Feasibility and safety of left bundle branch area pacing in cardiac amyloidosis. A single center experience.

BACKGROUND: Conventional right ventricle (RV) pacemaker stimulation has been associated with worse clinical outcomes in patients with cardiac amyloidosis (CA). Left bundle branch area pacing (LABPP) has been suggested as a promising alternative. We sought to assess the safety, feasibility, and outcomes of LABPP in patients with CA. METHODS: We retrospectively analyzed echocardiography and pacing parameters and clinical outcomes in 23 consecutive patients with CA and LBBAP implanted from June 2020 to October 2022. RESULTS: LBBAP was successfully performed in 22 over 23 patients (19 male, 78.6 ± 11.7 years, 20 ATTR, mean LVEF 45.5 ± 16.2%). After the procedure, 9 patients showed Qr pattern and 11 a qR pattern in V1 on ECG. Average procedure time was 67 ± 28 min. After 7.7 ± 5.2 months follow-up, no procedure-related complications had occurred. Although, a significant reduction in QRS width (p = .001) was achieved, we did not observe significant changes in LVEF and Nt ProBNP at 6 months of follow-up. Pacing parameters were stable during follow-up: LBB capture threshold and R wave amplitude were 1.0 ±  0.5 V and 10.6 ± 6.0 mV versus 0.8 ±  0.1 V, p = .21 and 10.6 ± 5.1 mV (p = .985) at follow up. CONCLUSION: LBBAP is safe and feasible pacing technique for patients with CA. LBBAP is associated with significant narrowing of QRSd without worsening in LVEF and Nt-proBNP.

Trapped p waves causing loss of physiological left bundle branch pacing.

We present the case of a 75-year-old woman with severe aortic stenosis and moderate left ventricular dysfunction, who underwent elective transcatheter aortic valve replacement. After the procedure, the patient developed a left bundle branch block and a long PR interval. For this reason, a dual chamber pacemaker with pacing in the left bundle branch area was implanted. On device interrogation, we confirmed the presence of functional atrial undersensing causing loss of ventricular electric resynchronization. This case highlights the importance of recognizing this problem and, by means of device reprogramming and pharmacological intervention, suggests a stepwise approach to solve it.

Estimation of the QTc interval in the presence of right bundle branch block: A comparative study using validated formulae for left bundle branch block.

BACKGROUND: Adequate measurement of the QT interval is of clinical importance in order to identify patients at higher risk for ventricular arrhythmias. Previous studies have described different methods to estimate baseline QT in patients with left bundle branch block (LBBB). However, the evidence regarding the assessment of the QT in patients with right bundle branch block (RBBB) is scarce. AIM: To analyze the feasibility and reliability of the different formulae described for LBBB in the estimation of the baseline QT in the presence of RBBB. METHODS: We performed an observational study including patients who underwent electrophysiology study and/or ablation. Two types of RBBB were considered: 1) pacing-induced and 2) transient true RBBB. QRS, JT and QT intervals were measured during baseline and RBBB. Estimated QTc was calculated using LBBB formulae: Bogossian, Rautaharju, Tabatabaei, Tang-Rabkin, Yankelson, Wang. Linear correlation and intraclass correlation coefficients (ICC) were used to assess the reliability of these formulae for the estimation of baseline QTc. RESULTS: We finally included a total of 100 patients. Correlations between baseline and estimated QTc were strong (R > 0.7) for all the formulae except for Tabatabaei. Yankelson and Wang showed the highest reliability (ICC = 0.775 and 0.727, respectively). Yankelson appeared to be the most accurate formula, with a mean estimated QTc closest to baseline values. CONCLUSION: Previously described formulae for LBBB exhibited marked differences regarding reliability in the estimation of the QTc interval in the presence of RBBB. According to our results, Yankelson showed the most consistent and accurate agreement in this setting.

Incidencia, tasa de éxito, complicaciones y factores predictores de empleo de la vía femoral en procedimientos percutáneos de extracción de electrodos / Incidence, success rate, complications and predictive factors of the use of the femoral route for the removal of the electrodes after percutaneous procedures

Resumen Introducción: en los procedimientos de extracción de electrodos, la vía femoral se usa cuando la vía superior ha fracasado. Objetivo: describir la incidencia, el éxito, las complicaciones y los predictores de uso de la vía femoral. Métodos: se realizó un análisis de la incidencia del uso de la vía femoral y los factores predictores en pacientes a quienes se les realizó extracción de electrodos entre noviembre de 2011 y noviembre de 2017. Resultados: se incluyeron 85 pacientes, con edad media de 62,36 ± 11,15 años. El 38,9% de los dispositivos eran marcapasos. Se extrajeron 135 electrodos, 59,3% de fijación pasiva. La mediana de tiempo desde el implante fue de 102 (60-174) meses. Se empleó la ruta femoral en el 25,9% de los procedimientos. Se obtuvo éxito clínico en el 92,9% de los pacientes. La extracción no fue exitosa en el 22,7% de los procedimientos cuando se usó la vía femoral, en comparación con el 1,6% cuando se usó la vía superior (p 0,004). La extracción no fue completa en el 36,4% de los procedimientos cuando se empleó la vía femoral en comparación con el 9,5% por vía superior (p 0,007). Los factores que predijeron el empleo de la ruta femoral fueron la presencia de electrodos de fijación pasiva [OR IC 95% 13,69 (3,06-62,5) p 0,001] y el tiempo desde el implante del electrodo [OR IC 95% por cada 10 meses 1,04 (1,00-1,09) p 0,044]. Conclusiones: se empleó la ruta femoral en el 25,9% de los procedimientos. No fue eficaz en el 22,7% de las intervenciones. Los factores que predijeron su utilización fueron la presencia de electrodos de fijación pasiva y el tiempo desde el implante del electrodo.

Abstract Introduction: The femoral route is used in electrode removal procedures when the upper route has failed. Objective: To describe the incidence, success rate, complications and predictive factors for the use of the femoral route. Methods: An analysis was performed on the incidence of use of the femoral route and the predictive factors in patients in whom electrode removal was carried out between November 2011 and November 2017. Results: The study included 85 patients with a mean age of 62.36 ± 11.5 years. Pacemakers made up 38.9% of the devices. A total of 135 electrodes, 59.3% of passive fixation, were removed. The median time since the implant was 102 (60-174) months. The femoral route was used in 25.9% of the procedures. Clinical success was achieved in 92.9% of the patients. The removal was not successful in 22.7% of the procedures when the femoral route was used, compared to 1.6% when the upper route was used (P = .004). The removal was not completed in 36.4% of the procedures when the femoral route was used, compared to 9.5% with the upper route (P = .007). The factors that predicted the use of the femoral route were the presence of passive-fixation electrodes (OR = 13.69: 95% CI; 3.06 - 62.5, P = .001), and the time since the electrodes were implanted (OR = 1.04, 95% CI; 1.00 - 1.09, P = .044, for every 10 months). Conclusions: The femoral route was employed in 25.9% of the procedures. It was not effective in 22.7% of the interventions. The factors that predicted its use were the presence of passive-fixation electrodes and the time since the electrode implant.