Mortality risk score for patients with Chagas cardiomyopathy and pacemaker.

BACKGROUND: Prognosis of Chronic Chagasic Cardiomyopathy (CCC) patients depends on functional and clinical factors. Bradyarrhythmia requiring pacemaker is a common complication. Prognosis of these patients is poorly studied, and mortality risk factors are unknown. We aimed to identify predictors of death and to define a risk score for mortality in a large cohort of CCC patients with pacemaker. METHODS: It was an observational, unicentric and prospective study. The endpoint was all-cause mortality. Cox regression was used to identify predictors of death and to define a risk score. Bootstrapping method was used to internal score validation. RESULTS: We included 555 patients and after a mean follow-up of 3.7±1.5 years, 100 (18%) deaths occurred. Predictors of death were: right ventricular dysfunction (HR [hazard ratio] 2.24; 95%CI 1.41-3.53; P = 0.001); heart failure class III or IV (HR 2.16; 95% confidence interval [95%CI] 1.16-4.00; P = 0.014); renal disease (HR 2.14; 95%CI 1.24-3.68; P = 0.006); left ventricular end-systolic diameter > 44mm (HR 1.97; 95%CI 1.26-3.05; P = 0.003); atrial fibrillation (HR 1.94; 95%CI 1.25-2.99; P = 0.003) and cardiomegaly on X-ray (HR 1.87; 95%CI 1.10-3.17; P = 0.020). The score identified patients with: low (0-20 points), intermediate (21-30 points) and high risk (>31points). The optimism-corrected C-statistic of the predictive model was 0.751 (95% CI 0.696-0.806). Internal validation with bootstrapping revealed a calibration slope of 0.946 (95% CI 0.920-0.961), reflecting a small degree of over-optimism and C-statistic of 0.746 (95% CI 0.692-0.785). CONCLUSIONS: This study identified predictors of mortality in CCC patients with pacemaker defining a simple, validated and specific risk score.

Effect of Occurrence of Lamin A/C (LMNA) Genetic Variants in a Cohort of 101 Consecutive Apparent "Lone AF" Patients: Results and Insights.

Objective: Mutations in the Lamin A/C (LMNA) gene are commonly associated with cardiac manifestations, such as dilated cardiomyopathy (DCM) and conduction system disease. However, the overall spectrum and penetrance of rare LMNA variants are unknown. The present study described the presence of LMNA variants in patients with "lone atrial fibrillation (AF)" as their sole clinical presentation. Methods: One-hundred and one consecutive patients with "lone AF" criteria were initially screened by genetic testing. Genetic variants were classified according to the American College of Genetic and Genomic criteria. All subjects were evaluated through clinical and familial history, ECG, 24-h Holter monitoring, echocardiogram, cardiac magnetic resonance, treatment response, and the present relatives of LMNA carriers. In addition, whole-exome data from 49,960 UK Biobank (UKB) participants were analyzed to describe the overall penetrance of rare LMNA missense and loss of function (LOF) variants. Results: Three missense variants in LMNA were identified in probands with AF as their first and unique clinical manifestation. Other five first-degree relatives, after the screening, also presented LMNA gene variants. Among 49,960 analyzed UKB participants, 331 carried rare LMNA missense or LOF variant. Participants who carried a rare LMNA variant were significantly associated with higher odds of arrhythmic events and of an abnormal ECG in the per-protocol ECG exam (p = 0.03 and p = 0.05, respectively). Conclusion: Although a rare occurrence, our findings emphasize the possibility of an initial presentation of apparently "lone AF" in LMNA gene variant carriers.

