Comparison of t wave alternans in patients with cardiomyopathy and healthy controls

Objective: To compare T wave alternans in patients with cardiomyopathy and healthy controls

Study Design: Cross-sectional comparative study

Place and Duration of Study: Department of Cardiac Electrophysiology, Armed Forces Institute of Cardiology Rawalpindi, from Feb 2016 to Aug 2016

Material and Methods: Sixty patients with cardiomyopathy [any type] along with sixty healthy controls of matched age and gender were recruited through non-probability purposive sampling. Patients with diabetes mellitus, cerebrovascular accident, heart failure, bundle branch block, systemic arterial hypertension and ongoing antiarrhythmic therapy were excluded from the study. DMS 300-4L Holters were used to obtain ambulatory ECG recordings. Cardio Scan premier 12 lux software was used for analysis of T wave alternans

Results: Total one twenty subjects were enrolled in the study. Cardiomyopathic patients with positive T wave alternans were 13 [21.7 %] out of 60, while only 4 [6.7%] out of 60 healthy controls demonstrated positive T wave alternans. There was significant variation in frequency of patients with positive T wave alternans as compared to healthy controls with p-value of 0.02. In cases the mean value of T wave alternans was 55.10 micro v +/- 33.58 while 39.45 micro v +/- 13.53 in controls. The difference in mean value of T wave alternans between cases and controls was significant with p-value of 0.001

Conclusion: The frequency of patients with cardiomyopathy having positive T wave alternans was significantly higher as compared to the healthy controls

Comparison of ventricular late potentials in patients with cardiomyopathy and healthy controls

Background: Ventricular late potentials [VLPs] are low amplitude high frequency signals present in the terminal part of QRS complex detected by signal averaged ECG. They have emerged as robust tools for arrhythmia risk stratification in patients with cardiac diseases. Early detection of ventricular late potentials in patients with cardiomyopathy can help in risk stratification of ventricular arrhythmias leading to sudden cardiac death. The purpose of this study was to compare VLPs in patients with cardiomyopathy and healthy controls

Methods: The study was conducted in Department of Cardiac Electrophysiology, Armed Forces Institute of Cardiology, Rawalpindi. Sixty patients with cardiomyopathy [any type] along with 60 healthy controls were selected through non-probability purposive sampling. Patients meeting inclusion criteria were selected for Signal-Averaged ECG [SAECG]

Results: Ventricular late potentials were seen in 14 [23.3%] out of 60 patients with cardiomyopathy, while only 5 [8.3%] out of 60 healthy controls demonstrated ventricular late potentials. There was significant variation in frequency of patients with ventricular late potentials as compared to healthy controls [p=0.02]. The mean value of fQRS was 107.53+/-37.70 in cases while 80.32+/-24.19 in controls and the difference was statistically significant [p<0.001] while insignificant for RMS and LAS [p=0.52 and 0.87 respectively]

Conclusion: The frequency of patients with cardiomyopathy having ventricular late potentials is significantly higher compared to healthy controls

Association of ventricular late potentials with mitral regurgitation in patients with mitral valve prolapse

To determine association of ventricular late potentials with mitral valve regurgitation in patients with mitral valve prolapse. Descriptive cross sectional study. Armed Forces Institute of Cardiology/National Institute of Heart Diseases, Rawalpindi from May 2006 to February 2007. Thirty Seven Patients with confirmed diagnosis of mitral valve prolapse on 2 dimensional echo echocardiography were selected for the study. Patients having myocardial infarction, ischemic heart disease, hypertension and diabetes mellitus were excluded. Signal Averaged ECG of every patient was recorded using 1200 EPX High Resolution Electrocardiograph and was analyzed for the presence or otherwise of ventricular late potentials. Male to female ratio of study patients was 23:14 with mean age of 26.27 +/- 6.18 years. Twelve patients out of 37 had mitral valve regurgitation. Out of these, 8 [67%] patients had ventricular late potentials on signal averaged ECG. Only 1 [4%] patient without mitral valve regurgitation showed ventricular late potentials. Association between ventricular late potentials and mitral regurgtation was found statistically significant [p = 0.001]. Ventricular late potentials are hghly associated with mitral valve regurgitation in patients with mitral valve prolapse. These can act as noninvasive predictors of ventricular tachyarrhythmias and sudden cardiac death in these patients

Qt interval prolongation and ventricular arrhythmias in patients with chronic heart failure

To determine the association of QTc interval prolongation with ventricular arrhythmias in patients with chronic heart failure. Descriptive study. This study was conducted at Armed Forces Institute of Cardiology/National Institute of Heart Diseases, Rawalpindi, Pakistan from April 2013 to August 2013. Fifty three heart failure patients were monitored for 48 hours using ambulatory holter electrocardiography recorders. Digital ECG data was analyzed for QTc interval along with frequency and severity of arrhythmias. Association of prolonged QTc interval with ventricular arrhythmias and severity of arrhythmias was analyzed. Cardiac arrhythmias were observed in 79.2% patients. QT analysis revealed that 69.8% patients had prolonged QTc interval, 86.4% patients with prolonged QTc had ventricular arrhythmias. Of these 66% patients were found to have severe ventricular arrhythmias. Comparison of mean QTc interval of our study population with a reference value showed significantly higher QTc interval of our study group than the test value. Arrhythmia frequency and severity significantly increases with an increase in QTc interval in heart failure demonstrating association of prolonged QTc interval with high risk of severe ventricular arrhythmias and sudden cardiac death in chronic heart failure

