Congenial short QT syndrome: A review focused on electrocardiographic features

Congenital short QT syndrome is a very low prevalence inherited primary arrhythmia syndrome first reported in 2000 by Gussak et al., who described two families with a short QT interval, syncope, and sudden cardiac death. In 2004, Ramon Brugada et al. identified the first genetic type of this entity. To date, a total of nine genotypes have been described. The diagnosis is easy from the electrocardiogram (ECG), not only due to the short QT duration, but also based on other aspects covered in this review. During 24-h Holter monitoring, paroxysmal atrial fibrillation spontaneously converting to sinus rhythm may be found. Even though the T wave may appear symmetric on the ECG, the T loop of the vectorcardiogram confirms that the T wave is constantly asymmetric due to the presence of dashes closer to each other in the efferent branch. In this review, we also describe the minus-plus T wave sign that we have described in a previously published article. In addition to congenital causes, we briefly highlight the existence of numerous acquired causes of short QT interval.

ISE/ISHNE Expert Consensus Statement on ECG Diagnosis of Left Ventricular Hypertrophy: The Change of the Paradigm. The joint paper of the International Society of Electrocardiology and the International Society for Holter Monitoring and Noninvasive Electrocardiology

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria, i.e. the increased QRS complex amplitude in defined leads. The classical ECG diagnostic paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces. These increased forces are reflected in the augmented QRS amplitude in the corresponding leads. However, the clinical observations document increased QRS amplitude only in the minority of patients with LVH. The low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm.

Left septal fascicular block: Evidence, causes, and diagnostic criteria

The existence of a tetrafascicular intraventricular conduction system is widely accepted by researchers. In this review, we have updated the criteria for left septal fascicular block (LSFB) and the differential diagnosis of prominent anterior QRS forces. More and more evidence points to the fact that the main cause of LSFB is critical proximal stenosis of the left anterior descending coronary artery before its first septal perforator branch. The most important characteristic of LSFB that has been incorporated in the corresponding diagnostic electrocardiographic criteria is its transient/intermittent nature mostly observed in clinical scenarios of acute (ie, acute coronary syndrome including vasospastic angina) or chronic (ie, exercise-induced ischemia) ischemic coronary artery disease. In addition, the phenomenon proved to be phase 4 bradycardia rate dependent and induced by early atrial extrastimulus. Finally, we believe that intermittent LSFB has the same clinical significance as "Wellens syndrome" and the "de Winter pattern" in the acute coronary syndrome scenario.

Evaluation of autonomic cardiac modulation and body composition in elderly submitted to the protocol of exercise and the gametherapy: A clinical trial protocol (SPIRIT compliant)

INTRODUCTION

Aging affects the cardiovascular system by impairing the amount and strength of cardiac pumping. Heart rate variability (HRV) is a safe parameter to assess variations in the cardiovascular system, providing data on sympathetic and parasympathetic activations.

OBJECTIVES

Our primary aim is to investigate the cardiac autonomic modulation and body composition of active older adults participating in a physical exercise protocol and gametherapy. Our secondary aim is to assess their functional capacity, cognitive function, balance, respiratory pressures, and functional autonomy.

METHOD

This randomized clinical trial will include 100 active older adults aged 60 to 80 years. The exercise group (EG) will perform 24 supervised training sessions (strength and aerobic) for 12 weeks (2 60-minutes sessions per week). The gametherapy group (GG) will exercise using gametherapy. Assessments will occur on the first week, after the 12th week, after wash out and in the end of cross over. The primary outcome will be HRV and body composition (bioimpedance). Secondary outcomes will be functional capacity (6-minute walk test), cognitive function (mini-mental state examination), risk of falls and balance (berg balance scale and timed up and go test), inspiratory and expiratory pressures (manovacuometry) and functional autonomy (functional reach test and group of Latin American development to maturity [GDLAM] protocol).

DISCUSSION

This study will provide relevant information about the effects of physical training (physical exercises and gametherapy) on HRV and other variables in active older adults.

Non-specific intraventricular conduction delay or atypical LBBB - How to predict acute coronary occlusion?

We describe two patient cases with acute coronary syndrome (ACS) and broad QRS in the acute phase electrocardiogram (ECG). The patients' ECG findings resembled left bundle branch block (LBBB), but with atypical features. Broad QRS not fulfilling the criteria for LBBB or right bundle branch block (RBBB) is diagnosed as non-specific intraventricular conduction delay (NSIVCD). The case report deals with the challenges of predicting acute coronary occlusion in patients with NSIVCD in their acute phase ECG. In one of the cases, the ECG changed from typical LBBB to NSIVCD or atypical LBBB with the development of systolic dysfunction and clinical heart failure.

