Cardiac resynchronization therapy in non-ischemic cardiomyopathy: a comparative non-randomized study of His Bundle pacing versus biventricular pacing.

BACKGROUND: Cardiac resynchronization therapy (CRT) via permanent His bundle pacing (pHBP) has gained acceptance globally, but robust studies comparing pHBP-CRT with classic CRT are lacking. In this study, we aimed to compare the improvement in left ventricular ejection fraction (LVEF) after pHBP-CRT versus classic CRT. METHODS: This was a single-center study comparing a prospective series of pHBP-CRT with a historical series of CRT via classic biventricular pacing (BVP). Patients with non-ischemic cardiomyopathy, baseline LVEF < 35%, left bundle branch block (LBBB), and CRT indications were selected. RESULTS: Fifty-one patients underwent classic CRT and 52 patients underwent pHBP-CRT. In the classic CRT group, the median (interquartile range) basal LVEF was 30% (IQR, 29-35%) before implantation and 40% (35-48%) at follow-up. In the pHBP-CRT group, the median basal LVEF was 30% (28-34%) before implantation and 55% (45-60%) at follow-up, with significant differences between both modalities at follow-up (p = 0.001). The median long term His recruitment threshold with LBBB correction was 1.25 (1-2.5) V at 0.4 ms in cases of pHBP-CRT, compared to a left ventricular coronary sinus threshold of 1.25 (1-1.75) V in cases of classic CRT (p = 0.48). After CRT, the median paced QRS was 135 (120-145) ms for pHBP-CRT versus 140 (130-150) ms for BVP-CRT (p = 0.586). CONCLUSIONS: The improvement in LVEF was superior with pHBP-CRT than with classic CRT. The thresholds at follow-up were similar in both groups.

Early improvement of left ventricular ejection fraction by cardiac resynchronization through His bundle pacing in patients with heart failure.

AIMS: Permanent His bundle pacing (p-HBP) can correct intraventricular conduction disorders and could be an alternative to traditional cardiac resynchronization therapy (CRT) via the coronary sinus. We describe the short-term impact of HBP on left ventricular ejection fraction (LVEF) and improvement of left intraventricular synchrony. METHODS AND RESULTS: This prospective descriptive study, performed from January 2018 to February 2019, included patients with left bundle branch block (LBBB) and an CRT indication who were resynchronized by p-HBP. We used the Medtronic C315 His catheter or a combination of the CPS-Direct-Universal introducer, CPS-AIM™-Universal subselector (Abbot), and SelectSecure™ MRI-SureScan™ 3830 lead. Correction of the LBBB by HBP had been previously checked. At 1 month of follow-up, we analysed the quantification of LVEF and measurement of the delay of the septal wall with the posterior wall as a parameter of intraventricular synchrony. We included 48 patients with LBBB and an indication for CRT. With HBP, we corrected the LBBB in 81% of patients (n = 39), and we achieved cardiac resynchronization through permanent HBP in 92% of these patients (n = 36). Left ventricular ejection fraction and intraventricular mechanical resynchronization improved in all patients, which was demonstrated by echocardiography through the improvement of the delay of the septal wall with the posterior wall from 138 ms (range 131-151) to 41 ms (19-63). CONCLUSION: There is early improvement after p-HBP in LVEF and left ventricular electromechanical synchronization in patients with LBBB, heart failure, and an indication for CRT.

Exclusion of fluoroscopy use in catheter ablation procedures: six years of experience at a single center.

