Improved relationship between left and right ventricular electrical activation after cardiac resynchronization therapy in heart failure patients can be quantified by body surface potential mapping

OBJECTIVES: Few studies have evaluated cardiac electrical activation dynamics after cardiac resynchronization therapy. Although this procedure reduces morbidity and mortality in heart failure patients, many approaches attempting to identify the responders have shown that 30% of patients do not attain clinical or functional improvement. This study sought to quantify and characterize the effect of resynchronization therapy on the ventricular electrical activation of patients using body surface potential mapping, a noninvasive tool. METHODS: This retrospective study included 91 resynchronization patients with a mean age of 61 years, left ventricle ejection fraction of 28%, mean QRS duration of 182 ms, and functional class III/IV (78%/22%); the patients underwent 87-lead body surface mapping with the resynchronization device on and off. Thirty-six patients were excluded. Body surface isochronal maps produced 87 maximal/mean global ventricular activation times with three regions identified. The regional activation times for right and left ventricles and their inter-regional right-to-left ventricle gradients were calculated from these results and analyzed. The Mann-Whitney U-test and Kruskall-Wallis test were used for comparisons, with the level of significance set at p≤0.05. RESULTS: During intrinsic rhythms, regional ventricular activation times were significantly different (54.5 ms vs. 95.9 ms in the right and left ventricle regions, respectively). Regarding cardiac resynchronization, the maximal global value was significantly reduced (138 ms to 131 ms), and a downward variation of 19.4% in regional-left and an upward variation of 44.8% in regional-right ventricular activation times resulted in a significantly reduced inter-regional gradient (43.8 ms to 17 ms). CONCLUSIONS: Body surface potential mapping in resynchronization patients yielded electrical ventricular activation times for two cardiac regions with significantly decreased global and regional-left values but significantly increased regional-right values, thus showing an attenuated inter-regional gradient after the cardiac resynchronization therapy

Indicação de cardioversor desfibrilador implantável após morte súbita por fibrilação ventricular em pré-operatório de catarata: relato de caso

Introdução: A fibrilação ventricular (FV) é um evento grave e fatal na maioria dos pacientes. Neste relato, descrevemos um caso de parada cardíaca durante pré-operatório de cirurgia de catarata em um paciente, com indicação subsequente de cardioversor desfibrilador implantável (CDI) para prevenção secundária de morte súbita cardíaca (MSC). Trata-se de um homem, 72 anos de idade, admitido para cirurgia de catarata com cardiomiopatia dilatada de etiologia desconhecida (DCM). O paciente apresentava hipertensão arterial, diabetes mellitus, hipotireoidismo e dislipidemia. Durante o período pré-operatório foi administrado, para realização de facectomia, colírio de tropicamida, fenilefrina e proximetacaína e, na sequência, o paciente desenvolveu FV e parada cardíaca. A parada foi revertida após 13 minutos de manobras de reanimação. O paciente foi encaminhado à Unidade de Estimulação Cardíaca de nossa instituição para avaliação. A ressonância magnética cardíaca não mostrou fibrose miocárdica e a coronariografia foi normal. Conclusão: Descrevemos um caso de FV intra-hospitalar, que acometeu paciente com DCM sem substrato anatômico arritmogênico. O mecanismo mais provável da arritmia ventricular foi hiperautomatismo induzido por estresse pré-operatório. O implante de CDI foi indicado para prevenção secundária de MSC, e afastadas causas reversíveis ou controláveis.Introduction: Ventricular fibrillation is a potentially fatal event. We describe herein a case of cardiac arrest during preoperative of cataract surgery in a patient, referred to implantable cardioverter defibrillator (ICD) for secondary prevention of sudden cardiac death (SCD) afterwards. A 72-year-old man was admitted for cataract surgery with dilated cardiomyopathy of unknown etiology (DCM). The patient presented hypertension, diabetes mellitus, hypothyroidism and dyslipidemia. Preoperative medication consisted of eyedrops of phenylephyne, proximetacaine and tropicamide. The patient developed ventricular fibrillation (VF) and cardiac arrest right after the administration of the eyedrops. which was reverted after 13 minutes of reanimate maneuvers. The patient was referred to the Cardiac Pacing Unit of our institution for evaluation. Cardiac MRI showed no myocardial fibrosis and coronary angiography was normal. Conclusion: We describe a case of in-hospital VF, in a patient without arrhythmogenic anatomical substrate. The most likely mechanism of ventricular arrhythmia was hyper automatism induced by preoperative stress. The ICD was implanted for secondary prevention SCD, considering controllable or reversible causes were ruled out

Ativação elétrica ventricular na ressincronização cardíaca caracterizada pelo mapeamento eletrocardiográfico de superfície Ventricular electrical activation in cardiac resynchronization as characterized by body surface potential mapping