Northwest axis in the electrocardiogram - A sign of right ventricular remodeling in tetralogy of Fallot. A case report

The typical ECG changes in tetralogy of Fallot are right axis deviation, large R waves in the anterior precordial leads and large S waves in the lateral precordial leads. We present a patient with extreme deviation of the frontal QRS axis between -90° and ± 180°. The child underwent open heart surgery twice before one year of age and a third time at nine years of age. The axis change persisted into adulthood.

The S1S2S3 electrocardiographic pattern - Prevalence and relation to cardiovascular and pulmonary diseases in the general population

BACKGROUND

There is lack of studies exploring the incidence and association with diseases of the S1S2S3 electrocardiogram (ECG) pattern in the general population.

SUBJECTS AND METHODS

This population study included 6299 individuals aged 30+, and explored the prevalence and association between S1S2S3 and cardiovascular and pulmonary diseases. Criteria for the S1S2S3-I and S1S2S3-II ECG pattern were fulfilled when there was an S wave in the leads I, II and III, and the S-wave amplitude was greater than the R-wave amplitude in one or two of the leads, respectively.

RESULTS

The S1S2S3-I ECG pattern was found in 2332 subjects (36.9%). After age adjustment, hypertension was associated with S1S2S3-I (Odds ratio [OR] 1.25, 95% CI 1.12-1.41, p < 0.001). This age-adjusted association was statistically significant among men but not among women (OR 1.37, 1.16-1.62, p < 0.001 and OR 1.13, 0.97-1.33, p = 0.126, respectively). The S1S2S3-II ECG pattern was present in 193 subjects (3.1%). After age adjustment, heart failure proved to be associated with S1S2S3-II (OR 1.85, 1.18-2.90, p = 0.007). Dividing the population by sex, resulted in a statistically significant age-adjusted association for men but not for women (OR 2.30, 1.22-4.33, p = 0.010 and OR 1.59, 0.83-3.03, p = 0.159, respectively). Interactions with sex were statistically non-significant.

CONCLUSION

In the general adult population, the prevalence of the S1S2S3 ECG pattern is markedly affected by the diagnostic ECG criteria. The S1S2S3-I pattern was associated with hypertension, while S1S2S3-II was associated with heart failure, and both associations were enhanced in men. The associations with other studied cardiovascular and pulmonary diseases were minor and not clinically useful for risk stratification.

Early ischemic ST-segment and T-wave changes during balloon angioplasty

BACKGROUND

Acute coronary occlusion results in increased T-wave amplitude and ST-segment elevation in the ECG leads facing the ischemic region.

MATERIAL AND METHODS

We performed continuous ECG recording in 34 patients during balloon occlusion of the left anterior descending (LAD), left circumflex (LCx) and right coronary artery (RCA). Delta (Δ) ST and ΔT amplitudes were calculated by subtracting the preinflation values from the values measured during balloon inflation.

RESULTS

Occlusion of the LAD resulted in greater increase in the amplitude of the T wave than of the ST segment in lead V2 (ΔT +3.4 mm, inter-quartile range [IQR] 1-6 mm; ΔST +1.4 mm, 0.5-3 mm). During RCA occlusion, ΔST and ΔT didn't differ significantly. LCx occlusion resulted in significant differences between ΔST and ΔT in all leads, except aVF and V3-V4. In two patients (LCx), we observed a biphasic ST-T response: an initial negative change of the T-wave amplitude was followed by a positive change in leads V1-V2. In leads II, III, aVF and V4-V6, there was an initial positive change, followed by a final negative change towards the end of the occlusion.

CONCLUSION

Continuous 12‑lead ECG recording during balloon occlusion of the LCx resulted in significant differences between the ΔST and ΔT values in all leads except aVF and V3-V4. LAD and RCA occlusion resulted in less evident differences between the ST-segment and T-wave changes. A change in polarity of T-wave changes during balloon occlusion (initial negative and final positive change, or vice versa) proved to be a rare finding.

Prevalence and long-term prognostic implications of prolonged QRS duration in left ventricular hypertrophy: a population-based observational cohort study

OBJECTIVES

ECG left ventricular hypertrophy (ECG-LVH) has been associated with left ventricular dysfunction and adverse prognosis, but little is known about the prevalence and prognostic significance of different levels of QRS duration in the presence of ECG-LVH in a general population.

DESIGN

Population-based observational prospective cohort study.

PARTICIPANTS

Nationally representative random cluster of Finnish adult population.