Registro brasileiro de estimulação fisiológica da sociedade brasileira de arritmias cardíacas - SOBRAC / Brazilian registry of physiological stimulation of the brazilian society of cardiac arrhythmias - SOBRAC

INTRODUÇÃO: Resultados favoráveis foram relatados com estimulação direta do sistema de excito-condutor cardíaco, o que tem motivado a inclusão desta técnica em recomendações e diretrizes atuais. Entretanto, não há dados disponíveis dessa prática no Brasil. OBJETIVOS: Descrever as características demográficas, eletrocardiográficas e ecocardiográficas assim como os achados intra e peri-operatórios dos pacientes submetidos a estimulação fisiológica no Brasil. MÉTODOS: Trata-se de um registro multicêntrico realizado em 15 centros no Brasil. A técnica cirúrgica utilizada seguiu a rotina dos centros participantes. RESULTADOS: 180 pacientes (64,9% homens, 74,8±12,5 anos) foram incluídos na análise entre maio e setembro de 2021. Características clínicas: 82,7% eram hipertensos, 33,5% diabéticos, 51,9% tinham antecedente de sincope, 23,2% DAC e 0,7% doença de Chagas; 76,7% apresentavam-se em CF-NYHA I ou II. A cardiopatia subjacente e o motivo do implante estão ilustrados na figura 1. Em 13,5% dos pacientes, o CDI foi concomitantemente indicado. Quanto aos achados eletrocardiográficos, 89,2% dos pacientes apresentavam-se em ritmo sinusal e 10,8% em FA/flutter atrial. O QRS basal médio era de 131±32ms; 28,1% dos pacientes apresentavam BRE e 31,4% BRD. A FEVE média foi de 54,14±16,66%. Todos os centros reportaram sucesso do implante. O tempo médio de fluoroscopia foi de 17,6±14,5min e a duração média do procedimento 81,8±43,8. Dispositivo bicameral foi predominante na maior parte dos casos (figura 2). Em 75,1% dos casos, o eletrodo ventricular foi posicionado no RE/septo profundo (LVAT médio 77,7±10,7ms, potencial de RE reportado em 25,7%) enquanto o feixe de His foi a posição escolhida em 24,9% dos casos. Em 6,6% dos pacientes procedeu-se HOT/LOT-CRT. A onda R média foi 9,8mV e o limiar de captura 1,17V x 1,0ms. A duração média do QRS final foi 107,46 ± 18,6ms. As taxas de complicações foram baixas (figura 3). CONCLUSÕES: O implante de marcapasso fisiológico é factível e seguro. As características dos pacientes incluídos nesse registro brasileiro, a preferência quanto ao tipo de estimulação (RE) e os resultados intra e pós operatórios precoces estão alinhados com as publicações internacionais mais recentes.

Síndrome de Kearns Sayre - relato de caso / Kearns Sayre Syndrome - case report

A Síndrome de Kearns Sayre (SKS) é uma miopatia de origem mitocondrial rara. Caracterizase pela tríade de oftalmoplegia externa, retinose pigmentar e acometimento do sistema de condução cardíaco, descrita em 1958. O objetivo deste relato de caso é descrever um caso de SKS e discutir achados clínicos com ênfase no acometimento cardíaco. Paciente J.A., masculino, 35 anos, com sintomas iniciais de diplopia, estrabismo e ptose. Evoluiu com alteração da motricidade ocular extrínseca, retinopatia pigmentosa e fraqueza muscular difusa o que levou à hipótese de SKS. O diagnóstico definitivo foi feito através de biópsia do bíceps que revelou padrão miopático mitocondrial. Em seguida, encaminhado para investigação de distúrbio de condução. Em primeira consulta evidenciado eletrocardiograma com ritmo sinusal, BAV 1° grau, bloqueio de ramo esquerdo, pausa sinusal e ritmo juncional de 40 bpm. Ecocardiograma com FE 62% e contratilidade preservada. Indicado implante de marcapasso (MP) atrioventricular. Atualmente, com necessidade de 100% de pacing ventricular sem escape ventricular e fibrilação atrial paroxística em anticoagulação. Desde então, segue em acompanhamento ambulatorial. A SKS é uma doença genética relacionada a mutação do DNA mitocondrial. As mitocôndrias são responsáveis pela produção de ATP e fornecimento de energia para diversas funções metabólicas. Por isso, tecidos com alto gasto energético, são os mais acometidos em tais anomalias genéticas. As manifestações cardiológicas ocorrem em 57% dos casos. As alterações eletrocardiográficas mais comuns são bloqueio divisional anterossuperior e bloqueio de ramo direito. Tipicamente ocorre progressão para bloqueio atrioventricular avançado. Morte súbita está associada em até 20% dos casos. A Sociedade Europeia, em sua diretriz de estimulação cardíaca artificial 2021, orienta implante de MP diante do achado de prolongamento de intervalo PR e evidência de bloqueio atrioventricular de qualquer grau, bloqueio de ramo ou bloqueio fascicular. A SKS é uma doença incomum e com repercussão clínica importante. Se negligenciada, o acometimento cardíaco é potencialmente fatal. Assim, cabe ao cardiologista estar atento ao momento ideal de indicação de MP.