BACKGROUND: Nonfluoroscopic mapping systems have demonstrated significant reduction of radiation exposure in radiofrequency (RF) catheter ablation procedures. However, their use as only imaging guide is still limited. OBJECTIVE: To evaluate the usefulness of a completely nonfluoroscopic approach to catheter ablation of supraventricular arrhythmias using the Ensite-NavX™ electroanatomical navigation system. METHODS: During 6 years, all consecutive patients referred for RF catheter ablation of regular supraventricular tachycardia (SVT) were admitted for a "zero-fluoroscopy" approach and studied prospectively. The only exclusion criterion was the need to perform a transseptal puncture. RESULTS: A total of 340 procedures were performed on 328 patients (179 men, age 55.7 ± 18.6 years). One hundred fifty-three patients had typical atrial flutter (AFL), 146 had AV nodal reentrant tachycardia (AVNRT), 35 had AV reciprocating tachycardia (AVRT), 4 patients had incisional atrial flutter (IAF), and 2 had focal atrial tachycardia (AT). Procedural success was achieved in 337 of the cases (99.1%). In 322 (94.7%), the procedure was completed without any fluoroscopy use. Mean procedure time was 110.5 ± 51.8 minutes. Mean RF application time was 9.8 ± 12.8 minutes and the number of RF lesions was 16.43 ± 15.8. Only 1 major complication related to vascular access was recorded. During follow-up, there were 12 recurrences (3.5%) (8 patients from the AVNRT group, 4 patients from the AP group). CONCLUSION: RF catheter ablation of SVT with an approach completely guided by the NavX system and without use of fluoroscopy is feasible, safe, and effective.

Direct left ventricular endocardial pacing: an alternative when traditional resynchronization via coronary sinus is not feasible or effective.

BACKGROUND: Biventricular pacing through the coronary sinus (CS) is effective for the treatment of patients with heart failure and left bundle-branch block. However, this approach is not always feasible. Although surgical epicardial lead implantation is an alternative, the technique may be deleterious in some patients. Thus, direct left ventricular (LV) endocardial pacing under local anesthesia may be an option. OBJECTIVE: We describe our technique and analyze the results of direct LV endocardial pacing. METHOD: Fourteen patients with failed resynchronization via CS (April 2006-September 2011) were selected. Using a femoral approach, we performed transseptal puncture and LV mapping, then fixed the active lead where the longest electrical delay was observed; the generator was placed in the anterior thigh. For resynchronization, eight patients with a device previously implanted through the upper veins received a single-chamber generator that was set to the VVT mode to sense the subclavian pacing spike. Six patients received a complete femoral resynchronization system with either a defibrillator or pacemaker. Patients were followed for 6-54 months. RESULTS: The LV lead was successfully implanted in all cases. Two patients experienced excessive bleeding and two died during follow-up. All except one improved at least one New York Heart Association class and experienced improved left ventricle ejection fraction. One patient with recurrent episodes of ventricular fibrillation was asymptomatic. CONCLUSION: Direct LV endocardial pacing is safe and may be a less risky, more efficient alternative than surgical epicardial lead implantation for resynchronization via CS.

Major cardiovascular risk factors in Latin America: a comparison with the United States. The Latin American Consortium of Studies in Obesity (LASO).

BACKGROUND: Limited knowledge on the prevalence and distribution of risk factors impairs the planning and implementation of cardiovascular prevention programs in the Latin American and Caribbean (LAC) region. METHODS AND FINDINGS: Prevalence of hypertension, diabetes mellitus, abnormal lipoprotein levels, obesity, and smoking were estimated from individual-level patient data pooled from population-based surveys (1998-2007, n=31,009) from eight LAC countries and from a national survey of the United States (US) population (1999-2004) Age and gender specific prevalence were estimated and age-gender adjusted comparisons between both populations were conducted. Prevalence of diabetes mellitus, hypertension, and low high-density lipoprotein (HDL)-cholesterol in LAC were 5% (95% confidence interval [95% CI]: 3.4, 7.9), 20.2% (95% CI: 12.5, 31), and 53.3% (95% CI: 47, 63.4), respectively. Compared to LAC region's average, the prevalence of each risk factor tended to be lower in Peru and higher in Chile. LAC women had higher prevalence of obesity and low HDL-cholesterol than men. Obesity, hypercholesterolemia, and hypertriglyceridemia were more prevalent in the US population than in LAC population (31 vs. 16.1%, 16.8 vs. 8.9%, and 36.2 vs. 26.5%, respectively). However, the prevalence of low HDL-cholesterol was higher in LAC than in the US (53.3 vs. 33.7%). CONCLUSIONS: Major cardiovascular risk factors are highly prevalent in LAC region, in particular low HDL-cholesterol. In addition, marked differences do exist in this prevalence profile between LAC and the US. The observed patterns of obesity-related risk factors and their current and future impact on the burden of cardiovascular diseases remain to be explained.

