Deepak Bhakta

Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States

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Publications (34)210.89 Total impact

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  • Deepak Bhakta, Lynne D. Foreman
    Trends in Cardiovascular Medicine 02/2015; DOI:10.1016/j.tcm.2015.02.009 · 2.07 Impact Factor
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    ABSTRACT: -The cardiac cytoskeleton plays key roles in maintaining myocyte structural integrity in health and disease. In fact, human mutations in cardiac cytoskeletal elements are tightly linked with cardiac pathologies including myopathies, aortopathies, and dystrophies. Conversely, the link between cytoskeletal protein dysfunction in cardiac electrical activity is not well understood, and often overlooked in the cardiac arrhythmia field. -Here, we uncover a new mechanism for the regulation of cardiac membrane excitability. We report that βII spectrin, an actin-associated molecule, is essential for the post-translational targeting and localization of critical membrane proteins in heart. βII spectrin recruits ankyrin-B to the cardiac dyad, and a novel human mutation in the ankyrin-B gene disrupts the ankyrin-B/βII spectrin interaction leading to severe human arrhythmia phenotypes. Mice lacking cardiac βII spectrin display lethal arrhythmias, aberrant electrical and calcium handling phenotypes, and abnormal expression/localization of cardiac membrane proteins. Mechanistically, βII spectrin regulates the localization of cytoskeletal and plasma membrane/sarcoplasmic reticulum protein complexes that include the Na/Ca exchanger, RyR2, ankyrin-B, actin, and αII spectrin. Finally, we observe accelerated heart failure phenotypes in βII spectrin-deficient mice. -Our findings identify βII spectrin as critical for normal myocyte electrical activity, link this molecule to human disease, and provide new insight into the mechanisms underlying cardiac myocyte biology.
    Circulation 01/2015; DOI:10.1161/CIRCULATIONAHA.114.013708 · 14.95 Impact Factor
  • Deepak Bhakta, Rahul Jain
    Heart rhythm: the official journal of the Heart Rhythm Society 03/2013; 10(5). DOI:10.1016/j.hrthm.2013.01.025 · 4.92 Impact Factor
  • William J Groh, Deepak Bhakta
    JAMA The Journal of the American Medical Association 07/2012; 308(4):337-8; author reply 338. DOI:10.1001/jama.2012.6807 · 30.39 Impact Factor
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    ABSTRACT: There is controversy whether proceduralist-directed, nurse-administered propofol sedation (PDNAPS) is safe. To assess the frequency of adverse events when PDNAPS is used for implantable cardioverter-defibrillator (ICD)-related procedures and to determine the patient and procedural characteristics associated with adverse events. Consecutive ICD-related procedures using PDNAPS from May 2006 to July 2009 at a tertiary-care hospital were evaluated. Serious adverse events were defined as procedural death, unexpected transfer to an intensive care unit, respiratory failure requiring intubation/bag-mask ventilation, or hypotension requiring vasoconstrictor/inotrope support. Nonserious adverse events were defined as hypotension requiring fluid resuscitation or hypoxemia requiring augmented respiratory support with non-rebreather mask, oral airway, or jaw lift. Of 582 patients (age 64 ± 14 years, 72.3% males) undergoing ICD-related procedures using PDNAPS, 58 (10.0%) patients had serious adverse events with no procedural death and 225 (38.7%) had nonserious adverse events. Longer procedure duration (relative risk [RR] = 2.1 per hour; 95% confidence interval [CI] = 1.6-2.8; P < .001) and biventricular implant (RR = 2.7; CI = 1.4-5.3; P = .003) were independent predictors of serious adverse events. A longer procedure duration (RR = 1.4 per hour; CI = 1.1-1.7; P = .001), heart failure class (RR = 1.4 per 1 class; CI = 1.1-1.7; P = .002), and use of propofol infusion (RR = 3.5; CI = 2.2-5.7; P < .001) were independent predictors of nonserious adverse events. PDNAPS for shorter ICD procedures including single- and dual-chamber implants, generator changes, and defibrillation threshold testing have acceptable rates of serious adverse events and manageable nonserious adverse events and should be considered for further study. Biventricular implants and other complex procedures should be done with an anesthesiologist.
    Heart rhythm: the official journal of the Heart Rhythm Society 03/2012; 9(3):342-6. DOI:10.1016/j.hrthm.2011.10.009 · 4.92 Impact Factor
