Brett D Atwater

Duke University Medical Center, Durham, North Carolina, United States

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Publications (18)52.16 Total impact

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    ABSTRACT: Battery failure is an uncommon complication of implantable cardioverter-defibrillators (ICD), but unanticipated battery depletion can have life threatening consequences.
    Heart rhythm: the official journal of the Heart Rhythm Society 07/2014; · 4.56 Impact Factor
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    ABSTRACT: Background Battery failure is an uncommon complication of implantable cardioverter-defibrillators (ICD), but unanticipated battery depletion can have life threatening consequences. Objective Describe the prevalence of a novel mechanism of battery failure in St. Jude Medical Fortify and Unify ICDs. Methods Cases of premature Fortify battery failure from a single center are reported. A search (1/1/2010 through 11/30/2013) for Fortify and Unify premature batter failure was conducted of the Food and Drug Administration’s Manufacturer and User Facility Device Experience Database (MAUDE), and these findings were supplemented with information provided by St. Jude Medical. Results Premature battery failure for two Fortify ICDs in our practice were attributed to the presence of Lithium clusters near the cathode, causing short circuiting and high current drain. The prevalence of this mechanism of premature battery failure was 0.6% in our practice. A MAUDE search identified 39 cases of Fortify (30) and Unify (9) premature battery depletion confirmed by the manufacturer, representing a 0.03% prevalence. Four additional Fortify and 2 Unify cases were identified in MAUDE as suspected premature battery depletion, but in these cases the pulse generator was not returned to the manufacturer for evaluation. St. Jude Medical identified 10 cases of premature battery failure due to Lithium clusters in Fortify devices (9) and Unify devices (1), representing a 0.004% prevalence. Conclusions The deposition of Lithium clusters near the cathode is a novel mechanism of premature battery failure. The prevalence of this problem is unknown. Providers should be aware of this mechanism for patient management.
    Heart Rhythm. 01/2014;
  • Journal of Cardiovascular Electrophysiology 08/2013; · 3.48 Impact Factor
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    ABSTRACT: Dabigatran is approved for prevention of stroke or systemic embolism in patients with nonvalvular atrial fibrillation (AF). The safety and effectiveness of periprocedural dabigatran in ablation for AF are unknown. We performed a meta-analysis of all studies comparing periprocedural dabigatran with warfarin for anticoagulation in AF ablation. Studies of >100 patients with post-procedure follow-up were included. Outcomes were compared by calculating maximum likelihood estimates with confidence intervals. The co-primary endpoints were neurological events and major bleeding. Ten cohort studies were included, including a total of 1,501 patients receiving dabigatran and 2,356 receiving warfarin. The mean age was 59-64 years and inclusion of women varied (10-33 %). Intra-procedural unfractionated heparin and irrigated ablation catheters were used routinely. Adverse events were low overall; however, the dabigatran group demonstrated a numerical excess of neurological events (10/1,501 [0.7 %] versus 4/2,356 [0.2 %]), but equivalent major bleeding outcomes (24/1,501 [1.6 %] versus 40/2,356 [1.7 %]). In the meta-analysis, there was a nonsignificant trend towards higher rates of the composite primary endpoints (any neurological event or major bleeding) in the dabigatran group. Dabigatran demonstrated a significantly higher rate of neurological events (estimated absolute risk difference 0.0047, 95 % confidence interval 0.0007 to 0.0099). Compared with warfarin, dabigatran may be associated with a higher frequency of periprocedural neurological events following radiofrequency ablation of AF. Randomized clinical trials are needed to definitively assess the safety and efficacy of novel oral anticoagulant use for periprocedural anticoagulation for ablation of AF.