A 'polypill' aimed at preventing cardiovascular disease could prove highly cost-effective for use in Latin America.

We evaluated the cost-effectiveness of administering a daily "polypill" consisting of three antihypertensive drugs, a statin, and aspirin to prevent cardiovascular disease among high-risk patients in Latin America. We found that the lifetime risk of cardiovascular disease could be reduced by 15 percent in women and by 21 percent in men if the polypill were used by people with a risk of cardiovascular disease equal to or greater than 15 percent over ten years. Attaining this goal would require treating 26 percent of the population at a cost of $34-$36 per quality-adjusted life-year. Offering the polypill to women at high risk and to men age fifty-five or older would be the best approach and would yield acceptable incremental cost-effectiveness ratios. The polypill would be very cost-effective even in the country with the lowest gross national income in our study. However, policy makers must weigh the value of intervention with the polypill against other interventions, as well as their country's willingness and ability to pay for the intervention.

Ventricular resynchronization therapy by direct His-bundle pacing using an internal cardioverter defibrillator.

AIMS: Cardiac resynchronization therapy (CRT) has been demonstrated to improve the functional class of patients with refractory heart failure if QRS width is >120 ms. Addition of an internal cardioverter defibrillator diminishes the prevalence of mortality of such patients. The technique for CRT requires selective stimulation of the left ventricle (LV), commonly undertaken through the coronary sinus. This procedure is not always feasible. Direct His-bundle pacing (DHBP) might be an alternative for CRT. METHODS AND RESULTS: Patients were selected from a population with refractory heart failure derived for CRT and internal cardioverter defibrillator insertion. Of those, patients in whom LV stimulation via the coronary sinus was not achievable and DHBP obtained left bundle branch block disappearance were included. Direct His-bundle pacing corrected basal conduction disturbances in 13 of the 16 patients (81%) selected. In four patients in whom DHBP was attempted, the electrode was not successfully fixed. In the nine remaining patients, a definitive resynchronization by DHBP was achieved, with consequent improvement in functional class and parameters of LV function as assessed by echocardiography. CONCLUSION: Direct His-bundle pacing might be an alternative treatment for CRT in selected cases.

Electrical and mechanical cardiac resynchronisation by novel direct his-bundle pacing in a heart failure patient.

Efficacy of standard cardiac resynchronisation therapy (CRT) by biventricular pacing via coronary sinus depends on the target site for left ventricular (LV) pacing, which in a not insignificant number of patients is limited by anatomical constraints. Direct His-bundle pacing (DHBP) is considered an alternative method of pacing for patients requiring cardiac stimulation in order to obviate detrimental effects of right ventricular pacing on LV function. However, its role in CRT has not been investigated, with scarce number of cases recently reported. We present a case of a heart failure patient in whom CRT was considered and treated by DHBP. In addition to electrical resynchronisation and optimal clinical response, echocardiography showed successful ventricular mechanical synchrony. To our knowledge, these latter findings are for the first time described in the setting of CRT by DHBP.

Permanent His-bundle pacing: seeking physiological ventricular pacing.