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    ABSTRACT: We assessed implant rates, indications, characteristics, and outcomes in patients with the neuromuscular disease, myotonic dystrophy type 1 (DM1) receiving a pacemaker or an implantable cardioverter-defibrillator (ICD). Device use was evaluated in a prospective, multicenter registry of 406 genetically confirmed adult patients followed for 9.5 ± 3.2 years. Forty-six (11.3%) had or received a pacemaker and 21 (5.2%) received an ICD. Devices were primarily implanted for asymptomatic conduction abnormalities and left ventricular (LV) systolic dysfunction. However, 7 (15.2%) pacemakers were implanted for third-degree atrioventricular block and 6 (28.6%) ICDs were implanted for ventricular tachyarrhythmias (ventricular tachycardia [VT] or fibrillation [VF]). Patients receiving devices were older and more frequently had heart failure, LV systolic dysfunction, atrial tachyarrhythmias, and ECG conduction abnormalities compared to nondevice patients. Five (10.9%) pacemaker patients underwent upgrade to an ICD, 3 for LV systolic dysfunction, 1 for VT/VF, and 1 for progressive conduction disease. Seventeen (27.4%) of the 62 patients with devices were pacemaker-dependent at last follow-up. Three (14.3%) ICD patients had appropriate therapies. Twenty-four (52.2%) pacemaker patients died including 13 of respiratory failure and 7 of sudden death. Seven (33.3%) ICD patients died including 2 of respiratory failure and 3 of sudden death. The patients with ICDs and sudden death all had LV systolic dysfunction and 1 death was documented due to inappropriate therapies.  DM1 patients commonly receive antiarrhythmia devices. The risk of VT/VF and sudden death suggests that ICDs rather than pacemakers should be considered for these patients.
    Journal of Cardiovascular Electrophysiology 12/2011; 22(12):1369-75. DOI:10.1111/j.1540-8167.2011.02200.x · 2.88 Impact Factor
  • Deepak Bhakta, Lynne D Foreman
    Heart rhythm: the official journal of the Heart Rhythm Society 08/2011; 8(12):1887-8. DOI:10.1016/j.hrthm.2011.08.018 · 4.92 Impact Factor
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    ABSTRACT: Cardiac tamponade (CT) is a possible complication of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Although the incidence of CT is not higher when RFCA is performed with a therapeutic international normalized ratio (INR), outcomes of CT are unclear. We compared outcomes among patients with and without a therapeutic INR who developed CT as a complication of RFCA of AF. The subjects of this retrospective study were 40 consecutive patients who developed CT during RFCA of AF at 3 centers. We divided the patients into 2 groups: RFCA performed with INR < 2 (group 1) and INR ≥ 2 (group 2). There were 23 patients in group 1 and 17 patients in group 2. Baseline clinical and procedure characteristics were not different between the 2 groups. Heparin was reversed by protamine in 83% and 94% of patients (P = .37), and warfarin was reversed by fresh frozen plasma or factor VIIa in 17% and 35% of patients (P = .27) in groups 1 and 2, respectively. All patients were successfully treated by percutaneous drainage, and none required surgical intervention. There were no significant differences in the amount of initial pericardial drainage (523 ± 349 ml vs. 409 ± 157 ml, P = .22) or the duration of drainage (P = .14) between the 2 groups. All patients survived to hospital discharge. Median length of hospital stay was 2 days longer in group 1 (P <.01). Cardiac tamponade is not more severe or difficult to manage in the presence of therapeutic anticoagulation with warfarin in patients undergoing RFCA of AF.
    Heart rhythm: the official journal of the Heart Rhythm Society 06/2011; 8(6):805-8. DOI:10.1016/j.hrthm.2011.01.020 · 4.92 Impact Factor
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    ABSTRACT: Myotonic dystrophy type 1 (DM1) is a neurologic disorder with known cardiac involvement, including left ventricular systolic dysfunction (LVSD), heart failure (HF), atrioventricular and intraventricular conduction system disease, and sudden death. We studied the prevalence of these conditions and associated findings in a large population with DM1. History, physical examination, genetic testing, and electrocardiography were performed on 406 patients with DM1, and cardiac imaging was performed on 180 (44.3%) of these patients. Left ventricular systolic dysfunction and clinical HF were found in 34 (18.9%) of 180 and in 23 (5.7%) of 