Conduction system pacing: how far are we from the "electrical" bypass?

Conduction system pacing is an alternative practice to conventional right ventricular apical pacing. It is a method that maintains physiologic ventricular activation, based on a correct pathophysiological basis, in which the pacing lead bypasses the lesion of the electrical fibers and the electrical impulse transmits through the intact adjacent conduction system. For this reason, it might be reasonably characterized by the term "electrical bypass" compared to the coronary artery bypass in revascularization therapy. In this review, reference is made to the sequence of events in which conventional right ventricular pacing may cause adverse outcomes. Furthermore, there is a reference to alternative strategies and pacing sites. Interest focuses on the modalities for which there are data from the literature, namely for the right ventricular (RV) septal pacing, the His bundle pacing (HBP), and the left bundle branch pacing (LBBP). A more extensive reference is about the HBP, for which there are the most updated data. We analyze the considerations that limit HBP-wide application in three axes, and we also present the data for the implantation and follow-up of these patients. The indications with their most important studies to date are then described in detail, not only in their undoubtedly positive findings but also in their weak aspects, because of which this pacing mode has not yet received a strong recommendation for implementation. Finally, there is a report on LBBP, focusing mainly on its points of differentiation from HBP.

Two Cases of Acute Myocarditis in Young Male Adults After mRNA Vaccines Against COVID-19: Similarities and Differences.

Background: The advent of the new coronavirus SARS-CoV-2 has created unprecedented situations, both in terms of health and socio-economic level, worldwide. The emergence of vaccines against this highly contagious virus has raised hopes for its effective inhibition. The efficacy of vaccines, in more than a year of their application in clinical practice, is indisputable, both in terms of reducing serious hospitalizations and deaths, especially in high-risk populations. As with any new medication, the quest and investigation for side effects are reasonable. Myocarditis is one of the extremely rare side effects reported in mRNA vaccines, especially in young males. Case presentation: We present two cases of myocarditis that occurred in our hospital in a short time between them and compare them point by point to identify similarities and differences in order to draw conclusions about the severity of this side effect and its outcome. Conclusion: The benefits of vaccination against Covid-19 outweigh possible untoward effects and especially myocarditis. Health workers must close monitor the vaccinated patients for possible future cardiovascular complications.

Spontaneous Dissection of the Coronary Vessels. Epidemiological and Coronary Angiographic Study.

INTRODUCTION: Spontaneous dissection of the coronary arteries is relatively rare and usually does not affect life expectancy. However specific types have been implicated to episodes of sudden cardiac death and myocardial ischemia. The recognition of both clinical and imaging characteristics contributes to appropriate decision and patient management. AIM: The aim of the study is the epidemiological and Coronary Angiographic (CA) estimation of patients with spontaneous dissection of the coronary arteries, who were hospitalized in the cardiology department with Acute Coronary Syndrome or were submitted to coronary angiographic examination in the laboratory. MATERIAL AND METHODS: The epidemiological, clinical and angiographic data of 31 patients who were hospitalized in our department and suffered from spontaneous dissection of the coronary vessels were studied retrospectively. RESULTS: In 31 patients (11 men and 20 women, mean age 52.8+18.6 years) who were hospitalized for acute coronary syndrome (ACS), spontaneous dissection of coronary arteries was detected. Precipitating factors were hypertension in 12 patients (38.71%), dyslipidemia in 13 patients (42%) and smoking in 17 patients (54.84%). Among the women, 13 (65%) had a history of hypertension in pregnancy, preeclampsia or/and gestational diabetes. In 8 patients, the coronary angiography showed multivessel disease, while in 12 patients there were no significant lesions in the coronary vessels. Fourteen women (70%) reported a history of depression compared to none in men. CONCLUSION: The incidence of spontaneous dissection of the coronary vessels in this sample of patients from northern Greece is similar to that of the other centers. The incidence is greater in females with hormonal changes and depression. In a large number there were no significant atherosclerotic lesions.

The Mean Platelet Volume in the Prognosis of Coronary Artery Disease Severity and Risk Stratification of Acute Coronary Syndromes.

INTRODUCTION: Platelets play a crucial role in thrombotic episodes. Mean Platelet Volume (MPV) is the primary indicator of platelet's activation; its measurement is easy and time-effective. AIM: We tested the hypothesis that MPV is correlated with SYNTAX score in patients that suffered from an Acute Coronary Syndrome (ACS). MATERIAL AND METHODS: One hundred and four (104) patients (79 male-25 female, mean age 64.2±11.1 years), who were hospitalized for an ACS and underwent coronary angiography, were included in the study. Syntax score, as an indicator of the severity of coronary artery disease (CAD), was calculated. We tried to investigate the correlation between the first measured MPV, CRP, Creatinine and high sensitivity Troponin with the Syntax score of the patient and the association of MPV and a possible Major Advanced Cardiac Event (MACE) during hospitalization. RESULTS: The patients were divided into four groups according to the SYNTAX score: Group A (SYNTAX score: 0, n=12), group B: Mild CAD (SYNTAX score: 1-22, n=68), group C: Moderate CAD (SYNTAX score: 23-32, n=12), and group D: Severe CAD (SYNTAX score: ≥ 33, n=12). Four patients (3.8%) developed a MACE during their hospitalization. MPV was significantly correlated to Syntax score (r=0.658, p<0.001) and was found to be an independent predictor factor of MACE with HR=6.8 (95% Confidence Interval 1.46-33.36). The cut-off value of MPV was 7.5 with a sensitivity of 98% and a specificity of 30.8%. CONCLUSION: We determined a positive correlation between MPV and Syntax score, transforming this simple test in a possible factor of risk stratification in ACS.

The Importance of the 15-lead Versus 12-lead ECG Recordings in the Diagnosis and Treatment of Right Ventricle and Left Ventricle Posterior and Lateral Wall Acute Myocardial Infarctions.

INTRODUCTION: The 12-lead ECG at admission of patients suffering from acute myocardial infarction (AMI) is mandatory for accurate diagnosis and prompt therapeutic measures, mainly reperfusion. It has been shown that recording additional ECG leads may improve the diagnostic accuracy and therefore, the prognosis of selected cases. AIM: The aim of the study was to assess the usefulness of the 15-lead ECG (12 classic plus 3 posterior leads) in the management of chest pain patients, especially when 12-lead ECG is not diagnostic of AMI. METHODS: Total amount of 186 consecutive patients (127 men, 59 women, mean age 69.7±13.8 years) were admitted with an acute coronary syndrome. The initial ECG recorded the 12 classic leads, and subsequently, the 3 additional posterior leads. Demographic and clinical data, including ECG alterations and selected treatment strategy, were also studied. The cumulative impact of the 15-lead ECG on the diagnosis and management of AMI were, overall, evaluated. RESULTS: The 12-lead ECG was diagnostic of ST-elevation AMI (STEMI) in 158 patients (Group A-84.5%) who were promptly reperfused. On the other hand, the interpretation of the posterior leads was required in 28 patients (Group B-15.1%) to establish the STEMI diagnosis warranting reperfusion therapy. Multivariate analysis illustrated that the 15-lead ECG was the only factor associated with achieving the STEMI diagnosis in non-conclusive 12-lead ECG cases (OR=2.43-p=0.04). CONCLUSION: The use of the 15-lead ECG contributes to a faster and more accurate diagnosis of STEMI, particularly in the Emergency Department, facilitating the prompt reperfusion therapy.