Terapia de resincronización cardíaca. Incidencia y mecanismos involucrados en la reducción de la insuficiencia mitral funcional / Cardiac Resynchronization Therapy. Incidence and Mechanisms Involved in the Reduction of Functional Mitral Regurgitation

RESUMEN Introducción: La insuficiencia mitral funcional (IMF) es común en pacientes con insuficiencia cardíaca (IC). La IMF moderada/ grave (M/G) se asocia a peor pronóstico. Objetivo: Describir la prevalencia de IMF y los mecanismos involucrados en su reducción en respondedores a la terapia de resincronización cardíaca (TRC) a los 6 meses comparados con 12 y 24 meses. Métodos: Entre 2009 y 2018 fueron tratados 338 pts. Respondedores: reducción de CF NYHA ≥1 grado o aumento de la fracción de eyección ventricular izquierda (FEVI) ≥5% (absoluto). La IMF se graduó en 4 puntos: No-IMF, leve, M y G, y se la relacionó con las mediciones ecocardiográficas. Características Basales: edad 64 ±10 años, hombres 71%, CF-NYHA IIIII 92%, bloqueo de rama izquierda (BRI) 67%, QRS ≥150 ms 75%, diámetro diastólico del VI (DDVI) 68 ± 9 mm, diámetro sistólico del VI (DSVI) 52 ± 12 mm, FEVI 24 ± 7%. Resultados: La prevalencia de IMF fue del 92,6%. A los 6 meses, 86% fueron respondedores y 23% de ellos mejoraron de IMF-M/G a IMF-Leve/No-IMF. Hubo un fuerte remodelado inverso: DDVI 68 ± 10 vs 63 ± 11 mm, (p = 0,0001), DSVI 55 ± 12 vs 50 ± 13 mm, (p = 0,0006) y FEVI 25 ± 11 vs 33 ± 10%, (p = 0,00001). Comparando 6 con 12 meses 89,4% fueron respondedores, 8% mejoraron de IMF-M/G a IMF-Leve/No-IMF. Comparando 6 con 24 meses 88% fueron respondedores, 14,6% mejoraron de IMF-M/G a IMF-Leve/No-IMF. Entre 6 y 12 y 6 y 24 meses no hubo remodelado inverso significativo. Conclusiones: La prevalencia de IMF fue elevada. El mayor remodelado inverso y reducción de la IMF se observaron a los 6 meses, siendo el primero el principal mecanismo en la reducción de la IMF. Esta mejoría se sostuvo a los 12 y 24 meses.

ABSTRACT Background: Functional mitral regurgitation (FMR) is common in heart failure, and moderate/severe (M/S) FMR is associated with worse prognosis. Objective: The aim of this study was to describe the prevalence of FMR and the mechanisms involved in its reduction in responders to cardiac resynchronization therapy (CRT) at 6 months compared with 12 and 24 months. Methods: Between 2009 and 2018, 338 patients received CRT. Patients showing NYHA functional class (FC) reduction ≥1 or left ventricular ejection fraction (LVEF) absolute increase ≥5% were considered responders. Functional mitral regurgitation was graded using a 4-point scale into none-, mild-, M- and S-FMR, and was related to echocardiographic measurements. Baseline patient characteristics were: age 64±10 years, men 71%, NYHA FC II-III 92%, left bundle branch block (LBBB) 67%, QRS ≥150 ms 75%, LV diastolic diameter (LVDD) 68±9 mm, LV systolic diameter (LVSD) 52±12 mm, and LVEF 24±7%. Results: The prevalence of FMR was 92.6%. At 6 months, 86% were responders, 23% improved from M/S-FMR to mild/none-FMR and there was strong reverse remodeling: LVDD 68±10 vs. 63±11 mm, (p=0.0001), LVSD 55±12 vs. 50±13 mm, (p=0.0006) and LVEF 25±11 vs. 33±10%, (p=0.00001). Comparing 6 with 12 months, 89.4% were responders and 8% improved M/S-FMR to mild/none-FMR. Comparing 6 with 24 months, 88% were responders and 14.6% improved M/S-FMR to mild/none-FMR. Between 6 and 12 and 6 and 24 months, there was no significant reverse remodeling. Conclusions: The prevalence of FMR was high. The highest reverse remodeling and FMR reduction was observed at 6 months, the former being the main mechanism of FMR reduction. This improvement persisted at 12 and 24 months.

Radiofrequency ablation of supraventricular arrhythmias after orthotopic heart transplantation: Long-term follow-up of a single-center experience.

