Angel R Leon

Emory University, Atlanta, Georgia, United States

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Publications (66)413.97 Total impact

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    ABSTRACT: The subcutaneous ICD system (S-ICD) uses a novel detection algorithm previously shown to discriminate induced tachyarrhythmias (ventricular vs supraventricular) effectively. To evaluate the role of the S-ICD discrimination algorithm in reducing the incidence of spontaneous inappropriate shocks. There were 314 subjects who underwent implantation with an S-ICD System as part of the S-ICD Clinical Investigation (IDE Trial). Subjects were grouped according to programming at discharge, to either a single shock zone or two shock zones, with a discrimination algorithm in the lower rate zone. This cohort had 226 (72%) subjects with dual zone programming and 88 (28%) subjects with single zone programming. Over a mean follow-up period of 661 ± 174 days, inappropriate shocks occurred in 23 subjects from the dual zone sub-group (10.2%) and 23 subjects from the single zone sub-group (26.1%; P < 0.001), with 2 year inappropriate shock free rates of 89.7% vs 73.6%; respectively (HR=0.38; P = 0.001). Freedom from appropriate shocks did not differ between sub-groups (92.2% vs 90.3%; HR=0.82; P=0.64). Moreover, mean time to appropriate therapy did not differ between sub-groups and there was only one episode of arrhythmic syncope in the cohort. The addition of a second shock zone with an active discrimination algorithm was strongly associated with a reduction in inappropriate shocks with the S-ICD system and did not result in prolongation of detection times or increased syncope. These data support the use of dual zone programming as a standard setting for S-ICD patients.
    Heart rhythm: the official journal of the Heart Rhythm Society 04/2014; · 4.56 Impact Factor
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    ABSTRACT: The recently commercially available Subcutaneous Implantable Cardioverter-Defibrillator (S-ICD) utilizes a completely subcutaneous electrode configuration to treat potentially lethal ventricular tachyarrhythmia. Clinical trials have proven its effectiveness in detecting and treating ventricular fibrillation and tachycardia. The S-ICD offers the advantage of eliminating the need for intravenous and intracardiac leads and their associated risks and shortcomings. However, its major disadvantage is its inability to provide bradycardia rate support and anti-tachycardia pacing to terminate ventricular tachycardia. This article reviews the S-ICD clinical trials and the advantages and disadvantages of this novel technology to help the physician identify its role and select candidates that will benefit from this device.
    Journal of the American College of Cardiology 01/2014; · 14.09 Impact Factor
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    ABSTRACT: Background The subcutaneous ICD system (S-ICD) uses a novel detection algorithm previously shown to discriminate induced tachyarrhythmias (ventricular vs supraventricular) effectively. Objective To evaluate the role of the S-ICD discrimination algorithm in reducing the incidence of spontaneous inappropriate shocks. Methods There were 314 subjects who underwent implantation with an S-ICD System as part of the S-ICD Clinical Investigation (IDE Trial). Subjects were grouped according to programming at discharge, to either a single shock zone or two shock zones, with a discrimination algorithm in the lower rate zone. Results This cohort had 226 (72%) subjects with dual zone programming and 88 (28%) subjects with single zone programming. Over a mean follow-up period of 661 ± 174 days, inappropriate shocks occurred in 23 subjects from the dual zone sub-group (10.2%) and 23 subjects from the single zone sub-group (26.1%; P < 0.001), with 2 year inappropriate shock free rates of 89.7% vs 73.6%; respectively (HR=0.38; P = 0.001). Freedom from appropriate shocks did not differ between sub-groups (92.2% vs 90.3%; HR=0.82; P=0.64). Moreover, mean time to appropriate therapy did not differ between sub-groups and there was only one episode of arrhythmic syncope in the cohort. Conclusions The addition of a second shock zone with an active discrimination algorithm was strongly associated with a reduction in inappropriate shocks with the S-ICD system and did not result in prolongation of detection times or increased syncope. These data support the use of dual zone programming as a standard setting for S-ICD patients.
