Electrophysiological study in chagasics with syncope and conduction disorder

BACKGROUND

Investigation of syncope involves the use of electrophysiological study, particularly in patients with cardiac conduction disorder. There is conflicting evidence about the role of electrophysiological study in patients with Chagas disease.

OBJECTIVE

The objective of this study was to evaluate the electrophysiological study findings in patients with Chagas disease and bundle branch block and/or divisional block presenting with syncope.

METHODS

This is a retrospective study of patients with Chagas disease and cardiac conduction disorder who underwent electrophysiological study from 2017 to 2021 for the investigation of syncope in a tertiary hospital in São Paulo, Brazil. Those with non-interpretable ECG, known coronary artery disease, and/or other cardiomyopathies were excluded. HV interval and electrophysiological study-induced malignant ventricular arrhythmias data were analyzed.

RESULTS

A total of 45 patients (60.2±11.29 years, 57.8% males) were included. The mean HV interval was 58.37 ms±10.68; 22.2% of the studied population presented an HV interval of ≥70 ms; and malignant ventricular arrhythmias were induced in 57.8% patients. The use of beta-blockers and amiodarone (p=0.002 and 0.036, respectively), NYHA functional class≥II (p=0.013), wide QRS (p=0.047), increased HV interval (p=0.02), Rassi score >6.5 (p=0.003), and reduced left ventricular ejection fraction (p=0.031) were associated with increased risk of inducible malignant ventricular arrhythmias.

CONCLUSION

More than half of the patients with Chagas disease, syncope, and cardiac conduction disorder have inducible malignant ventricular arrhythmias. Prolonged HV interval was observed in only 20% of population. Wide QRS, prolonged HV, reduced ejection fraction, and higher Rassi score were associated with increased risk of malignant ventricular arrhythmias.

CHA2DS2-VASc score, P-wave indexes, and echocardiographic parameters in sinus rhythm patients without valvular heart disease

OBJECTIVE

The aim of this study was to evaluate the correlation between P-wave indexes, echocardiographic parameters, and CHA2DS2-VASc score in patients without atrial fibrillation and valvular disease.

METHODS

This retrospective cross-sectional study included patients of a tertiary hospital with no history of atrial fibrillation, atrial flutter, or valve disease and collected data from June 2021 to May 2022. The exclusion criteria were as follows: unavailable medical records, pacemaker carriers, absence of echocardiogram report, or uninterpretable ECG. Clinical, electrocardiographic [i.e., P-wave duration, amplitude, dispersion, variability, maximum, minimum, and P-wave voltage in lead I, Morris index, PR interval, P/PR ratio, and P-wave peak time], and echocardiographic data [i.e., left atrium and left ventricle size, left ventricle ejection fraction, left ventricle mass, and left ventricle indexed mass] from 272 patients were analyzed.

RESULTS

PR interval (RHO=0.13, p=0.032), left atrium (RHO=0.301, p<0.001) and left ventricle diameter (RHO=0.197, p=0.001), left ventricle mass (RHO=0.261, p<0.001), and left ventricle indexed mass (RHO=0.340, p<0.001) were positively associated with CHA2DS2-VASc score, whereas P-wave amplitude (RHO=-0.141, p=0.02), P-wave voltage in lead I (RHO=-0.191, p=0.002), and left ventricle ejection fraction (RHO=-0.344, p<0.001) were negatively associated with the same score. The presence of the Morris index was associated with high CHA2DS2-VASc (p=0.022).

CONCLUSION

Prolonged PR interval, Morris index, increased left atrium diameter, left ventricle diameter, left ventricle mass, and left ventricle indexed mass values as well as lower P-wave amplitude, P-wave voltage in lead I, and left ventricle ejection fraction values were correlated with higher CHA2DS2-VASc scores.