METHODS

We assessed the prevalence and long-term (median 15.9 years) prognostic significance of QRS duration in ECG-LVH, and compared the risk to individuals without ECG-LVH in a predominantly middle-aged random sample of 6033 Finnish subjects aged over 30 years (mean age 52.2, SD 14.6 years), who participated in a health examination including a 12-lead ECG.

MAIN OUTCOME MEASURES

Cardiovascular and all-cause mortality, incidence of heart failure (HF).

RESULTS

ECG-LVH was present in 1337 (22.2%) subjects; 403 of these (30.1%) had QRS duration ≥100 ms and 100 (7.5%) had ≥110 ms. The increased risk of mortality in ECG-LVH became evident after a QRS threshold of ≥100 ms. After controlling for known clinical risk factors, QRS 100-109 ms was associated with increased cardiovascular (HR 1.38, 95% CI 1.01 to 1.88, p=0.045) and QRS≥110 ms with cardiovascular (1.74, 95% CI 1.07 to 2.82, p=0.025) and all-cause mortality (1.52, 95% CI 1.02 to 2.25, p=0.039) in ECG-LVH. The risk of new-onset HF was two-fold in subjects with QRS 100-109 ms and threefold in subjects with QRS ≥110 ms, even after adjustment for incident myocardial infarction within the follow-up. When the prognosis was compared with subjects without ECG-LVH, subjects with ECG-LVH but QRS duration <100 ms displayed similar mortality rates with or without ECG-LVH but higher rates of incident HF.

CONCLUSIONS

In ECG-LVH, the risk of excess mortality and new-onset HF markedly increases with longer QRS duration, but even QRS duration within normal limits in ECG-LVH carried a risk of HF compared with the risk in individuals without ECG-LVH.

Transient ascending ST-segment depression and widening of the S wave in 3-channel Holter monitoring-A sign of dromotropic disturbance in the right ventricular outflow tract in the Brugada syndrome: A report of five cases

BACKGROUND

Brugada syndrome (BrS) is somewhat a challenging diagnosis, due to its dynamic pattern. One of the aspects of this disease is a significant conduction disorder located in the right ventricular outflow tract (RVOT), which can be explained as a consequence of low expression of Connexin-43. This decreased conduction speed is responsible for the typical electrocardiographic pattern. Opposite leads located preferably in inferior leads of the electrocardiogram may show a deep and widened S wave associated with ascending ST segment depression. Holter monitoring electrocardiographic (ECG) aspects is still a new frontier of knowledge in BrS, especially in intermittent clinical presentations.

METHODS

We describe, as an exploratory analysis, five case series of intermittent type 1 BrS to demonstrate the appearance of ascending ST segment depression and widening of the S wave, during 3-channel 24h-Holter monitoring (C1, C2 and C3) with bipolar leads.

RESULTS

In the five cases described, the ST segment depression was observed mainly in C2, but in some cases also in C1 and C3. Only case 1 presented concomitant intermittent elevation of the ST segment in C1. All cases were intermittent.

CONCLUSION

The recognition of an ECG pattern with ascending ST-segment depression and widening of the S wave in 3-channel Holter described in this case series should raise a suspicion of the BrS and suggests the counterpart of a dromotropic disturbance registered in the RVOT and/or reciprocal changes.

Validation of a Simple Electrocardiographic Algorithm for Detection of Ventricular Tachycardia

Fundamento

O diagnóstico diferencial de taquicardia de QRS largo, entre taquicardia ventricular (TV) ou taquicardia supraventricular com condução aberrante (TSV-A) é algumas vezes difícil de ser feito na sala de emergência.

Objetivo

Avaliar a acurácia de um algoritmo novo e simples para a detecção de TV no eletrocardiograma (ECG) em pacientes com taquicardia de QRS largo.

Métodos

ECGs de 12 derivações para detecção de taquicardia de QRS largo foram obtidos prospectivamente de 120 pacientes durante estudo eletrofisiológico. Seis médicos com diferentes experiências analisaram os ECGs, e fizeram o diagnóstico com base no algoritmo D12V16, que envolve a análise da polaridade predominante do complexo QRS nas derivações I, II, V1 e V6. O diagnóstico foi comparado com os obtidos pelo algoritmo tradicional de Brugada e pelo estudo eletrofisiológico, o qual é considerado padrão ouro. Adotou-se um nível de significância de 5% (p<0,05) nas análises estatísticas.