Screening of High Risk Patients with Mitral Valve Prolapse - Role of Heart Rate Variability

To screen out patients with Mitral Valve Prolapse at high risk of ventricular arrhythmogenesis, based upon Heart Rate Variability. Department of Cardiac Electrophysiology Armed Forces Institute of Cardiology/National Institute of Heart Diseases, Rawalpindi from May 2007 to March 2008. This cross sectional study included 37 patients with mitral valve prolapse. Patients with acute or old myocardial infarction, diabetes mellitus, ischemic heart disease and systemic hypertension were excluded. Patients were holtered for 24 hours and time domain analysis of heart rate variability was carried out. Statistical time domain measures of heart rate variability i.e. SDNN, SDANN and RMSSD were calculated. Descriptive statistics were used to calculate frequencies and percentages of categorical variables using SPSS version 22. Mean values of SDNN, SDANN and RMSSD were 141.62 +/- 30.80, 125.16 +/- 25.58 and 28.40 +/- 8.06 milliseconds respectively. Two patients [5.40%] had reduced HRV in all the three indices. In one patient [2.70%] values of SDNN and SDANN were reduced whereas in another one patient [2.70%] the values of SDNN and RMSSD were reduced. In remaining one patient only SDNN was found to be reduced. There is a subset of patients with mitral valve prolapse with reduced heart rate variability which may be at risk of ventricular arrhythmogenesis

Impact of Functional Class of Heart Failure on Severity of Ventricular Arrhythmia

To study the impact offunctional class of heart failure [NYHA] on the severity of ventricular arrhythmias in patients with heart failurebased upon 48 hours ambulatory ECG [Holter] recordings. Descriptive cross sectional study. Study was conducted at Armed Forces Institute of Cardiology/Nationallnstitute of Heart Diseases, from April2013 to August 2013. A descriptive cross sectional study was conducted at Armed Forces Institute of Cardiology/National Institute of Heart Diseases, from April 2013 to August 2013. In 53 heart failure patients' detailed history and 2 dimensional echocardiography were recordedto assess the functional class and left ventricular ejection fraction. Patients were then subjected to 48-hour Holter monitoring using ambulatory [Holter] electrocardiography recorders. Digital ECG data was acquired and manually edited. Arrhythmias were analyzed for frequency, type and severity. Statistical analysis was done to determine associations between arrhythmia severity and NYHA class of heart failure. Male: female ratio was 3.4: 1with mean age of 60 years. Mean ejection fraction was 21.69% and 86% patients had NYHAclass Ill and IV. 57% of these patients also had severe cardiac arrhythmias. Prevalence and severity of arrhythmias in heart failure is dependent upon degree of ventricular dysfunction and presenting NYHA functional class.There is a significantly higher prevalence of severe ventriculararrhythmias amongst patients with reduced ejection fraction and advanced NYHA functional class

Heart rate variability from 24 hours versus 72 hours holter monitoring in patients with mitral valve prolapse

To compare recorded heart rate variability from 24 hours with that recorded from 72 hours holter monitoring in patients with mitral valve prolapse. Cross sectional study. Department of Clinical Cardiac Electrophysiology Armed Forces Institute of Cardiology/National Institute of Heart Diseases, Rawalpindi from May 2007 to March 2008. Patients from 15 to 38 years of age with confirmed diagnosis of mitral valve prolapse on 2 dimensional echocardiography were included. Patients with acute myocardial infarction [MI], Ischemic heart disease, diabetes mellitus or hypertension were excluded. Total 37 patients were included in the study through non-probability consecutive sampling. All these patients underwent 72 hours holter monitoring using Reynolds medical holter monitors 'life card CF'. Statistical time domain measures of heart rate variability i.e. standard deviation of all NN intervals [SDNN], standard deviation of the averages of NN intervals [SDANN] and square root of the mean of the squares of differences between adjacent NN intervals [RMSSD]. Mean values of SDNN, SDANN and RMSSD from 24 hours holter monitoring were 141.62 ms, 125.16 ms and 28.40 ms whereas those recorded from 48 hours of holter monitoring were 136.94 ms, 122.37 ms and 26.46 ms respectively. Difference between none of the variables from the two recordings was significant. Heart rate variability remains the same irrespectively of the length of holter monitoring

Types and frequency of cardiac arrhythmias in patients with heart failure

To determine the types and frequency of cardiac arrhythmias in patients with heart failure based on 48 hours ambulatory ECG recordings. Cross sectional descriptive study. Armed Forces Institute of Cardiology/National Institute of Heart Diseases, from April 2013 to August 2013. Fifty three heart failure patients with ejection fraction of