A cohort study of cardiac resynchronization therapy in patients with chronic Chagas cardiomyopathy.

Aims: Cardiac resynchronization therapy (CRT) is an established procedure for patients with heart failure. However, trials evaluating its efficacy did not include patients with chronic Chagas cardiomyopathy (CCC). We aimed to assess the role of CRT in a cohort of patients with CCC. Methods and results: This retrospective study compared the outcomes of CCC patients who underwent CRT with those of dilated (DCM) and ischaemic cardiomyopathies (ICM). The primary endpoint was all-cause mortality and the secondary endpoints were the rate of non-advanced New York Heart Association (NYHA) class 12 months after CRT and echocardiographic changes evaluated at least 6 months after CRT. There were 115 patients in the CCC group, 177 with DCM, and 134 with ICM. The annual mortality rates were 25.4%, 10.4%, and 11.3%, respectively (P < 0.001). Multivariate analysis adjusted for potential confounders showed that the CCC group had a two-fold [hazard ratio 2.34 (1.47-3.71), P < 0.001] higher risk of death compared to the DCM group. The rate of non-advanced NYHA class 12 months after CRT was significantly higher in non-CCC groups than in the CCC group (DCM 74.0% vs. ICM 73.9% vs. 56.5%, P < 0.001). Chronic Chagas cardiomyopathy and ICM patients had no improvement in the echocardiographic evaluation, but patients in the DCM group had an increase in left ventricular ejection fraction and a decrease in left ventricular end-diastolic diameter. Conclusion: This study showed that CCC patients submitted to CRT have worse prognosis compared to patients with DCM and ICM who undergo CRT. Studies comparing CCC patients with and without CRT are warranted.

Predictors of death in chronic Chagas cardiomyopathy patients with pacemaker.

BACKGROUND: Chronic Chagas cardiomyopathy (CCC) is the most serious and frequent manifestation of Chagas disease. Conduction abnormalities and bradycardia requiring pacemaker are common. The aim of this study was to determine the rate and predictors of death in CCC patients with pacemaker. METHODS: In this single-center prospective cohort study we assessed the outcome of 396 CCC patients with pacemaker, followed-up for at least 24months. All patients underwent a clinical and device assessment, 12-lead electrocardiography and echocardiography. RESULTS: During the median follow-up of 1.9years (Interquartile range 1.6-2.4), there were 65 (16.4%) deaths, yielding an annual mortality rate of 8.6%. The major cause was sudden death (33.8%), followed by heart failure (HF), 32.3%. All the investigated variables were examined as potential predictors of death. The final multivariate logistic regression model included five independent variables: advanced HF functional class (OR [odds ratio] 6.71; 95% confidence interval [95% CI] 1.95-23.2; P=0.003), renal disease (OR 5.71; 95% CI 1.80-18.0; P=0.003), QRS ≥150ms (OR 2.80; 95% CI 1.08-7.27; P=0.034), left atrial enlargement (OR 2.75; 95% CI 1.09-6.95; P=0.032) and left ventricular ejection fraction ≤43% (OR 2.31; 95% CI 1.07-4.97; P=0.032). The model had good discrimination, confirmed by bootstrap validation (optimism-adjusted c-statistic of 0.78) and the calibration curve showed a proper calibration (slope=0.972). CONCLUSIONS: CCC patients with pacemaker have a high annual mortality rate despite that the pacemaker related variables were not predictors of death. The independent predictors of death can help us to identify the poor prognosis patients.

Evidence for cardiac safety and antiarrhythmic potential of chloroquine in systemic lupus erythematosus.