Resultados

De acordo com o estudo eletrofisiológico, 82 ECGs eram de TV e 38 de TSV-A. Doenças cardíacas estruturais estavam presentes em 71 (86,6%) dos pacientes com TV e em oito (21,1%) com TSV-A. O algoritmo de Brugada teve uma maior sensibilidade global (87,2%), enquanto o algoritmo D12V16 apresentou maior especificidade global (85,1%) para TV. Tanto o algoritmo D12V16 como o de Brugada apresentou um alto valor preditivo positivo (90,9% vs. 85,8%, respectivamente) e acurácia similar (73,8% vs. 81,4%, respectivamente) para o diagnóstico de TV. Nos avaliadores experientes, a acurácia foi maior utilizando o algoritmo de Brugada que o algoritmo D12V16, mas a acurácia dos dois algoritmos foi similar segundo os avaliadores menos experientes.

Conclusão

O algoritmo simplificado pode ser um método útil para reconhecer TV no ECG, principalmente para médicos menos experientes. (Arq Bras Cardiol. 2021; [online].ahead print, PP.0-0)

Relevance of the vectorcardiogram in the Brugada syndrome with "northwest QRS axis"

The outcome in the Brugada syndrome (BrS) is more benign in female than in male individuals. However, outcome could be adversely affected by sinus node dysfunction (SND). Long sinus pauses indicate an overlap between the phenotypes of BrS and SND. We present a 29-year-old woman with syncopal episodes at rest since adolescence.

Electrocardiographic and Echocardiographic Abnormalities in Patients with Risk Factors for Atrial Fibrillation

The electrocardiogram and various echocardiography modalities are important risk markers for atrial fibrillation (AF). Electrocardiographic criteria of left atrial enlargement, advanced interatrial block, and PR-interval prolongation are atrial risk markers for AF. Transthoracic echocardiography is elementary for risk stratification of AF. Transesophageal echocardiography is a valuable tool to detect cardiac sources of embolism if early cardioversion is necessary. Intracardiac echocardiography is a real-time tool for guidance of percutaneous interventions, including radiofrequency ablation and left atrial appendage closure in patients with AF.

A rare combination of atrial and intraventricular conduction disturbances: Atypical type I advanced interatrial block, left posterior fascicular block and transient right bundle branch block

According to the first 2012 consensus report about interatrial block, the diagnosis of advanced interatrial block (A-IAB) consists of a P-wave duration ≥120 ms with biphasic "plus-minus" (±) polarity in the three leads of the inferior wall in the electrocardiogram. At the end of 2018, a new concept was introduced: the atypical A-IAB due to changes in the polarity or duration of the P-wave. The prevalence of these atypical patterns in different scenarios is currently unknown, but the patterns should be considered as risk factors of embolic stroke of undetermined source. When the A-IAB pattern is associated with clinical arrhythmic manifestations, it is known as the Bayés' Syndrome. We present a characteristic case of atypical A-IAB, and the rare left posterior fascicular block and transient right bundle branch block.

Electrocardiographic "Northwest QRS Axis" in the Brugada Syndrome: A Potential Marker to Predict Poor Outcome

Conduction delay in the right ventricular outflow tract as manifested in the electrocardiogram constitutes a high-risk predictor of ventricular arrhythmias in patients with Brugada syndrome. We present a case with a right QRS axis between –90° and ±180°. This feature has never been reported in the context of Brugada syndrome. (Level of Difficulty: Advanced.)

Relation of intraventricular conduction delay to risk of new-onset heart failure and structural heart disease in the general population

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Subjects with high-risk of developing heart failure ought to be identified.

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Non-specific IVCD and LBBB were associated with risk of new-onset heart failure.

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LBBB also carried a risk of novel structural heart disease in 15-year follow-up.

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Their presence should alert clinician even in subjects free of any known heart disease.

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Right bundle branch block and other blocks were not associated with increased risk.

Background

Intraventricular conduction delays (IVCDs) are hallmarks of heart failure (HF) and structural heart disease (SHD) but their prognostic value for HF and SHD is unclear.

Methods

Relation of eight IVCDs and the incidence of first-time HF or SHD was studied in a nationally representative random sample of 6080 Finnish subjects aged ≥ 30 years (mean age 52.1, SD 14.5 years) who participated in the health examination including 12-lead ECG.

Results

During 16.5 years’ follow up, half of the subjects with left bundle branch block (LBBB) and one third of the subjects with non-specific IVCD developed HF. After controlling for known clinical risk factors the hazard ratio (HR) for new-onset HF for LBBB was 3.29 (95% confidence interval 1.93–5.63, P < 0.001) and 3.53 for non-specific IVCD (1.65–7.55, P = 0.001). In corresponding analysis, LBBB predicted SHD with HR 2.60 (1.21–5.62, P = 0.015). Excluding subjects with history of heart disease, including coronary heart disease, did not have impact on results. Right bundle branch block and other IVCDs displayed no relation to endpoints.

