Background-Autonomic denervation is an alternative approach for patients with symptomatic bradycardia. No consensus exists on the critical targets and end points of the procedure. The aim of this study was to identify immediate end points and critical atrial regions responsible for vagal denervation. Methods and Results-We enrolled 14 patients (50% men; age: 34.0±13.8 years) with cardioinhibitory syncope, advanced atrioventricular block or sinus arrest, and no structural heart disease. Anatomic mapping of ganglionated plexuses was performed, followed by radiofrequency ablation. Heart rate, sinus node recovery time, Wenckebach cycle length, and atrial-His (AH) interval were measured before and after every radiofrequency pulse. Wilcoxon signed-rank test was used for comparison. Significant shortening of the R-R interval (P=0.0009), Wenckebach cycle length (P=0.0009), and AH intervals (P=0.0014) was observed after ablation. The heart rate elevation was 23.8±12.5%, and the Wenckebach cycle length and AH interval shortening was 18.1±11% and 24.6±19%, respectively. Atropine bolus injection (0.04 mg/kg) did not increase heart rate further. Targeting a single spot of the left side (64% of the patients) or right side (36%) of the interatrial septum was observed to be responsible for ≥80% of the final R-R and AH interval shortening during ablation. Conclusions-Targeting specific sites of the interatrial septum is followed by an increase in heart rate and atrioventricular nodal conduction properties and might be critical for vagal attenuation. The R-R interval, Wenckebach cycle length, and AH interval shortening, associated with a negative response to atropine, could be considered immediate end points of the procedure.

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AimAcute and subacute cardiotoxicity are characterized by prolongation of the corrected QT interval (QTc) and other measures derived from the QTc interval, such as QTc dispersion (QTdc) and transmural dispersion of repolarization (DTpTe). Although anthracyclines prolong the QTc interval, it is unclear whether breast cancer patients who undergo the ACT chemotherapy regimen of anthracycline (doxorubicin: A), cyclophosphamide (C) and taxane (T) may present with QTc, QTdc and DTpTe prolongation.MethodsTwenty-three consecutive patients with breast cancer were followed prospectively during ACT chemotherapy and were analyzed according to their QT measurements. QTc, QTdc and DTpTe measurements were determined by a 12-lead electrocardiogram (EKG) prior to chemotherapy (baseline), immediately after the first phase of anthracycline and cyclophosphamide (AC) treatment, and immediately after T treatment. Serum troponin and B-type natriuretic peptide (BNP) levels were also measured.ResultsCompared to baseline values, the QTc interval was significantly prolonged after the AC phase (439.7 ± 33.2 ms vs. 472.5 ± 36.3 ms, p = 0.001) and after T treatment (439.7 ± 33.2 ms vs. 467.9 ± 42.6 ms, p < 0.001). Troponin levels were elevated after the AC phase (23.0 pg/mL [min-max: 6.0–85.0] vs. 6.0 pg/mL [min-max: 6.0–22.0], p < 0.001) and after T treatment (25.0 pg/mL [min-max: 6.0–80.0] vs. 6.0 pg/mL [min-max: 6.0–22.0], p < 0.001) compared to baseline values.ConclusionIn this prospective study of patients with non-metastatic breast cancer who underwent ACT chemotherapy, significant QTc prolongation and an elevation in serum troponin levels were observed.

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Fundamento: No tratamento da fibrilação atrial (FA), a arritmia sustentada mais frequente, com ablação por cateter (ABL) ou cardioversão elétrica (CVE), o período periprocedimento é uma das fases mais críticas. Atualmente, o uso de novos anticoagulantes orais de ação direta (DOAC) é cada vez mais frequente, no entanto, no mundo real, ainda existem poucos dados de estudos sobre a incidência de trombo no átrio esquerdo (TrAE) ou contraste espontâneo denso (CE) no ecocardiograma transesofágico (ETE). Objetivo: Analisar a prevalência de TrAE, por ETE, em pacientes em uso de DOAC submetidos à CVE/ABL. Secundariamente: avaliar a associação de comorbidades com a presença de trombos e CE. Métodos: Estudo de coorte retrospectivo, unicêntrico, com pacientes do Ambulatório de Arritmia (InCor-HCFMUSP). Foram selecionados e analisados dados clínicos e ecocardiográficos no prontuário da instituição de pacientes com indicação de procedimentos e em uso de DOACs. Considerado um nível de significância de 5%. Resultados: Foram incluídos 354 pacientes, no total de 400 procedimentos, de março de 2012-março de 2018. TrAE foi encontrado em 11 pacientes (2,8%), associado com idade avançada (p=0,007) e CHA2DS2-VASc maior (p<0,001). Foi encontrado CE no AE no procedimento antes da ETE em 29 pacientes (7,3%), com menor FEVE (p <0,038) e maior dimensão do AE (p <0,0001). Conclusão: A incidência de TrAE e CE em pacientes em uso de DOAC no contexto de CVE/ABL de FA, embora pequena, não é desprezível. Pacientes com escore CHA2DS2-VASc maior, principalmente mais idosos e com diâmetro do AE maior, são mais propensos a esses achados ecocardiográficos.

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BackgroundBrugada syndrome and long‐QT syndrome may account for at least one third of unexplained sudden cardiac deaths. Dental care in patients with cardiac channelopathies is challenging because of the potential risk of life‐threatening events. We hypothesized that the use of local dental anesthesia with lidocaine with and without epinephrine is safe and does not result in life‐threatening arrhythmias in patients with channelopathies.Methods and ResultsWe performed a randomized, double‐blind pilot trial comparing the use of 2% lidocaine without a vasoconstrictor and with 1:100 000 epinephrine in 2 sessions of restorative dental treatment with a washout period of 7 days (crossover trial). Twenty‐eight–hour Holter monitoring was performed, and 12‐lead electrocardiography, digital sphygmomanometry, and anxiety scale assessments were also conducted at 3 time points. Fifty‐six dental procedures were performed in 28 patients (18 women, 10 men) with cardiac channelopathies: 16 (57.1%) had long‐QT syndrome, and 12 (42.9%) had Brugada syndrome; 11 (39.3%) of patients had an implantable defibrillator. The mean age was 45.9±15.9 years. The maximum heart rate increased after the use of epinephrine during the anesthesia period from 82.1 to 85.8 beats per minute (P=0.008). In patients with long‐QT syndrome, the median corrected QT was higher, from 450.1 to 465.4 ms (P=0.009) at the end of anesthesia in patients in whom epinephrine was used. The other measurements showed no statistically significant differences. No life‐threatening arrhythmias occurred during dental treatment.ConclusionsThe use of local dental anesthesia with lidocaine, regardless of the use of a vasoconstrictor, did not result in life‐threatening arrhythmias and appears to be safe in stable patients with cardiac channelopathies.Clinical Trial RegistrationURL: http://www.clinicaltrials.gov. Unique identifier: NCT03182777.

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