BACKGROUND: Supraventricular arrhythmias (SVAs), commonly managed with radiofrequency ablation (RFA), may occur after orthotopic heart transplantation (OHT). METHODS: We retrospectively assessed 514 consecutive patients (pts.) undergoing OHT between January 1990 and July 2016 in a single-center. Patients with SVAs managed with RFA were included. Mechanisms of genesis of SVAs, association with surgical techniques and outcomes, were analyzed. RESULTS: Of 514 pts undergoing OHT, 53% (272 pts.) were managed with bicaval (BC) technique and 47% (242 pts.) with biatrial (BA) technique. Mean follow-up 10 ± 8.4 years. Nine pts. (1.7%) developed SVA requiring RFA. The BC technique was performed in 4 pts., 3 pts. presented cavotricuspid isthmus-dependent atrial flutter (CTI AFL), and 1 pt. double loop AFL. Five pts. were managed with BA technique, 4 pts. presented CTI AFL, and 1 pt. atrial tachycardia (AT). Mean time between OHT and SVA occurrence was 6.6 ± 5.5 years. The procedure was successful in 89% (8 pts.). Arrhythmia recurrence was seen in 3 pts (37%), all with BA technique. CONCLUSION: Supraventricular arrhythmias in heart transplantation may be associated with the surgical scar. Identifying the mechanism is vital to choose the appropriate treatment with radiofrequency ablation.

Miocardiopatía no compactada: Estratificación de riesgo de muerte súbita para indicación de cardiodesfibrilador automático implantable / Non-Compaction Cardiomyopathy: Risk Stratification of Sudden Death for Automatic Cardioverter Defibrillator Implantation

Introducción La miocardiopatía no compactada es una entidad rara. Su historia natural incluye insuficiencia cardíaca, eventos tromboembólicos, arritmias y muerte súbita (MS). En ausencia de datos de estudios aleatorizados o registros, las Guías ACC/AHA/HRS 2008 recomiendan el cardiodesfibrilador automático implantable (CDAI) en todos los pacientes con miocardiopatía no compactada para reducir el riesgo de muerte súbita. Objetivo Describir la evolución de pacientes con miocardiopatía no compactada de acuerdo con criterios seleccionados de estratificación de riesgo de muerte súbita para decidir el implante de un CDAI. Material y métodos Se analizaron 80 pacientes. El diagnóstico se estableció mediante criterios ecocardiográficos y de resonancia magnética nuclear cardíaca. Los criterios para el implante de un CDAI como prevención secundaria incluyeron muerte súbita y taquicardia ventricular sostenida (TVS); como prevención primaria comprendieron fracción de eyección del ventrículo izquierdo (FEVI) < 30% o ≥ 2 factores de riesgo (antecedentes familiares de muerte súbita [AFMS], síncope y TV no sostenida). Resultados Grupo CDAI (n = 26) para prevención secundaria (n = 3): 3 pacientes sufrieron muerte súbita (2 TVS). Grupo CDAI para prevención primaria (n = 23): 10 pacientes tuvieron FEVI < 30%, 1 FEVI < 30% + AFMS, 1 FEVI < 30% + síncope, 5 FEVI < 30% + TV no sostenida, 3 TV no sostenida + síncope, 2 TV no sostenida + AFMS y 1 TVS en estudio electrofisiológico. El seguimiento fue de una mediana de 16,61 meses. Dos pacientes fueron sometidos a un trasplante cardíaco, 3 recibieron choques apropiados y 4 pacientes, choques inapropiados. Grupo sin CDAI (n = 54): 4 pacientes tuvieron síncope y 4 TV no sostenida. El seguimiento fue de una mediana de 12,15 meses. Dos pacientes fallecieron por insuficiencia cardíaca y 3 fueron sometidos a un trasplante cardíaco. Conclusiones El 32,5% de los pacientes con miocardiopatía no compactada recibieron un CDAI, el 88,5% por prevención primaria; el 11,5% recibieron choques apropiados. No hubo muerte súbita en pacientes sin CDAI; la muerte sobrevino por progresión de la insuficiencia cardíaca. Este registro sugiere que los pacientes con miocardiopatía no compactada podrían estratificarse para seleccionar a aquellos que tienen mayor riesgo de muerte súbita y podrían beneficiarse con el implante de un CDAI.

