Bundle branch reentrant tachycardia in a patient with a calcified bicuspid aortic valve and normal ventricular function

Arrhythmias in Patients With Valvular Heart Disease: Gaps in Knowledge and the Way Forward

The prevalence of both organic valvular heart disease (VHD) and cardiac arrhythmias is high in the general population, and their coexistence is common. Both VHD and arrhythmias in the elderly lead to an elevated risk of hospitalization and use of health services. However, the relationships of the two conditions is not fully understood and our understanding of their coexistence in terms of contemporary management and prognosis is still limited. VHD-induced left ventricular dysfunction/hypertrophy and left atrial dilation lead to both atrial and ventricular arrhythmias. On the other hand, arrhythmias can be considered as an independent condition resulting from a coexisting ischemic or non-ischemic substrate or idiopathic ectopy. Both atrial and ventricular VHD-induced arrhythmias may contribute to clinical worsening and be a turning point in the natural history of VHD. Symptoms developed in patients with VHD are not specific and may be attributable to hemodynamical consequences of valve disease but also to other cardiac conditions including arrhythmias which are notably prevalent in this population. The issue how to distinguish symptoms related to VHD from those related to atrial fibrillation (AF) during decision making process remains challenging. Moreover, AF is a traditional limit of echocardiography and an important source of errors in assessment of the severity of VHD. Despite recent progress in understanding the pathophysiology and prognosis of postoperative AF, many questions remain regarding its prevention and management. Furthermore, life-threatening ventricular arrhythmias can predispose patients with VHD to sudden cardiac death. Evidence for a putative link between arrhythmias and outcome in VHD is growing but available data on targeted therapies for VHD-related arrhythmias, including monitoring and catheter ablation, is scarce. Despite growing evidences, more research focused on the prognosis and optimal management of VHD-related arrhythmias is still required. We aimed to review the current evidence and identify gaps in knowledge about the prevalence, prognostic considerations, and treatment of atrial and ventricular arrhythmias in common subtypes of organic VHD.

Clinical Significance of Ventricular Tachyarrhythmias in Patients Undergoing Valve Replacement: A Nationwide Population-Based Study

Background: The clinical significance and outcomes of ventricular tachyarrhythmias (VTa) in patients undergoing valve replacement have rarely been reported.

Objective: This study aimed to investigate the incidence and outcome of VTa after surgical valve replacement.

Methods: We conducted a population-based retrospective cohort study using data obtained from the Taiwan National Health Insurance Research Database. In total, 10,212 patients were selected after 1:1 propensity-score matching based on the type of prosthetic valve used (mechanical vs. bioprosthetic). Various outcomes during long-term follow-up were analyzed.

Results: After a median follow-up period of 59.6 months, the crude incidence rate of VTa after surgical valve replacement was 4.8/1,000 person-years, and the cumulative incidence of VTa persistently increased after surgery. Furthermore, the occurrences of VTa after valve replacement significantly increased the risk of cardiovascular (CV) death (P < 0.001, HR 1.67, 95% CI 1.41–1.96), stroke- (P < 0.001, HR 1.66, 95% CI 1.37–2.01), atrial fibrillation- (P < 0.001, HR 2.80, 95% CI 2.42–3.24), and congestive heart failure-related hospitalization (P < 0.001, HR 2.61, 95% CI 2.30–2.95). Among patients with VTa, all-cause mortality (P = 0.001, HR 0.49, 95% CI 0.32–0.75) and CV death (P = 0.047, HR 0.58, 95% CI 0.34–0.99) in those with implantable cardioverter-defibrillator (ICD) implantation were lower than those without.

Conclusion: The crude incidence rate of VTa after surgical valve replacement was 4.8/1,000 person-years, and the cumulative incidence of VTa persistently increased during follow-up. The presence of VTa after surgical valve replacement increases hospitalization and CV death, while ICD implantation reduced the mortality rate in these patients.

[Bundle branch reentry VT : Diagnosis, mapping, and ablation]

Macroreentry in the His-Purkinje system can result in sustained ventricular tachycardia (VT) termed bundle branch reentry VT. Bundle branch reentry is usually associated with His-Purkinje disease and depressed left ventricular function. In the case of typical bundle branch reentry, the right bundle is activated in the anterograde direction and ventricular depolarization begins at the distal end of the right bundle on the ventricular septum generating a typical left bundle branch block QRS morphology. However, atypical surface ECGs can also be found in patients with severe left ventricular dysfunction and involvement of the right ventricle complicating the diagnosis of bundle branch reentry VT. It is important to diagnose bundle branch reentry VT because patients with bundle branch reentry VT may suffer from a high rate of serial implantable cardioverter defibrillator (ICD) interventions based on VT recurrences due to immediate reinitiation of the arrhythmia. Ablation of the right bundle branch easily cures bundle branch reentry VT and can prevent frequent ICD interventions. After ablation of bundle branch reentry VT, mortality remains high due to the severe left ventricular dysfunction in many patients, and the patients are candidates for cardiac resynchronization therapy (CRT-D).

Atypical Surface ECG Complicating the Diagnosis of Bundle Branch Reentry Tachycardia

BACKGROUND

Typical left bundle branch block (LBBB) during ventricular tachycardia (VT) is a diagnostic criterion of bundle branch reentry tachycardia (BBRT) with activation of the right bundle in the anterograde direction.

METHODS AND RESULTS

Eleven patients (seven male, 60 ± 12 years) with nonischemic cardiomyopathy (left ventricular ejection fraction 37 ± 16%) presenting with BBRT were successfully treated by ablation of the right bundle. Among them, five patients had atypical surface electrocardiograms (ECGs) differing from a typical LBBB during the VT. Three patients with severe enlargement and dysfunction of the left ventricle had broadened irregular QRS complexes with rR or RS configuration in lead V6 during the BBRT. Two patients with enlargement and/or hypokinesia of the right ventricle had entirely or almost entirely negative complexes (QS) in the chest leads (V1-V6) during the VT. Activation mapping in these two patients revealed that the exit site of the BBRT was in the anterior right ventricle generating a negative concordance in the precordial leads.

CONCLUSIONS

Atypical surface ECGs with broadened irregular QRS complexes or negative concordance in the precordial leads can complicate the correct diagnosis of BBRT in patients with severe left ventricular dysfunction and involvement of the right ventricle.