OBJETIVOS: Avaliar a ativação elétrica cardíaca usando Mapeamento Eletrocardiográfico de Superfície (MES), em pacientes com ICC e bloqueio de ramo esquerdo [BRE] submetidos a terapia de ressincronização cardíaca (CRT) com implante de marca-passo átrio-biventricular (MP-BIV). MÉTODOS: Foram analisados os tempos médios de ativação elétrica cardíaca no ventrículo direito (tempo médio de ativação do VD [mVD]), área ântero-septal (mAS), e ventrículo esquerdo (mVE), de 28 pacientes (idade média 61,2±9,5 anos, ICC classe III-IV NYHA, fração de ejeção <40%, BRE com QRS médio 181,2±19,4ms, SÂQRS= -8,5º±68,6º), mostrados nos mapas de linhas isócronas do MES, antes e após implante de marca-passo átrio-biventricular, e comparados a valores obtidos em um grupo controle composto de indivíduos normais [GNL], em três situações: (1) BRE nativo, (2) estimulação do VD; e (3) estimulação átrio-biventricular. RESULTADOS: situação (1): mVD e mAS foram semelhantes (41,0±11,8ms x 43,6±13,4ms), com mVE tardio (81,0±12,5ms, p<0,01) perdendo o sincronismo com o VD e a área ântero-septal; situação (2): mVD foi maior que no GNL (86,8±22,9ms, p<0,001), com maior diferença entre mAS e mVE (63,4±20,7ms x 102,7±20,3ms; p<0,001); situação (3): mVE e mVD foram semelhantes (72,0±32,0ms x 71,6±32,3ms), mVD foi maior que no GNL e BRE nativo (71,6±32,3ms x 35,1±10,9ms e 41,0±11,8ms; p<0,001), mAS se aproximou do GNL e BRE nativo (51,3±32,8ms x 50,1±11,4ms e 43,6±13,4ms). CONCLUSÃO: Pelo mapeamento eletrocardiográfico de superfície, tempos de ativação semelhantes no VD e VE e próximos daqueles da região ântero-septal indicam padrões de ativação ventricular sincronizada em portadores de ICC e BRE durante estimulação átrio-biventricular.<br>OBJECTIVES: To assess cardiac electrical activation by using body surface potential mapping (BSPM), in patients with congestive heart failure (CHF) and left bundle branch block (LBBB) undergoing cardiac resynchronization therapy (CRT) with biventricular pacemaker (BIV-PM) implantation. METHODS: Mean cardiac electrical activation times were analyzed in the right ventricle (RV) (mean RV activation time = mRV), anteroseptal area (mAS), and left ventricle (mLV) of 28 patients (mean age 61.2 ± 9.5 years; NYHA class III-IV CHF; ejection fraction <40%; LBBB of mean QRS 181.2±19.4ms, SÂQRS -8.5º±68.6º), as shown in their BSPM isochronous maps, before and after implantation of atriobiventricular pacemaker, comparing those with values obtained from a control group of normal individuals [CG], in three situations: (1) native LBBB; (2) RV pacing; and (3) atriobiventricular pacing. RESULTS: Situation (1): mRV and mAS values were similar (41.0±11.8ms x 43.6±13.4ms), with delayed mLV (81.0±12.5ms, p<0.01) and asynchronous with RV and AS areas; situation (2): mRV was greater than in CG (86.8±22.9ms, p<0.001), with greater difference between mAS and mLV (63.4±20.7ms vs. 102.7±20.3ms; p<0,001); situation (3): mLV and mRV were similar (72.0±32.0ms vs. 71.6±32.3ms), mRV was greater than in CG and native LBBB (71.6±32.3ms vs. 35.1±10.9ms and 41.0±11.8ms; p<0.001), and mAS was close to CG and native LBBB values (51.3±32.8ms vs. 50.1±11.4ms and 43.6±13.4ms). CONCLUSION: The body surface potential mapping showed that RV and LV activation times which are similar, and are close to those of the AS area, suggest patterns of synchronized ventricular activation in patients with CHF and LBBB during atriobiventricular pacing

Efficacy of Antibiotic Prophylaxis Before the Implantation of Pacemakers and Cardioverter-Defibrillators Results of a Large, Prospective, Randomized, Double-Blinded, Placebo-Controlled Trial

Background-Although routinely administered, definitive evidence for the benefits of prophylactic antibiotics before the implantation of permanent pacemakers and implantable cardioverter-defibrillators from a large double-blinded placebo-controlled trial is lacking. The purpose of this study was to determine whether prophylactic antibiotic administration reduces the incidence of infection related to device implantation. Methods and Results-This double blinded study included 1000 consecutive patients who presented for primary device (Pacemaker and implantable cardioverter-defibrillators) implantation or generator replacement randomized in a 1:1 fashion to prophylactic antibiotics or placebo. Intravenous administration of I g of cefazolin (group 1) or placebo (group 2) was done immediately before the procedure. Follow-up was performed 10 days, 1, 3, and 6 months after discharge. The primary end point was any evidence of infection at the surgical incision (pulse generator pocket), or systemic infection related to be procedure. The safety committee interrupted the trial after 649 patients were enrolled due to a significant difference in favor of the antibiotic arm (group 1: 2 of 314 infected patients-0.63%; group 11: 11 of 335 to 3.28%; RR=0.19; P=0.016). The following risk factors were positively correlated with infection by univariate analysis: nonuse of preventive antibiotic (P=0.016); implant procedures (versus generator replacement: P=0.02); presence of postoperative hematoma (P=0.03) and procedure duration (P=0.009). Multivariable analysis identified nonuse of antibiotic (P=0.037) and postoperative hematoma (P=0.023) as independent predictors of infection. Conclusions-Anti biotic prophylaxis significantly reduces infectious complications in patients undergoing implantation of pacemakers or cardioverter-defibrillators. (Circ Arrhythmia Electrophysiol. 2009;2:29-34.