    Heart Rhythm. 01/2014;
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    ABSTRACT: The most frequent complications associated with implantable cardioverter-defibrillators (ICDs) involve the transvenous leads. A subcutaneous implantable cardioverter-defibrillator (S-ICD) has been developed as an alternative system. This study evaluated the safety and effectiveness of the S-ICD System (Cameron Health/Boston Scientific) for the treatment of life-threatening ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation). This prospective, nonrandomized, multicenter trial included adult patients with a standard indication for an ICD, who neither required pacing nor had documented pace-terminable ventricular tachycardia. The primary safety end point was the 180-day S-ICD System complication-free rate compared with a prespecified performance goal of 79%. The primary effectiveness end point was the induced ventricular fibrillation conversion rate compared with a prespecified performance goal of 88%, with success defined as 2 consecutive ventricular fibrillation conversions of 4 attempts. Detection and conversion of spontaneous episodes were also evaluated. Device implantation was attempted in 321 of 330 enrolled patients, and 314 patients underwent successful implantation. The cohort was followed for a mean duration of 11 months. The study population was 74% male with a mean age of 52±16 years and mean left ventricular ejection fraction of 36±16%. A previous transvenous ICD had been implanted in 13%. Both primary end points were met: The 180-day system complication-free rate was 99%, and sensitivity analysis of the acute ventricular fibrillation conversion rate was >90% in the entire cohort. There were 38 discrete spontaneous episodes of ventricular tachycardia/ventricular fibrillation recorded in 21 patients (6.7%), all of which successfully converted. Forty-one patients (13.1%) received an inappropriate shock. The findings support the efficacy and safety of the S-ICD System for the treatment of life-threatening ventricular arrhythmias. http://www.clinicaltrials.gov. Unique identifier: NCT01064076.
    Circulation 08/2013; 128(9):944-953. · 15.20 Impact Factor
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    ABSTRACT: OBJECTIVES: This study sought to investigate the prevalence, predictors, and outcomes of patients with postoperative ventricular arrhythmia (POVA) in a large cohort of patients. BACKGROUND: New-onset POVA after cardiac surgery (CS) is uncommon and has controversial prognostic value. METHODS: A total of 14,720 consecutive patients undergoing CS at Emory University between January 2004 and July 2010 were included in the study. Data on all-cause mortality were obtained from Social Security Administration death records. Multivariable regression models were constructed to determine the risk factors for POVA and to estimate the independent impact of POVA on long-term survival after adjusting for 40 different covariates. RESULTS: POVA occurred in 248 patients (1.7%). Patients with POVA were older (63.5 vs. 61.6 years), had lower left ventricular ejection fraction (EF) (43.7 vs. 51.3), and had greater comorbidities (Society of Thoracic Surgeons mortality risk score of 7.2% vs. 3.1%, p < 0.001). Multivariable analysis showed that older age (odds ratio [OR]: 1.018 per 1-year increase, p < 0.001), emergent surgery (OR: 1.77, p = 0.019), and the presence of PVD (OR: 1.41, p = 0.049) were associated with a higher incidence of POVA, whereas higher left ventricular EF (OR: 0.97 per 1% increase, p < 0.001), mild chronic obstructive pulmonary disease (OR: 0.37, p < 0.001), and off-pump surgery (OR: O.41, p < 0.001) were associated with a lower incidence of POVA. POVA was associated with substantially increased adjusted long-term mortality (hazard rate: 2.53, p < 0.001) over 3.5 years of follow-up. CONCLUSIONS: POVA is associated with increased long-term mortality after CS. Older age, PVD, lower EF, and emergent surgery are associated with a higher risk of POVA, whereas off-pump surgery seems to be protective.
    Journal of the American College of Cardiology 11/2012; · 14.09 Impact Factor
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    ABSTRACT: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality and improves symptoms in patients with systolic heart failure (HF) and ventricular dyssynchrony. This randomized, double-blind, controlled study evaluated whether optimizing the interventricular stimulating interval (V-V) to sequentially activate the ventricles is clinically better than simultaneous V-V stimulation during CRT. Patients with New York Heart Association (NYHA) III or IV HF, meeting both CRT and implantable cardioverter-defibrillator indications, randomly received either simultaneous CRT or CRT with optimized V-V settings for 6 months. Patients also underwent echocardiography-guided atrioventricular delay optimization to maximize left ventricular filling. The V-V optimization involved minimizing the left ventricular septal to posterior wall motion delay during CRT. The primary objective was to demonstrate noninferiority using a clinical composite end point that included mortality, HF hospitalization, NYHA functional class, and patient global assessment. Secondary end points included changes in NYHA classification, 6-minute hall walk distance, quality of life, peak VO(2), and event-free survival. The composite score improved in 75 (64.7%) of 116 simultaneous patients and in 92 (75.4%) of 122 optimized patients (P < .001, for noninferiority). A prespecified test of superiority showed that more optimized patients improved (P = .03). New York Heart Association functional class improved in 58.0% of simultaneous patients versus 75.0% of optimized patients (P = .01). No significant differences in exercise capacity, quality of life, peak VO(2), or HF-related event rate between the 2 groups were observed. These findings demonstrate modest clinical benefit with optimized sequential V-V stimulation during CRT in patients with NYHA class III and IV HF. Optimizing V-V timing may provide an additional tool for increasing the proportion of patients who respond to CRT.
