Browsing by Author "Das, Mithilesh K."

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    Fragmented ECG as a risk marker in cardiovascular diseases
    (Bentham Science, 2014-08) Jain, Rahul; Singh, Robin; Yamini, Sundermurthy; Das, Mithilesh K.; Department of Medicine, IU School of Medicine
    Various noninvasive tests for risk stratification of sudden cardiac death (SCD) were studied, mostly in the context of structural heart disease such as coronary artery disease (CAD), cardiomyopathy and heart failure but have low positive predictive value for SCD. Fragmented QRS complexes (fQRS) on a 12-lead ECG is a marker of depolarization abnormality. fQRS include presence of various morphologies of the QRS wave with or without a Q wave and includes the presence of an additional R wave (R') or notching in the nadir of the R' (fragmentation) in two contiguous leads, corresponding to a major coronary artery territory. fQRS represents conduction delay from inhomogeneous activation of the ventricles due to myocardial scar. It has a high predictive value for myocardial scar and mortality in patients CAD. fQRS also predicts arrhythmic events and mortality in patients with implantable cardioverter defibrillator. It also signifies poor prognosis in patients with nonischemic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and Brugada syndrome. However, fQRS is a nonspecific finding and its diagnostic prognostic should only be interpreted in the presence of pertinent clinical evidence and type of myocardial involvement (structural vs. structurally normal heart).
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    Fragmented QRS Complexes on 12‐Lead ECG: A Marker of Cardiac Sarcoidosis as Detected by Gadolinium Cardiac Magnetic Resonance Imaging
    (Wiley, 2009-10) Homsi, Mohamed; Alsayed, Lamaan; Safadi, Bilal; Mahenthiran, Jo; Das, Mithilesh K.; Medicine, School of Medicine
    Background: Fragmented QRS complexes (fQRS) on a 12‐lead ECG are a marker of myocardial scar in patients with coronary artery disease. Cardiac sarcoidosis is also associated with myocardial granuloma formation and scarring. We evaluated the significance of fQRS on a 12‐lead ECG compared to Gadolinium‐delayed enhancement images (GDE) in cardiac magnetic resonance imaging (CMR). Method and results: The ECGs of patients (n = 17, mean age: 52 ± 11 years, male: 53%) with established diagnosis of sarcoidosis who underwent a CMR for evaluation of cardiac involvement were studied. ECG abnormalities included bundle branch block, Q wave, and fQRS. fQRS, Q wave, and bundle branch block were present in 9 (53%), 1 (6%), and 4 (24%) patients, respectively. The sensitivity and specificity of fQRS for detecting abnormal GDE were 100% and 80%, respectively. Sensitivity and specificity of Q waves were 11% and 100%, respectively. Conclusions: fQRS on a 12‐lead ECG in patients with suspected cardiac sarcoidosis are associated with cardiac involvement as detected by GDE on CMR.
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    Paroxysmal Lone Atrial Fibrillation Is Associated With An Abnormal Atrial Substrate: Characterizing The "Second Factor"
    (Cardiofront, 2009-08) Mitchell, Charles R.; Das, Mithilesh K.; Medicine, School of Medicine
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    Simulation of mechanical environment in active lead fixation: effect of fixation helix size
    (The American Society of Mechanical Engineers, 2011-06) Zhao, Xuefeng; Wenk, Jonathan F.; Burger, Mike; Liu, Yi; Das, Mithilesh K.; Combs, William; Ge, Liang; Guccione, Julius M.; Kassab, Ghassan S.; Biomedical Engineering, School of Engineering and Technology
    The risk of myocardial penetration due to active-fixation screw-in type pacing leads has been reported to increase as the helix electrodes become smaller. In order to understand the contributing factors for lead penetration, we conducted finite element analyses of acute myocardial micro-damage induced by a pacemaker lead screw-in helix electrode. We compared the propensity for myocardial micro-damage of seven lead designs including a baseline model, three modified designs with various helix wire cross-sectional diameters, and three modified designs with different helix diameters. The comparisons show that electrodes with a smaller helix wire diameter cause more severe micro-damage to the myocardium in the early stage. The damage severity, represented by the volume of failed elements, is roughly the same in the middle stage, whereas in the later stage the larger helix wire diameter generally causes more severe damage. The onset of myocardial damage is not significantly affected by the helix diameter. As the helix diameter increases, however, the extent of myocardial damage increases accordingly. The present findings identified several of the major risk factors for myocardial damage whose consideration for lead use and design might improve acute and chronic lead performance.
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    Ventricular tachycardia exacerbated by left bundle branch area pacing
    (Elsevier, 2023-06-28) Tanawuttiwat, Tanyanan; Kellett, Eric; Das, Mithilesh K.; Fore, Lukas J.; Miller, John M.; Medicine, School of Medicine