AIMS: Right ventricular apical pacing can have deleterious effects and the His bundle has been widely reported to be an alternative site. This paper presents our experience with permanent His-bundle pacing (HBP). METHODS AND RESULTS: Patients referred for pacemaker implants (regardless of block type) were screened to determine if temporary HBP corrected conduction dysfunctions (threshold < or =2.5 V for 1 ms) and provided infra-Hisian 1:1 conduction of at least 120 s/m. Of the 182 patients selected, HBP corrected conduction dysfunctions in 133 (73%) patients, 42 (32%) of whom were rejected for the permanent procedure due to high thresholds. His-bundle lead implantation was attempted in the remaining 91 patients and was successful in 59 (65% of all attempts, 44% of all possible cases). CONCLUSION: In some patients, permanent HBP may be an alternative to right ventricular apical pacing.

Implante de un desfibrilador biventricular con estimulación endocárdica transeptal de ventrículo izquierdo vía venosa femoral / Implantation via the femoral vein of a biventricular defibrillator with transseptal endocardial left ventricular pacing

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[Progress in cardiac pacing]. / Novedades en estimulación cardiaca.

This review article summarizes the fundamental principles of radiological protection for interventional cardiologists. In addition, the scientific articles on cardiac pacing that have had the greatest impact in the last year are also summarized. Two cardiac pacing techniques are described: His-bundle pacing and cardiac contractility modulation.

Novedades en estimulación cardiaca / Progress in cardiac pacing

En esta revisión se abordan los conocimientos básicos para la protección radiológica del cardiólogo intervencionista. Se realiza un resumen de los artículos científicos sobre estimulación cardiaca de mayor impacto durante el último año. Se describen dos técnicas de estimulación: la estimulación hisiana y la modulación de la contractilidad cardiaca (AU)

This review article summarizes the fundamental principles of radiological protection for interventional cardiologists. In addition, the scientific articles on cardiac pacing that have had the greatest impact in the last year are also summarized. Two cardiac pacing techniques are described: His-bundle pacing and cardiac contractility modulation (AU)

Posibilidades y realidades de la estimulación permanente del haz de His / The potential and reality of permanent his bundle pacing

La estimulación apexiana puede ser perjudicial. Intentamos averiguar cuántos pacientes propuestos para estimulación cardiaca definitiva podrían ser estimulados permanentemente en el haz de His y en cuántos se consigue. La totalidad de los bloqueos suprahisianos y la mayoría de los considerados «infrahisianos» (71,4%) se corrigen con la estimulación del His, pero sólo se consigue permanentemente en el 55% de los intentos y en el 35,4% de todos los casos posibles (AU)

Right ventricular apex pacing can have deleterious effects. Our aims were to investigate how many patients referred for permanent pacing were suitable candidates for permanent His bundle pacing, and to determine the proportion in whom such pacing was successful. All cases of suprahisian block and most cases of infrahisian block (71.4%) were corrected by temporary His bundle pacing. However, permanent His bundle pacing was achieved in only 55% of cases in which it was attempted, and in only 35.4% of all possible cases (AU)

The potential and reality of permanent his bundle pacing.

Right ventricular apex pacing can have deleterious effects. Our aims were to investigate how many patients referred for permanent pacing were suitable candidates for permanent His bundle pacing, and to determine the proportion in whom such pacing was successful. All cases of suprahisian block and most cases of infrahisian block (71.4%) were corrected by temporary His bundle pacing. However, permanent His bundle pacing was achieved in only 55% of cases in which it was attempted, and in only 35.4% of all possible cases.