Conclusion

LBBB and non-specific IVCD were associated with more than three-fold risk of new-onset HF. Furthermore, LBBB was associated with novel SHD. Their presence should alert clinician even in subjects free from any known heart disease.

Long-term outcome of intraventricular conduction delays in the general population

Background

Previous population studies have presented conflicting results regarding the prognostic impact of intraventricular conduction delays (IVCD).

Methods

We studied long‐term prognostic impact and the association with comorbidities of eight IVCDs in a random sample of 6,299 Finnish subjects (2,857 men and 3,442 women, mean age 52.8, SD 14.9 years) aged 30 or over who participated in the health examination including 12‐lead ECG. For left bundle branch block (LBBB) and non‐specific IVCD (NSIVCD), two different definitions were used.

Results

During 16.5 years’ follow‐up, 1,309 of the 6,299 subjects (20.8%) died and of these 655 (10.4%) were cardiovascular (CV) deaths. After controlling for known clinical risk factors, the hazard ratio for CV death, compared with individuals without IVCD, was 1.55 for the Minnesota definition of LBBB (95% confidence interval 1.04–2.31, p = .032) and 1.27 (95% confidence interval 0.80–2.02, p = .308) for the Strauss’ definition of LBBB. Subjects with NSIVCD were associated with twofold to threefold increase in CV mortality depending on the definition. While right bundle branch block, left anterior fascicular block and incomplete bundle branch blocks were associated with seemingly higher mortality, this was no longer the case after adjustment for age and sex. The presence of R‐R’ pattern was not associated with any adverse outcome.

Conclusions

In a population study with long‐term follow‐up, NSIVCD and Minnesota definition of LBBB were independently associated with CV mortality. Other IVCDs had no significant impact on prognosis. The prognostic impact of LBBB and NSIVCD was affected by the definition of the conduction disorder.

Evaluation of sleep quality and daytime somnolence in patients with chronic obstructive pulmonary disease in pulmonary rehabilitation

Background

Dyspnea, fatigue, and decline in sleep quality are symptoms of chronic obstructive pulmonary disease (COPD). Pulmonary rehabilitation programs have been shown to ameliorate dyspnea and fatigue. However, only a few studies have investigated the effects of pulmonary rehabilitation on the sleep quality of COPD patients. In this study, we analyzed the benefits of a pulmonary rehabilitation program to sleep quality and daytime somnolence in COPD patients.

Methods

This study was a study of 30 moderate-severe COPD patients. All patients were evaluated by a pulmonologist and underwent polysomnography before participating in the study. For this study, we selected only ex-smokers and patients with sleep apnea were referred to the sleep clinic. These participants were prospectively recruited and not selected based on program completion. Before the start of the program, sleep quality and daytime somnolence of the participants were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS), respectively. Rehabilitation program consisted of muscular training sessions conducted at the gym 3 times per week for 12 weeks. After rehabilitation program, the patients were reassessed and their sleep quality and daytime somnolence were reevaluated using the PSQI and the ESS, respectively.

Results

Before rehabilitation, PSQI evaluation revealed that 73% of the participants had poor sleep quality, and ESS evaluation showed that 86.7% of the participants experienced daytime somnolence. After pulmonary rehabilitation, the PSQI specifically improved in terms of subjective sleep quality and sleep duration (< 0.001), habitual sleep efficiency (0.001), and sleep latency and sleep alterations (0.002) and there was also improvement in the ESS (< 0.001).

Conclusion

Pulmonary rehabilitation program of gradually increasing intensity has the potential to provide sleep-related benefits to patients with COPD who have poor sleep quality and daytime somnolence.

Trial registration

Registro Brasileiro de Ensaios Clínicos (ReBEC) RBR62b4z2.

Is aerobic exercise training during hemodialysis a reliable intervention for autonomic dysfunction in individuals with chronic kidney disease? A prospective longitudinal clinical trial

Introduction

Physical exercises help in the rehabilitation and recovery of various diseases. Cardiovascular and hypertension problems are the main causes of people being affected by kidney problems, which as a consequence, affects the heart rate variability (HRV) of the individual. Physical activity developed in a well-planned and thorough way can be a component in the treatment of this problem.

Objective

We aimed to evaluate the effects of aerobic exercise intervention during hemodialysis on autonomic heart rate regulation in individuals with chronic kidney disease (CKD).

Methods

This was a longitudinal trial conducted in 19 CKD patients. The patients underwent three weekly sessions of aerobic exercise during hemodialysis for 30 mins for 12 weeks (three months).