406 of enrolled subjects, respectively, yielding an overall prevalence of LVSD/HF in 41 (10.1%) of 406. Increasing age, male sex, electrocardiographic conduction abnormalities, presence of atrial and ventricular arrhythmias, and implanted devices were all significantly associated with LVSD/HF, whereas cytosine-thiamine-guanine repeat length and neuromuscular severity score were not. The interval≥240 milliseconds (relative risk 4.1, 95% CI 1.7-9.6, P=.001) and QRS duration≥120 milliseconds (relative risk 4.2, 95% CI 2.0-8.5, P<.001) were significant predictors of LVSD/HF. The presence of LVSD/HF was also significantly associated with all-cause death (relative risk 3.9, 95% CI 2.3-6.4, P<.001) and cardiac death (relative risk 5.7, 95% CI 2.6-12.4, P<.001). A significant prevalence of LVSD/HF exists in patients with DM1. The presence of LVSD/HF in DM1 is significantly associated with all-cause and cardiac death.
    American heart journal 12/2010; 160(6):1137-41, 1141.e1. DOI:10.1016/j.ahj.2010.07.032 · 4.56 Impact Factor
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    ABSTRACT: Nonischemic dilated cardiomyopathy (NICM) is associated with diffuse global hypokinesia on echocardiography. However, NICM also may be associated with segmental wall-motion abnormalities (SWMAs) even in the presence of global hypokinesia, probably secondary to patchy myocardial scars. Because myocardial scars serve as substrate for reentry, the purpose of this study was to determine whether SWMA is a predictor of ventricular arrhythmic events in NICM. Echocardiographic parameters and appropriate implantable cardioverter-defibrillator (ICD) therapy for arrhythmic events (shock or antitachycardia pacing) were studied in NICM patients with an ICD. Two-dimensional echocardiography of the left ventricle was recorded in a 16-segment model. SWMA was defined by the presence of akinesia or moderate to severe hypokinesia in at least two segments. Patients were divided into one of two groups according to the presence (SWMA group) or the absence (non-SMWA group) of SWMA. SWMA was present in 47.5% of 101 patients (mean age 58.0 ± 15.6 years, 85% male, primary prophylaxis indication 46%, mean ejection fraction 26% ± 9%, mean follow-up 29 ± 18.4 months) studied. No significant difference in mean age, ejection fraction, and QRS duration was seen between SWMA and non-SWMA groups. The SWMA group had a significantly higher incidence of arrhythmic events than did the non-SWMA group (65% vs 15%, P <.001). Kaplan-Meier survival analysis revealed that SMWA was associated with significantly reduced time to first arrhythmic event (P = .001). SWMA (P <0.001), New York Heart Association heart failure class (P = .016), and secondary prevention indication for ICD placement (P = .005) were significant independent predictors of an arrhythmic event. SWMA did not predict mortality. SWMA is an independent predictor of arrhythmic events in patients with NICM.
    Heart rhythm: the official journal of the Heart Rhythm Society 10/2010; 7(10):1390-5. DOI:10.1016/j.hrthm.2010.05.039 · 4.92 Impact Factor
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    Mark Alber Meshil, Deepak Bhakta
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    ABSTRACT: In recent years, nonpharmacological therapies for atrial fibrillation (AF) have emerged given the limitations of medical therapy. Advancements in particular have been made in the areas of radiofrequency catheter ablation and AF surgery, and have been accompanied by substantial technological improvements. This article will discuss several different modalities of nonpharmacological AF management including catheter ablation, AF surgery and device-based therapy.
    Cardiovascular Therapeutics 10/2010; 28(5):264-77. DOI:10.1111/j.1755-5922.2010.00199.x · 2.54 Impact Factor
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    Journal of the American College of Cardiology 03/2010; 55(10). DOI:10.1016/S0735-1097(10)60117-9 · 15.34 Impact Factor
