[New conduction disturbances and pacemaker indications after CoreValve® transcatheter aortic valve replacement. Incidence and follow up in a single center experience]. / Desarrollo de trastornos de conducción e indicaciones de marcapasos postimplante de válvula aórtica CoreValve® por vía endovascular. Incidencia y seguimiento en un solo centro.

INTRODUCTION: Transcatheter aortic valve implantation (TAVI) is currently reserved for patients with symptomatic aortic stenosis and high surgical risk. One major limiting factor related to TAVI procedural complications is conduction abnormalities and the need for permanent pacemaker implantation. OBJECTIVES: Evaluate the incidence of new conduction disturbances and pacemaker indications in patients with TAVI CoreValve® prosthesis (Medtronic Inc. Minneapolis, Minnesota, United States). METHODS: We included 28 patients, mean age 80 years. ECG parameters were evaluated previous and after implantation. All patients were monitorized during TAVI. Follow up Holter monitoring was performed at one, 6 and 12 months after the procedure and we also evaluated telemetry of implanted pacemaker. RESULTS: In previous ECG we found 7 patients had right bundle branch block and 7 patients had left bundle brunch block (LBBB). The post implant ECG showed 7 new LBBB: 3 during valvuloplasty and 4 on the end of it. Six patients required pacemaker implantation for permanent or paroxysmal complete AV block (CAVB). At one year follow up, 3 patients with LBBB during valvuloplasty had a normal ECG, one still had LBBB and one an asymptomatic CAVB found in Holter monitoring. CONCLUSIONS: Conduction abnormalities are frequent after CoreValve® aortic valve prosthesis implantation. The incidence of new LBBB was 25%. CAVB during or post TAVI require PM implantation. New LBBB may need a closer follow up because in a 3% of the cases it may progress to CAVB.

Lack of current implantable cardioverter defibrillator guidelines application for primary prevention of sudden cardiac death in Latin American patients with heart failure: a cross-sectional study.

AIMS: This cross-sectional study evaluated the application of accepted international implantable cardioverter defibrillator (ICD) guidelines for primary prevention of sudden cardiac death in patients with heart failure. METHODS AND RESULTS: The PLASMA (Probabilidad de Sufrir Muerte Arritmica) study was designed to characterize management of cardiac patients in Latin America. Twelve centres included 1958 consecutively admitted patients in cardiology units in 2008 and 2009. Discharged patients were evaluated for primary prevention, ICD indication and prescription by general cardiologists. Of 1711 discharged patients, 1525 (89%) had data available for evaluating indication status. Class I indications for ICD therapy were met for 153 (10%) patients based on collected data. Only 20 (13%, 95% confidence interval: 7.7-18.4%) patients with indication were prescribed an ICD. Patients prescribed an ICD were younger than patients who were not prescribed an ICD (62 vs. 68 years, P < 0.01). The reasons given by cardiologists for not prescribing an ICD for 133 patients with an indication were: indication criteria not met (75%), life expectancy <1 year (9.7%), rejection by the patient (5.2%), no medical coverage paying for the device (3.7%), psychiatric patient (2.2%), and other reasons (4.2%). CONCLUSIONS: In Latin America, international guidelines for primary prevention ICD implantation are not well followed. The main reason is that cardiologists believe that patients do not meet indication criteria, even though study data confirm that criteria are met. This poses a significant challenge and underlines the importance of continuous and improved medical education.

Current and emerging therapeutic options for the treatment of chronic chagasic cardiomyopathy.

Chagas' disease is an endemic disease in Latin America caused by a unicellular parasite (Trypanosoma cruzi) that affects almost 18 million people. This condition involves the heart, causing heart failure, arrhythmias, heart block, thromboembolism, stroke, and sudden death. In this article, we review the current and emerging treatment of Chagas' cardiomyopathy focusing mostly on management of heart failure and arrhythmias. Heart failure therapeutical options including drugs, stem cells and heart transplantation are revised. Antiarrhythmic drugs, catheter ablation, and intracardiac devices are discussed as well. Finally, the evidence for a potential role of specific antiparasitic treatment for the prevention of cardiovascular disease is reviewed.