Results

HRV was analyzed before and after the protocol training. Linear indices of HRV were not different between before and after the protocol training. Nonlinear HRV analysis indicated reduced values of determinism (p=0008, Cohen's d=0.82) and entropy (p=003, Cohen's d=0.84) after the training protocol.

Conclusion

In conclusion, aerobic exercise training during hemodialysis did not improve autonomic control of heart rate in CKD patients.

Left Septal Fascicular Block Following Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy

Left septal fascicular block, or blockage of the middle fibers of the left bundle branch, is known to be suggestive of a critical proximal obstruction of the left anterior descending coronary artery before its first septal perforator branch. We describe the case of a 68-year-old male who exhibited this transient intraventricular dromotropic disturbance following alcohol septal ablation for hypertrophic obstructive cardiomyopathy.

Transient high-degree right bundle branch block masking the type 1 Brugada ECG pattern associated with possible transient early repolarization syndrome

The Brugada syndrome (BrS) was the last electrocardiographic syndrome described in the 20th century. The initial description included right bundle branch block (RBBB), persistent ST-segment elevation in the right precordial leads, absence of structural heart disease, and propensity to unexplained syncope and/or sudden death mainly during nocturnal rest. Currently, we know that the first three components are not constant or true since RBBB is present in only 28% of cases, the ST-segment elevation is dynamic, at times absent, and there are discrete structural changes in the right ventricular outflow tract. Additionally, the presence of RBBB can hide the typical type 1 Brugada ECG pattern. We present a very unusual case of spontaneous transient RBBB that revealed a hidden type 1 Brugada ECG pattern that could be seen in the beat with normal ventricular conduction.

Predicting the outcome of acute pulmonary embolism by dynamic changes of the QRS complex in lead V1

Electrocardiography can provide useful prognostic information in acute pulmonary embolism (APE). Several abnormal QRS changes in lead V1, including notched or fragmented QRS, incomplete or complete right bundle branch block (IRBBB or CRBBB) and the QR sign, which are associated with APE, are of prognostic significance. To illustrate this, we describe lead V1 QRS changes in combination with the clinical state of six APE patients. The dynamic ECG changes suggest that a change from a diminution of the S wave amplitude to notched S wave, next to RBBB and then to the QR sign indicate worsening of the patients' condition, and vice versa. Also, a diminution of the S wave amplitude in lead V1 associated with a final R' wave in the right precordial accessory leads indicates the possibility of hidden RBBB. Understanding dynamic QRS changes in APE may aid in risk stratification.

Re-evaluating the electro-vectorcardiographic criteria for left bundle branch block

The criteria for left bundle branch block have gained growing interest in the last few years. In this overview, we discuss diagnostic and prognostic aspects of different criteria. It was already shown that stricter criteria, including longer QRS duration and slurring/notching of the QRS, better identify responders to cardiac resynchronization therapy. We also include aspects of ST/T concordance and discordance and vectorcardiography, which could further improve in the fine-tuning of the left bundle branch criteria.

Left ventricular noncompaction and orthodromic atrioventricular tachycardia observed in a patient with neurofibromatosis type 1

Isolated left ventricular noncompaction (LVNC) was described for the first time in 1984. It is a rare congenital disease, characterized by prominent trabecular meshwork pattern and deep intertrabecular recesses, communicated with the left ventricular chamber. Clinical presentation varies from asymptomatic patients, to those developing supraventricular and ventricular arrhythmias, thromboembolism, heart failure and sudden cardiac death. We present an unusual case, where the patient with Neurofibromatosis type 1 presented with a wide complex orthodromic atrioventricular reentrant tachycardia (AVRT) and a diagnosis of left posterior paraseptal accessory pathway in association with LVNC.

Epsilon wave: A review of historical aspects

The epsilon wave of the electrocardiogram (ECG) together with fragmented QRS (fQRS), the terminal conduction delay, incomplete right bundle branch block (IRBBB) and complete/advanced RBBB (CRBBB) of peripheral origin are part of a spectrum of ventricular depolarization abnormalities of arrhythmogenic cardiomyopathy(AC). Although the epsilon wave is considered a major diagnostic criterion for AC since 2010 (AC Task Force Criteria), its diagnostic value is limited because it is a sign of the later stage of the disease. It would be more appropriate to say that the epsilon wave is a “hallmark” of AC, but is of low diagnostic sensitivity. Although the epsilon wave has high specificity for AC, it can be present in other pathological conditions. In this update we will cover the nomenclature, association with disease states and electrocardiographic aspects of the epsilon wave.