Efectos de la estimulación cardiaca convencional. Estimulación en sitios alternativos / Effect of conventional cardiac pacing. Alternative pacing sites

Desde la primera publicación del abordaje transvenoso para la implantación de marcapasos en 1959, el ápex del ventrículo derecho ha sido el sitio tradicional de estimulación por ser de fácil acceso y proporcionar estabilidad a largo plazo y umbrales crónicos de estimulación óptimos. La estimulación en orejuela derecha y ápex de ventrículo derecho ha permitido establecer una frecuencia cardiaca estable y lograr la sincronía auriculoventricular, dos de los objetivos principales de la estimulación eléctrica extrínseca; sin embargo, con ello no se ha conseguido lograr un patrón de activación y sincronía fisiológicos. Múltiples estudios publicados en los últimos años han puesto de manifiesto los efectos perjudiciales de la estimulación convencional, tanto funcionales como estructurales, con las consiguientes morbilidad y mortalidad. De ahí el interés surgido en la búsqueda de sitios alternativos de estimulación que permitan obtener despolarización y contracción miocárdica fisiológicas. En este capítulo se plantea la posibilidad de estimulación auricular en sitios alternativos, con el objetivo fundamental de prevenir las arritmias auriculares. Se revisan, asimismo de forma pormenorizada, las evidencias demostradas hasta el momento acerca de los efectos hemodinámicos y funcionales de la estimulación en tracto de salida de ventrículo derecho, así como su influencia en la duración del QRS y su correlación con la función ventricular. Finalmente, se desarrolla la estimulación permanente del haz de His, con las ventajas que supone la activación ventricular vía sistema específico de conducción (AU)

Since the appearance of the first publication on the transvenous approach to pacemaker implantation in 1959, the apex of the right ventricle has been the conventional site for pacing because it is readily accessible, it provides long-term stability, and the chronic pacing threshold is optimal. Pacing in the right atrial appendage and the ventricular apex enables the heart rate to be stabilized and atrioventricular synchrony to be established, two of the main objectives of extrinsic electrical pacing. However, it does not lead to the establishment of physiologic activation and synchrony patterns. Numerous studies published over the past few years have demonstrated the deleterious effects, both functional and structural, of conventional pacing, and its associated morbidity and mortality. These findings have triggered a search for alternative pacing sites that would enable more physiologic myocardial depolarization and contraction to be achieved. This article discusses the possibility of using alternative atrial pacing sites, with the fundamental aim of preventing atrial arrhythmia. In addition, it also contains a detailed review of the evidence published to date on the hemodynamic and functional effects of right ventricular outflow tract pacing, its influence on the QRS duration, and its correlation with ventricular function. Finally, there is a discussion of permanent His bundle pacing, and the possible advantages associated with ventricular activation via this particular conduction system (AU)

[Permanent His-bundle pacing in patients with infra-Hisian atrioventricular block]. / Estimulación hisiana definitiva en pacientes con bloqueos infrahisianos.

INTRODUCTION AND OBJECTIVES: Permanent His-bundle pacing is effective in patients with supra-Hisian atrioventricular block. We report our experience in patients with infra-Hisian atrioventricular block. METHODS: The study involved selected patients referred for syncope and intraventricular conduction disturbance, infra-Hisian atrioventricular block, with left ventricular dyssynchrony and no coronary sinus access. All patients underwent electrophysiological study to evaluate infra-Hisian atrioventricular conduction, both at baseline and after flecainide administration. We selected patients with an indication for permanent pacing in whom His-bundle pacing produced a narrow QRS complex. Leads were implanted in the right atrium, in the bundle of His, and at the apex of the right ventricle, and connected to the atrial, left ventricular, and right ventricular terminals, respectively, of a biventricular pacemaker generator. All pacemakers were programmed in DDD mode with a left ventricle-right ventricle interval of 80 ms. RESULTS: Between February and December 2004, seven patients met the study's inclusion criteria. The His-bundle lead was implanted successfully in five. The His-bundle pacing threshold remained stable in two patients, whereas it increased in three. During follow-up, at between 2 and 12 months, no lead dislodgement or failure to capture was observed. Echocardiography did not disclose any deterioration in ventricular function, or any worsening of or new valvular incompetence, but showed that ventricular dyssynchrony had disappeared in previously affected patients. CONCLUSIONS: His-bundle pacing is the only pacing mode capable of inducing a physiologically normal ventricular contraction. It can be used in some patients with infra-Hisian atrioventricular block.