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    ABSTRACT: Myocardial scar is a substrate for reentrant ventricular arrhythmias and is associated with poor prognosis. Fragmented QRS (fQRS) on 12-lead ECG represents myocardial conduction delays due to myocardial scar in patients with coronary artery disease (CAD). The purpose of this study was to determine whether fQRS is associated with increased ventricular arrhythmic event and mortality in patients with CAD and nonischemic dilated cardiomyopathy (DCM). Arrhythmic events and mortality were studied in 361 patients (91% male, age 63.3 +/- 11.4 years, mean follow-up 16.6 +/- 10.2 months) with CAD and DCM who received an implantable cardioverter-defibrillator for primary or secondary prophylaxis. fQRS included various RSR' patterns (QRS duration <120 ms), such as > or =1 R prime or notching of the R wave or S wave present on at least two contiguous leads of those representing anterior (V(1)-V(5)), lateral (I, aVL, V(6)), or inferior (II, III, aVF) myocardial segments. fQRS was present in 84 (23%) patients (fQRS group) and absent in 100 (28%) patients (non-fQRS group). Wide QRS (wQRS; QRS duration > or =120 ms) was present in 177 (49%) patients. Kaplan-Meier analysis revealed that event-free survival for an arrhythmic event (implantable cardioverter-defibrillator shock or antitachycardia pacing) was significantly lower in the fQRS group than in the non-fQRS and wQRS groups (P <.001 and P <.019, respectively). fQRS was an independent predictor of an arrhythmic event but not of death. fQRS on 12-lead ECG is a predictor of arrhythmic events in patients with CAD and DCM. fQRS is associated with a significantly decreased time to first arrhythmic event compared with non-fQRS and wQRS.
    Heart rhythm: the official journal of the Heart Rhythm Society 01/2010; 7(1):74-80. DOI:10.1016/j.hrthm.2009.09.065 · 4.92 Impact Factor
  • Muscle & Nerve 11/2009; 40(5):901-2. DOI:10.1002/mus.21345 · 2.31 Impact Factor
  • Cardiac Mapping, Third Edition, 02/2009: pages 366 - 375; , ISBN: 9781444303438
  • John M Miller, Deepak Bhakta, Mithilesh K Das
    Journal of Cardiovascular Electrophysiology 10/2008; 20(2):145-6. DOI:10.1111/j.1540-8167.2008.01308.x · 2.88 Impact Factor
  • Deepak Bhakta, Lynne D Foreman
    Heart rhythm: the official journal of the Heart Rhythm Society 09/2008; 5(8):1204-5. DOI:10.1016/j.hrthm.2008.05.005 · 4.92 Impact Factor
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    ABSTRACT: Sudden death can occur as a consequence of cardiac-conduction abnormalities in the neuromuscular disease myotonic dystrophy type 1. The determinants of the risk of sudden death remain imprecise. We assessed whether the electrocardiogram (ECG) was useful in predicting sudden death in 406 adult patients with genetically confirmed myotonic dystrophy type 1. A patient was characterized as having a severe abnormality if the ECG had at least one of the following features: rhythm other than sinus, PR interval of 240 msec or more, QRS duration of 120 msec or more, or second-degree or third-degree atrioventricular block. Patients with severe abnormalities according to the entry ECG were older than patients without severe abnormalities, had more severe skeletal-muscle impairment, and were more likely to have heart failure, left ventricular systolic dysfunction, or atrial tachyarrhythmia. Such patients were more likely to receive a pacemaker or an implantable cardioverter-defibrillator during the follow-up period. During a mean follow-up period of 5.7 years, 81 patients died; there were 27 sudden deaths, 32 deaths from progressive neuromuscular respiratory failure, 5 nonsudden deaths from cardiac causes, and 17 deaths from other causes. Among the 17 patients who died suddenly in whom postcollapse rhythm was evaluated, a ventricular tachyarrhythmia was observed in 9. A severe ECG abnormality (relative risk, 3.30; 95% confidence interval [CI], 1.24 to 8.78) and a clinical diagnosis of atrial tachyarrhythmia (relative risk, 5.18; 95% CI, 2.28 to 11.77) were independent risk factors for sudden death. Patients with adult myotonic dystrophy type 1 are at high risk for arrhythmias and sudden death. A severe abnormality on the ECG and a diagnosis of an atrial tachyarrhythmia predict sudden death. (ClinicalTrials.gov number, NCT00622453.)
    New England Journal of Medicine 07/2008; 358(25):2688-97. DOI:10.1056/NEJMoa062800 · 54.42 Impact Factor

Publication Stats

472 Citations
210.89 Total Impact Points

Institutions

  • 2003–2015
    • Indiana University-Purdue University Indianapolis
      • • Krannert Institute of Cardiology
      • • Department of Medicine
      Indianapolis, Indiana, United States
  • 2003–2013
    • Indiana University-Purdue University School of Medicine
      • Department of Medicine
      Indianapolis, Indiana, United States
  • 2010
    • Richard L. Roudebush VA Medical Center
      Indianapolis, Indiana, United States
  • 2009
    • University of Leipzig
      Leipzig, Saxony, Germany
  • 2005
    • Indiana University East
      Indiana, United States