Background Non-compaction cardiomyopathy is a rare disease. The natural history of this condition includes heart failure, thromboembolic events, arrhythmias and sudden death (SD). In the absence of information from randomized studies or registries, the 2008 ACC/AHA/HRS guidelines recommended cardioverter defibrillator implantation in all patients with non-compaction cardiomyopathy to reduce the risk of sudden death. Objective To describe the outcomes of patients with non-compaction cardiomyopathy according to the selection criteria used for risk stratification of sudden death for automatic implantable cardioverter defibrillator therapy. Material and Methods A total of 80 patients were analyzed. The diagnosis was made using criteria from echocardiography and cardiac magnetic resonance imaging. The criteria used for implantation of an ICD were sudden death and sustained ventricular tachycardia (SVT) for secondary prevention, and left ventricular ejection fraction (LVEF) <30% or ≥2 risk factors (family history of sudden death [FHSD], syncope and non-sustained VT). Results Group ICD (n=26) for secondary prevention (n=3): 3 patients presented sudden death (2 SVT). Group ICD for primary prevention (n=23): 10 patients had LVEF <30%, 1 LVEF <30% + FHSD, 1 LVEF <30% + syncope, 5 LVEF <30% + nonsustained VT, 3 non-sustained VT + syncope, 2 non-sustained + FMSD and 1 VT in the electrophysiologic study. Median follow-up was 16.61 months. Two patients underwent heart transplantation, 3 received appropriate ICD shocks, while ICD shocks were inappropriate in 4 patients. Group without ICD (n=54): 4 patients presented syncope and 4 non-sustained VT. Median follow-up was 12.15 months. Two patients died due to heart failure and 3 underwent cardiac transplantation. Conclusions ICD was implanted in 32.5% of patients with non-compaction cardiomyopathy, 88.5% for primary prevention; appropriate shocks were received in 11.5% of patients. None of the patients who did not receive an ICD presented sudden death; these patients died due to heart failure progression. This registry suggests that patients with non-compaction cardiomyopathy might be stratified to select those at a higher risk of sudden death who might beneficiate from ICD therapy.

Subsensado de fibrilación ventricular espontánea como causa de muerte súbita en un niño / Undersensing of Spontaneous Ventricular Fibrillation as a Cause of Sudden Death in a Child

Se han comunicado casos aislados de subsensado de fibrilación ventricular por el cardiodesfibrilador implantable. La mayoría de ellos ocurrieron durante la medición de umbrales desfibrilatorios. Se ha sugerido que este tipo de subsensado podría ser una causa potencial de muerte súbita. En esta presentación se describe a un paciente de 4 años con miocardiopatía hipertrófica que sufrió un episodio espontáneo de fibrilación ventricular, con una gran alternancia en la amplitud de los electrogramas ventriculares locales, que fue subsensado y no tratado por el dispositivo y provocó muerte súbita.

In few cases implantable cardiodefibrillators have been reported to undersense ventricular fibrillation, and most of them happened during the measurement of defibrillation thresholds. This type of undersensing has been suggested as a potential cause of sudden death. In this case report we describe a 4-year old boy with hypertrophic myocardiopathy who suffered a spontaneous episode of ventricular fibrillation with a great alternation in the amplitude of local ventricular electrograms. The episode was undersensed by the device and therefore it was not treated, causing the child's death.

Cardiodefibrilador automático implantable: incidencia, causas y predictors de mortalidad. Valor de los registros prospectivos / Implantable automatic cardiodefibrillator: incidence causes and predictors of mortality. Value of the prospective records

The implantable automatic cardiodefibrilator (IACD) has proved to be an effective tool in the prevention of both primary and secondary sudden death. Even so, the mortality of patients receiving an IACD still remains elevated. Recent data, obtained from the secondary analysis of different studies, suggest that the discharges of the deice, between other clinical variables, both electrocardiiographic and ultrasonographic could be associated to a higher mortality, maybe due to a contribution to the progression of the cardiac insufficiency. The aims of this report were to evaluate the incidence of mortality, causes of death and the time since the implantation till the death, to analyze appropriate an inappropriate shocks and other variaables as potential predictors of mortality in patients with IACD. The results obtained in this study are detailed in the article

Cardiodesfibriladores implantables: ¿se puede predecir un umbral desfibrilatorio elevado antes del implante? / Implanted cardiodefibrillator: can be predictible and elevated defibrillation threshold testing previous to the implantation?

Implanted cardiodefibrillators devices are being used with increasing frequency to provide primary and secondary prevention of arrhythmic sudden death. Between March 2003 through Febraury 2005, 99 consecutive patients were included in a study to test the defibrillation threshold at the time of an implantable cardiofibrillator insertion. The systematic measurement of defribillation threshold during the insertions of an implanted defibrillator, still is a necessary resource in order to identify patients in whom the margins of standard security could not guarantee a successful defibrillation. The possibility to identify elevated defibrillation threshold testing is very important to be determined at the time of indications for the insertion of an implanted cardiodefibrillator. These consideations are discussed in the article

Cardiodesfibriladores implantables: ¿se puede predecir un umbral desfibrilatorio elevado antes del implante? / Implanted cardiodefibrillator: can be predictible and elevated defibrillation threshold testing previous to the implantation?

