Aborted Sudden Death Due to Severe Ventricular Arrhythmia in Timothy Syndrome

Abstract Timothy Syndrome is a rare autosomal dominant multisystem genetic condition. The CACNA1C gene, codifier of the CaV1.2 calcium channel, is affected, resulting in the loss of voltage-dependent calcium channel inactivation. Relevant clinical characteristics: (1) corrected QT interval greater than 480ms; (2) syndactyly. Death often occurs during childhood, and results from ventricular tachyarrhythmias. This study presents the case of a female newborn who suffered a cardiorespiratory arrest, secondary to ventricular arrhythmia. A prolonged QT interval, combined with 2:1 AV block, was also identified, requiring a definitive cardiac pacemaker implant that, during inpatient care, developed pulmonary sepsis, followed by death.

Left Atrial Size Contribution to the Predictive Capacity of Two Scores for Atrial Fibrillation in the Postoperative Period of Cardiac Surgeries

Abstract Background: Postoperative atrial fibrillation (POAF) is a common complication associated with undesirable outcomes; hence, the provision of appropriate tools is important to help identify patients at risk. Objectives: To evaluate the predictive capacity of the CHADS2 and CHA2DS2-VASc scores, alone and combined with left atrial (LA) size, for the onset of POAF in patients undergoing coronary artery bypass grafting and/or valvular surgery. Methods: We performed a retrospective cohort study on 144 patients. A decision tree was used to identify the cut-off values of the CHADS2 and CHA2DS2-VASc scores and LA size in order to calculate sensitivity, specificity, predictive-value positive (PVP), and predictive-value negative (PVN), in addition to regression models. The receiver operating characteristic (ROC) curve was used to estimate the accuracy of the models. The level of significance adopted was 5%. Results: Patients who developed POAF were older (p = 0.050), had reduced left ventricular ejection fraction (p = 0.045), longer hospital length of stay (p = 0,018), but their mean CHADS2 (p = 0.077) and CHA2DS2-VASc (p = 0.109) scores were similar to those of patients with no arrhythmia. LA size improved the predictive capacity of the CHADS2 score, in terms of specificity and PVP, and of the CHA2DS2-VASc score, in terms of sensitivity and PVN. However, the CHADS2 (OR = 1.198; CI95% = 0.859-1.156) and CHA2DS2-VASc (OR = 1.047; CI95% = 0.784-1.401) scores were not predictors of POAF, either alone or in combination with LA size (OR = 1.163; CI95% = 0.829-1.648 and OR = 1.065; CI95% = 0.795-1.433). Conclusion: The CHADS2 and CHA2DS2-VASc scores alone or in combination with LA size did not show good predictive capacity for POAF.

Association between Microvolt T-Wave Alternans and Malignant Ventricular Arrhythmias in Chagas Disease / Associação entre Microalternância de Onda T e Arritmias Ventriculares Malignas na Doença de Chagas

Abstract Background: Sudden cardiac death is the most frequent death mechanism in Chagas disease, responsible for 55% to 65% of the deaths of patients with chronic Chagas cardiomyopathy (CCC). The most often involved electrophysiological mechanisms are ventricular tachycardia and ventricular fibrillation. The implantable cardioverter defibrillator (ICD) has a beneficial role in preventing sudden death due to malignant ventricular arrhythmias, and, thus the correct identification of patients at risk is required. The association of microvolt T-wave alternans (MTWA) with the appearance of ventricular arrhythmias has been assessed in different heart diseases. The role of MTWA is mostly unknown in patients with CCC. Objectives: To evaluate the association between MTWA and the occurrence of malignant ventricular arrhythmias in patients with CCC. Method: This is a case-control study including patients with CCC and ICD, with history of malignant ventricular arrhythmias (case group), and patients with CCC and no history of those arrhythmias (control group). The MTWA test results were classified as negative and non-negative (positive and indeterminate). The significance level adopted was a = 0.05. Results: We recruited 96 patients, 45 cases (46.8%) and 51 controls (53.1%). The MTWA test was non-negative in 36/45 cases (80%) and 15/51 controls (29.4%) [OR = 9.60 (95%CI: 3.41 - 27.93)]. After adjustment for known confounding factors in a logistic regression model, the non-negative result continued to be associated with malignant ventricular arrhythmias [OR = 5.17 (95%CI: 1.05 - 25.51)]. Conclusion: Patients with CCC and history of malignant ventricular arrhythmias more often have a non-negative MTWA test as compared to patients with no history of arrhythmia.

Resumo Fundamento: A morte súbita cardíaca é o mecanismo de morte mais comum na doença de Chagas, responsável pelo óbito de 55% a 65% dos pacientes com cardiomiopatia chagásica crônica (CCC). Os mecanismos mais frequentemente envolvidos são as taquiarritmias ventriculares. O cardioversor-desfibrilador implantável (CDI) apresenta impacto na redução da mortalidade por arritmias ventriculares e faz-se necessária a correta identificação de pacientes sob risco. A associação de microalternância de onda T (MTWA) com o aparecimento de arritmias ventriculares foi avaliada em diferentes cardiopatias através de um teste. O papel da MTWA na identificação de pacientes sob risco na CCC permanece incerto. Objetivo: Avaliar a associação entre MTWA e a ocorrência de arritmias ventriculares malignas na CCC. Método: Trata-se de um estudo caso-controle, que incluiu pacientes com CCC em uso de CDI, com história prévia de arritmias ventriculares malignas (casos) ou sem história prévia (controles). Os resultados do teste foram classificados em negativo e não negativo (positivo e indeterminado). O nível de significância foi a = 0,05. Resultado: Foram recrutados 96 pacientes, 45 no grupo caso (46,8%) e 51 no grupo controle (53,1%). O teste de MTWA apresentou resultado não negativo em 36/45 pacientes no grupo caso (80%) e 15/51 no grupo controle (29,4%), OR = 9,60 (IC95%: 3,41 - 27,93). Após ajuste para fatores de confusão num modelo de regressão logística, o resultado não negativo continuou associado à presença de arritmias ventriculares malignas, com OR = 5,17 (IC95%: 1,05 - 25,51). Conclusão: Na CCC, pacientes com história de arritmia ventricular maligna apresentam maior frequência de teste de MTWA não negativo quando comparados a pacientes sem ocorrência prévia de arritmias.