Estimulación hisiana definitiva en pacientes con bloqueos infrahisianos / Permanent his-bundle pacing in patients with infra-hisian atrioventricular block

Introducción y objetivos. La estimulación permanente del haz de His es eficaz en los bloqueos auriculoventriculares suprahisianos. Mostramos nuestra experiencia en bloqueos infrahisianos. Métodos. Seleccionamos a pacientes derivados por síncopes y trastornos de la conducción intraventricular, bloqueo auriculoventricular completo y con asincronía intraventricular izquierda con seno coronario no accesible. En todos se practicó un estudio electrofisiológico en el que se evaluó la conducción infrahisiana basal y tras la administración de flecainida. Entre los pacientes con indicación de marcapasos permanente se seleccionó a aquellos en los que la estimulación del haz de His provocaba un complejo QRS estrecho. Implantamos electrodos en la aurícula derecha, el haz de His y el ápex de ventrículo derecho, conectándolos a las salidas auricular, ventricular izquierda y ventricular derecha de un marcapasos biventricular. Se programaron en modo DDD con un intervalo ventrículo izquierdo-ventrículo derecho de 80 ms. Resultados. Desde febrero hasta diciembre de 2004 se estudió a 10 pacientes, de los que 7 cumplieron criterios de inclusión; en 5 pudo implantarse un electrodo hisiano. El umbral de estimulación hisiana permaneció estable en 2 y mostró incrementos en 3. Durante el seguimiento de 2 a 12 meses no se han observado dislocamientos o pérdidas de captura. Ecocardiográficamente no ha habido deterioro de la función ventricular ni incompetencias valvulares, y la asincronía intraventricular mejoró en el caso de que estuviera presente. Conclusiones. La estimulación hisiana constituye el único modo de provocar una contracción ventricular más fisiológica y su utilización es posible en algunos casos de bloqueo infrahisiano

Introduction and objectives. Permanent His-bundle pacing is effective in patients with supra-Hisian atrioventricular block. We report our experience in patients with infra-Hisian atrioventricular block. Methods. The study involved selected patients referred for syncope and intraventricular conduction disturbance, infra-Hisian atrioventricular block, with left ventricular dyssynchrony and no coronary sinus access. All patients underwent electrophysiological study to evaluate infra-Hisian atrioventricular conduction, both at baseline and after flecainide administration. We selected patients with an indication for permanent pacing in whom His-bundle pacing produced a narrow QRS complex. Leads were implanted in the right atrium, in the bundle of His, and at the apex of the right ventricle, and connected to the atrial, left ventricular, and right ventricular terminals, respectively, of a biventricular pacemaker generator. All pacemakers were programmed in DDD mode with a left ventricle-right ventricle interval of 80 ms. Results. Between February and December 2004, seven patients met the study's inclusion criteria. The His-bundle lead was implanted successfully in five. The His-bundle pacing threshold remained stable in two patients, whereas it increased in three. During follow-up, at between 2 and 12 months, no lead dislodgement or failure to capture was observed. Echocardiography did not disclose any deterioration in ventricular function, or any worsening of or new valvular incompetence, but showed that ventricular dyssynchrony had disappeared in previously affected patients. Conclusions. His-bundle pacing is the only pacing mode capable of inducing a physiologically normal ventricular contraction. It can be used in some patients with infra-Hisian atrioventricular block

Cardiac resynchronization through selective His bundle pacing in a patient with the so-called InfraHis atrioventricular block.

We present a case of infraHis AV block in which selective His bundle pacing with His-ventricular conduction through the conduction system was accomplished. While further investigations are developed, this approach may be an alternative for cardiac resynchronization in cases of difficult coronary sinus access.

Respuesta. Tipo de estimulación ventricular tras ablación del nodo AV / Response. Ventricular pacieng after atrioventricular node ablation

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