Sudden Death After Transcatheter Aortic Valve Implantation. Are Bradyarrhythmias Always The Cause?

Cardiac fibrosis as a predictor for sudden cardiac death after transcatheter aortic valve implantation

BACKGROUND

Cardiac fibrosis plays a major pathophysiological role in any form of chronic heart disease, and high levels are associated with poor outcome. Diffuse and focal cardiac fibrosis are different subtypes, which have different pathomechanisms and prognostic implications. The total fibrosis burden in endomyocardial biopsy tissue was recently proved to play an independent prognostic role in aortic stenosis patients after transcatheter aortic valve implantation (TAVI).

AIMS

Here, for the first time, we aim to assess the specific impact of different fibrosis subtypes on sudden cardiac death (SCD) as a primary reason for cardiovascular mortality after TAVI.

METHODS

The fibrosis pattern was assessed histologically in the left ventricular biopsies obtained during TAVI interventions in 161 patients, who received a structured follow-up thereafter.

RESULTS

Receiver operating characteristic analyses, performed 6, 12, 24 and 48 months after TAVI, showed diffuse, but not focal, fibrosis as a significant predictor for SCD at all timepoints, with the highest area under the curve at the first time point and a decrease in its SCD predictivity over time. In both multivariate Cox proportional hazards and Fine-Gray competing risk models, including both fibrosis subtypes, as well as age, sex and ejection fraction, high diffuse fibrosis remained statistically significant. Accordingly, it represents an independent SCD predictor, most importantly for the occurrence of early events.

CONCLUSIONS

The burden of diffuse cardiac fibrosis plays an important and independent prognostic role regarding SCD early after TAVI. Therefore, the histological evaluation of fibrosis topography has value as a prognostic tool for TAVI patients and may help to tailor individualised approaches to optimise their postinterventional management.

A Case of Bundle Branch Re-entrant Ventricular Tachycardia 1 Year After Transcatheter Aortic Valve Replacement

Bundle branch re-entrant ventricular tachycardia (VT) (BBR-VT) is a unique type of ventricular tachycardia often seen in patients with advanced heart diseases. Rarely, it is found in patients with a structurally normal heart. We describe a case of BBR-VT in a patient with normal ventricular function, a year after transcatheter aortic valve replacement (TAVR) for aortic stenosis. A 73-year-old man with a past medical history of non-obstructive coronary artery disease and severe aortic stenosis status post-TAVR with a 23-mm Sapien valve (Edwards Lifesciences, Irvine, CA, USA) about 1 year prior presented with palpitations and syncope. The electrocardiogram (ECG) showed a wide complex tachycardia with a left bundle branch block (LBBB) pattern and atrioventricular dissociation. The tachycardia was incessant and paroxysmal during 24-h telemetry monitoring. An electrophysiology study showed a normal A-H interval of 90 ms and a prolonged H-V interval of 84 ms with evidence of a split His. A hemodynamically stable VT was induced with a cycle length of 453 ms, which was identical to the clinical VT. This was diagnosed to be BBR-VT given the typical ECG pattern of LBBB, the presence of His inscription before each ventricular signal, and the H-H interval variation-predicted V-V variation when there was a wobble in tachycardia cycle length. Injury of the His-Purkinje system post-TAVR can provide the substrate for the development of BBR-VT. Current published literature shows early occurrence post-TAVR, but our case suggests that the timing between the index procedure and arrhythmia occurrence can be variable.

Syncope After Transcatheter Aortic Valve Replacement: Two Faces of Abnormal Intraventricular Conduction

Conduction system damage is the most common complication of transcatheter aortic valve replacement (TAVR), which frequently requires placement of a permanent pacemaker. Bundle branch reentry (BBR) is a well-recognized mechanism of ventricular tachycardia (VT) in the setting of abnormal intraventricular conduction. We describe a case of a patient with post-TAVR intraventricular conduction abnormalities who presented with intermittent advanced atrioventricular block and BBR VT and discuss the potential risks, diagnosis, and management of BBR after TAVR.

Factors associated with early cardiac complications following transcatheter aortic valve implantation with transapical approach

Purpose

To estimate the incidence of postprocedural early cardiac complications among patients undergoing transcatheter aortic valve implantation, through transapical approach (TA-TAVI), and to identify factors independently associated with the occurrence of them.

Patients and methods

A retrospective cohort study of 90 patients, who had undergone TA-TAVI in a tertiary hospital of Liverpool, UK, during a 5-year period (September 2008–October 2013), was conducted. Data on patient demographics, periprocedural characteristics and cardiac complications presented within 30-day post TA-TAVI were collected, retrospectively, using the hospital’s electronic database.

Results

The overall 30-day incidence of cardiac complications was estimated at 18.9% (n=17/90). The rate of new onset of atrial fibrillation (AF), atrioventricular block requiring permanent pacemaker implantation, shockable cardiac arrest rhythm and cardiac tamponade was 11.1%, 3.3%, 2.2% and 2.2%, respectively. Bivariate analysis found that absence of preoperative AF (p=0.01), receiving of oral inotropes preprocedurally (p=0.01), intravenous inotropic support postprocedurally (p=0.01) and requirement for postprocedural tracheal intubation (p=0.001) were the main factors associated with increased probability for patient cardiac morbidity.

Conclusion

It seems that patients with absence of AF and oral inotropic support preprocedurally and those with post TA-TAVI mechanical ventilatory and intravenous inotropic support have greater probability to develop cardiac complications. This knowledge allows the early identification of high-risk patients and supports clinicians to apply both preventive and therapeutic interventions for the optimum patient management and care. In addition, administrators could allocate the health care system resources effectively.