Implantable cardioverter defibrillators and Chagas' disease: results of the ICD Registry Latin America.

AIMS: Chagas' disease is an endemic parasitic affliction in Latin America. It is frequently associated with ventricular tachyarrhythmia and sudden death. The aim of this study is to assess the evolution of patients with Chagas' disease treated with an implantable cardioverter defibrillator (ICD). METHODS AND RESULTS: Eighty-nine chagasic patients with ICD were included for analysis from the Medtronic ICD Registry Latin America. At implant, mean age was 59 +/- 10 years, and 72% were male. Eighty-one patients (91%) had secondary prevention indications. Mean left ventricular ejection fraction was 40 +/- 11%, and mean follow-up was 12 +/- 7 months. During follow-up, six patients died (6.7%); three due to congestive heart failure, one due to sudden death, and two due to non-cardiac cause. Hospitalization occurred in seven patients. Thirty-eight patients (42%) received appropriate ICD therapies. A total of 737 episodes were detected by the ICD. The mean period between ICD implantation and the first appropriate therapy was 104 days. Electrical storms were observed in 14 of the 89 patients (15.7%). Inappropriate therapies were observed in seven patients. CONCLUSION: This registry confirms that ICD therapy provides protection by effectively terminating life-threatening arrhythmias in patients with Chagas' disease. This is especially so when patients receive the device for secondary prevention.

[Initiation mode of ventricular tachyarrhythmias in chronic Chagas' cardiomyopathy]. / Modo de inicio de las taquiarritmias ventriculares en la cardiopatía chagásica crónica.

AIM: The purpose of this study was to investigate the modes of initiation of malignant ventricular tachyarrhythmias in patients with Chagas' cardiomyopathy (ChC) with an implantable cardioverter-defibrillator (ICD) through the analysis of stored intracardiac electrograms. Specifically, we analyzed the incidence of ventricular arrhythmias preceded by the short-long-short-pattern (sls). METHODS: We analyzed 179 spontaneous malignant ventricular tachyarrhythmias episodes in 15 patients with Chagas' cardiomyopathy with an ICD. The mean cycle length in normal sinus rhythm before initiation of the malignant ventricular tachyarrhythmias, the ventricular tachycardia (VT) cycle length, the prematurity ratio and the number of ventricular premature contractions (VPCs) (single, pairs or multiple) that triggered malignant ventricular tachyarrhythmias were compared between the two different initiation modes. RESULTS: Mean age: 60.4 +/- 5.7 -years-old, mean EF, 33.2 +/- 8.5%, 9 men and 6 women. A sls-pattern was found in 43.5% of the malignant ventricular tachyarrhythmias. Baseline cycle length (795 +/- 16 vs 788 +/- 14 ms), VT cycle length (320 +/- 7.7 ms vs 329 +/- 5.7 ms) and prematurity ratio (0.57 +/- 11 vs 0.60 +/- 12) were similar between sls and non-sls-sequences. Multiple VPCs as a trigger of malignant ventricular tachyarrhythmias was significantly less often in sls-events than in non-sls events (14% vs 40%; P < 0.0001). CONCLUSIONS: In this select population of patients with ChC, we observed a high prevalence of sls-pattern just before initiation of malignant ventricular tachyarrhythmias. Multiple VPCs were often associated with a non-sls trigger mode.