Influence of antidepressant drugs on DNA methylation of ion channels genes in blood cells of psychiatric patients

Aim: This study investigated the influence of antidepressant drugs on methylation status of KCNE1, KCNH2 and SCN5A promoters and ECG parameters in adult psychiatric patients. Materials & methods: Electrocardiographic evaluation (24 h) and blood samples were obtained from 34 psychiatric patients before and after 30 days of antidepressant therapy. Methylation of promoter CpG sites of KCNE1, KCNH2 and SCN5A was analyzed by pyrosequencing. Results: Three CpG and four CpG sites of KCNE1 and SCN5A, respectively, had increased % methylation after treatment. Principal component analysis showed correlations of the methylation status with electrocardiographic variables, antidepressant doses and patient age. Conclusion: Short-term treatment with antidepressant drugs increase DNA methylation in KCNE1 and SCN5A promoters, which may induce ECG alterations in psychiatric patients.

Association between HV interval and electrocardiographic findings in individuals with syncope and left bundle branch block

Funding Acknowledgements

Type of funding sources: None.

Introduction

The occurrence of syncope is associated with increased mortality in patients with left bundle branch block (LBBB). Among syncope risk scores, it is consensual that electrocardiographic (ECG) abnormalities and the presence of underlying cardiac disease are prominent factors. However, there is no further investigation directed towards this population and there is few that could add to clinical judgement in such cases, until electrophysiological study (EPS) is performed. The method’s modest sensitivity limits its practical usage in spite of current literature recommendation. Therefore, identifying those patients more prone to serious events is of clinical significance.

Objectives and methods

This was a cross-sectional study of patients with syncope and LBBB undergoing EP study in a tertiary hospital, which aimed to assess the relation between ECG parameters and prolonged HV interval on EPS.

Results

Ninety-four consecutive patients were eligible for the final analysis. Mean age was 63.1 ± 11.9 years (68.1% male). As for main comorbidities, the prevalence of smoking was 39.3%, hypertension 84%, diabetes mellitus 29.7%, coronary artery disease 28.7% and reduced left ventricle ejection fraction (LVEF) (≤ 40%) 48.9%. In the univariable analysis, LVEF ≤ 40% appeared to be somewhat important but this was not confirmed upon logistic regression. QRS duration ≥ 165 ms (OR 7.79; p = 0.0005) and PR interval ≥ 220 ms (OR 7.10; p = 0.003) were independent predictors for HV interval ≥ 70 ms. For each 10 ms increase in QRS and PR duration, the odds of HV interval ≥ 70 ms enhanced by 39.8% and 27.1%, respectively. For the subgroup presented with such outcome, mean QRS was 170.88 ± 26.81 ms, significantly larger than the patients with HV interval &lt; 70 ms. When combined, QRS ≥ 165 ms and PR interval ≥ 220 ms had an accuracy of 80% to predict an HV interval ≥ 70 ms in the EPS. Other analyzed data were not systematically associated with the evaluated outcome.

Conclusion

In patients with syncope and LBBB, prolonged QRS and PR interval were independent predictors of increased HV interval on EP study. Larger studies are needed to confirm these findings.