    American heart journal 11/2012; 164(5):735-41. · 4.65 Impact Factor
  • Heart Rhythm. 09/2012; 9(9):1579–1580.
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    ABSTRACT: The aim of this study was to create a simple risk index to predict new-onset atrial fibrillation (AF) after coronary artery bypass grafting in patients with histories of AF. AF after coronary artery bypass grafting (referred to here as AF) is associated with increased morbidity and mortality. Identifying patients at high risk for developing AF may help identify a group of patients who might benefit from strategies to prevent postoperative AF. A cohort of 18,517 patients enrolled from January 1, 1996, to December 31, 2009, was used to derive a risk index for AF prediction. A multivariate logistic regression model determined the independent predictive impact of clinical and demographic characteristics on the occurrence of AF. A subset of these variables was used to construct a risk index to predict AF. This risk index was validated in a sequential cohort of 1,378 consecutive patients who underwent coronary artery bypass grafting from January 1, 2010, to June 30, 2011. AF occurred in 3,486 patients in the calibration cohort (18.83%) and in 269 patients in the validation cohort (19.52%). After considering patients' demographics, co-morbid conditions, and severity of illness, advanced age appeared as the most powerful predictor of AF (odds ratio 1.059/year, 95% confidence interval 1.055 to 1.063). Age, height, weight, and the presence of peripheral vascular disease contributed most to the prediction model. An AF risk index including these variables had adequate discriminatory power, with a concordance index of 0.68. In conclusion, using a large cohort of patients, a simple risk index relying only on preoperative clinical variables was developed, which will help predict AF. This risk index can be used clinically to identify patients at high risk for the development of AF.
    The American journal of cardiology 05/2012; 110(5):649-54. · 3.58 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:P216. · 4.44 Impact Factor
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    ABSTRACT: Atrioventricular (AV) delay in cardiac resynchronisation therapy (CRT) recipients are typically optimised at rest. However, there are limited data on the impact of exercise-induced changes in heart rate on the optimal AV delay and left ventricular function. The authors serially programmed AV delays in 41 CRT patients with intrinsic sinus rhythm at rest and during two stages of supine bicycle exercise with heart rates at 20 bpm (stage I) and 40 bpm (stage II) above baseline. The optimal AV delay during exercise was determined by the iterative method to maximise cardiac output using Doppler echocardiography. Results were compared to physiological change in PR intervals in 56 normal controls during treadmill exercise. The optimal AV delay was progressively shortened (p<0.05) with escalating exercise level (baseline: 123±26 ms vs. stage I: 102±24 ms vs stage II: 70±22 ms, p<0.05). AV delay optimisation led to a significantly higher cardiac output than without optimisation did during stage I (6.2±1.2 l/min vs. 5.2±1.2 l/min, p<0.001) and stage II (6.8±1.6 l/min vs. 5.9±1.3 l/min, p<0.001) exercise. A linear inverse relationship existed between optimal AV delays and heart rates in CRT patients (AV delay=241-1.61×heart rate, R2=0.639, p<0.001) and healthy controls (R2=0.646, p<0.001), but the slope of regression was significantly steeper in CRT patients (p<0.001). Haemodynamically optimal AV delay shortened progressively with increasing heart rate during exercise, which suggests the need for programming of rate-adaptive AV delay in CRT recipients.
