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.

Fragmented surface ECG was a poor predictor of appropriate therapies in patients with Chagas' cardiomyopathy and ICD implantation (Fragmented ECG in CHAgas' Cardiomyopathy Study).

BACKGROUND: Main causes of death in chronic Chagas' cardiomyopathy (CChC) are progressive congestive heart failure and sudden cardiac death. Implantable cardioverter defibrillators (ICD) have been proved an effective therapy to prevent sudden death in patients with CChC. Identification of predictors of sudden death remains a challenge. OBJECTIVE: To determine whether surface fragmented ECG (fQRS) helps identifying patients with CChC and ICDs at higher risk of presenting appropriate ICD therapies. METHODS: Multicenter retrospective study. All patients with CChC and ICDs were analyzed. Clinical demographics, surface ECG, and ICD therapies were collected. RESULTS: A total of 98 patients were analyzed. Another four cases were excluded due to pacing dependency. Mean age was 55.5 ± 10.4 years, male gender 65%, heart failure New York Heart Association class I 47% and II 38%. Mean left ventricular ejection fraction (LVEF) 39.6 ± 11.8%. The indication for ICD was secondary prevention in 70% of patients. fQRS was found in 56 patients (59.6%). Location of fragmentation was inferior (57.1%), lateral (35.7%), and anterior (44.6%). Rsr pattern was the more prevalent (57.1%). Predictors of appropriate therapy in the multivariate model were: increased age (P = 0.01), secondary prevention indication (P = 0.01), ventricular pacing >50% of the time (P = 0.004), and LVEF <30% (P = 0.01). The presence of fQRS did not identify patients at higher risk of presenting appropriate therapies delivered by the ICD (P = 0.87); regardless of QRS interval duration. CONCLUSIONS: fQRS is highly prevalent among patients with CChC. It has been found a poor predictor of appropriate therapies delivered by the ICD in this population.

Cardiovascular Magnetic Resonance Imaging Evidence of Edema in Chronic Chagasic Cardiomyopathy.

The persistence of inflammatory processes in the myocardium in varying degrees of chronic Chagas heart disease has been poorly investigated. We hypothesized that edema could occur in patients with chronic chagasic cardiomyopathy and corresponds to the persistence of inflammatory processes in the myocardium. Eighty-two Chagas disease (CD) seropositive patients (64.6% females; age = 58.9 ± 9.9) without ischemic heart disease or conditions that cause myocardial fibrosis and dilation were considered. Late gadolinium enhancement (LGE) and T2-weighted magnetic resonance imaging of edema were obtained and represented using a 17-segment model. Patients were divided into three clinical groups according to the left ventricular (LV) ejection fraction (EF) as G1 (EF > 60%; n=37), G2 (35% > EF < 60%; n=33), and G3 (EF < 35%; n=12). Comparisons were performed by the Fisher or ANOVA tests. Bonferroni post hoc, Spearman correlation, and multiple correspondence analyses were also performed. Edema was observed in 8 (9.8%) patients; 2 (5.4%) of G1, 4 (12.1%) of G2, and 2 (16.7%) of G3. It was observed at the basal inferolateral segment in 7 (87.5%) cases. LGE was observed in 48 (58.5%) patients; 16 (43.2%) of G1, 21 (63.6%) of G2, and 11 (91.7%) of G3 (p < 0.05). It was observed in the basal inferior/inferolateral/anterolateral segments in 35 (72.9%) patients and in the apical anterior/inferior/lateral and apex segments in 21 (43.7%), with midwall (85.4%; n=41), subendocardial (56.3%; n=27), subepicardial (54.2%; n=26), transmural (31.2%; n=15), and RV (1.2%; n=1) distribution. Subendocardial lesions were observed only in patients with LVEF < 35%. There was no involvement of the mid-inferolateral/anterolateral segments with an LVEF > 35% (p < 0.05). Deteriorations of the LV and RV systolic functions were positively correlated (r s =0.69; p < 0.05) without evidence of LGE in the RV. Edema can be found in patients with chagasic cardiomyopathy in the chronic stage. In later stages of cardiac dilation with low LVEF, the LGE pattern involves subendocardium and mid locations. Deteriorations of RV and LV are positively correlated without evidence of fibrosis in the RV.

