Background: A myocardial bridge (MB) has been associated with ventricular arrhythmia and sudden death during exercise. QT dispersion (QTd) is a measure of abnormal repolarization and may predict ventricular arrhythmia. We investigated the frequency of ventricular arrhythmias during exercise and the QTd at rest and after exercise, in patients with an MB compared to a normal cohort. Read More
Ann Noninvasive Electrocardiol 2017 Sep 12. Epub 2017 Sep 12.
Department of Cardiovascular Medicine and Electrophysiology, Staten Island University Hospital, Northwell Health, Staten Island, NY, USA.
Hypertrabeculation/noncompaction of the myocardium is a rare disorder that involves most commonly the left ventricle of the heart and it has been recognized as a distinct cardiomyopathy by the World Health Organization. However, it is extremely rare for this condition to involve exclusively the right ventricle. We report the cases of three patients who presented with ventricular tachyarrhythmia and sudden cardiac death. Read More
Background: Despite substantial progress in the field of differentiation between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with wide QRS complexes, differentiation between VT and preexcited SVT remains largely unresolved due to significant overlap in QRS morphology. Our aim was to assess the specificities of various single ECG criteria and sets of criteria (Brugada algorithm, aVR algorithm, Steurer algorithm, and the VT score) for diagnosis of VT in a sizable cohort of patients with preexcitation.
Methods: We performed a retrospective study of consecutive accessory pathway ablation procedures to identify preexcited tachycardias. Read More
Background: The total cosine R-to-T (TCRT), a vectorcardiographic marker reflecting the spatial difference between the depolarization and repolarization wavefronts, has been used to predict ventricular tachycardia/fibrillation (VT/VF) and sudden cardiac death (SCD) in different clinical settings. However, its prognostic value has been controversial.
Objective: This systematic review and meta-analysis evaluated the significance of TRCT in predicting arrhythmic and/or mortality endpoints. Read More
Ann Noninvasive Electrocardiol 2017 Aug 30. Epub 2017 Aug 30.
Department of Cardiology, Faculty of Medicine, Karabuk University, Karabuk, Turkey.
Long QT syndrome may lead to fatal dysrhythmia. Prolongation of QT interval due to pregabalin has been shown in rats and no data is available in humans. We report a 80-year-old female patient using pregabalin. Read More
Ann Noninvasive Electrocardiol 2017 Aug 24. Epub 2017 Aug 24.
Division of Cardiology, Queen's University, Kingston, ON, Canada.
In patients with manifest anterograde ventricular preexcitation, the electrocardiographic manifestation of the anomalous conduction through the simultaneous conduction over the atrioventricular (AV) node and the accessory pathway ("delta wave"); depends on several factors, the most representative being the conduction velocity over one or another connection. Occasionally, ventricular ectopic beats may present with retrograde penetration over one or both conduction pathways (AV node and/or accessory pathway), impacting on the morphology of the next immediate anterogradely conducted QRS. We present a case of a young patient with WPW syndrome and ectopic ventricular beats with different manifestations on the postectopic QRS due to concealed penetration of different conduction pathways. Read More
Background: The study was designed to examine P wave morphology (PWM) in precordial leads (V1 -V6 ) during ectopic atrial tachycardia (EAT) originating from low right atrium (RA) to identify the anatomic sites of these foci in children.
Methods: Twenty-three consecutive pediatric patients (56% females, mean age 8.5 ± 2. Read More
Pregnancy may predispose to paroxysmal supraventricular tachycardia (SVT), in subjects with or without identifiable heart disease. Many physiological conditions such as autonomic nervous system changes, altered systemic hemodynamics, etc. can contribute to the onset of arrhythmias during pregnancy. Read More
Background: To evaluate the influence of functional training on the geometric indices of heart rate variability (HRV) and fractal correlation properties of the dynamics of heart rate in menopausal women.
Methods: Of 39 women who were in the period of menopause for more than a year and who did not practice any regular physical activity were divided into: Functional training group (FTG = 50 ± 4.5 years; 67. Read More
Background: Artifact is common in cardiac RR interval data derived from 24-hr recordings and has a significant impact on heart rate variability (HRV) measures. However, the relative impact of progressively added artifact on a large group of commonly used HRV measures has not been assessed. This study compared the relative sensitivity of 38 commonly used HRV measures to artifact to determine which measures show the most change with increasing increments of artifact. Read More
Since its initial description by Jervell and Lange-Nielsen in 1957, the congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. A prolonged QT interval in the surface electrocardiogram is the sine qua non of the LQTS and is a surrogate measure of the ventricular action potential duration (APD). Congenital as well as acquired alterations in certain cardiac ion channels can affect their currents in such a way as to increase the APD and hence the QT interval. Read More
Background: Although abnormalities of the QT interval are associated with atrial fibrillation (AF), it is unclear whether ventricular depolarization (QRS duration) or repolarization (JT interval) is a more important marker of AF risk.
