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ABSTRACT: BACKGROUND: The efficacy of shock in converting different ventricular tachyarrhythmias has not been well characterized in a large, natural-practice setting. OBJECTIVE: To determine shock success rate by energy and ventricular rhythm in a large cohort of patients with implantable cardioverter defibrillators (ICD). METHODS: Two thousand patients with 5279 shock episodes were randomly sampled for analysis from the LATITUDE remote monitoring system. Within an episode, the rhythm preceding therapy (shock or antitachycardia pacing (ATP) was adjudicated. Patients who died after unsuccessful ICD shocks did not transmit final remote monitoring data and were not included in the study. RESULTS: Of 3677 shock episodes for ventricular tachyarrhythmia, 2679 were treated with shock initially and were classified as monomorphic (MVT, N=1544), polymorphic ventricular tachycardia (MVT/PVT, N=371), or ventricular fibrillation (VF, N=764). First, second and final shock success averaged 90.3%, 96.4% and 99.8 %, respectively. After unsuccessful initial ATP (n=998), the first, second and final shock was successful in 84.8%, 92.9% and 100% of episodes. Success after the first or second shock was significantly lower after failed ATP compared to shock as initial therapy (both p<.001). Among episodes treated with shock initially, the success rate for MVT (89.2%) when treated with energy level ≤20 J was significantly higher than VF (80.8%, p=.04). The level of shock energy was a significant predictor of the success of the first shock (OR =1.16, 95% CI 1.03-1.30, p=.013). CONCLUSION: The first shock success rate as an initial therapy is approximately 90%, but was lower following failed ATP. Programming a higher level of energy after ATP is suggested.
Heart rhythm: the official journal of the Heart Rhythm Society 01/2013; · 4.56 Impact Factor
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ABSTRACT: Approximately 12-21% of implantable cardioverter defibrillator (ICD) patients receive inappropriate shocks. We sought to determine the incidence and causes of noise/artifact and oversensing (NAO) resulting in ICD shocks.
A random sample of 2,000 patients who received ICD and cardiac resynchronization therapy defibrillator shocks and were followed by a remote monitoring system was included. Seven electrophysiologists analyzed stored electrograms from the 5,279 shock episodes. Episodes were adjudicated as appropriate or inappropriate shocks.
Of the 5,248 shock episodes with complete adjudication, 1,570 (30%) were judged to be inappropriate shocks. Of these 1,570, 134 (8.5%) were a result of NAO. The 134 NAO episodes were determined to be due to external noise in 76 (57%), lead connector-related in 37 (28%), muscle noise in 11 (8%), oversensing of atrium in seven (5%), T-wave oversensing in two (2%), and other noise in one (1%). The ICD shock itself resulted in a marked decrease in the level of noise in 60 of 134 (45%) NAO episodes, and the magnitude of this effect varied with the type of NAO (58% for external noise, 35% for muscle, 27% for lead/connector, and 0% for oversensing; P = 0.03). There was no significant difference in NAO likelihood based on type of lead (integrated bipolar 89/1,802 vs dedicated bipolar 9/140, P = 0.67).
External noise and lead/connector noise were the primary causes, while T-wave oversensing was the least common cause of NAO resulting in ICD shock. Noise/artifact decreased immediately after a shock in nearly half of episodes. The specific ICD lead type did not impact the likelihood of NAO.
Pacing and Clinical Electrophysiology 04/2012; 35(7):863-9. · 1.35 Impact Factor
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Leslie A Saxon
Circulation 12/2011; 124(25):2803-4. · 14.74 Impact Factor
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Journal of Cardiovascular Electrophysiology 12/2011; 23(5):541-2. · 3.06 Impact Factor
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ABSTRACT: The decision to implant a CRT or CRT-D device is an important one that requires a careful look at the patient and discussion with the patient as to the benefits and risks associated with each approach. The good news is that CRT provided in any device is a robust therapy that improves many measures of heart failure outcome in very high-risk patients. We argue that in most circumstances, it is much easier to turn a tachycardia device off than not to have the benefit of prompt defibrillation should a tachycardia event occur. While cost is always a consideration, the responsibility of the physician is to individualize patient care and advocate for each patient, based upon the best available therapies.
Heart Failure Reviews 08/2011; 17(6):777-9. · 3.20 Impact Factor
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ABSTRACT: We evaluated the frequency of appropriate and inappropriate shocks and survival in patients using dual-zone programming versus single-zone programming.