    Heart (British Cardiac Society) 08/2011; 98(1):54-9. · 5.01 Impact Factor
  • Circulation 07/2011; 124(2):e37; author reply e38. · 15.20 Impact Factor
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    ABSTRACT: Numerous criteria believed to define a positive response to cardiac resynchronization therapy have been used in the literature. No study has investigated agreement among these response criteria. We hypothesized that the agreement among the various response criteria would be poor. A literature search was conducted with the keywords "cardiac resynchronization" and "response." The 50 publications with the most citations were reviewed. After the exclusion of editorials and reviews, 17 different primary response criteria were identified from 26 relevant articles. The agreement among 15 of these 17 response criteria was assessed in 426 patients from the Predictors of Response to Cardiac Resynchronization Therapy (PROSPECT) study with Cohen's kappa-coefficient (2 response criteria were not calculable from PROSPECT data). The overall response rate ranged from 32% to 91% for the 15 response criteria. Ninety-nine percent of patients showed a positive response according to at least 1 of the 15 criteria, whereas 94% were classified as a nonresponder by at least 1 criterion. kappa-Values were calculated for all 105 possible comparisons among the 15 response criteria and classified into standard ranges: Poor agreement (kappa< or =0.4), moderate agreement (0.4<kappa<0.75), and strong agreement (kappa> or =0.75). Seventy-five percent of the comparisons showed poor agreement, 21% showed moderate agreement, and only 4% showed strong agreement. The 26 most-cited publications on predicting response to cardiac resynchronization therapy define response using 17 different criteria. Agreement between different methods to define response to cardiac resynchronization therapy is poor 75% of the time and strong only 4% of the time, which severely limits the ability to generalize results over multiple studies.
    Circulation 05/2010; 121(18):1985-91. · 15.20 Impact Factor
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    ABSTRACT: We sought to investigate the association between new-onset atrial fibrillation after coronary artery bypass graft (CABG) (post-operative atrial fibrillation [POAF]) and long-term mortality in patients with no history of atrial fibrillation. POAF predicts longer hospital stay and greater post-operative mortality. A total of 16,169 consecutive patients with no history of AF who underwent isolated CABG at our institution between January 1, 1996, and December 31, 2007, were included in the study. All-cause mortality data were obtained from Social Security Administration death records. A multivariable Cox proportional hazards regression model was constructed to determine the independent impact of new-onset POAF on long-term survival after adjusting for several covariates. The covariates included age, sex, race, pre-operative risk factors (ejection fraction, New York Heart Association functional class, history of myocardial infarction, index myocardial infarction, stroke, chronic obstructive pulmonary disease, peripheral arterial disease, smoking, diabetes, renal failure, hypertension, dyslipidemia, creatinine level, dialysis, redo surgery, elective versus emergent CABG, any valvular disorder) and post-operative adverse events (stroke, myocardial infarction, acute respiratory distress syndrome, and renal failure), and discharge cardiac medications known to affect survival in patients with coronary disease. New-onset AF occurred in 2,985 (18.5%) patients undergoing CABG. POAF independently predicted long-term mortality (hazard ratio: 1.21; 95% confidence interval: 1.12 to 1.32) during a mean follow-up of 6 years (range 0 to 12.5 years). This association remained true after excluding from the analysis those patients who died in-hospital after surgery (hazard ratio: 1.21; 95% confidence interval: 1.11 to 1.32). Patients with POAF discharged on warfarin experienced reduced mortality during follow-up. In this large cohort of patients, POAF predicted long-term mortality. Warfarin anticoagulation may improve survival in POAF.
    Journal of the American College of Cardiology 03/2010; 55(13):1370-6. · 14.09 Impact Factor
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    ABSTRACT: QRSduration (QRSd) is associated with higher mortality and morbidity in patients with left ventricular (LV) dysfunction. The association between QRSd and atrial fibrillation (AF) has not been studied in this patient population. To investigate the association between QRSd and AF in patients with LV dysfunction. Data were obtained from the National Registry to Advance Heart Health (ADVANCENT) registry, a prospective multicenter registry of patients with left ventricular ejection fraction (LVEF) < or = 40%. A total of 25 268 patients from 106 centers in the United States, were enrolled between June 2003 and November 2004. Demographic and clinical characteristics of patients were collected from interviews and medical records. : Mean age was 66.3+/-13 years, 71.5% were males, and 81.9% were white. A total of 14 452 (57.8%) patients had a QRSd < 120 ms, 5304 (21.2%) had a QRSd between 120 and 150 ms, and 5269 (21%) had a QRSd > 150 ms. Atrial fibrillation occurred in 20.9%, 27.5%, and 35.5% of patients in the QRS groups, respectively (P < 0.0001). After adjusting for potential AF risk factors (age, gender, race, body mass index, hypertension, diabetes, renal failure, cancer, lung disease, New York Heart Association [NYHA] class, ejection fraction, etiology of cardiomyopathy) and the use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, and lipid lowering drugs, QRS duration remained independently associated with AF (odds ratio: 1.20, 95% confidence interval: 1.14-1.25). In this large cohort of patients, QRSd was strongly associated with AF and therefore may predict the occurrence of this arrhythmia in patients with LV dysfunction. This association persisted after adjusting for disease severity, comorbid conditions, and the use of medications known to be protective against AF.