Methods: This analysis included 4,181 (95% white; 59% women) participants from the Cardiovascular Health Study (CHS) who were free of baseline AF and major intraventricular delay. A linear scale was used to compute heart rate adjusted QT (QTa), QRS (QRSa ), and JT (JTa ) intervals. Read More
Electrical ventricular separation, as a special complete intraventricular block, denotes that ventricles be electrically separated into two or more parts caused by severe and wide damage of myocardium and conduction. Electrical ventricular separation can be divided into homologous and heterologous, homologous electrical ventricular separation is a rare phenomenon, literally the excitement of whole ventricle originate from supraventricle, on ECG, there are two different QRS waves which connect with an isoelectric line, one ST segment and T wave. We report a valve heart disease presented with complicated electrophysiological characteristics, which has reversed complex homologous electrical ventricular separation with second degree intraventricular block. Read More
Background: Experimental evidence suggests that ranolazine decreases susceptibility to ischemia-induced arrhythmias independent of effects on coronary artery blood flow.
Objective: In symptomatic diabetic patients with non-flow-limiting coronary artery stenosis with diffuse atherosclerosis and/or microvascular dysfunction, we explored whether ranolazine reduces T-wave heterogeneity (TWH), an electrocardiographic (ECG) marker of arrhythmogenic repolarization abnormalities shown to predict sudden cardiac death.
Methods: We studied all 16 patients with analyzable ECG recordings during rest and exercise tolerance testing before and after 4 weeks of ranolazine in the double-blind, crossover, placebo-controlled RAND-CFR trial (NCT01754259). Read More
A long run of PVCs "sandwiched" in between the sinus beats resulting in an almost doubling of the heart rate-interpolated PVCs in bigeminy-is described. This case illustrates three interesting aspects of interpolated PVCs. Although they are not uncommon, long runs of interpolated PVCs in bigeminy are rare findings. Read More
Obesity is a rising epidemic worldwide driving people to search for remedy through nonconventional therapies. Hydroxycut products are popular supplements used as weight loss aids. Many reports revealed serious adverse effects related to their ingestion. Read More
Background: Cheyne-Stokes respiration (CSR) has been investigated primarily in outpatients with heart failure. In this study we compare CSR and periodic breathing (PB) between healthy and cardiac groups.
Methods: We compared CSR and PB, measured during 24 hr of continuous 12-lead electrocardiographic (ECG) Holter recording, in a group of 90 hospitalized patients presenting to the emergency department with symptoms suggestive of acute coronary syndrome (ACS) to a group of 100 healthy ambulatory participants. Read More
We present a case of a young man with Duchenne muscular dystrophy cardiomyopathy (DMDC) having an implantable cardioverter defibrillator for secondary prevention, who presented with electrical storm shortly after β-blocker interruption. The patient was stabilized and remained free of ventricular arrhythmias soon after reinitiating b-adrenoreceptor antagonists. The present case highlights the importance of sympathetic blockage in patients with DMDC due to existing pathophysiology of excess diastolic Ca(2+) leak from sarcoplasmic reticulum as a result of ryanodine receptor dysfunction. Read More
Background: Supraventricular tachycardias (SVT) are a common arrhythmia therefore an accurate diagnosis is of clinical importance. Although an ECG performed during tachycardia greatly aids diagnosis, patient history and predisposing factors also improve diagnostic accuracy.
Methods: This prospective study included 100 consecutive patients undergoing electrophysiological study for SVT with the aim to reassess their clinical characteristics and describe frequent predisposing factors, such as the "sign of lace-tying" that to our knowledge has not previously been reported. Read More
The electrocardiogram (ECG) interpretation in patients with cardiac resynchronization therapy (CRT) is often a perplexing problem. The difficulty in the device evaluation increases in the presence of unfamiliar timing cycles and a lead dysfunction. Authors describe a special function of a Biotronik CRT devices called the left ventricle T-wave protection (LVTP), and demonstrate its behavior in a patient with left ventricular (LV) lead failure. Read More
Background: Kinetic oscillation stimulation in the nasal cavity (KOS) has been shown to have positive symptomatic effects in subjects with non-allergic rhinitis and in patients with migraine.