Modo de inicio de las taquiarritmias ventriculares en la cardiopatía chagásica crónica / Initiation mode of ventricular tachyarrhythmias in chronic Chagas' cardiomyopathy

AIM: The purpose of this study was to investigate the modes of initiation of malignant ventricular tachyarrhythmias in patients with Chagas' cardiomyopathy (ChC) with an implantable cardioverter-defibrillator (ICD) through the analysis of stored intracardiac electrograms. Specifically, we analyzed the incidence of ventricular arrhythmias preceded by the short-long-short-pattern (sls). METHODS: We analyzed 179 spontaneous malignant ventricular tachyarrhythmias episodes in 15 patients with Chagas' cardiomyopathy with an ICD. The mean cycle length in normal sinus rhythm before initiation of the malignant ventricular tachyarrhythmias, the ventricular tachycardia (VT) cycle length, the prematurity ratio and the number of ventricular premature contractions (VPCs) (single, pairs or multiple) that triggered malignant ventricular tachyarrhythmias were compared between the two different initiation modes. RESULTS: Mean age: 60.4 +/- 5.7 -years-old, mean EF, 33.2 +/- 8.5%, 9 men and 6 women. A sls-pattern was found in 43.5% of the malignant ventricular tachyarrhythmias. Baseline cycle length (795 +/- 16 vs 788 +/- 14 ms), VT cycle length (320 +/- 7.7 ms vs 329 +/- 5.7 ms) and prematurity ratio (0.57 +/- 11 vs 0.60 +/- 12) were similar between sls and non-sls-sequences. Multiple VPCs as a trigger of malignant ventricular tachyarrhythmias was significantly less often in sls-events than in non-sls events (14% vs 40%; P < 0.0001). CONCLUSIONS: In this select population of patients with ChC, we observed a high prevalence of sls-pattern just before initiation of malignant ventricular tachyarrhythmias. Multiple VPCs were often associated with a non-sls trigger mode.

Arritmia ventricular en el postoperatorio inmediato de cirugía cardiovascular / Postoperating ventricular arrhythmia in the immediate one of cardiovascular surgery

Objetivos: Determinar la incidencia, factores predisponentes y la evolución hospitalaria de la arritmia ventricular compleja en el postoperatorio inmediato de cirugía cardíaca. Material y métodos: Se analizó las primeras 96 hs. del postoperatorio de cirugía cardíaca en 35 pacientes (pts) consecutivos, considerando como arritmia ventricular compleja (AC) a la taquicardia ventricular autolimitada, sostenida y fibrilación ventricular. Se registraron factores predisponentes pre, intra y postoperatorios y la evolución hospitalaria. Resultados: Se efectuo revascularización miocárdica en 273 pts (77 por ciento), cirugía valvular en 74 pts (21 por ciento) y procedimientos combinados en 8 pts (2 por ciento). Presentaron AC 25 pts (7 por ciento), detectando Taquicardia Ventricular Sostenida en 11 pts (44 por ciento) y Fibrilación Ventricular en 7 pts (28 por ciento). La Arritmia ventricular compleja resultó más frecuente en pts sometidos a revascularización miocárdica (9,1 por ciento vs 0 por ciento; p<0,005), asociada al uso de intrópicos (64 por ciento vs 34 por ciento, p<0, 005) o por isquemia o infarto perioperatorio (48 por ciento vs 16 por ciento, p<0,0001). El tiempo de bomba fue mayor en pacientes con Arritmia ventricular compleja (142,4 ± 45,1 vs 106,3 ± 30,1 min.; p<0,0005). Las variables independientes de riesgo fueron: Revascularización miocárdiaca (OR 7,52), uso de inotrópicos (OR 2,63) e incrento del tiempo de bomba (OR 1,02). Sólo el 0.5 por ciento de las Arritmias ventriculares complejas no presentaron factores desencadenantes. La mortalidad del grupo con arritmias fue 52 por ciento, y sin ellas 5 por ciento (p<0,001). La mortalidad por toda causa en Taquicardia Ventricular Autolimitada fue 14 por ciento, 45 por ciento en Taquicardia ventricular sostenida y 100 por ciento en Fibrilación ventricular. Conclusiones: La Arritmia ventricular compleja es una complicación de alta mortalidad, relacionada a factores inherentes al procedimiento de revascularización miocárdiaca.