For the ALTITUDE REDUCES study, patients were followed for 1.6 ± 1.1 years. The 12-month incidence of any shock was lower for dual-versus single-zone programmed detection at rates ≤170 bpm and between 170-200 bpm (P < 0.001). Appropriate shock rates at 1 year were also lower with dual-zone programming in these rate intervals (single zone 9.1%, 5.4%, P < 0.001, dual zone 6.7%, 4.7%, P < 0.02). There were no detectable differences between single- and dual-zone shock incidence at detection rates ≥ 200 bpm (P = 0.14). Inappropriate shock incidence was less with dual- versus single-zone detection at all detect rates <200 bpm, but not at rates ≥200 bpm (P < 0.001, P = 0.37). The lowest risk of appropriate and inappropriate shock was associated with dual-zone programming and detection rates ≥200 bpm (2.1%). Dual-zone detection was associated with more nonsustained and diverted therapy episodes but these patients did not have an increased risk of death compared to patients with single-zone programming. Patients programmed to low detection rate, single-zone detection and shock-only therapy also had the highest preshock mortality risk (P = 0.05).
Shock incidence is lowest with either single- or dual-zone detection ≥200 bpm. For detection rates <200 bpm, dual-zone programming is associated with a reduction in the incidence of total shocks, appropriate shocks, and inappropriate shocks.
Journal of Cardiovascular Electrophysiology 05/2011; 22(9):1023-9. · 3.06 Impact Factor
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ABSTRACT: Electrophysiology procedures vary in invasiveness, duration, and anesthesia utilized. While complications are low and efficacy high, cases are elective and patient experiences related to anxiety, pain, and perceived outcomes are not well studied. We sought to determine if a 30-minute audio compact disc (CD) that teaches relaxation techniques and wellness perception prior to an elective procedure impacts validated measures of anxiety, pain, and procedural outcomes.
Sixty-one patients were randomly assigned to a control group (CG) (N(CG) = 31) or interventional group (IG) (N(IG) = 30). Both groups answered a baseline Hospital Anxiety and Depression Scale (HADS-A) survey consisting only of anxiety assessment questions. The IG listened to the CD the night prior to their procedure. Heart rate and blood pressure were monitored on admission and prior to the procedure. Postprocedure, both groups completed two HADS-A surveys as well as two Patient Experience Surveys (PES). There was no statistical difference in the demographics and the rate of procedural complications between the groups. The statistical significance of our data was determined using a Student's t-test and χ(2) test.
At baseline, both groups had equal amounts of anxiety prior to their procedures (P = 0.2). The patients in the IG had lower systolic blood pressures during admission and prior the administration of analgesics in comparison to the CG. Postprocedure, results from administering the HADS-A demonstrated that the IG had 33% lower anxiety (P = 0.02) than CG patients.
The implementation of basic relaxation teaching techniques prior to planned electrophysiology procedures lowers systolic blood pressure and postprocedural anxiety.
Pacing and Clinical Electrophysiology 04/2011; 34(7):821-6. · 1.35 Impact Factor
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ABSTRACT: With the advent of cardiac resynchronization therapy, it was unclear what percentage of biventricular pacing would be required to obtain maximal symptomatic and mortality benefit from the therapy. The optimal percentage of biventricular pacing and the association between the amount of continuous pacing and survival is unknown.
The purpose of this study was to assess the optimal percentage of biventricular pacing and any association with survival in a large cohort of networked patients.
A large cohort of 36,935 patients followed up in a remote-monitoring network, the LATITUDE Patient Management system (Boston Scientific Corp., Natick, Massachusetts), was assessed to determine the association between the percentage of biventricular pacing and mortality.
The greatest magnitude of reduction in mortality was observed with a biventricular pacing achieved in excess of 98% of all ventricular beats. Atrial fibrillation and native atrial ventricular condition can limit a high degree of biventricular pacing. Incremental increases in mortality benefit are observed with an increasing percentage of biventricular pacing.
Every effort should be made to reduce native atrioventricular conduction with cardiac resynchronization therapy systems in an attempt to achieve biventricular pacing as close to 100% as possible.
Heart rhythm: the official journal of the Heart Rhythm Society 04/2011; 8(9):1469-75. · 4.56 Impact Factor
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ABSTRACT: The increasing use of remote monitoring with the associated large retrievable databases provides a unique opportunity to analyze observations on implantable cardioverter-defibrillator (ICD) therapies. Adjudication of a large number of stored ICD electrograms (EGMs) presents a unique challenge. The ALTITUDE study group was designed to use the LATITUDE remote monitoring system to evaluate ICD patient outcomes across the United States.
Of 81,081 patients on remote monitoring, a random sample of 2,000 patients having 5,279 shock episodes was selected. The ALTITUDE EGM review committee was comprised of seven electrophysiologists from four institutions. An online EGM adjudication system was designed. Episodes were classified as appropriate (70% of shock episodes) or inappropriate ICD therapies (30%). Light's Kappa was used to assess agreement. Interobserver and intraobserver Kappa scores for dual-chamber ICDs were 0.84 (0.71-0.91) and 0.89 (0.82-0.95), consistent with substantial agreement. Interobserver and intraobserver Kappa scores for single-chamber ICDs were 0.61 (0.54-0.67) and 0.69 (0.59-0.79). The rhythm categories of "nonsustained arrhythmia" and "polymorphic and monomorphic ventricular tachycardia" resulted in the greatest degree of discordant adjudication between reviewers.
