Issues in QT interval measurement

The QT interval, apart from clinical implications is crucial for safety assessment of new drugs under development. A QTc prolongation of even 10 msec in a study group is a warning signal for a new drug. There are various issues involved in the measurement of the QT interval especially regarding the ending of the T wave and different morphological pattern of T-U complex. The other issue is significant spontaneous variability in the QT interval, resulting in spurious QT prolongation and unnecessary concern. To minimize all these confounding factors, all clinical trials for assessing QT interval prolongation should be randomized and double blinded with appropriate control groups including placebo. ECG measurements should be done by trained readers with electronic calipers at ECG core Lab. ECGs should be compared with multiple baseline values with multiple, time-matched on-treatment values

Local Anaesthesia Suppressing Idiopathic Ventricular Tachycardia - A Cause of Non-inducible Arrhythmia During Electrophysiology Study

AbstractA 13year old boy having idiopathic ventricular tachycardia had non-inducible tachycardia twice on electrophysiology (EP) study due to suppression of arrhythmia by local anaesthetic agent, lignocaine. This case report demonstrates a cause of non-inducibility or arrhythmia during EP study and effect of lignocaine in suppression of idiopathic ventricular tachycardia

Evaluation of Syncope: An Overview

Syncope is defined as a sudden temporary loss of consciousness associated with a loss of postural tone, with spontaneous recovery that does not require electrical or chemical cardioversion. Syncope is a common symptom, accounting for 1% to 6% of hospital admission and up to 3% of emergency room visits. Loss of consciousness is also common in healthy young adults, although most do not seek medical attention. Syncope is a frequent symptom in the elderly. The evaluation and management of syncope has dramatically changed over the past 15 years. In the early 1980s, several studies showed that the cause of syncope was often not established, and subgroups were identified with high mortality and sudden death rates.1,2 ,3, 4 Later a large number of studies on electrophysiology testing appeared, which led to a better understanding of the roles and limitations of tests in syncope.5,6,7,8 Although tilt table testing started in 1980s, it assumed an important role in the evaluation of syncope in 1990s, showing that neurally mediated mechanism is a common etiology of unexplained syncope.9,10,11,12 The purpose of this article is to highlight the clinical approach and management of syncope

Digitalis toxicity: ECG vignette

Abstract“Digitalis toxicity, often candidly indexed as poisoning, has plagued the medical profession for over 200 years. The situation qualifies as a professional disgrace on the basis of three items: the situation persists, physicians are often slow to recognize it and, over the decades, writers have been harsh in their denunciation of fellow physicians when toxicity has occurred….” These are the opening remarks of an essay published in 1983 on the 2nd centenary of William Withering's ‘magic potion from foxglove's extract for dropsy.’ Even today, after many decades, these words appear relevant! We present and discuss an interesting ECG of digitalis toxicity

Occult etiologies of complete atrioventricular block: Report of two cases

AbstractIn 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

Peeling off the Mask: Pseudo Myocardial Infarction Pattern on Electrocardiogram During AICD Implantation

AbstractLead induced transient right bundle branch block is not uncommon during pacemaker implantation. We describe a patient with old anterior wall myocardial infarction with severe left ventricular dysfunction presenting with recurrent ventricular tachycardia who developed transient right bundle branch block and pseudomyocardial infacrction pattern during AICD implantation

Editorial - Hypertrophic Cardiomyopathy: The Elusive Terrorist?

Described a century ago, hypertrophic cardiomyopathy (HCM) is a unique disease with characteristic inappropriate myocardial hypertrophy that occurs in the absence of obvious cause for hypertrophy.(1-5) The macroscopic and microscopic features of this disease have been under detailed study since 1950. This is particularly significant in the background of it being one of the most common genetically transmitted cardiac disorders. There is scant data regarding this in Indian literature. In this context, the present study by Phadke et al of 14 cases of HCM is commendable. Phadke et al have critically analysed the pathological data of 14 retrospective cases of HCM. Their study spans 15 years during which time they confirmed HCM in about 14% of all cases of cardiomyopathy as identified in post-mortem. The macroscopic features include marked myocardial hypertrophy with relatively small left ventricular cavity. The finding that predominant left ventricular involvement is commoner than right ventricular is commensurate with our clinical experience..

Arrhythmia Care In India - Poised For The Big Leap

Till the late 1980s, there was precious little one could do to permanently cure arrhythmias. Cardiac surgery did not live up to its promise for ventricular tachycardia. For WPW syndrome, surgery was too invasive a procedure, with a significant chance of major complications. Electrophysiologists spent hours trying to unravel tachycardia mechanisms, and were often referred to as "electrophilosophers". Since the advent of RF ablation, this scenario underwent a sea change. Suddenly one was able to get rid of many arrhythmias with a much less invasive procedure. Electrophysiology centers mushroomed and got upgraded in the developed world

Hypertrophic cardiomyopathy: the elusive terrorist?

Described a century ago, hypertrophic cardiomyopathy (HCM) is a unique disease with characteristic inappropriate myocardial hypertrophy that occurs in the absence of obvious cause for hypertrophy.(1-5) The macroscopic and microscopic features of this disease have been under detailed study since 1950. This is particularly significant in the background of it being one of the most common genetically transmitted cardiac disorders. There is scant data regarding this in Indian literature. In this context, the present study by Phadke et al of 14 cases of HCM is commendable. Phadke et al have critically analysed the pathological data of 14 retrospective cases of HCM. Their study spans 15 years during which time they confirmed HCM in about 14% of all cases of cardiomyopathy as identified in post-mortem. The macroscopic features include marked myocardial hypertrophy with relatively small left ventricular cavity. The finding that predominant left ventricular involvement is commoner than right ventricular is commensurate with our clinical experience..

Atrial Fibrillation Ablation - Are we ready?

Atrial fibrillation (AF) is the most common arrhythmia in day to day practice. It contributes to morbidity in the form of heart failure and stroke and increased overall and cardiovascular mortality1. Moreover, no treatment of AF to date has resulted in a lower overall death rate. Anti arrhythmic therapy for AF may also contribute to increased mortality in this subgroup2. Even though AFFIRM investigators showed no apparent benefit from rhythm control, these results cannot be generalized to younger patients, more symptomatic patients and those with rheumatic valvular disease. Catheter ablation for the same seems to be an attractive approach