Methods: To evaluate the effect of KOS on autonomic function, we assessed heart rate variability (HRV) in this small exploratory study in 12 healthy subjects. KOS treatment was performed using a minimally invasive system with a single-use catheter inserted into the nasal cavity. Read More
Introduction: Carbon-ion irradiation of rabbit hearts has improved left ventricular conduction abnormalities through upregulation of gap junctions. However, to date, there has been no investigation on the effect of carbon-ion irradiation on electrophysiological properties in human. We investigated this effect in patients with mediastinum extra-cardiac cancer treated with carbon-ion radiotherapy that included irradiating the heart. Read More
Background: To assess the prevalence, the appearance, and the distribution, as well as the fluctuation over time of early repolarization patterns after four years in a female population derived from the French aviation sector.
Methods: This was a retrospective longitudinal study from 1998 to 2010 of a population of female employees who received a full clinical examination and an electrocardiogram (ECG) upon their recruitment and after a period of four years.
Results: A total of 306 women were included (average of 25. Read More
Aim: Optimization of coronary sinus (CS) lead position to the latest activated left ventricular (LV) area is important to increase cardiac resynchronization therapy (CRT) response. We aimed to detect the relationship between coronary sinus lead delay index (CSDI) and echocardiographic, electrocardiographic response to CRT treatment.
Methods: We prospectively included 137 consecutive patients with heart failure (HF) diagnosis, QRS ≥ 120 ms, left bundle branch block (LBBB), New York Heart Association score (NYHA) II-IV, LV ejection fraction (LVEF) <35% and scheduled for CRT (84 male, 53 female; mean age 65. Read More
A 15-year-old girl suffered recurrent syncopal episodes during 7 years. Events were precipitated by exercise or emotional stress, leading to the diagnosis of reflex syncope. Exercise testing induced recurrent salvos of nonsustained right ventricular outflow tract tachycardia. Read More
Background: Although the majority of Class III congestive heart failure (HF) patients treated with cardiac resynchronization therapy (CRT) show a clinical benefit, up to 40% of patients do not respond to CRT. This paper reports the design of the MultiPoint Pacing (MPP) trial, a prospective, randomized, double-blind, controlled study to evaluate the safety and efficacy of CRT using MPP compared to standard biventricular (Bi-V) pacing.
Methods: A maximum of 506 patients with a standard CRT-D indication will be enrolled at up to 50 US centers. Read More
Background: In the human electrocardiogram, there is a lag of adaptation of the QT interval to heart rate changes, usually termed QT/RR hysteresis (QT-hys). Subject-specific quantifiers of QT-hys have been proposed as potential biomarkers, but there is no consensus on the choice of the quantifier.
Methods: A comprehensive literature search was conducted to identify original articles reporting quantifiers of repolarization hysteresis from the surface ECG in humans. Read More
Background: Information regarding suitability for subcutaneous defibrillator (sICD) implantation in tetralogy of Fallot (ToF) and systemic right ventricle is scarce and needs to be further explored. The main objective of our study was to determine the proportion of patients with ToF and systemic right ventricle eligible for sICD with both, standard and right-sided screening methods. Secondary objectives were: (i) to study sICD eligibility specifically in patients at high risk of sudden cardiac death, (ii) to identify independent predictors for sICD eligibility, and (iii) to compare the proportion of eligible patients in a nonselected ICD population. Read More
Background: Predictors and implications of early left ventricular ejection fraction (LVEF) improvement with guideline-directed medical therapy (GDMT) in new-onset idiopathic nonischemic cardiomyopathy (NICM) with narrow QRS complex are not well described. The objectives were to describe predictors of LVEF improvement after 3 months on GDMT and adverse cardiac events based on post-GDMT LVEF status (≤35% vs. >35%). Read More
We report three patients with intermittent loss of the preexcitation pattern in the ECG that had undergone an electrophysiological study. Despite apparently poorly conducting accessory pathway (AP), in each case a fast anterograde conduction, either during spontaneous atrial fibrillation or during incremental atrial pacing (on isoproterenol) was documented; shortest preexcited RR intervals of 200-240 ms were observed. We review the literature and conclude that intermittent preexcitation observed on resting 12-lead ECG lacks sufficient specificity for the diagnosis of an AP with long refractory period and cannot be considered a substitute for electrophysiological study in patients with this electrocardiographical phenomenon. Read More
Background: Cardiac restitution is the ability of the heart to recover from one beat to the next. Ventricular arrhythmia vulnerability can occur when the heart does not properly adjust to sudden changes in rate or in hemodynamics leading to excessive temporal and/or spatial heterogeneity in conduction or repolarization. Restitution has historically been used to study, by invasive means, the dynamics of the relationship between action potential duration (APD) and diastolic interval (DI) in sedated subjects using various pacing protocols. Read More
Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. Read More
Background: The clinical significance of electrocardiogram in the assessment of patients with idiopathic dilated cardiomyopathy (IDCM) is currently unknown. The aim of this study was to determine the feasibility of recording serial changes in Sokolow-Lyon voltage (∆%QRS-voltage) in one year to estimate left ventricular reverse remodeling (LVRR) and predict a prognosis of IDCM patients under tailored medical therapy.
