising from the LVOT 37–39 . These could have served as anatomic substrate for VAs, leading to misclassification as idiopathic VA while structural heart disease was mostly ruled out using echocardiography 39 .…”

“…Recent studies have shown concealed myocardial abnormalities in patients with apparently idiopathic PVC using cMRI data, especially in those with PVCs arising from the LVOT. [37][38][39] These could have served as anatomic substrate for VAs, leading to misclassification as idiopathic VA while structural heart disease was mostly ruled out using echocardiography. 39 Finally, further prospective studies are needed to assess the accuracy and usefulness of the algorithm.…”

“…[37][38][39] These could have served as anatomic substrate for VAs, leading to misclassification as idiopathic VA while structural heart disease was mostly ruled out using echocardiography. 39 Finally, further prospective studies are needed to assess the accuracy and usefulness of the algorithm.…”

Magnetic Resonance Detects Structural Heart Disease in Patients with Frequent Ventricular Ectopy and Normal Echocardiographic Findings

“…However, the studies behind this evidence were performed in different settings and populations, and a majority were carried out with restrictive inclusion criteria and in selected groups. In some studies the patient had not been evaluated before CMR with both the exercise test and echocardiogram [16,21,30,31], or only patients with specific PVC morphologies were included [32,33].…”