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.

Validation of the 2014 European Society of Cardiology Sudden Cardiac Death Risk Prediction Model in Hypertrophic Cardiomyopathy in a Reference Center in South America.

Sudden cardiac death (SCD) is a common cause of death in hypertrophic cardiomyopathy (HC). Our aim was to conduct an external and independent validation in South America of the 2014 European Society of Cardiology (ESC) SCD risk prediction model to identify patients requiring an implantable cardioverter defibrillator. This study included 502 consecutive patients with HC followed from March, 1993 to December, 2014. A combined end point of SCD or appropriate implantable cardioverter defibrillator therapy was assessed. For the quantitative estimation of individual 5-year SCD risk, we used the formula: 1 - 0.998(exp(Prognostic index)). Our database also included the abnormal blood pressure response to exercise as a risk marker. We analyzed the 3 categories of 5-year risk proposed by the ESC: low risk (LR) <4%; intermediate risk (IR) ≥4% to <6%, and high risk (HR) ≥6%. The LR group included 387 patients (77%); the IR group 39 (8%); and the HR group 76 (15%). Fourteen patients (3%) had SCD/appropriate implantable cardioverter defibrillator therapy (LR: 0%; IR: 2 of 39 [5%]; and HR: 12 of 76 [16%]). In a receiver-operating characteristic curve, the new model proved to be an excellent predictor because the area under the curve for the estimated risk is 0.925 (statistical C: 0.925; 95% CI 0.8884 to 0.9539, p <0.0001). In conclusion, the SCD risk prediction model in HC proposed by the 2014 ESC guidelines was validated in our population and represents an improvement compared with previous approaches. A larger multicenter, independent and external validation of the model with long-term follow-up would be advisable.

Relation of interatrial block to new-onset atrial fibrillation in patients with Chagas cardiomyopathy and implantable cardioverter-defibrillators.

Chagas cardiomyopathy is an endemic disease in Latin America. A significant proportion of patients develop atrial fibrillation (AF), which may result in stroke and increased morbidity or mortality. Interatrial block (IAB) has been associated with the development of AF in different clinical scenarios. The aim of our study was to determine whether IAB can predict new-onset AF in patients with Chagas cardiomyopathy and implantable cardioverter-defibrillators (ICDs). We conducted a retrospective study of patients with Chagas cardiomyopathy and ICDs from 14 centers in Latin America. Demographics, clinical, and device follow-up were collected. Surface electrocardiograms were scanned at 300 dpi and maximized ×8. Semiautomatic calipers were used to determine P-wave onset and offset. Partial IAB was defined as a P wave of >120 ms and advanced IAB as a P wave of >120 ms with biphasic morphology (±) in inferior leads. AF events and ICD therapies were reviewed during follow-up by 2 independent investigators. A total of 80 patients were analyzed. Mean age was 54.6 ± 10.4 years, and 52 (65%) were male. Mean left ventricular ejection fraction was 40 ± 12%. IAB was detected in 15 patients (18.8%), with 8 (10.0%) partial and 7 (8.8%) advanced. During a follow-up of 33 ± 20 months, 11 patients (13.8%) presented with new AF. IAB (partial + advanced) was strongly associated with new AF (p <0.0001) and inappropriate therapy by the ICD (p = 0.014). In conclusion, IAB (partial + advanced) predicted new-onset AF in patients with Chagas cardiomyopathy and ICDs.