Association of variants in MYH7, MYBPC3 and TNNT2 with sudden cardiac death-related risk factors in Brazilian patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterized by unexplained left ventricular hypertrophy (LVH) and is one of the major causes of sudden cardiac death (SCD). An exon-targeted gene sequencing strategy was used to investigate the association of functional variants in sarcomeric genes (MYBPC3, MYH7 and TNNT2) with severe LVH and other SCD-related risk factors in Brazilian HCM patients. Clinical data of 55 HCM patients attending a Cardiology Hospital (Sao Paulo city, Brazil) were recorded. Severe LVH, aborted SCD, family history of SCD, syncope, non-sustained ventricular tachycardia and abnormal blood pressure in response to exercise were evaluated as SCD risk factors. Blood samples were obtained for genomic DNA extraction and the exons and untranslated regions of the MYH7, MYBPC3 and TNNT2 were sequenced using Nextera® and MiSEq® reagents. Variants were identified and annotated using in silico tools, and further classified as pathogenic or benign according to the American College of Medical Genetics and Genomics guidelines. Variants with functional effects were identified in MYBPC3 (n = 9), MYH7 (n = 6) and TNNT2 (n = 4). The benign variants MYBPC3 p.Val158Met and TNNT2 p.Lys263Arg were associated with severe LVH (p < 0.05), and the MYH7 p.Val320Met (pathogenic) was associated with family history of SCD (p = 0.037). Increased risk for severe LVH was found in carriers of MYBPC3 Met158 (c.472 A allele, OR = 13.5, 95% CI = 1.80-101.12, p = 0.011) or combined variants (MYBPC3, MYH7 and TNNT2: OR = 12.39, 95% CI = 2.14-60.39, p = 0.004). Carriers of TNNT2 p.Lys263Arg and combined variants had higher values of septum thickness than non-carriers (p < 0.05). Molecular modeling analysis showed that MYBPC3 158Met reduces the interaction of cardiac myosin-binding protein C (cMyBP-C) RASK domain (amino acids Arg215-Ala216-Ser217-Lys218) with tropomyosin. In conclusion, the variants MYBPC3 p.Val158Met, TNNT2 p.Lys263Arg and MYH7 p.Val320Met individually or combined contribute to the risk of sudden cardiac death and other outcomes of hypertrophic cardiomyopathy.

Home-based training program in patients with chronic heart failure and reduced ejection fraction: a randomized pilot study

OBJECTIVES

We aimed to compare the effects of home-and center-based exercise training programs on functional capacity, inspiratory muscle strength, daily physical activity level, and quality of life (QoL) in patients with chronic heart failure (CHF) over a 12-week period.

METHODS

This study included 23 patients with CHF (left ventricular ejection fraction 31±6%) randomized to a home-based (n=11) or center-based (n=12) program. Patients underwent 12 weeks of aerobic training (60%-70% heart rate reserve): walking for the home-based and supervised cycling for the center-based group, both combined with resistance training (50% of 1 maximum repetition). At baseline and after 12 weeks of training, we assessed cardiopulmonary test variables, 6-min walk test distance (6 MWD), steps/day with accelerometry, and QoL (Minnesota Living with Heart Failure questionnaire). Maximal inspiratory pressure and handgrip strength were measured at baseline and after 4, 8, and 12 weeks of training. ClinicalTrials.gov: NCT03615157.

RESULTS

There were no adverse events during training in either group. The home- and center-based training groups obtained similar improvements in peak oxygen uptake, maximal ventilation, and 6 MWD. However, there were significant between-group differences: center-based training was more effective in improving maximal inspiratory pressure (p=0.042), number of steps/day (p=0.001), and QoL (p=0.039).

CONCLUSIONS

Home-based training is safe and can be an alternative to improve the exercise capacity of patients with stable CHF. However, center-based training was superior in improving inspiratory muscle strength, QoL, and daily physical activity.

Analysis of Circulating miR-1, miR-23a, and miR-26a in Atrial Fibrillation Patients Undergoing Coronary Bypass Artery Grafting Surgery

Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery. From a pathophysiological point of view, a myriad of factors such as trauma, atrial dilation, ischemia, mechanical myopericarditis, autonomic imbalance, loss of connexins, AF nest remodeling, inflammation, sutures, and dysfunction caused by postextracorporeal circulation can contribute to postoperative atrial fibrillation (POAF) resulting in a longer hospital stay and consequently higher cost. Recent studies showed that short fragments of RNA, called microRNA (miRNA), can contribute to the development of several cardiovascular diseases, including AF. The aim of this study was to evaluate the levels of circulating miRNAs (miR-1, -23a, and -26a) that can be involved in POAF. Patients submitted to coronary artery bypass graft surgery were grouped in POAF (24 patients) and without POAF (24 patients). Results showed older age, longer clamp-time, and more days in the intensive care unit as well as a longer total hospital stay in the POAF group. Preoperative levels of circulating miRNAs were similar. Analysis of miRNAs revealed significantly lower circulating levels of miRNA-23a (P  =  0.02) and -26a (P  =  0.01) in the POAF group during the postoperative period. Receiver operating characteristic (ROC) analysis showed the area under the ROC curve of miR-23a and miR-26a for predicting FA was 0.63 (95% confidence interval [CI]: 0.51-0.74; P  =  0.02) and 0.66 (95% CI: 0.55-0.77; P  =  0.01), respectively. Our data suggests that circulating miRNA-23a and -26a may be involved in the underlying biology of postoperative AF development.