    Journal of Interventional Cardiac Electrophysiology 07/2013; · 1.39 Impact Factor
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    ABSTRACT: BACKGROUND: Proper positioning of the left ventricular (LV) lead improves clinical outcomes and survival in patients receiving cardiac resynchronization therapy (CRT). Techniques of LV lead insertion using contrast injection and a telescoping system of delivery catheters to support advancement of the lead into the target branch may allow more efficient, targeted lead placement. We sought to evaluate the impact of an LV lead implant approach using telescoping-support catheters (group TS) on success rate, lead location, and procedural time compared to standard over-the-wire implant techniques (group OTW). METHODS: Four hundred thirty-seven consecutive patients undergoing CRT implantation were divided into group TS (n = 105) or group OTW (n = 332) based upon a review of the operative technique used for LV lead implantation. The primary outcome was success of LV lead implantation at the index procedure. Secondary endpoints included optimal positioning of the LV lead and reduction in procedural fluoroscopy time. RESULTS: Failed LV lead placement was lower (1.9% vs 8.1%, P = 0.02) and optimal lead positioning was achieved more often for group TS than group OTW (87% vs 75%, P = 0.01). In addition, there were significantly shorter fluoroscopy times for group TS versus group OTW (29.6 minutes vs 41.9 minutes, P < 0.01). CONCLUSION: A CRT-implant approach using contrast injection and a telescoping-support catheter system results in fewer failed LV lead implants, improved LV lead location, and shorter procedure times.
    Pacing and Clinical Electrophysiology 02/2013; · 1.75 Impact Factor
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    ABSTRACT: Several studies based on claims data have reported underutilization of evidence-based heart failure (HF) therapies. The degree to which these estimates fail to account for therapeutic contraindications is unclear. We identified patients with HF and left ventricular ejection fraction ≤45% seen between January 1, 2010, and July 1, 2010, at a tertiary care Veterans Affairs Medical Center. Medical records were abstracted to evaluate utilization of and contraindications to β-blocker, angiotensin-converting enzyme inhibitor, aldosterone antagonist, anticoagulation for atrial fibrillation, implantable cardioverter-defibrillator, and cardiac resynchronization therapies. Of the 178 patients with HF and an ejection fraction ≤45%, 78 (44%) received every guideline-recommended therapy. After accounting for medical contraindications, 77 (72%) of 107 patients received every guideline-recommended therapy. Adherence to recommendations for β-blocker (98%), angiotensin-converting enzyme inhibitor/angiotensin blocker (95%), and anticoagulation (97%) were better than adherence to implantable cardioverter-defibrillator (82%), cardiac resynchronization therapy (59%), or aldosterone antagonist (51%) recommendations. In adjusted analysis, lower New York Heart Association functional class and care by a cardiologist were associated with improved guideline adherence (P < .001). Many patients with HF have therapeutic contraindications, and a failure to account for these may lead to a large underestimation of the true guideline adherence rates.
    American heart journal 11/2012; 164(5):750-755.e1. · 4.65 Impact Factor
  • Brett D Atwater, James P Daubert
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    ABSTRACT: Sudden cardiac arrest is the one of the most common causes of death in developed countries and accounts for between 180,000 and over 450,000 per year in the USA. Antiarrhythmic drug approaches to prevention of sudden cardiac death have been resoundingly ineffective. The implantable cardioverter defibrillator (ICD) constitutes one of the most important and well validated therapeutic advances in modern cardiovascular medicine. Consequently, ICD use has increased exponentially, although implementation has been quite variable geographically and with respect to other measures. In view of the expanded use of ICDs, the potential shortcomings and risks of ICD therapy have attracted attention. This commentary summarises the weaknesses, disadvantages and risks of the ICD in a balanced fashion in light of their proven life-saving benefits.
    Heart (British Cardiac Society) 03/2012; 98(10):764-72. · 5.01 Impact Factor
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    ABSTRACT:   Cardiovascular magnetic resonance imaging (cMRI) may provide a noninvasive method to test for pulmonary vein (PV) isolation after ablation for atrial fibrillation (AF) by detecting changes in PV contraction. PV contraction (the maximal percentage change in PV cross-sectional area [CSA] during the cardiac cycle) measured 1 month before and 2 months after PV isolation was compared in 63 PVs from 16 patients with medically refractory AF. Repeat cMRI imaging and invasive catheter mapping was performed prior to repeat PV ablation in 50 PVs from 14 additional patients with recurrent AF. Contraction in PVs with sustained isolation after the initial ablation was compared to contraction in PVs with electrical reconnection to adjacent atrium. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff PV contraction value for prediction of PV-atrial reconnection after ablation. The cutoff value was then prospectively tested in 40 PVs from 12 additional patients. PV contraction decreased after AF ablation (22.4 ± 10% variation in CSA before ablation vs 10.1 ± 8% variation in CSA after ablation, P < 0.00001). PVs with sustained isolation on invasive mapping contracted less than PVs with electrical reconnection to adjacent atrium (13.7 ± 10.6% vs 21.4 ± 9.3%, P = 0.021). PV contraction produced a c-index of 0.74 for prediction of PV-atrial reconnection after ablation and >17% variation in PV CSA predicted reconnection with a sensitivity of 84.6% and specificity of 66.7%. PV contraction is reduced by ablation. PV contraction measurement may provide a noninvasive method to test for PV isolation after ablation procedures.