AIMS: To perform a comprehensive evaluation of heart rhythm disorders and the influence of disease/therapy factors in a large systemic lupus erythematosus (SLE) cohort. METHODS AND RESULTS: Three hundred and seventeen consecutive patients of an ongoing electronic database protocol were evaluated by resting electrocardiogram and 142 were randomly selected for 24 h Holter monitoring for arrhythmia and conduction disturbances. The mean age was 40.2 ± 12.1 years and disease duration was 11.4 ± 8.1 years. Chloroquine (CQ) therapy was identified in 69.7% with a mean use of 8.5 ± 6.7 years. Electrocardiogram abnormalities were detected in 66 patients (20.8%): prolonged QTc/QTd (14.2%); bundle-branch block (2.5%); and atrioventricular block (AVB) (1.6%). Age was associated with AVB (P = 0.029) and prolonged QTc/QTd (P = 0.039) whereas anti-Ro/SS-A and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores were not (P > 0.05). Chloroquine was negatively associated with AVB (P = 0.01) as was its longer use (6.1 ± 6.9 vs. 1.0 ± 2.5 years, P = 0.018). Time of CQ use was related with the absence of AVB [odds ratio (OR) = 0.103; 95% confidence interval (CI) = 0.011-0.934, P = 0.043] in multiple logistic regression. Holter monitoring revealed abnormalities in 121 patients (85.2%): supraventricular ectopies (63.4%) and tachyarrhythmia (18.3%); ventricular ectopies (45.8%). Atrial tachycardia/fibrillation (AT/AF) were associated with shorter CQ duration (7.05 ± 7.99 vs. 3.63 ± 5.02 years, P = 0.043) with a trend to less CQ use (P = 0.054), and older age (P < 0.001). Predictors of AT/AF in multiple logistic regression were age (OR = 1.115; 95% CI = 1.059-1.174, P < 0.001) and anti-Ro/SS-A (OR = 0.172; 95% CI = 0.047-0.629, P = 0.008). CONCLUSIONS: Chloroquine seems to play a protective role in the unexpected high rate of cardiac arrhythmias and conduction disturbances observed in SLE. Further studies are necessary to determine if this antiarrhythmic effect is due to the disease control or a direct effect of the drug.

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.

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 ...

Global and regional ventricular repolarization study by body surface potential mapping in patients with left bundle-branch block and heart failure undergoing cardiac resynchronization therapy.

BACKGROUND: The controversial effects promoted by cardiac resynchronization therapy (CRT) on the ventricular repolarization (VR) have motivated VR evaluation by body surface potential mapping (BSPM) in CRT patients. METHODS: Fifty-two CRT patients, mean age 58.8 ± 12.3 years, 31 male, LVEF 27.5 ± 9.2, NYHA III-IV heart failure with QRS181.5 ± 14.2 ms, underwent 87-lead BSPM in sinus rhythm (BASELINE) and biventricular pacing (BIV). Measurements of mean and corrected QT intervals and dispersion, mean and corrected T peak end intervals and their dispersion, and JT intervals characterized global and regional (RV, Intermediate, and LV regions) ventricular repolarization response. RESULTS: Global QTm (P < 0.001) and QTc(m) (P < 0.05) were decreased in BIV; QTm was similar across regions in both modes (P = ns); QTc(m) values were lower in RV/LV than in Intermediate region in BASELINE and BIV (P < 0.001); only RV/Septum showed a significant difference (P < 0.01) in the BIV mode. QTD values both of BASELINE (P < 0.01) and BIV (P < 0.001) were greater in the Intermediate than in the LV region. CRT effect significantly reduced global/regional QTm and QTc(m) values. QTD was globally decreased in RV/LV (Intermediate: P = ns). BIV mode significantly reduced global T peak end mean and corrected intervals and their dispersion. JT values were not significant. CONCLUSIONS: Ventricular repolarization parameters QTm, QTc(m), and QTD global/regional values, as assessed by BSPM, were reduced in patients under CRT with severe HF and LBBB. Greater recovery impairment in the Intermediate region was detected by the smaller variation of its dispersion.