Recommendations of the Brazilian Society of Cardiac Arrhythmias for holter monitoring services

Background

There are innumerous indicators to assure the quality of a service. However, medical competence and the proper performance of a procedure determine its final quality. The Brazilian Society of Cardiac Arrhythmias recommends minimum parameters necessary to guarantee the excellence of ambulatory electrocardiographic monitoring services.

Objective

To recommend minimum medical competences and the information required to issue a Holter monitoring report.

Methods

This study was grounded in the concept of evidence-based medicine and, when evidence was not available, the opinion of a writing committee was used to formulate the recommendation. That committee consisted of professionals with experience on the difficulties of the method and management in providing services in that area.

Results

The professional responsible for the Holter monitoring analysis should know cardiovascular pathologies and have consistent formation on electrocardiography, including cardiac arrhythmias and their differential diagnoses. The report should be written in a clear and objective way. The minimum parameters that comprise a Holter report should include statistics of the exam, as well as quantification and analysis of the rhythm disorders observed during monitoring.

Conclusion

Ambulatory electrocardiographic monitoring should be performed by professionals knowledgeable about electrocardiographic analysis, whose report should comprise the minimum parameters mentioned in this document.

Electrophysiological characteristics of Chagas disease

Objective:

Chagas disease has become a global problem due to changing migration patterns. An electrophysiological study is generally indicated for assessing sinus node function, conduction through the atrioventricular node and His-Purkinje system, in addition to evaluating the mechanisms of arrhythmia. The aim of this study was to describe the characteristics of electrophysiological study findings in patients with Chagas disease.

Methods:

A retrospective descriptive study of 115 consecutive patients with Chagas disease undergoing an electrophysiological study over the last three years in a tertiary hospital in Brazil. Baseline characteristics, electrocardiogram, echocardiogram, and 24-hour Holter monitoring findings were recorded and correlated with the electrophysiological study findings.

Results:

The corrected sinus node recovery time and sinoatrial conduction time were abnormal in 6.9% and 26.1% of patients, respectively. Thirty-seven (32.2%) had abnormal atrioventricular conduction. Intraventricular conduction was abnormal in 39 (33.9%). Approximately 48% had induced sustained ventricular arrhythmias, most of which were monomorphic (83.6%). Right bundle branch block was the most common morphology (52.7%). Fifty-one percent were associated with symptoms/hemodynamic instability, 60% required electrical cardioversion, and 27.3% needed overdrive suppression. The most common site of origin was the left ventricular inferoseptal wall (18.2%), followed by the left ventricular posterobasal wall (11%). Patients with an ejection fraction<40% had a 1.94-fold increased risk of ventricular arrhythmias compared to those with an ejection fraction>60% (OR: 1.94; 95%CI: 1.12-3.38; p=0.01). The presence of complex ventricular arrhythmias on Holter did not predict inducible ventricular arrhythmias.

Conclusions:

Chagas patients with a low ejection fraction have an increased risk of inducible ventricular arrhythmias. Sinus node dysfunction, and atrioventricular node and His-Purkinje conduction abnormalities occur in about one-third of patients. Complex ventricular arrhythmias on Holter were not associated with an increased risk of inducible ventricular arrhythmias.