    Journal of Cardiovascular Electrophysiology 02/2011; 22(2):169-74. · 3.48 Impact Factor
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    ABSTRACT: Several studies that used claims and registry data have reported that 40% to 80% of patients eligible for an implantable cardioverter defibrillator (ICD) fail to receive one in clinical practice, and the rates are especially high among women and blacks. The extent and documented reasons for nonuse of ICDs among patients with left ventricular systolic dysfunction are unknown. Using hospital claims and clinical data, we identified patients hospitalized with a heart failure diagnosis and left ventricular ejection fraction ≤30% between January 1, 2007, and August 30, 2007, at a tertiary-care center. Using claims data, we determined placement of an ICD or cardiac resynchronization therapy with defibrillation device at any time up to 1 year after hospitalization. Medical records for patients without an ICD were abstracted to determine reasons for nonuse. Patients with an ICD were compared with patients without an ICD and also with patients without an ICD who did not have any contraindication for an ICD as identified through chart abstraction. Of the 542 potentially eligible patients identified, 224 (41%) did not have an ICD. In the initial adjusted analysis, female sex (odds ratio=1.90; 95% CI, 1.28 to 2.81) and increasing age (odds ratio=1.07; 95% CI, 1.04 to 1.11) were associated with a higher likelihood of not having an ICD. After detailed chart review, of the 224 patients without an ICD, 117 (52%) were ineligible for the device and 38 (17%) patients refused the device, resulting in only 69 (13%) patients eligible for an ICD who failed to receive one. In this subsequent adjusted analysis, remaining factors associated with a higher likelihood of not having an ICD were absence of ventricular arrhythmias (odds ratio=4.93; 95% CI, 2.56 to 9.50), noncardiology hospital service (odds ratio=3.73; 95% CI, 1.98 to 7.04), and lack of health insurance (odds ratio=3.10; 95% CI, 1.48 to 6.46). On the basis of a detailed chart review, the true rate of ICD underuse may be substantially lower than previous estimates. In addition, after accounting for ICD eligibility criteria, patient sex and age disparities in ICD therapy were no longer present.
    Circulation Cardiovascular Quality and Outcomes 02/2011; 4(2):146-51. · 5.66 Impact Factor
  • Brett D Atwater, James P Daubert
    Journal of Cardiovascular Electrophysiology 02/2010; 21(6):685-7. · 3.48 Impact Factor
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    ABSTRACT: Catheter-directed atrial fibrillation (AF) ablation is contraindicated among patients with left atrial appendage (LAA) thrombus. The prevalence of LAA thrombus among fully anticoagulated patients undergoing AF ablation is unknown. We retrospectively evaluated the prevalence of LAA thrombus among 192 consecutive patients undergoing AF ablation between July 2006 and January 2009. Seven of 192 patients (3.6%) had evidence of thrombus on transesophageal echocardiogram (TEE) despite being fully anticoagulated on warfarin (international normalized ratio [INR] 2-3) for 4 consecutive weeks prior to echocardiogram. Univariate analysis demonstrated that structural heart disease, large left atrial dimension, and number of AF ablations were associated with thrombus. Three patients with thrombus had paroxysmal AF with normal LV function. Despite full anticoagulation, 3.6% of patients undergoing AF ablation had LAA thrombus. We recommend that all patients, regardless of LV function or left atrial size, should undergo preprocedural TEE to exclude the presence of LAA thrombus.