Implanted cardiodefibrillators devices are being used with increasing frequency to provide primary and secondary prevention of arrhythmic sudden death. Between March 2003 through Febraury 2005, 99 consecutive patients were included in a study to test the defibrillation threshold at the time of an implantable cardiofibrillator insertion. The systematic measurement of defribillation threshold during the insertions of an implanted defibrillator, still is a necessary resource in order to identify patients in whom the margins of standard security could not guarantee a successful defibrillation. The possibility to identify elevated defibrillation threshold testing is very important to be determined at the time of indications for the insertion of an implanted cardiodefibrillator. These consideations are discussed in the article

Which patients with congestive heart failure may benefit from biventricular pacing?

BACKGROUND: Biventricular pacing improves the clinical status and ventricular function in patients with congestive heart failure (CHF) and intraventricular conduction delay. However, patient selection criteria including NYHA functional class, rhythm, PR interval, QRS duration (QRSd), left ventricular ejection fraction (LVEF), left ventricular diastolic diameter (LVDD), and other variables are not clearly defined. OBJECTIVE: To determine which and how many patients referred for an initial cardiac transplantation evaluation may be eligible for biventricular pacing (BP) according to the criteria of recently completed trials of cardiac resynchronization therapy (CRT). METHODS: This was a retrospective review of 200 patients, whose mean age was 51 +/- 13 years (173 men). Sinus rhythm was present in 88% of the patients, 107 had a QRSd > 120 ms, and 38% had left bundle branch block. LVDD was 72.5 +/- 12 mm and LVEF 21.7 +/- 9.3%; 54% had mitral regurgitation. RESULTS: When NYHA class, electrocardiographic, and ventricular function criteria were considered separately, a high proportion of patients appeared to be candidates for CRT: 70.5% were in NYHA functional class III/IV, 34% had QRSd > or = 150 ms, 60% had LVDD > or = 60 mm and 53.5% LVEF < or = 35%. However, the proportions of patients eligible for CRT were different according to the selection criteria of recently completed trials: 18% of the patients with InSync criteria, 13% of the patients with MUSTIC SR criteria, 0.5% with MUSTIC AF criteria, 27% of patients with MIRACLE criteria, and 35% of the patients with CONTAK CD criteria (without considering indications for implantable cardioverter defibrillator). CONCLUSION: In this population-based study, a wide range of patients (13% to 35%) would have been candidates for CRT, according to the selection criteria of different completed trials.

Marcapasos VDD: Descripción de sus características / VDD systems: Characteristics

Publicaciones recientes reflejan el interés creciente en el implante de sistemas con estimulación ventricular aurículo-sincronizada (VDD) con catéter único. En pacientes con bloqueo A-V de alto grado o completo y función sino-auricular-normal, el marcapaseo VDD aparece como la indicación más racional. Este artículo resume algunas de las características más sobresalientes de dos sistemas VDD

Marcapasos VDD: Descripción de sus características / VDD systems: Characteristics

Publicaciones recientes reflejan el interés creciente en el implante de sistemas con estimulación ventricular aurículo-sincronizada (VDD) con catéter único. En pacientes con bloqueo A-V de alto grado o completo y función sino-auricular-normal, el marcapaseo VDD aparece como la indicación más racional. Este artículo resume algunas de las características más sobresalientes de dos sistemas VDD (AU)

Ensayos clínicos con amiodarona. Presente y futuro / Multicenter trials about amiodarone. Present and future

Desarrollada primero en Bélgica como un compuesto antianginoso, la amiodarona demostró más tarde poseer propiedades antiarrítmicas y electrofisiológicas: bloqueante de los canales de sodio y calcio y bloqueante simpático inespecífico. Ejerce efectos sobre el metabolismo tiroideo, inhibe la actividad de los canales de potasio sensibles al trifosfato de adenosina y actúa como un inhibidor de la enzima fosfolipasa. El objetivo del artículo es exponer una revisión de varios estudios multicéntricos con amiodarona (algunos de ellos en marcha) en pacientes con insuficiencia cardíaca, en aquellos sobrevivientes a una taquicardia o fibrilación ventricular extrahospitalaria y en pacientes sobrevivientes a un infarto agudo de miocardio

Ensayos clínicos con amiodarona. Presente y futuro / Multicenter trials about amiodarone. Present and future

Desarrollada primero en Bélgica como un compuesto antianginoso, la amiodarona demostró más tarde poseer propiedades antiarrítmicas y electrofisiológicas: bloqueante de los canales de sodio y calcio y bloqueante simpático inespecífico. Ejerce efectos sobre el metabolismo tiroideo, inhibe la actividad de los canales de potasio sensibles al trifosfato de adenosina y actúa como un inhibidor de la enzima fosfolipasa. El objetivo del artículo es exponer una revisión de varios estudios multicéntricos con amiodarona (algunos de ellos en marcha) en pacientes con insuficiencia cardíaca, en aquellos sobrevivientes a una taquicardia o fibrilación ventricular extrahospitalaria y en pacientes sobrevivientes a un infarto agudo de miocardio (AU)