Severe hypercalcemia from multiple myeloma as an acquired cause of short QT

An otherwise healthy 64-year-old man with recently diagnosed multiple myeloma was admitted to hospital with hypercalcemia and renal failure. Despite his electrocardiogram showing short QT/QTc intervals, he was admitted without cardiac monitoring. He died suddenly a few hours later, likely from a fatal arrhythmia. This case illustrates that pronounced QT shortening from hypercalcemia is an underappreciated malignant finding that can portend a significant risk for arrhythmia and sudden cardiac death. In addition, we also discuss the causes of hypercalcemia associated short QT/QTc intervals and its ECG features.

Electro-vectorcardiographic and electrophysiological aspects of Ebstein's anomaly

Ebstein's anomaly is a congenital heart disease where the most important anatomic feature is the inferior displacement of the tricuspid valve leaflets. Vectorcardiographic features are mainly forgotten and electrocardiographic features may be unrecognized by cardiologists handling adult patients.

Acute inferior myocardial infarction with right ventricular involvement and several clinical-electrocardiographic markers of poor prognosis

Right ventricular involvement in inferior myocardial infarction is a marker of poor prognosis. We present a case of a 62-year-old man with very recent onset of acute chest pain and cardiac shock with the triad of elevated jugular venous pressure, distension of the jugular veins on inspiration, and clear lung fields. In addition, the admission electrocardiogram showed a slurring J wave or lambda-like wave and conspicuous ST segment depression in several leads, predominantly in the lateral precordial (V4-V6), all clinical-electrocardiographic features of ominous prognosis.

Transient left septal fascicular block and left anterior fascicular block as a consequence of proximal subocclusion of the left anterior descending coronary artery

The association of left anterior fascicular block (LAFB) with left septal fascicular block (LSFB) characterizes a left bifascicular block subtype rarely described in the literature, probably due to the fact that most researchers are not aware of the existence of the left septal fascicle. We describe a case with this transient intraventricular dromotropic disturbance due to left anterior descending coronary artery subocclusion.

Transient left septal fascicular block in the setting of acute coronary syndrome associated with giant slurring variant J-wave

We report a case of acute coronary syndrome with transient prominent anterior QRS forces (PAF) caused by proximal subocclusion of the left anterior descending (LAD) coronary artery before the first septal perforator branch. The ECG change indicates left septal fascicular block (LSFB) with associated slurring-type giant J-wave. Currently, this J-wave variant is considered as a lambda-like wave or QRS-ST-T "triangulation". Its presence is indicative of poor prognosis because of the risk for cardiac arrest as a consequence of ventricular tachycardia/ventricular fibrillation (VT/VF).

The congenital long QT syndrome Type 3: An update

Congenital long QT syndrome type 3 (LQT3) is the third in frequency compared to the 15 forms known currently of congenital long QT syndrome (LQTS). Cardiac events are less frequent in LQT3 when compared with LQT1 and LQT2, but more likely to be lethal; the likelihood of dying during a cardiac event is 20% in families with an LQT3 mutation and 4% with either an LQT1 or an LQT2 mutation. LQT3 is consequence of mutation of gene SCN5A which codes for the Nav1.5 Na+ channel α-subunit and electrocardiographically characterized by a tendency to bradycardia related to age, prolonged QT/QTc interval (mean QTc value 478 ± 52 ms), accentuated QT dispersion consequence of prolonged ST segment, late onset of T wave and frequent prominent U wave because of longer repolarization of the M cell across left ventricular wall.

Electrocardiographic Markers of Sudden Cardiac Death (Including Left Ventricular Hypertrophy)

Although the electrocardiograph (ECG) was invented more than 100 years ago, it remains the most commonly used test in clinical medicine. It is easy to perform, relatively cheap, and results are readily available. Interpretation, however, needs expertise and knowledge. New data, phenomenon, and syndromes are continually discovered by the ECG. It is important to differentiate between normal and abnormal ECGs first and then try to correlate the findings with clinical pathologies. Furthermore, the ECG is an integral part of the screening model for a variety of conditions such as channelopathies, athletes, preoperative risk profile, and remains the cardiologist's best friend.

Main artifacts in electrocardiography

Electrocardiographic artifacts are defined as electrocardiographic alterations, not related to cardiac electrical activity. As a result of artifacts, the components of the electrocardiogram (ECG) such as the baseline and waves can be distorted. Motion artifacts are due to shaking with rhythmic movement. Examples of motion artifacts include tremors with no evident cause, Parkinson's disease, cerebellar or intention tremor, anxiety, hyperthyroidism, multiple sclerosis, and drugs such as amphetamines, xanthines, lithium, benzodiazepines, or shivering (due to hypothermia, fever (rigor due to shaking), cardiopulmonary resuscitation by chest compression (oscillations of great amplitude) and patients who move their limbs during the test, causing sudden irregularities in the ECG baseline that may resemble premature contractions or interfere with ECG wave shapes, or other supraventricular and ventricular arrhythmias. When the skeletal muscles experience shaking, the ECG is "bombarded" by apparently random electrical activity.

