Characterization of Myocardial Recovery in Patients With Tachycardiomyopathy.

Background: The degree and time course of improvement in left ventricular (LV) function with treatment in patients with tachycardiomyopathy (TCMP) is highly variable. This study aims to clinically characterize the recovery of TCMP based on the extent and course of improvement in LV function and identify predictors of complete myocardial recovery.

Methods: In this prospective, single-center, observational study, patients with suspected TCMP who underwent successful tachyarrhythmia termination/control were included.

Is the right ventricular function affected by permanent pacemaker?

Aims: The effect of right ventricular (RV) pacing on left ventricular (LV) function has been extensively evaluated, but the effect on RV function per se has not been evaluated systematically. We aimed to assess the effect of dual chamber pacemaker on RV function.

Methods And Results: All consecutive patients undergoing dual chamber pacemaker from January 2018 to March 2019 for AV block with a structurally normal heart were included.

Validation of electrocardiographic criteria for identifying left ventricular dysfunction in patients with previous myocardial infarction.

Background: Eleven criteria correlating electrocardiogram (ECG) findings with reduced left ventricular ejection fraction (LVEF) have been previously published. These have not been compared head-to-head in a single study. We studied their value as a screening test to identify patients with reduced LVEF estimated by cardiac magnetic resonance (CMR) imaging.

Simple electrocardiographic measures improve sudden arrhythmic death prediction in coronary disease.

Aims: To determine whether the combination of standard electrocardiographic (ECG) markers reflecting domains of arrhythmic risk improves sudden and/or arrhythmic death (SAD) risk stratification in patients with coronary heart disease (CHD).

Methods And Results: The association between ECG markers and SAD was examined in a derivation cohort (PREDETERMINE; N = 5462) with adjustment for clinical risk factors, left ventricular ejection fraction (LVEF), and competing risk. Competing outcome models assessed the differential association of ECG markers with SAD and competing mortality.

Estimating Myocardial Infarction Size With a Simple Electrocardiographic Marker Score.

Background Myocardial infarction (MI) size is a key predictor of prognosis in post-MI patients. Cardiovascular magnetic resonance (CMR) is the gold standard test for MI quantification, but the ECG is less expensive and more widely available. We sought to quantify the relationship between ECG markers and cardiovascular magnetic resonance infarct size.

Reference values of ECG parameters derived from 906 echocardiographically confirmed healthy Indian children: A population-based study from Gujarat.

Introduction: There are few published studies on reference ranges of ECG parameters in children; some ethnic differences have been described.

Methods: We studied digital 12‑lead ECGs (1000 samples/s) from 906 healthy rural Indian children (467 boys: 439 girls) aged 5-15 years. PR, QRS, and QT were measured using superimposed median beat.

A pilot study comparing two sites for incision during pacemaker implantation and their influence on the scar.

Objective: There are two most common incisions that are used during most pacemaker implantation procedures, with the first type of incision being inferior and parallel to the clavicle (Group C) and the second type of incision along the deltopectoral groove (Group D). We evaluated the scars resulting from the two types of incision to objectively evaluate the degree of superiority in cosmetic outcomes, between these two types of incisions.

Methods: Seventy-six patients who underwent left pre-pectoral pacemaker insertion were evaluated, close to 6 months after the date of the pacemaker implantation, using a simple scoring system based on atrophy, contour and colour of the scar.

For neonatal ECG screening there is no reason to relinquish old Bazett's correction.

Aims: There is an almost endless controversy regarding the choice of the QT correction formula to be used in electrocardiograms (ECG) in neonates for screening for long QT syndrome (LQTS). We compared the performance of four commonly used formulae and a new formula derived from neonates.

Methods And Results: From a cohort of 44 596 healthy neonates prospectively studied in Italy between 2001 and 2006, 5000 ECGs including 17 with LQTS-causing mutation identified by genotyping were studied using four QT correction formulae [Bazett's (QTcB), Fridericia's (QTcF), Framingham (QTcL), and Hodges (QTcH)].

Sudden Death in Patients With Coronary Heart Disease Without Severe Systolic Dysfunction.

Importance: The majority of sudden and/or arrhythmic deaths (SAD) in patients with coronary heart disease occur in those without severe systolic dysfunction, for whom strategies for sudden death prevention are lacking.

Objective: To provide contemporary estimates of SAD vs other competing causes of death in patients with coronary heart disease without severe systolic dysfunction to search for high-risk subgroups that might be targeted in future trials of SAD prevention.

Design, Setting, And Participants: This prospective observational cohort study included 135 clinical sites in the United States and Canada.

Individual-Specific QT Interval Correction for Drugs With Substantial Heart Rate Effect Using Holter ECGs Extracted Over a Wide Range of Heart Rates.

Although fixed QT correction methods are typically used to adjust for the effect of heart rate on the QT interval in thorough QT/QTc studies, individual-specific QT correction (QTcI = QT/RR ) is advisable for drugs that increase the heart rate by >5 to 10 beats/minute (bpm). QTcI is traditionally derived using resting drug-free electrocardiograms (ECGs) collected at prespecified times. However, the resting heart rate range in healthy individuals is narrow, and extrapolation of inferences from these data to higher heart rates could be inappropriate.

Atypical Variants of Takotsubo Cardiomyopathy: Twin Case Reports.