Tratamento da Fibrilação Atrial na Sala de emergência/ Management of Atrial Fibrilllation in the Emergency Room

A fibrilação atrial motiva a ida do paciente ao pronto socorro devido a sintomatologia que provoca. Palpitações, cansaço repentino, incapacidade de realizar esforços habituais são queixas frequentes. A incidência desta arritmia aumenta com a idade e, por esta razão, a maioria dos indivíduos que procura as emergências em hospital corresponde àqueles de idade avançada. A conduta com o paciente na sala de emergência depende da forma de apresentação clínica, da sintomatologia, da duração da arritmia e do risco de tromboembolismo sistêmico. Em pacientes com instabilidade hemodinâmica a cardioversão elétrica é mandatória para restabelecer o ritmo sinusal normal e estabilizar as condições clínicas. No paciente com fibrilação atrial sem repercussão hemodinâmica, apenas com sintomas leves a moderados, a conduta vai desde o controle da frequência ventricular, até a cardioversão química ou elétrica eletivas. A conduta a ser tomada deverá ser individualizada para oferecer a melhor opção terapêutica ao paciente. Os pacientes com fibrilação atrial paroxística têm grande possibilidade de ter a arritmia interrompida espontaneamente e, por esta razão uma conduta expectante pode ser suficiente em alguns casos. A grande dificuldade está nos pacientes com a forma permanente. A não ser que já estejam em uso de anticoagulantes, quando a reversão poderá ser tentada, aqueles que não fazem uso desta classe de fármacos deverão ser criteriosamente avaliados quanto ao risco de tromboembolismo sistêmico. Se a arritmia dura menos que 48 h a reversão poderá ser considerada. Caso o paciente tenha fatores de risco para tromboembolismo ou a fibrilação atrial tenha duração maior que 48 h ou for desconhecida é fundamental que se implemente a anticoagulação preventiva e a cardioversão será realizada em outra ocasião quando a taxa do RNI estiver entre 2 e 3. Nos pacientes com a forma permanente da fibrilação atrial, resta apenas o controle da resposta ventricular e a utilização de anticoagulantes naqueles de alto risco para formação de trombos. O  papel do ecocardiograma transesofágico para a cardioversão da fibrilação atrial sem anticoagulação prévia é controverso e não deve ser utilizado no sala de emergência rotineiramente para guiar a decisão clínica.Management of Atrial Fibrilllation in the Emergency RoomPatients with atrial fibrillation (AF) go to the emergency room because they are frequently symptomatic. Palpitations, shortness of breath and a sudden feeling of inability to perform regular activities are the most common complaints. The incidence of AF increases with age and are exactly the old people who most come to the hospital with AF. The approach to the patient with AF depends on several aspects including how the arrhythmia appears, how much it lasts and also the risks of peripheral thromboembolism. Patients with hemodynamic instability need urgent electrical cardioversion to reestablish normal clinical conditions. Other patients with only mild to moderate symptoms, the approach includes heart rate control, electrical or chemical cardioversion and, in patients with high risk for thromboembolism, anticoagulation has to be implemented if there is no contraindication. In patients with paroxysmal AF, the conservative approach can be considered because there is a great chance for spontaneous reversion. On the contrary, chemical (with propafenone or amiodarone) or electrical cardioversion, with or without anticoagulation, depending on arrhythmia duration and risk factor for thrombus formation, can be planned. Patients with the permanent form of AF bring the greatest difficulty regarding arrhythmia treatment. If the patient is already taking oral anticoagulants, or the arrhythmia duration is less them 48 h and there is no risk for thromboembolism, chemical or electrical cardioversion can be promptly done when the patient come do the emergency suit. Otherwise,  these patients have to be evaluated regarding thromboembolic risks and warfarin started when appropriately indicated. In these cases, only rate control is done and cardioversion has to be postponed and planned for the next three to four weeks when the INR is in the therapeutic range (between 2 and 3). Finally, for patients with the permanent form of AF, only rate control ad eventually anticoagulation with warfarin will be indicated. The role of transesophageal echocardiogram for cardioversion without anticoagulation is controversial and cannot be routinely indicated and performed to guide cardioversion without anticoagulation.