Transient left septal and anterior fascicular block associated with type 1 electrocardiographic Brugada pattern

The left septal fascicular block (LSFB) or blockage of the middle fibers of the left bundle branch is probably caused mainly by - in the developed world - the proximal obstruction of the left anterior descending artery (LAD) before its first anterior septal perforator branch (S₁). The association of transient LSFB and left anterior fascicular block (LAFB) - left bifascicular block - and the electrocardiographic type 1 Brugada pattern (BrP) has not been described in the literature yet.

Effectiveness of functional training on cardiorespiratory parameters: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Functional training is a new training vision that was prepared from the gesture imitation of daily activities. Although your use has become popular in clinical practice, the influence of the several cardiorespiratory adjustments performed during the functional training in different populations and conditions is unknown. So, the aim of this systematic review was to gather information in the literature regarding the influence of functional training on cardiorespiratory parameters.

METHODS

We conducted search strategies on MEDLINE, PEDro, EMBASE, SportDiscus and Cochrane to identify randomized controlled trials investigating the effects of functional training on cardiorespiratory parameters. Methodological quality of the included studies was assessed using the PEDro scale. Grading of Recommendations Assessment, Development and Evaluation (GRADE) summarized the evidence.

RESULTS

Five original studies were included. Effects favoured functional training on oxygen consumption (VO₂ ) at intermediate-term follow-up: weighted mean difference -1·0 (95% CI: 5·4-3·3), P = 0·642, and a small and not clinically important effect observed on VO₂ favouring control at intermediate-term follow-up (i.e. mean difference of 1·30 (95% CI 1·07-1·53), P<0·001).

CONCLUSION

According to the GRADE system, there is very low quality evidence that functional training is better than other interventions to improve cardiovascular parameters. This result encourages new searches about the theme.

Myotonic dystrophy and Brugada syndrome: A common pathophysiologic pathway?

Type 1 myotonic dystrophy (DM1) is a hereditary neuromuscular disease affecting multiple organs in human adults. Here we report a 42-year-old man diagnosed with DM1. Having a history of progressive muscular weakness and gradual loss of visual acuity, he was referred to us by his ophthalmologist for risk assessment of undergoing cataract surgery. Cardiology workup revealed type 1 Brugada ECG pattern, positive late potentials and inducible ventricular fibrillation in an electrophysiology study. Literature review revealed that those ECG changes may be observed in DM1, suggesting that DM1 and Brugada syndrome may share a common pathophysiologic pathway.

Mid-ventricular Hypertrophic Obstructive Cardiomyopathy with Apical Aneurysm Complicated with Syncope by Sustained Monomorphic Ventricular Tachycardia

Mid-ventricular hypertrophic obstructive cardiomyopathy with secondary formation of apical aneurysm is a rare variant of hypertrophic cardiomyopathy. They have a unique behavior because unlike other variants it causes sustained monomorphic ventricular tachycardia, which makes it particularly severe.

P-wave dispersion: an update

P-wave dispersion (PWD, Pd or Pdis) is a noninvasive electrocardiographic (ECG) marker for atrial remodeling and predictor for atrial fibrillation (AF). PWD is defined as the difference between the widest and the narrowest P-wave duration recorded from the 12 ECG leads. Increased P-wave duration and PWD reflect prolongation of intraatrial and interatrial conduction time with lack of a well-coordinated conduction system within the atrial muscles, with inhomogeneous, asynchronic, pro-inflammatory and anti-inflammatory effect mediated by interleukin-6 (IL-6) in patients with the CG + GG genotype IL-6 -634C/G polymorphism [1] and discontinuous propagation of sinus impulses mainly between the left and right atria, interstitial/extracellular fibroblast activation and collagen deposition with fibrosis (via TGF-β) in atrial tissue, insufficient blood supply, significant not isotropic myoelectric activity, and thin wall thickness and consequent expansion tendency all well-known electrophysiological characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation (PAF) [2].

Normality that is abnormal

Supernormal conduction is defined as better-than-expected conduction in patients with depressed conduction during a short interval in the ventricular cycle. It is mainly observed in long-duration electrocardiogram (ECG) assessments. Its occurrence during 12-lead ECG is uncommon and its interpretation demands knowledge on electrophysiological alterations that are hard to understand. By reporting this case we aim to propose a rationale sequence that should be considered when facing an ECG with these same features, which would enable a greater accuracy to make a definitive diagnosis.