Takotsubo cardiomyopathy (TTC) is a well-known entity. We present two rare presentations of the same. Our first patient was diagnosed to have hypertrophic cardiomyopathy with ventricular tachycardia (VT), for which an ICD had been implanted.

Occult etiologies of complete atrioventricular block: Report of two cases.

In patients presenting with complete atrioventricular (AV) block, the common causes are degeneration of the conduction system, acute myocardial infarction, congenital and metabolic disorders (such as azotemia). However, at times, no cause can be ascribed and the label congenital or degenerative is applied depending on the patient's age and the QRS complex width. We present two cases of patients with complete AV block, who were subsequently found to have rare etiologies - sarcoidosis (with isolated feature of AV block) and non-Hodgkin's lymphoma.

Routine health check-ups: A boon or a burden?

Healthcare provider institutions in India now offer structured health check-up 'packages' for routine screening of common diseases. While some tests included within their ambit are in keeping with international and Indian recommendations, some are entirely unwarranted. Unnecessary and inappropriate screening tests may cause more harm than benefit.

Comparison of the spatial QRS-T angle derived from digital ECGs recorded using conventional electrode placement with that derived from Mason-Likar electrode position.

Background: The spatial QRS-T angle is ideally derived from orthogonal leads. We compared the spatial QRS-T angle derived from orthogonal leads reconstructed from digital 12-lead ECGs and from digital Holter ECGs recorded with the Mason-Likar (M-L) electrode positions.

Methods And Results: Orthogonal leads were constructed by the inverse Dower method and used to calculate spatial QRS-T angle by (1) a vector method and (2) a net amplitude method, in 100 volunteers.

Detecting moxifloxacin-induced QTc prolongation in thorough QT and early clinical phase studies using a highly automated ECG analysis approach.

Background And Purpose: Exposure-response (ER) modelling (concentration-QTc analysis) is gaining as much acceptance as the traditional by-time analysis of the placebo-adjusted change from baseline in the QTc interval (ΔΔQTcF). It has been postulated that intensive ECG analysis and ER modelling during early-phase drug development could be a cost-effective approach of estimating QT liability of a new drug, in a small number of subjects.

Experimental Approach: We used a highly automated analysis of ECGs from 46 subjects from a crossover thorough QT/QTc study to detect ΔΔQTcF with moxifloxacin.

Sudden Cardiac Death in India: A Growing Concern.

The incidence of sudden cardiac death (SCD) is based on studies from North America and Western Europe with very few countries in Asia having conducted robust studies evaluating the occurrence of SCD. This paper reviewed published data on SCD, with a focus on India. In recent years, varying methods of assessment such as verbal autopsies, questionnaires, and quantification of surrogate endpoints such as cardiovascular disease profiles have been used to estimate the incidence of SCD.

Comparison of two methods of estimating reader variability in QT interval measurements in thorough QT/QTc studies.

Background: Two methods of estimating reader variability (RV) in QT measurements between 12 readers were compared.

Methods: Using data from 500 electrocardiograms (ECGs) analyzed twice by 12 readers, we bootstrapped 1000 datasets each for both methods. In grouped analysis design (GAD), the same 40 ECGs were read twice by all readers.

Cardiovascular safety monitoring during oncology drug development and therapy.

Assessments of cardiac and cardiovascular toxicity are prominent components of drug safety endeavors during drug development and clinical practice. Oncologic drugs bring several challenges to both domains. First, during drug development, it is necessary to adapt the ICH E14 "Thorough QT/QTc Study" because the cytotoxic nature of many oncologics precludes their being administered to healthy individuals.

Drug-induced QT prolongation when QT interval is measured in each of the 12 ECG leads in men and women in a thorough QT study.

Lead II is commonly used to study drug-induced QT prolongation. Whether other ECG leads too show comparable QT prolongation is not known. We studied moxifloxacin-induced QT prolongation in a thorough QT study in healthy subjects (54 males, 43 females).

Reader variability in QT measurement due to measurement error and variability in leads selection: a simulation study comparing 2-way vs. 3-way interaction ANOVA model.

Reader variability (RV) results from measurement differences or variability in lead used for QT measurements; the latter is not reflected in conventional methods for estimating RV. Mean and SD of QT intervals in 12 leads of 100 ECGs measured twice were used to simulate data sets with inter-RV of 5, 10, 15, 20, and 25 ms and intra-RV of 3, 6, 9, 12, and 15 ms. Six hundred twenty-five data sets were simulated such that different leads were used in Read1 and Read2 in 0, 10%, 20%, 30%, 40% of ECGs by 25 readers.

Are women more susceptible than men to drug-induced QT prolongation? Concentration-QTc modelling in a phase 1 study with oral rac-sotalol.

Aim: To study the differences in QTc interval on ECG in response to a single oral dose of rac-sotalol in men and women.

Methods: Continuous 12-lead ECGs were recorded in 28 men and 11 women on a separate baseline day and following a single oral dose of 160 mg rac-sotalol on the following day. ECGs were extracted at prespecified time points and upsampled to 1000 Hz and analyzed manually in a central ECG laboratory on the superimposed median beat.

Choice of an alternative lead for QT interval measurement in serial ECGs when Lead II is not suitable for analysis.

Introduction: Conventionally, QT interval is measured in lead II. There are no data to select an alternative lead for QT measurement when it cannot be measured in Lead II for any reason.

Methods And Results: We retrospectively analyzed ECGs from 1906 healthy volunteers from 41 phase I studies.