    Journal of Cardiovascular Electrophysiology 02/2010; 21(8):849-52. · 3.48 Impact Factor
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    ABSTRACT: The currently available sudden cardiac death (SCD) risk prediction tools fail to identify most at-risk patients and cannot delineate a specific patient's SCD risk. We sought to develop a tool to improve the risk stratification of patients with coronary artery disease. Clinical, demographic, and angiographic characteristics were evaluated among 37,258 patients who had undergone coronary angiography from January 1, 1985 to May 31, 2005, and who were found to have at least one native coronary artery stenosis of > or =75%. After a median follow-up of 6.2 years, SCD had occurred in 1,568 patients, 14,078 patients had died from other causes, and 21,612 patients remained alive. A Cox proportional hazards model identified 10 independent patient characteristic variables significantly associated with SCD. A simplified model accounting for 97% of the predictive capacity of the full model included the following 7 variables: depressed left ventricular ejection fraction, number of diseased coronary arteries, diabetes mellitus, hypertension, heart failure, cerebrovascular disease, and tobacco use. The Duke SCD risk score was created from the simplified model to predict the likelihood of SCD among patients with coronary artery disease. It was internally validated with bootstrapping (c-index = 0.75, chi-square = 1,220.8) and externally validated in patients with ischemic cardiomyopathy from the Sudden Cardiac Death Heart Failure Trial (SCD-HeFT) database (c-index = 0.64, chi-square = 14.1). In conclusion, the Duke SCD risk score represents a simple, validated method for predicting the risk of SCD among patients with coronary artery disease and might be useful for directing treatment strategies designed to mitigate the risk of SCD.
    The American journal of cardiology 12/2009; 104(12):1624-30. · 3.58 Impact Factor
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    Brett D Atwater, James Oujiri, Matthew R Wolff
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    ABSTRACT: The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial confirmed that percutaneous coronary intervention is no better than optimal medical therapy for the prevention of major adverse cardiac events in patients with stable angina. The impact of these findings on clinical practice remains unknown. Clinicians may more frequently opt for medical rather than procedural therapy of stable angina in response to the COURAGE trial. Clinical information was collected from patients with stable angina referred to our hospital for cardiac catheterization between January 1, 2007 and June 18, 2007 (n = 332). Catheterization referral volume and the use of medications and coronary revascularization were compared before and after the release of the COURAGE trial. There was a significant increase in anti-ischemia medication use prior to catheterization referral following the COURAGE trial (mean = 1.31 [SD 0.83] medications pre-COURAGE, mean = 1.54 [SD 0.84] medications post-COURAGE, P = 0.012). Among 217 patients with coronary disease on catheterization, treatment with medication rather than percutaneous or surgical revascularization increased after COURAGE (11.1% pre-COURAGE vs 23.0% post-COURAGE, P = 0.03). There was also a significant decrease in referral volume following the COURAGE trial (3.12 referrals/day pre-COURAGE vs 2.51 referrals/day post-COURAGE, P = 0.034). The COURAGE trial immediately impacted the management of stable angina. Catheterization referral volume decreased, medication use increased, and the use of medical therapy rather than revascularization increased among patients with coronary disease.
    Clinical Cardiology 07/2009; 32(8):E1-3. · 1.83 Impact Factor
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    ABSTRACT: While the combination of a patent foramen ovale (PFO) and thromboembolic disease is thought to portend increased morbidity and mortality, PFO presence in the setting of major pulmonary embolism (PE) may serve as a means to rescue patients from immediate hemodynamic collapse and death. We present two patients with major pulmonary embolism and right-to-left shunting consistent with PFO as seen on transthoracic echocardiography. In the setting of major PE, PFO may prevent acute right ventricular failure by acting as a 'pop-off' valve, alleviating increased ventricular pressures; but concomitantly portend deleterious effects in the form of paradoxical embolism and intractable hypoxemia.
    Southern medical journal 10/2008; 101(9):955-8. · 0.92 Impact Factor
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    Brett D Atwater, Zhaowei Ai, Matthew R Wolff
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    ABSTRACT: Myocarditis and pericarditis are identified at autopsy in up to 50% of patients with systemic lupus erythematosus. However, clinical symptoms of heart failure are unusual, occurring in only 5%-7% of patients. Drug-induced lupus is rare and typically causes classic lupus symptoms of rash, fever, pleuritis, renal insufficiency, and arthritis. We present an unusual case of drug-induced lupus from chronic phenytoin use in a man who presented with symptoms of fulminant myopericarditis. To our knowledge, this is the first such case reported in English.
