ISE/ISHNE expert consensus statement on the ECG diagnosis of left ventricular hypertrophy: The change of the paradigm.

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria. The classical paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces, reflected in the augmented QRS amplitude. However, the low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm. The theoretical background for voltage measured at the body surface is defined by the solid angle theorem, which relates the measured voltage to spatial and non-spatial determinants. The spatial determinants are represented by the extent of the activation front and the distance of the recording electrodes. The non-spatial determinants comprise electrical characteristics of the myocardium, which are comparatively neglected in the interpretation of the QRS patterns. Various clinical conditions are associated with LVH. These conditions produce considerable diversity of electrical properties alterations thereby modifying the resultant QRS patterns. The spectrum of QRS patterns observed in LVH patients is quite broad, including also left axis deviation, left anterior fascicular block, incomplete and complete left bundle branch blocks, Q waves, and fragmented QRS. Importantly, the QRS complex can be within normal limits. The new paradigm stresses the electrophysiological background in interpreting QRS changes, i.e., the effect of the non-spatial determinants. This postulates that the role of ECG is not to estimate LV size in LVH, but to understand and decode the underlying electrical processes, which are crucial in relation to cardiovascular risk assessment.

Congenital 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.

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.

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.

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 12­lead 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.

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.

The prognostic significance of the electrical QRS axis on long-term mortality in acute coronary syndrome patients - The TACOS study.

INTRODUCTION: There are several potential causes of QRS-axis deviation in the ECG, but there is limited data on the prognostic significance of QRS-axis deviation in ACS patients. SUBJECTS AND METHODS: We evaluated the long-term prognostic significance of acute phase frontal plane QRS-axis deviation and its shift during hospital stay in ACS patients. A total of 1026 patients who met the inclusion criteria were divided into three categories: normal (n = 823), left (n = 166) and right/extreme axis (n = 37). RESULTS: The median survival time was 9.0 years (95% CI 7.9-10.0) in the normal, 3.6 years (95% CI 2.4-4.7) in the left and 1.3 years (95% CI 0.2-2.4) in the right/extreme axis category. Both short and long-term all-cause mortality was lowest in the normal axis category and highest in the right/extreme axis category. Compared to normal axis, both admission phase QRS-axis deviation groups were independently associated with a higher risk of all-cause mortality. When including left ventricular hypertrophy in the ECG, only the right/extreme axis retained its statistical significance (aHR 1.76; 95% CI 1.16-2.66, p = 0.007). Axis shift to another axis category had no effect on mortality. CONCLUSION: In ACS patients, acute phase QRS-axis deviation was associated with higher risk of all-cause mortality. Among the axis deviation groups, right/extreme QRS-axis deviation was the strongest predictor of mortality in the multivariable analysis. Further studies are required to investigate to what extent this association is caused by pre-existing or by ACS-induced axis deviations. QRS-axis shift during hospital stay had no effect on all-cause mortality.

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.

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.

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.

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.

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.

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.

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.

Electro-vectorcardiographic demonstration of rate-independent transient left posterior fascicular block.

Left posterior fascicular block (LPFB) is a rare intraventricular conduction disorder of rare occurrence, especially as an isolated entity. Its transient form is even rarer and maybe rate-independent or rate-dependent intermittent LPFB (phase 3 block, tachycardia-dependent and phase 4 block or bradycardia-dependent). We present a case of a young adult male whose baseline ECG/VCG showed the typical LPFB pattern. A treadmill stress test revealed rate-independent intermittent LPFB with random occurrence. Imaging exams ruled out structural heart disease. To our knowledge, this is the first case in the literature of a rate-independent intermittent LPFB with no underlying structural heart disease.

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.

Current aspects of the basic concepts of the electrophysiology of the sinoatrial node.

Cardiac pacemaker cells, also named P-cells (pale cytoplasm, pacemaker, phylogenetically primitive), including cells of the sinoatrial node, are heterogeneous in size, morphology, and electrophysiological characteristics. The exact extent to which these cells differ electrophysiologically in the human heart is unclear, yet it is critical for the understanding of normal cellular function. In this review, we describe major ionic currents and Ca2+ clocks acting on Ca2+ release in the sarcoplasmic reticulum. We also explain the external regulation of the heart rate controlled by the two branches of the autonomic (involuntary) nervous system: the sympathetic and the parasympathetic nervous system. Vagal stimulus causes bradycardia, rapid and short-duration modulation, and controls rapid responses, and increases heart rate variability. A typical example is constituted by phasic or respiratory sinus arrhythmia, characterized by pronounced vagal activity, more frequent in children and young individuals.