Self-Expandable TAVI: Change in the Frontal QRS-T Angle

01About the study

Transcatheter aortic valve implantation (TAVI) replaces a severely stenotic aortic valve through the blood vessels. Electrical disturbances are relatively common afterward, particularly with self-expandable valves. They include new bundle branch block, marked QRS prolongation, high-grade atrioventricular block and the need for a permanent pacemaker.

This study, co-authored by Prof. Dr. Hakan Uçar, examined whether the change in the frontal QRS-T angle after the procedure was associated with those early electrical disturbances.

02What is the frontal QRS-T angle?

The frontal QRS-T angle is the angle, on the electrocardiogram, between the direction of ventricular activation and the direction of ventricular recovery. A wider angle has been studied as a noninvasive marker of ventricular electrical heterogeneity.

The measure in this study was not the pre-procedure angle alone. It was the difference between the post-procedure and pre-procedure angles, which the authors defined as the ΔQRS-T angle.

03What did the study investigate?

The question was whether the ΔQRS-T angle after self-expandable TAVI helps identify patients who develop electrical disturbances within 24 hours.

The primary endpoint was any of the following within 24 hours:

• New-onset bundle branch block
• QRS prolongation greater than 20 ms
• High-grade atrioventricular block
• Permanent pacemaker implantation

04Study design

This was a single-center retrospective observational cohort of consecutive patients undergoing self-expandable TAVI. The analysis included 135 patients.

The ΔQRS-T angle was the post-procedure frontal QRS-T angle minus the pre-procedure angle. Association was examined with logistic regression, and discrimination with ROC analysis.

05What was observed in the first 24 hours?

Electrical disturbances occurred in 66 of 135 patients (48.9%). The ΔQRS-T angle was larger in patients who developed a disturbance.

These figures describe this retrospective cohort. They are not success rates for predicting a pacemaker in the next patient.

In multivariable analysis, each one-degree increase in the ΔQRS-T angle was independently associated with electrical disturbances (odds ratio 1.02; 95% confidence interval 1.01–1.03; p = 0.006). The reported odds ratio for permanent pacemaker implantation was 1.016 (95% confidence interval 1.01–1.07; p = 0.02).

Discrimination was modest (area under the curve 0.619; 95% confidence interval 0.519–0.719). At a cut-off of 46.5°, sensitivity was 45.5% and specificity was 87.0%.

06How should this finding be read?

The authors report that the post-procedural change was independently associated with early electrical disturbances and pacemaker implantation, and that the measure needs external validation before routine clinical use.

07Study limitations

The limits visible from the abstract narrow how far the finding can be generalized.

• The study was retrospective and conducted at a single center.
• The endpoint was limited to the first 24 hours.
• Discrimination was modest, and sensitivity at the reported cut-off was low.
• The authors state that external validation is required before routine use.

08Authorship

On the PubMed author line, Prof. Dr. Hakan Uçar is the final author. The listed affiliation is the Department of Cardiology, Istanbul Aydin University VM Medical Park Florya Hospital. The open abstract does not include a CRediT contribution statement, and this page does not add one.

09Original publication