This method of adjudication of a large volume of stored EGM data prior to device therapies will allow new observations in regards to device performance and has the potential to improve device programming and design. There was substantial interreviewer agreement for rhythm classification. Agreement was greater for dual-chamber compared to single-chamber devices, indicating the atrial lead adds diagnostic value in rhythm interpretation.
Pacing and Clinical Electrophysiology 03/2011; 34(8):1003-12. · 1.35 Impact Factor
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ABSTRACT: Recent advances in stem cell biology and tissue engineering have put forth new therapeutic paradigms for treatment of myocardial disease. The aim of stem cell therapy for myocardial regeneration has been directed to induce angiogenesis for ischemic heart disease and/or introduction of new cardiomyocytes to improve the mechanical function of the failing heart. Encouraged by positive preliminary results in mouse models of myocardial infarction, clinical trials have utilized autologous skeletal myoblasts and bone-marrow-derived stem cells to treat patients in various clinical settings including acute myocardial injury, chronic angina, and heart failure. These studies have collectively shown, at best, modest improvement in cardiac function. This may be due to the fact that there is little evidence to support actual formation and/or integration of transplanted cells into the recipient myocardium. More recent and emerging data supports the finding that electrical stimulation may be an effective catalyst for sustained functional organization, integration, and maturation of transplanted cell populations into the host myocardium. A therapeutic model that utilizes electrical stimulation and/or achieves cardiac resynchronization in conjunction with stem cell transplantation may be an effective means to achieve successful myocardial regenerative therapy.
Journal of Cardiovascular Translational Research 02/2011; 4(1):61-5. · 2.61 Impact Factor
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ABSTRACT: Outcome data for patients receiving implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) devices treated outside of clinical trials are lacking. No clinical trial has evaluated mortality after device implantation or after shock therapy in large numbers of patients with implanted devices that regularly transmit device data over a network.
Survival status in patients implanted with ICD and CRT devices across the United States from a single manufacturer was assessed. Outcomes were compared between patients followed in device clinic settings and those who regularly transmit remote data collected from the device an average of 4 times monthly. Shock delivery and electrogram analysis could be ascertained from patients followed on the network, enabling survival after ICD shock to be evaluated. One- and 5-year survival rates in 185,778 patients after ICD implantation were 92% and 68% and were 88% and 54% for CRT-D device recipients. In 8228 patients implanted with CRT-only devices, survival was 82% and 48% at 1 and 5 years, respectively. For the 69,556 ICD and CRT-D patients receiving remote follow-up on the network, 1- and 5-year survival rates were higher compared with those in the 116,222 patients who received device follow-up in device clinics only (50% reduction; P<0.0001). There were no differences between patients followed on or off the remote network for the characteristics of age, gender, implanted device year or type, and economic or educational status. Shock therapy was associated with subsequent mortality risk for both ICD and CRT-D recipients.
Survival after ICD and CRT-D implantation in patients treated in naturalistic practice compares favorably with survival rates observed in clinical trials. Remote follow-up of device data is associated with excellent survival, but arrhythmias that result in device therapy in this population are associated with a higher mortality risk compared with patients who do not require shock therapy.
Circulation 12/2010; 122(23):2359-67. · 14.74 Impact Factor
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Leslie A Saxon
Journal of Cardiovascular Translational Research 11/2010; 4(1):1-2. · 2.61 Impact Factor
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ABSTRACT: Sustained ventricular tachycardia (VT) in patients with advanced cardiomyopathy is a potentially life-threatening arrhythmia. Newer treatment strategies have evolved that combine the use of catheter ablation to target the substrate for VT and ventricular assist devices (VADs) to hemodynamically support the failing ventricle. This editorial is targeted to the practicing clinician caring for these difficult patients. The current article reviews the use of percutaneous VADs to support catheter ablation of VT, the use of durable VADs to support the failing heart in patients with recurrent VT, ventricular arrhythmias in patients with durable VADs, and the use of catheter ablation to treat VT in patients with durable VADs.
Journal of Cardiovascular Electrophysiology 10/2010; 22(3):359-63. · 3.06 Impact Factor
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ABSTRACT: An understanding of detailed 3-D cardiac anatomy is important to the field of cardiac electrophysiology. Cardiovascular computed
tomographic angiography (CCTA) can comprehensively assess cardiovascular structure and function relevant to the assessment,
treatment, and follow-up of patients with electrophysiologically-related disease processes. CCTA provides 3-D visualization
of cardiac chambers, coronary vessels, and thoracic vasculature including structures particularly important to cardiac electrophysiology,
such as the coronary veins, pulmonary veins, and left atrium. This comprehensive technology is extremely useful for the identification
and characterization of cardiovascular substrates relevant to cardiac electrophysiology, and has great relevance to treatment
of arrhythmias through preprocedure planning, procedural facilitation, and procedural follow-up.