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 1 g of cefazolin (group I) 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 I: 2 of 314 infected patients-0.63%; group II: 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: Antibiotic prophylaxis significantly reduces infectious complications in patients undergoing implantation of pacemakers or cardioverter-defibrillators.

Efetividade do CDI na taquicardia ventricular sincopal e na parada cardíaca / ICD therapy efficacy is similar in cardiac arrest survivors and in patients with syncope due to ventricular tachycardia

Objetivo: Comparar o comportamento clínico-evolutivo de portadores de CDI por taquicardia ventricular (TV) sincopal ou parada cardíaca (PC) por TV/FV. Método: 585 pacientes foram submetidos a implante de CDI entre jan/2000 e jul/2005 para prevenção secundária de morte súbita cardíaca (MSC). Foram selecionados 415 pacientes de um banco de dados prospectivo, distribuídos em dois grupos: G1, com TV sincopal (n=318) e G2, com PC por TV/FV (n=97). As variáveis analisadas foram: idade, sexo, fração de ejeção do ventrículo esquerdo(FEVE), classe funcional de insuficiência cardíaca (CF IC), medicamentos, terapias de choque apropriadas (TCA) pelo CDI e óbitos. Para análise estatística...

Functional behavior of patients with conventional pacemakers undergoing cardiac resynchronization.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an efficient treatment for patients with heart failure (HF), severe ventricular dysfunction and intraventricular block. Conventional pacemakers (CPM) implanted in the right ventricular apical area cause alterations in the normal sequence of cardiac activation similar to those induced by LBBB (left bundle-branch block). Therefore, patients with CPM and advanced HF could be candidates to undergo CRT, but as only small numbers of patients have been evaluated so far, definitive conclusions are lacking. OBJECTIVE: To assess the clinical and functional outcome of cardiac resynchronization therapy (CRT) in patients with conventional pacemakers. METHODS: Patients with CPM, who were in NYHA HF functional class III/IV class refractory to drug therapy, and left ventricular ejection fraction (LVEF) ) <35% underwent CRT. Patients clinical-functional behavior was assessed prospectively six months after the procedure. The improvement of one HF-functional class was set as an effective response to the procedure. The following was assessed: QRS duration (ECG), diastolic diameter (LVDd), left ventricular systolic diameter (LVSd) and LVEF seen on the echocardiogram. For the statistical analysis, Students paired t test and Spearmans correlation were used. RESULTS: Twenty-nine patients (mean age 61.5) were evaluated. Of these, six were females, and chagasic cardiomyopathy was predominant. During the clinical follow-up of 22.7+/-13 months, 86.2% of the patients benefited from CRT. Within this group, the mean LVEF increased by 18% (p=0.013), QRS duration dropped by 11.8% (p=0.002) and no significant reduction in left ventricular intracavitary diameters was observed. CONCLUSION: CRT is effective for patients with CPM and advanced HF as it yields a high rate of response (86.2%), significantly improves LVEF and reduces QRS duration.

ICD patients with elevated defibrillation threshold: clinical behavior and therapeutic alternatives.

BACKGROUND: The ideal programming of the implantable cardioverter defibrillator (ICD) shock energy should be at least 10J above the defibrillation threshold (DFT), requiring alternative techniques when the DFT is elevated. OBJECTIVE: To assess the clinical behavior of ICD patients with DFT>25J and the efficacy of the chosen therapy. METHODS: Patients who had undergone ICD implantation between Jan/00 and Aug/04 (prospective database) and presented intraoperative DFT>25J were selected. The analyzed variables were: clinical characteristics, LVEF, rescue of arrhythmic events from ICD and causes of deaths. RESULTS: among 476 patients, 16 (3.36%) presented DFT>25J. The mean age was 56.5 years, and 13 patients (81%) were men. According to the baseline cardiomyopathy, 09 patients had Chagas' disease, 04 had ischemic cardiomyopathy and 03 had idiopathic cardiomyopathy. Mean LVEF was 0.37 and amiodarone was used by 94% of the patients. Mean follow-up (FU) period was 25.3 months. DFT was higher than maximum energy shock (MES) in 2 patients and it was necessary to implant an additional shock electrode (array). It was programmed MES in ventricular fibrillation zone of ICD therapy in the other patients. In the FU, 03 patients had 67 successful appropriate shock therapies (AST). There were 05 noncardiac and 02 heart failure deaths. The patients who died showed higher DFT levels (p=0.044) without correlation with death because there wasn't unsuccessful AST. CONCLUSION: In this cohort of ICD patients, the occurrence of elevated DFT (>25J) was low, leading to alternative therapies. There was an association with severe ventricular dysfunction, although without correlation to the causes of death.

