Right ventricular failure predicted from right bundle branch block: cardiac magnetic resonance imaging validation

Abstract

Background: Right ventricular (RV) failure has proven to be independently associated with adverse outcomes. Electrocardiographic parameters assessing RV function are largely unknown, making echocardiography the first line for RV function assessment. It is however, limited by geometrical assumptions and is inferior to cardiac magnetic resonance imaging (CMRI) which is widely regarded as the most accurate tool for assessing RV function. Methods:We seek to determine the correlation of ECG parameters of right bundle branch block (RBBB) with RV ejection fraction (EF) and RV dimensions using the CMRI. QRS duration, R amplitude and R' duration were obtained from precordial lead V1; S duration and amplitude were obtained from lead I and AVL. RV systolic dysfunction was defined as RV EF <40%. RV systolic dysfunction group (mean EF of 24±10%) were compared with normal RV systolic function group which acted as control (mean EF of 48±8%). CMRI and ECG parameters were compared between the two groups. Rank correlations and scatter diagrams between individual CMRI parameters and ECG parameters were done using medcalc for windows, version 12.5. Sensitivity, specificity and area under the curve (AUC) were calculated.Results: RV systolic dysfunction group was found to have larger RV end systolic volumes (90±42 vs. 59±40 mL, P=0.02). ECG evaluation of RV dysfunction group revealed longer R' duration (103±22 vs.84±18 msec, P=0.005) as compared to the control group. The specificity of R' duration >100 msec to detect RV systolic dysfunction was found to be 93%. R' duration was found to have an inverse correlation with RV EF (r=−0.49, P=0.007).Conclusions: Larger RV end systolic volumes seen with RV dysfunction can affect the latter part of right bundle branch leading to prolonged R' duration. We here found prolonged R' duration in lead V1 to have a highly specific inverse correlation to RV systolic function. ECG can be used as an inexpensive tool for RV function assessment and should be used alongside echocardiography to evaluate RV dysfunction when CMRI is not available.

Double outlet right ventricle in adults: Anatomic variability, surgical treatment, and late postoperative complications

“…However, some authors argue for the existence of significant impact of RBBB on both right and left ventricular systolic function. [68][69][70] Besides, there is a growing interest in cardiac resynchronization therapy in patients with failing systemic RV, signifying the possibility to restore the mechanical synchronization of contractility in both ventricles of the heart. 71 While the duration and fragmentation of QRS complex is an established risk factor for sudden cardiac death in patients with tetralogy of Fallot, in the study by Shen et al…”

“…The clinical significance of the RBBB remains controversial, and in clinical practice it is mostly treated as benign in terms of prognosis. However, some authors argue for the existence of significant impact of RBBB on both right and left ventricular systolic function 68–70 . Besides, there is a growing interest in cardiac resynchronization therapy in patients with failing systemic RV, signifying the possibility to restore the mechanical synchronization of contractility in both ventricles of the heart 71 .…”

Morphologic Characteristics and Function of Right Ventricle in Patients With Isolated Right Bundle Branch Block

“…8 In patient with RBBB, QRS width was inversely related with RV function appreciated on cardiac magnetic resonance imaging (CMR). 9 Furthermore, several studies have shown that RBBB has independent association with decreased RV function and which in itself is a predictor of adverse outcomes in patients with acquired heart disease. 10,11 However, very few numbers of study were available regarding Isolated RBBB and their impact on right ventricle morphology and function.…”