Methods: Sixty-eight consecutive patients with mild symptoms (52. Read More
Differentiation of a wide complex arrhythmia can pose as a clinical challenge in the acute care setting. Two broad differentials exist including ventricular tachycardia versus supraventricular tachycardia with aberrancy, underlying bundle branch block or intrinsic conduction defect. To aid in distinguishing between supraventricular tachycardia and ventricular tachycardia, Brugada criteria is commonly used, albeit new algorithms have become more common. Read More
Background: The clinical relevance of extended monitoring of AF in the general population is unclear. The study evaluated the detection of AF using transtelephonic electrocardiography and the clinical relevance of additional AF findings, especially with regard to stroke risk and mortality.
Methods: The data of 1678 volunteers participating in the tele-ECG-subproject of the Study of Health in Pomerania was evaluated. Read More
Background: T wave amplitudes during ventricular repolarization in the lead aVR (TAaVR) are shown to be associated with adverse cardiac events in patients with several cardiovascular diseases, such as postmyocardial infarction. However, the utility of TAaVR has not been previously evaluated in patients with cardiomyopathy who have received implantable cardioverter defibrillators (ICD). Patients with ischemic or nonischemic cardiomyopathy (ICM or NICM, respectively) and who received an ICD may experience worsening of their condition due to the introduction of electric shock during treatment. Read More
Background: Evaluation of corrected flow time (FTc) via ultrasonography is one of the suggested modalities for the assessment of intravascular volume status. This study aimed to compare the results of FTc of carotid artery measured via ultrasonography, as a measure of mechanical outcome of the cardiac cycle, with the results of FTc estimation from a new modified formula via electrocardiography (ECG), as a measure of electrical function of the cardiac cycle.
Methods: Healthy volunteers were evaluated before and after a passive leg raising (PLR) maneuver. Read More
Background: Prolongation of the QT on the surface electrocardiogram can be due to either genetic or acquired causes. Distinguishing congenital long QT syndrome (LQTS) from acquired QT prolongation has important prognostic and management implications. We aimed to investigate if quantitative T-wave analysis could provide a tool for the physician to differentiate between congenital and acquired QT prolongation. Read More
Patent foramen ovale (PFO) is thought to be a risk factor for decompression illness (DCI). Catheter-based closure procedure reduces the risk of DCI in selected scuba divers with PFO. Major complication of invasive approach are rare, minor, especially heart rhythm disturbances are reported relatively often. Read More
Background: J waves result mainly from an increased density of transient outward current (Ito ). Mechanical stretch to the heart activates multiple signal transduction pathways, in which Ito may be involved. The purpose of this study was to test the hypothesis that mechanical contact of lung cancer with the heart may manifest J waves. Read More
Background: Primary prevention of sudden cardiac death by means of implantable cardioverter-defibrillators constitutes the holy grail of arrhythmology. However, current risk stratification algorithms lead to suboptimal outcomes, by both allocating ICDs to patients not deriving any meaningful survival benefit and withholding them from those erroneously considered as low-risk for arrhythmic mortality.
Methods: In the present review article we will attempt to present shortcomings of contemporary guidelines regarding sudden death prevention in ischemic and dilated cardiomyopathy patients and present available data suggesting encouraging results following implementation of multifactorial approaches, by using multiple modalities, both noninvasive and invasive. Read More