    Clinical Cardiology 03/2010; 33(3):132-8. · 1.83 Impact Factor
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    ABSTRACT: Doppler tissue imaging (DTI)-based dyssynchrony parameters failed to predict response to cardiac resynchronization therapy (CRT) in the multicenter Predictors of Response to Cardiac Resynchronization Therapy (PROSPECT) trial. Large variability during the interpretation of DTI data was one of several factors thought to contribute to this failure. In this study, the authors hypothesized that using larger regions of interest (ROIs) to generate velocity curves from Doppler tissue images would significantly reduce the variability of DTI dyssynchrony parameters. The variability of 3 ROI sizes (6 x 6, 18 x 6, and 30 x 6 mm) was compared in 30 patients undergoing CRT. Variability due to manual ROI placement was determined for each ROI size by placing 3 ROIs in each myocardial segment, 6mm apart from one another. Thus, 3 velocity curves were generated for each segment and each ROI size. Four published dyssynchrony parameters were calculated from all permutations of the 3 ROI positions per segment. A mean modified coefficient of variation was calculated for each parameter and ROI size. The 6 x 6 mm ROI had a mean coefficient of variation of 27%. The 18 x 6 and 30 x 6 mm ROIs had significantly lower coefficients of variation (17% and 14%, respectively) than the 6 x 6 mm ROI (P < .01 for both). The 30 x 6 mm ROI also reduced the diagnostic inconsistency of dyssynchrony parameters by 44% (P = .024) compared with the 6 x 6 mm ROI. Using a 30 x 6 mm ROI instead of a 6 x 6 mm ROI to quantify tissue Doppler dyssynchrony reduces variability by 47% and diagnostic inconsistency by 44%. The authors recommend using a 30 x 6 mm ROI in future trials to minimize variability.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 06/2009; 22(5):478-85.e3. · 2.98 Impact Factor
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    ABSTRACT: Hypertension is the most common cause of left ventricular (LV) hypertrophy. However, multiple causes can lead to LV hypertrophy, each of which has different histological and mechanical properties. To assess the value of a novel speckle-tracking echocardiographic measurement of myocardial strain and strain rate in defining the mechanical properties of LV hypertrophy, 20 patients with asymmetric hypertrophic cardiomyopathy, 24 patients with secondary LV hypertrophy, 12 patients with biopsy-proved confirmed cardiac amyloidosis, and 22 age-matched healthy asymptomatic volunteers were studied. Patients with amyloidosis had severe diastolic dysfunction, and myocardial deformation was significantly decreased. The new technique allowed cardiac amyloid to be easily differentiated from the other categories. In patients with hypertrophic cardiomyopathy, there was segmental myocardium dysfunction as assessed by strain imaging. LV global systolic velocity and radial displacement were higher, and abnormal relaxation was more frequent, in the group with secondary LV hypertrophy than in normal controls. In conclusion, the observations from strain parameters derived from speckle tracking were consistent with the known underlying pathology of each condition, which speaks to the value of strain imaging. Cardiac amyloid profoundly alters all strain parameters, and analysis of these parameters could aid in the diagnosis.
    The American journal of cardiology 03/2009; 103(3):411-5. · 3.58 Impact Factor
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    ABSTRACT: Heart sounds based measurements such as S3 amplitude and systolic timing intervals (STIs) are known to be indicative of cardiac dysfunction. In this paper we investigate the correlation of these measurements from pacemaker device implant locations to echocardiographic hemodynamic metrics of E wave deceleration time (EDT), Ejection Fraction (EF) and Stroke Volume (SV). Simultaneous heart sounds and echocardiography measurements were made in 6 heart failure patients with cardiac resynchronization therapy (CRT) devices prior to CRT activation (baseline) and at 3 and 6 months post-CRT. In N=17 datasets, S3 amplitude was correlated to EDT (r=-0.86, p<0.05). Similarly STIs such as heart sounds based pre-ejection period (HSPEP) was correlated with EF (r = -0.81, p<0.01) and ejection time (HSET) with SV (r = 0.65, p=0.01). Longitudinal analysis in each patient showed consistent changes between % increase in S3 vs. % decrease in EDT (r= -0.83, p<0.01), % change in HSPEP vs. % change in EF (r= -0.80, p=0.03) and % change in SV (r= -0.72, p< 0.01). These results show proof of concept for using pacemaker derived measurements for monitoring HF patients. Further study is needed to determine their efficacy for chronic monitoring of HF patients.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2009; 2009:3016-9.
