Background
Conduction disturbances are the most frequent complication of transcatheter aortic valve replacement (TAVR). However, no data exists regarding the outcomes of intraprocedural high‐degree atrioventricular block (HAVB) or complete heart block (CHB) in patients without previous conduction disturbances.
Objectives
The aim of this study was to evaluate the outcomes of intraprocedural‐HAVB/CHB in patients without previous intraventricular conduction disturbances.
Methods
The occurrence of intraprocedural‐HAVB/CHB was assessed in 676 consecutive patients undergoing TAVR, and two groups were established according to its duration: persistent‐HAVB/CHB (PHAVB/CHB) and transient‐HAVB/CHB (THAVB/CHB), not present at the end of the procedure.
Results
Intraprocedural‐HAVB/CHB occurred in 50 patients (7.4%), being persistent in 32 (64.0%), and transient in 18 (36.0%). The use of Medtronic Corevalve Revalving System (MCRS) and a greater oversizing of the valve increased the risk of intraprocedural‐HAVB/CHB (p < 0.001). Permanent pacemaker implantation (PPI) was more frequent in the PHAVB/CHB than in the THAVB/CHB group (96.9% vs. 33.3%; p < 0.001). At 1‐month follow‐up, the PHAVB/CHB group showed a 98% ventricular pacing rate (VPR) compared to 16% in the THAVB/CHB group (p < 0.001), and similar VPR were observed at 1‐year follow‐up (98% vs. 37%, p < 0.001). Left ventricular ejection fraction (LVEF) decreased at 1‐year follow‐up in patients with PHAVB/CHB (−3.9 ± 1.8%, p = 0.003).
Conclusions
In TAVR recipients with no prior intraventricular conduction disturbances, intraprocedural‐HAVB/CHB occurred in 7.4% of cases. HAVB/CHB was persistent in most cases and determined a high rate of PPI post‐TAVR. Very high VPR at 1‐ and 12‐month follow‐up were observed, which in turn was associated with a negative effect on LVEF. These results support early PPI and close follow‐up in patients developing intraprocedural‐PHAVB/CHB.
Background: there is increasing interest for computing corrected QT intervals in patients with prolonged depolarization. We aimed to analyze the effect of prolonged QRS in the QT and in the diagnostic accuracy of frequency-correction. Methods and Results: in 28 patients admitted for self-expanding aortic valve implantation, sequential pacing was performed in the AAI mode in two different phases: before and immediately after the release of the prosthesis. We evaluated the accuracy of the Bazett, Fridericia, Framingham and Hodges formulas with the reference of the QT at 60 bpm (QTc/deviation). The widening of the QRS was the main contributor to the QT prolongation (Pearson 0.79; CI95%: 0.75–0.84). Prolongation in other intervals (ST segment and T-wave) significantly contribute in the higher frequency range (p < 0.05). The Bazett’s formula displayed the highest QTc/deviation, while Framingham and Hodges retrieved the lowest QTc/deviation and the best fit (p < 0.001). In addition, the Bazett’s formula displayed the highest correlation between variations in the QTc/deviation and the widening of the QRS (Pearson coefficient −0.54; p < 0.001) in comparison with the Fridericia, Framingham and Hodges formulas (−0.51, −0.37 and −0.38 respectively; p < 0.001). There was also a linear effect of the heart rate in the QTc/deviation obtained with the Bazett’s formula (p = 0.015), not observed for other formulas. Conclusions: The prolonged depolarization of the ventricles introduces direct and linear prolongation in the QT interval, but also a non-linear distortion in cardiac repolarization that contributes for QT prolongation at the higher frequency range. The Bazett’s formula displays significantly higher sensitivity to prolongation of ECG intervals.
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