Portadores de CDI com limiar de desfibrilação elevado: evolução clínica e alternativas terapêuticas / ICD patients with elevated defibrillation threshold: clinical behavior and therapeutic alternatives

FUNDAMENTO: A programação ideal da energia de choque do CDI deve ser pelo menos 10 J acima do limiar de desfibrilação (LDF), necessitando de técnicas alternativas quando o LDF é elevado. OBJETIVO: Avaliar o comportamento clínico dos portadores de CDI com LDF>25 J e a eficácia da terapêutica escolhida. MÉTODOS: Foram selecionados portadores de CDI, entre janeiro de 2000 e agosto de 2004 (banco de dados prospectivo), com LDF>25 J intra-operatório, e analisaram-se: características clínicas, FEVE, resgate de eventos arrítmicos pelo CDI e óbitos. RESULTADOS: dentre 476 pacientes, 16 (3,36 por cento) apresentaram LDF>25J. Idade média de 56,5 anos, sendo 13 pacientes (81 por cento) do sexo masculino. Quanto à cardiopatia de base 09 eram chagásicos, 04 isquêmicos e 03 com etiologia idiopática. A FEVE média dos pacientes foi 37 por cento e 94 por cento utilizavam amiodarona. O seguimento médio foi de 25,3 meses. Em 02 pacientes com LDF > Choque Máximo (CM), foi necessário implante de eletrodo de choque adicional (array), sendo mantido programação com CM em zona de FV (>182bpm) nos demais. Durante o seguimento 03 pacientes apresentaram 67 terapias de choque apropriadas (TCA) com sucesso. Ocorreram 07 óbitos sendo 5 por causas não cardíacas e 2 por insuficiência cardíaca avançada. Os pacientes que foram a óbito apresentaram níveis de LDF maiores (p=0,0446), entretanto sem relação com a causa dos mesmos tendo em vista que não ocorreram TCA sem sucesso. CONCLUSÃO: Nessa coorte de pacientes com CDI, a ocorrência de LDF elevado foi baixa, implicando terapêuticas alternativas. Houve associação com disfunção ventricular grave, entretanto sem correlação com as causas de óbito.

BACKGROUND: The ideal programming of the implantable cardioverter defibrillator (ICD) shock energy should be at least 10J above the defibrillation threshold (DFT), requiring alternative techniques when the DFT is elevated. OBJECTIVE: To assess the clinical behavior of ICD patients with DFT>25J and the efficacy of the chosen therapy. METHODS: Patients who had undergone ICD implantation between Jan/00 and Aug/04 (prospective database) and presented intraoperative DFT>25J were selected. The analyzed variables were: clinical characteristics, LVEF, rescue of arrhythmic events from ICD and causes of deaths. RESULTS: among 476 patients, 16 (3.36 percent) presented DFT>25J. The mean age was 56.5 years, and 13 patients (81 percent) were men. According to the baseline cardiomyopathy, 09 patients had Chagas' disease, 04 had ischemic cardiomyopathy and 03 had idiopathic cardiomyopathy. Mean LVEF was 0.37 and amiodarone was used by 94 percent of the patients. Mean follow-up (FU) period was 25.3 months. DFT was higher than maximum energy shock (MES) in 2 patients and it was necessary to implant an additional shock electrode (array). It was programmed MES in ventricular fibrillation zone of ICD therapy in the other patients. In the FU, 03 patients had 67 successful appropriate shock therapies (AST). There were 05 noncardiac and 02 heart failure deaths. The patients who died showed higher DFT levels (p=0.044) without correlation with death because there wasn't unsuccessful AST. CONCLUSION: In this cohort of ICD patients, the occurrence of elevated DFT (>25J) was low, leading to alternative therapies. There was an association with severe ventricular dysfunction, although without correlation to the causes of death.