    WMJ: official publication of the State Medical Society of Wisconsin 10/2008; 107(6):298-300.
  • Brett D Atwater, Lisa M Nee, Giorgio Gimelli
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    ABSTRACT: Right ventricular (RV) involvement in acute inferior left ventricular (LV) myocardial infarction increases the risks of cardiogenic shock and in-hospital mortality. Acutely impaired RV performance results in reduced LV preload and, in combination with impaired LV contractility, causes severely reduced LV stroke volume and cardiac output. Here we report long-term patient survival after acute biventricular myocardial infarction (MI) using simultaneous RV support with a TandemHeart percutaneous ventricular assist device (Cardiac Assist Technologies, Pittsburgh, Pennsylvania) and LV support with an intra-aortic balloon pump. Further evaluation of completely percutaneous biventricular support in acute MI is warranted.
    The Journal of invasive cardiology 08/2008; 20(7):E205-7. · 1.57 Impact Factor
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    ABSTRACT: Elevated B-type natriuretic peptide (BNP) levels are associated with increased risk for mortality in patients with non-ST-segment-elevation (NSTE) acute coronary syndromes (ACS). However, the optimal use of BNP measurement for the risk stratification of these patients remains unclear. This study was conducted to analyze patterns of, and factors associated with, BNP measurement in patients with NSTE ACS from the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the American College of Cardiology/American Heart Association Guidelines? (CRUSADE) quality improvement initiative from 2003 through 2006. The association of degree of BNP elevation with in-hospital mortality in patients with measured BNP levels across risk categories was also analyzed. A total of 16,323 of 77,071 patients (21.2%) from 486 hospitals had BNP levels measured; the rate of BNP measurement by quarter increased from 5.1% to 27.7% during this analysis. Factors most strongly associated with BNP measurement included signs of heart failure on presentation, older age, previous heart failure, faster presenting heart rate, and higher body mass index. The adjusted risk for mortality was higher in patients who had BNP levels measured than in those who did not (adjusted odds ratio 1.14, 95% confidence interval 1.03 to 1.25). In patients with BNP levels measured, a higher degree of BNP elevation was associated with incrementally higher in-hospital mortality rates across risk categories. BNP levels were measured in approximately 1/5 of patients with NSTE ACS in contemporary practice. BNP was most frequently measured in patients presenting with high-risk characteristics, but the association of incremental increases in BNP levels with higher mortality rates was similar across risk categories. In conclusion, more widespread measurement of BNP levels for risk stratification of patients with NSTE ACS may be warranted.
    The American Journal of Cardiology 01/2008; 100(12):1727-33. · 3.21 Impact Factor
  • Brett D Atwater, Matthew T Roe, Kenneth W Mahaffey
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    ABSTRACT: Platelet glycoprotein (Gp) IIb/IIIa receptor antagonists improve outcomes in patients with acute coronary syndromes without persistent ST-segment elevation, but relative effects depend on appropriate patient selection. Recent data from the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress ADverse Outcomes with Early Implementation of the ACC/AHA Guidelines) quality improvement initiative suggests that GpIIb/IIIa antagonists are underused in clinical practice. The relationship between GpIIb/IIIa inhibition and the magnitude of clinical benefit in the setting of acute coronary syndromes is complex. Several key factors should be considered for proper patient selection, including accurate patient risk stratification, incorporation of these agents with an early invasive management strategy and the concomitant use of other anti-thrombotic therapies. Current practice guidelines for the treatment of patients with non-ST-segment elevation acute coronary syndromes support the integration of an early invasive management with optimal pharmacological therapy, including GpIIb/IIIa antagonists.
    Drugs 02/2005; 65(3):313-24. · 4.13 Impact Factor

Publication Stats

63 Citations
52.16 Total Impact Points


  • 2009–2014
    • Duke University Medical Center
      • • Department of Medicine
      • • Division of General Internal Medicine
      Durham, North Carolina, United States
    • Duke University
      Durham, North Carolina, United States
  • 2005–2009
    • North Carolina Clinical Research
      Raleigh, North Carolina, United States
  • 2008
    • University of Wisconsin, Madison
      • Department of Medicine
      Madison, MS, United States