Crioablación con balón en fibrilación auricular paroxística: Experiencia inicial / Balloon Cryoablation for Paroxysmal Atrial Fibrillation: Initial Experience

Introducción: El aislamiento eléctrico de las venas pulmonares constituye la piedra angular en el tratamiento curativo de pacientes con fibrilación auricular paroxística (FAP) recurrente y sintomática. La crioablación con balón (CAB) es una alternativa a la radiofrecuencia, con disminución de los tiempos del procedimiento y de radioscopia. Objetivos: Describir los resultados inmediatos y la experiencia inicial en las primeras intervenciones de CAB de FAP en nuestro hospital. Material y métodos: Entre noviembre de 2013 y febrero de 2015, 23 pacientes fueron intervenidos con una CAB de FAP. Previo al procedimiento se les realizó una angiotomografía con reconstrucción de la aurícula izquierda y las venas pulmonares. Resultados: La edad promedio de los pacientes fue de 53 ± 11 años, 19 eran varones, el diámetro de la aurícula izquierda fue de 40 ± 7 mm, la FEVI fue de 58% ± 8%. El CHA2DS2VASc promedio fue de 0,6. La duración promedio de los procedimientos fue de 169 ± 47 minutos, con un tiempo de radioscopia de 39 ± 17 minutos. Se logró el aislamiento en 89/91 venas pulmonares (97,8%); en 2 pacientes se debió completar la lesión con radiofrecuencia. Un paciente (4,34%) presentó parálisis diafragmática transitoria, con recuperación espontánea a los 30 minutos. No hubo otras complicaciones. Con una mediana de seguimiento de 9,2 meses, 21 pacientes (91,3%) permanecieron en ritmo sinusal. Conclusiones: En esta experiencia inicial, la CAB de FAP se mostró como una técnica segura y eficaz en pacientes seleccionados. Presentó un éxito agudo alto en el aislamiento de las venas pulmonares. Durante el seguimiento, la tasa de recurrencia fue baja. Resta esperar los resultados del seguimiento extendido para conocer su impacto real.

Background: Pulmonary vein isolation is the cornerstone for the treatment of patients with recurrent and symptomatic paroxysmal atrial fibrillation (PAF). Balloon cryoablation (BCA) is an option to radiofrequency with shorter procedural and fluoroscopy times. Objectives: The aim of this study was to describe the immediate outcomes and the initial experience in the first BCA procedures for PAF in our hospital. Methods: Between November 2013 and February 2015, 23 patients underwent BCA for PAF. A computed tomography angiography with reconstruction of the left atrium and pulmonary veins was performed before the procedure. Results: Mean age was 53±11 years, 19 patients were men, left atrial dimension was 40±7 mm and LVEF was 58%±8%. Average CHA2DS2VASc score was 0.6. The average procedural time was 169±47 minutes, with a fluoroscopy time of 39±17 minutes. Isolation of the pulmonary veins was achieved in 89/91 pulmonary veins (97.8%), and 2 patients required additional radiofrequency catheter ablation. One patient (4.34%) presented transient paralysis of the diaphragm with spontaneous recovery after 30 minutes. No further complications were observed. After a median follow-up of 9.2 months, 21 patients (91.3%) remained with sinus rhythm. Conclusions: In this initial experience, BCA for PAF proved to be a safe and effective technique in selected patients. A high acute success rate was achieved for pulmonary vein isolation. During follow-up, the recurrence rate was low. The real impact of the procedure will be known when long-term outcomes become available.

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.

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.

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.

Monitoreo remoto en dispositivos implantables / Remote moitoring and implantable devices

Mechanical assist devices are being used with increasing frequency, for remote monitoring for the care of patients through information received at distance by mean of the technology of telecommunications. The aim of this report was to describe the alerts received from patients implanted with devices with the ability of transmission at distance, in order to evaluate their causes and the therapeutic measures introduced, when in these patients is instituted a permanent remote monitoring instead of a remote follow-up. The role of remote monitoring and follow-up of pacemakers and implantable cardioverter defibrillators, is revised.