Comportamento funcional dos portadores de marcapasso convencional submetidos a ressincronização cardíaca / Functional behavior of patients with conventional pacemakers undergoing cardiac resynchronization

FUNDAMENTO: A terapia de ressincronização cardíaca (TRC) é eficiente no tratamento de pacientes com insuficiência cardíaca (IC), disfunção ventricular grave e bloqueio intraventricular. O marcapasso convencional (MPC) em região apical de ventrículo direito provoca alterações da seqüência de ativação normal do coração semelhante às do BRE. Nesse sentido, pacientes com MPC e IC avançada poderiam ser candidatos a TRC, mas reduzidas casuísticas foram avaliadas e não há conclusões definitivas. OBJETIVO: Analisar o comportamento clínico-funcional da terapia de ressincronização cardíaca (TRC) nos portadores de marcapasso convencional. MÉTODOS: Pacientes com MPC, IC-CF(NYHA) III/IV refratária a terapêutica medicamentosa, fração de ejeção do ventrículo esquerdo (FEVE) <35 por cento, foram submetidos a TRC. O comportamento clínico-funcional foi avaliado prospectivamente após seis meses. A redução de uma CF-IC foi estabelecida como resposta efetiva ao procedimento. Foram analisados: duração do QRS (ECG), diâmetro diastólico (DDVE), diâmetro sistólico do ventrículo esquerdo (DSVE) e FEVE ao ECO. A análise estatística utilizou os testes t de Student pareado e a correlação de Spearman. RESULTADOS: Vinte e nove pacientes com idade média de 61,5 anos foram estudados. Seis eram do sexo feminino e houve predomínio da cardiomiopatia chagásica. Em seguimento clínico de 22,7±13 meses, 86,2 por cento dos pacientes melhoraram com a TRC. Nesse grupo, a FEVE média aumentou em 18 por cento (p=0,013); houve redução da duração do QRS em 11,8 por cento (p=0,002) e não houve redução significativa dos diâmetros intracavitários do ventrículo esquerdo. CONCLUSÃO: A TRC é efetiva para pacientes com MPC e IC avançada porque proporciona taxa elevada de responsivos (86,2 por cento), melhora significativa da FEVE e redução da duração do QRS.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an efficient treatment for patients with heart failure (HF), severe ventricular dysfunction and intraventricular block. Conventional pacemakers (CPM) implanted in the right ventricular apical area cause alterations in the normal sequence of cardiac activation similar to those induced by LBBB (left bundle-branch block). Therefore, patients with CPM and advanced HF could be candidates to undergo CRT, but as only small numbers of patients have been evaluated so far, definitive conclusions are lacking. OBJECTIVE: To assess the clinical and functional outcome of cardiac resynchronization therapy (CRT) in patients with conventional pacemakers. METHODS: Patients with CPM, who were in NYHA HF functional class III/IV class refractory to drug therapy, and left ventricular ejection fraction (LVEF) ) <35 percent underwent CRT. Patients’ clinical-functional behavior was assessed prospectively six months after the procedure. The improvement of one HF-functional class was set as an effective response to the procedure. The following was assessed: QRS duration (ECG), diastolic diameter (LVDd), left ventricular systolic diameter (LVSd) and LVEF seen on the echocardiogram. For the statistical analysis, Student’s paired t test and Spearman’s correlation were used. RESULTS: Twenty-nine patients (mean age 61.5) were evaluated. Of these, six were females, and chagasic cardiomyopathy was predominant. During the clinical follow-up of 22.7±13 months, 86.2 percent of the patients benefited from CRT. Within this group, the mean LVEF increased by 18 percent (p=0.013), QRS duration dropped by 11.8 percent (p=0.002) and no significant reduction in left ventricular intracavitary diameters was observed. CONCLUSION: CRT is effective for patients with CPM and advanced HF as it yields a high rate of response (86.2 percent), significantly improves LVEF and reduces QRS duration.