Ranjan K. Thakur

Michigan State University, Ист-Лансинг, Michigan, United States

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Publications (170)484.56 Total impact

  • Ranjan K Thakur · Andrea Natale
    Cardiac electrophysiology clinics 09/2015; 7(3):xiii. DOI:10.1016/j.ccep.2015.07.002
  • Ranjan K Thakur · Andrea Natale
    Cardiac electrophysiology clinics 06/2015; 7(2):xiii. DOI:10.1016/j.ccep.2015.04.001
  • [Show abstract] [Hide abstract]
    ABSTRACT: Life-threatening ventricular arrhythmias (VAs) and sudden cardiac death (SCD) are common in patients awaiting heart transplantation (HT), and the implantable cardioverter-defibrillator (ICD) is often used for primary prevention in this setting. Use of ICDs in these patients is not without risks and is sometimes contraindicated. The wearable cardioverter-defibrillator (WCD) may be a reasonable alternative to bridge the period of risk leading up to HT. We obtained a convenience sample of patients prescribed an WCD as a bridge therapy to HT. The available data consisted of demographics, cardiac transplantation status, associated comorbidities, device use, device-stored electrocardiogram (ECG) and reason for discontinuing the WCD. Statistical analyses were performed using SPSS version 17 and GraphPad PRISM 5. The registry included 121 patients consisting of 83 (69%) men and 38 (31%) women. The mean age was 44 ± 18 years. Mean ejection fraction was 25 ± 15%. Non-ischemic cardiomyopathy (CMP) was the underlying diagnosis in 67 (55%) patients, whereas 21 (17%) patients had ischemic CMP and 33 (27%) had a mixed or uncharacterized CMP. New York Heart Association Class III heart failure was present in 32% and 34% were in Class IV. Eighty-eight patients (73%) were being evaluated for HT or were on an HT waiting list, and 33 patients (27%) had had a prior HT, experienced rejection, and were awaiting re-transplantation. The patients wore the WCD for an average of 127 ± 392 days (median 39 days) with average daily use of 17 ± 7 hours (median 20 hours). Seven patients (6%) received appropriate WCD shocks. Fifty-one patients (42%) ended use after ICD implantation and 13 patients (11%) after HT. There were 11 deaths (9%). A significant proportion of patients on the HT waiting list will have VA. WCD use in our study showed high compliance and efficacy and a low complication rate, suggesting that the WCD is a reasonable bridge therapy for preventing SCD in patients awaiting HT. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.
    The Journal of Heart and Lung Transplantation 05/2015; DOI:10.1016/j.healun.2015.04.004 · 6.65 Impact Factor
  • Ranjan K. Thakur · Andrea Natale
    04/2015; 1(1):1-2. DOI:10.12945/j.agr.2015.00024-14
  • Source
    Vini Singh · Negar Salehi · Ranjan Kumar Thakur
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    ABSTRACT: Adenosine is an effective agent for termination of most re-entrant supraventricular arrhythmias involving the atrioventricular node and often also used as a diagnostic agent for wide QRS tachycardias. Adenosine terminates 90–99% of re-entrant supraventricular tachycardias but it may rarely accelerate tachycardias. Adenosine-induced tachycardia acceleration is a rare phenomenon, as only a handful of cases have been described in the literature. We present a case of a 36-year-old man with a narrow complex, short RP tachycardia at a rate of 165 bpm and an initial blood pressure of 110/78 mm Hg. A bolus of 12 mg of adenosine resulted in slowing of the tachycardia to 150 bpm for 2–3 s, followed by acceleration of the tachycardia to 185 bpm that lasted for approximately 20 s and returned to baseline at 165 bpm. The main mechanism of adenosine-induced acceleration may be the secondary sympathetic stimulation, which may be preceded by transient bradycardia and/or hypotension.
    Year: 01/2015
  • Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 12/2014; 6(4). DOI:10.1016/j.ccep.2014.08.010
  • Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 09/2014; 6(3). DOI:10.1016/j.ccep.2014.06.002
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Takotsubo cardiomyopathy (TCM) is generally a reversible cardiomyopathy with a favorable prognosis. Because of a risk of sudden cardiac death (SCD), a wearable cardioverter-defibrillator (WCD) is occasionally prescribed, although its utility is unknown. We reviewed a national database of TCM patients who were prescribed a WCD. The database collected baseline demographics, left ventricular ejection fraction (EF), usage compliance, documented arrhythmias, and final survival status. One-hundred and two patients with mean age 63¡12 years, 11% men, had an initial EF of 27¡7% at the time of WCD prescription. The mean days of use was 44¡31 days, with an average daily hours used of 20¡4 hours. The average follow-up period was 440¡374 days and 95% of patients wore the WCD .90% of prescribed days. Two patients (2%) experienced shocks for ventricular arrhythmias (VAs) and survived; two patients (2%) experienced significant bradyarrhythmias; one