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    ABSTRACT: To apply cross-correlation delay (XCD) analysis to myocardial phase contrast magnetic resonance (PCMR) tissue velocity data and to compare XCD to three established "time-to-peak" dyssynchrony parameters. Myocardial tissue velocity was acquired using PCMR in 10 healthy volunteers (negative controls) and 10 heart failure patients who met criteria for cardiac resynchronization therapy (positive controls). All dyssynchrony parameters were computed from PCMR velocity curves. Sensitivity, specificity, and receiver operator curve (ROC) analysis for separating positive and negative controls were computed for each dyssynchrony parameter. XCD had higher sensitivity (90%) and specificity (100%) for discriminating between normal and patient groups than any of the time-to-peak dyssynchrony parameters. ROC analysis showed that XCD was the best parameter for separating the positive and negative control groups. XCD is superior to time-to-peak dyssynchrony parameters for discriminating between subjects with and without dyssynchrony and may aid in the selection of patients for cardiac resynchronization therapy.
    Journal of Magnetic Resonance Imaging 12/2008; 28(5):1086-91. · 2.57 Impact Factor
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    ABSTRACT: To develop a method for quantifying left ventricular (LV) internal flow as a measure of dyssynchrony using standard cine cardiac magnetic resonance (CMR) images. CMR images were obtained from 10 healthy controls and 10 patients with dyssynchronous heart failure (class III/IV, LV ejection fraction <35%, pattern seen in an electrocardiogram QRS duration > 150 msec). The LV volume was reconstructed and divided into 16 regions. Internal flow was defined as the sum of the regional volume changes minus the global volume change during each time step in the cardiac cycle. Internal flow fraction (IFF) was defined as the total internal flow as a percentage of stroke volume during systole (IFF(systole)), diastole (IFF(diastole)), or the whole cycle (IFF(whole)). IFF(whole) was significantly increased in the patients (9.9 +/- 5.0% vs. 1.5 +/- 0.5% in the controls, P < 0.001). An IFF(whole) threshold of 4% discriminated between patients and controls with 90% sensitivity and 100% specificity. IFF(diastole) (2.3 +/- 0.8%) was greater than IFF(systole) (0.8 +/- 0.5%) in the normal controls (P < 0.001) while the patients had similar IFF(diastole) (7.8 +/- 4.2%) and IFF(systole) (12.0 +/- 7.8%). Left ventricular internal flow fraction can be quantified from standard CMR images. In this preliminary study, Left ventricular internal flow fraction discriminated patients with dyssynchronous heart failure from normal controls with 95% accuracy.
    Journal of Magnetic Resonance Imaging 08/2008; 28(2):375-81. · 2.57 Impact Factor
  • J. Julia Shin, Andrew L. Smith, Angel R. Leon
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    ABSTRACT: Heart failure is rapidly becoming a pervasive cause of cardiovascular disease in the USA. Despite significant advances in medical knowledge and treatment, heart failure remains a challenging problem, resulting in high morbidity and mortality. Comprehension of the pathophysiology and treatment of ventricular dysfunction has undergone an evolution over the past two decades. Initially composed of digitalis and diuretics, the pharmacologic armamentarium has expanded to include vasodilators, inhibitors of the renin–angiotensin–aldosterone system, as well as neurohormonal and sympathetic modulators. This polypharmaceutical approach underscores the complexity of heart failure pathophysiology. Despite these advances, there remain a substantial group of patients who do not tolerate, do not respond to, or worsen despite optimal medical therapy. Approximately half of patients with dilated cardiomyopathy succumb to sudden cardiac death, and refractory pump failure is the next most common cause of mortality in this population(1,2). In the early 1990s, the need for novel treatment modalities ushered in the era of device therapy for heart failure, namely, the use of implantable cardioverter– defibrillators (ICDs) and cardiac resynchronization therapy (CRT).
    07/2008: pages 211-226;

Publication Stats

6k Citations
413.97 Total Impact Points

Institutions

  • 1999–2014
    • Emory University
      • • School of Medicine
      • • Division of Cardiology
      • • Department of Biomedical Engineering
      Atlanta, Georgia, United States
  • 2008–2010
    • Georgia Institute of Technology
      • Department of Biomedical Engineering
      Atlanta, Georgia, United States
  • 2009
    • Boston Scientific
      Boston, Massachusetts, United States