Alternativas terapéuticas en la miocardiopatía hipertrófica / Therapeutics alternatives in hypertrophic cardiomyopathy

Para el tratamiento de la miocardiopatía htpertrófica obstructiva (MCHO) se han sugerido numerosas opciones. Como tratamiento inicial se utilizaron fármacos como los betabloqueantes, los bloqueantes cálcicos (especialmente el verapamilo) y la disopiramida. La miotomía-mioectomía septal ventricular representa el mejor tratamiento para los pacientes con MCHO y síntomas refractarios al tratamiento médico. La ablación septal con alcohol y la estimulación doble cámara se propusieron como opciones de tratamiento alternativo a la cirugía en pacientes de edad avanzada o enfermedades concomitantes. Es muy importante la identificación y el tratamiento de los pacientes con miocardiopatía hipertrófica que presentan alto riesgo de muerte súbita (MS). La amiodarona y el cardiodesfibrilador implantable son las opciones de tratamiento actualmente aceptadas para estos pacientes. Aún quedan por definir mejor sus indicaciones para la prevención primaria de MS en diferentes subgrupos de pacientes con esta patología. Por último, en pacientes con insuficiencia cardíaca grave intratable, y más raramente en aquellos con síncope arrítmico recurrente refractarios, puede efectuarse un trasplante cardíaco.

Hallazgos cardiológicos y de capacidad física en futbolistas argentinos de alto rendimiento / Cardiovascular and fitness changes in high perfomance soccer players

Las modificaciones generadas por el deporte de alto rendimiento en el aparato cardiovascular se han descripto en numerosos estudios. Sin embargo, son escasos los datos específicos en jugadores de fútbol profesionales. En el presente estudio se describen hallazgos en electrocardiogramas y ecocardiogramas, electrocardiogramas de señal promediada, monitoreos Holter de 24 horas con estudio de variabilidad de frecuencia cardíaca (que implican respuestas del sistema nervioso autónomo) y capacidades funcionales en diferentes grupos de futbolistas de alto rendimiento pertenecientes a instituciones deportivas profesionales de la Asociación de Fútbol Argentino. El presente trabajo incluyó jugadores de fútbol con niveles de entrenamiento uniforme y en el mismo período del año competitivo. De esta forma, se muestran resultados que pertenecen a poblaciones homogéneas. Se describen las frecuentes modificaciones electrocardiográficas, entre las cuales la bradicardia sinusal y los cambios en la repolarización ventricular son las más llamativas. No se detectaron potenciales ventriculares tardíos y los índices de variabilidad de frecuencia cardíaca son superiores a los hallados en sedentarios. Las dimensiones cavitarias y la masa ventricular izquierda fueron mayores que en los controles. Se estudiaron variables de potencia aeróbica y su relación con parámetros de composición corporal y se encontró una relación positiva entre el consumo de oxígeno máximo y al umbral anaeróbico y el índice de masa corporal. Las estimaciones de consumo de oxígeno máximo en pruebas de campo resultaron inferiores a las halladas en pruebas de laboratorio con medición directa de este parámetro.

Ablación por radiofrecuencia de fibrilación auricular paroxística y persistente / Radiofrequency ablation of paroxysmal and persistent atrial fibrillation

La ablación por radiofrecuencia (ARF) es aceptada en la actualidad como tratamiento de la fibrilación auricular (FA) paroxística y persistente. El objetivo del presente trabajo es comparar los resultados de la ablación por radiofrecuencia con diferentes técnicas...

Radiofrequency catheter ablation (RFA) is one of the currently accepted treatments for paroxysmal and persistent atrial fibrillation (AF). Different approaches are currently used. To analyze the results of RFA in patients (pts.) with paroxysmal and persistent AF performing different techniques...

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

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

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

Taquicardias con complejo QRS ancho: ¿Cómo establecer la diferencia?: parte I / Tachycardia with a wide QRS complex: part I

Las taquicardias con complejos QRS ancho revierten un valor pronóstico y terapéutico de gran importancia en la práctica clínica cotidiana. Se han descripto una cantidad importante de criterios que ayudan al diagnóstico diferencial de las mismas. Se considera oportuno describir la frecuencia de aparición, mecanismos, algoritmos, el aporte de drogas y estudios complementarios para establecer un diagnóstico apropiado