patient received two inappropriate shocks due to signal artifact; no patients experienced a detection failure; two patients died during the prescription period: one with asystole, and one while not wearing the WCD; five patients died after discontinuing WCD usage, two of whom had an EF 35% at the time of WCD discontinuation. The WCD was used with a compliance of .90%. The device detected VAs reliably with a low risk of inappropriate shocks. TCM may be associated with a significant risk of death due to tachy-or bradyarrhythmias and the risk of SCD may persist even if the EF improves. KEYWORDS. LifeVest, sudden cardiac death, Takotsubo cardiomyopathy, wearable cardioverter defibrillator. ISSN 2156-3977 (print) ISSN 2156-3993 (online) ' 2014 Innovations in Cardiac Rhythm Management
    Journal of the American College of Cardiology 08/2014; August(2014). DOI:10.1016/S0735-1097(13)60361-7 · 16.50 Impact Factor
  • Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 06/2014; 6(2):xiii. DOI:10.1016/j.ccep.2014.04.002
  • Source
    Journal of the American College of Cardiology 04/2014; 63(12). DOI:10.1016/S0735-1097(14)60296-5 · 16.50 Impact Factor
  • Samuel J. Asirvatham · Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 03/2014; 6(1):xiii–xiv. DOI:10.1016/j.ccep.2013.12.001
  • Cardiac electrophysiology clinics 03/2014; 6(1):169–180. DOI:10.1016/j.ccep.2013.10.004
  • Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 09/2013; 5(3):ix–x. DOI:10.1016/j.ccep.2013.07.002
  • Source
    Mehul B Patel · Khyati Pandya · Ranjan K Thakur
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    ABSTRACT: Upper limit of vulnerability (ULV) testing using T-wave scanning shocks at multiple coupling intervals correlates well with defibrillation threshold (DFT), but remains underutilized in clinical practice. We measured DFT and ULV at a single coupling interval (SCI), with the aim to identify adequate safety margin at a coupling interval that correlates best with DFT. Consecutive patients undergoing implantable cardioverter defibrillator implantation underwent simultaneous SCI-ULV and DFT assessment. Following a drive train of 400 ms, a T-wave-coupled shock was delivered. To minimize shocks, patients were randomized to programmed shock at 20 ms before peak (Group I), at peak (Group II), or 20 ms after peak (Group III) of T wave. An initial T-wave test shock at 9 J was followed by ±2 J shocks, until SCI-ULV was ascertained. Device rescue shocks were programmed at test shock +2 J and +4 J shocks followed by external rescue shock. There were 200 patients: 66 patients in Group I, 67 patients each in Groups II and III; mean age was 68.9 ± 12.4 years; 75% of patients men, 66% with ischemic heart disease and mean ejection fraction of 27.1 ± 7.1%. Overall, the mean number of ventricular fibrillation induction was 1.39 ± 0.8, mean SCI-ULV energy was 7.97 ± 3.39 J, and mean DFT was 8.68 ± 3.19 J. The correlation between SCI-ULV and DFT improved from Group I to Group III and was best in Group III (r(2) = 0.689). There were no major adverse events. SCI-ULV measured 20 ms after the peak of the T wave correlates well with DFT for assessment of adequate safety margin.
    Pacing and Clinical Electrophysiology 08/2013; 37(1). DOI:10.1111/pace.12251 · 1.13 Impact Factor
  • Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 06/2013; 5(2):xi–xii. DOI:10.1016/j.ccep.2013.03.001
  • Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 03/2013; 5(1):xiii–xiv. DOI:10.1016/j.ccep.2013.01.017
  • Peerawut Deeprasertkul · Asim Yunus · Ranjan Thakur
    Europace 02/2013; 15(7). DOI:10.1093/europace/eut003 · 3.67 Impact Factor
  • Ranjan Thakur · Andrea Natale
    Cardiac electrophysiology clinics 12/2012; 4(4):xvii. DOI:10.1016/j.ccep.2012.10.001
  • Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 09/2012; 4(3):xiii–xiv. DOI:10.1016/j.ccep.2012.06.010
  • Ranjan K. Thakur · Andrea Natale
    Cardiac electrophysiology clinics 06/2012; 4(2):xiii–xiv. DOI:10.1016/j.ccep.2012.03.003

Publication Stats

2k Citations
484.56 Total Impact Points


  • 1995–2015
    • Michigan State University
      • • Division of Cardiology
      • • Thoracic and Cardiovascular Institute
      • • Department of Internal Medicine
      Ист-Лансинг, Michigan, United States
    • University of Guelph
      Guelph, Ontario, Canada
    • Correctional Service of Canada
      Ottawa, Ontario, Canada
  • 2011
    • Lehigh Valley Health Network
      Allentown, Pennsylvania, United States
  • 2010
    • University of Michigan
      • Division of Cardiovascular Medicine
      Ann Arbor, Michigan, United States
  • 2002–2010
    • Sparrow Health System
      Lansing, Michigan, United States
    • King Edward Memorial Hospital
      Mumbai, Maharashtra, India
    • KEM Hospital
      Poona, Mahārāshtra, India
  • 1989–2002
    • Medical College of Wisconsin
      • Division of Cardiology
      Milwaukee, Wisconsin, United States
  • 1993–1997
    • The University of Western Ontario
      • Department of Medicine
      London, Ontario, Canada