12/2009: pages 293-308;
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ABSTRACT: We describe the case of a young patient with severe hypertrophic cardiomyopathy and marginal defibrillation thresholds (DFTs) at implant of a standard transvenous implantable cardioverter-defibrillator (ICD) system. The patient subsequently experienced multiple failed ICD shocks during a prolonged episode of spontaneous ventricular tachycardia/fibrillation. Placement of a second single-coil shocking lead in the azygous vein resulted in acceptable DFTs, but the new lead migrated superiorly within hours of the procedure. To stabilize the lead position, a vascular plug was placed in the distal azygous vein, and the shocking lead screw was actively fixated to the meshwork of the device. Subsequent testing confirmed both adequate defibrillation and stable lead position.
Journal of Cardiovascular Electrophysiology 07/2009; 21(1):99-102. · 3.06 Impact Factor
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Journal of Cardiovascular Electrophysiology 07/2009; 20(8):906-7. · 3.06 Impact Factor
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Andrew D. Sumner MD,
John P. Boehmer MD,
Leslie A. Saxon MD,
Peter Carson MD,
PhD Arthur M. Feldman MD,
Elizabeth Galle MPH,
PhD Michael R. Bristow MD,
Andrew D. Sumner,
John P. Boehmer, Leslie A. Saxon,
Peter Carson,
Arthur M. Feldman,
Elizabeth Galle,
Michael R. Bristow
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ABSTRACT: It is unknown whether statin use improves survival in patients with advanced chronic heart failure (HF) receiving cardiac resynchronization therapy (CRT). The authors retrospectively assessed the effect of statin use on survival in patients with advanced chronic HF receiving CRT alone (CRT-P) or CRT with implantable cardioverter-defibrillator therapy (CRT-D) in 1520 patients with advanced chronic HF from the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) trial database. Six hundred three patients (40%) were taking statins at baseline. All-cause mortality was 18% in the statin group and 22% in the no statin group (hazard ratio [HR] 0.85; confidence interval (CI), 0.67–1.07; P=.15). In a multivariable analysis controlling for significant baseline characteristics and use of CRT-P/CRT-D, statin use was associated with a 23% relative risk reduction in mortality (HR, 0.77; CI, 0.61–0.97; P=.03). Statin use is associated with improved survival in patients with advanced chronic HF receiving CRT. No survival benefit was seen in patients receiving statins and optimal pharmacologic therapy without CRT.
Congestive Heart Failure 06/2009; 15(4):159 - 164.
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Leslie A Saxon,
Brian Olshansky,
Kent Volosin,
Jonathan S Steinberg,
Byron K Lee,
Gery Tomassoni,
Thomas Guarnieri,
Anupama Rao,
Patrick Yong,
Elizabeth Galle,
Jill Leigh,
Fred Ecklund,
Michael R Bristow
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ABSTRACT: There are no randomized controlled trial data that evaluate mortality and hospitalization rates in cardiac resynchronization therapy (CRT) recipients based on left ventricular (LV) lead location. We analyzed the event-driven outcomes of mortality and hospitalization as well as functional outcomes including Functional Class, Quality-of-Life, and 6-minute walk distance in 1,520 patients enrolled in the COMPANION study of CRT versus optimal medical therapy.
Over a mean follow-up after implantation of 16.2 months, patients randomized to CRT, regardless of lead location, experienced benefit compared with optimized pharmacologic therapy (OPT), with respect to all-cause mortality or heart failure hospitalization. All but a posterior location showed benefit with respect to the all-cause mortality or all-cause hospitalization outcome. Mortality benefit in CRT-D patients was indifferent to LV lead position. All functional outcomes including 6-minute walk distance, Quality-of-Life (QOL) and Functional Class improved with CRT, regardless of LV lead location.
LV lead location was not a major determinant of multiple measures of response to CRT therapy in the COMPANION Trial. While acute data indicate that a left lateral LV lead location results in the most favorable hemodynamic response, these chronic data suggest that positioning an LV lead in an anterior rather than a lateral or posterior LV location has similar benefit.
Journal of Cardiovascular Electrophysiology 03/2009; 20(7):764-8. · 3.06 Impact Factor
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Mayo Clinic Proceedings 10/2008; 83(9):1022-5. · 5.70 Impact Factor
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Teresa De Marco,
Eugene Wolfel,
Arthur M Feldman,
Brian Lowes,
Michael B Higginbotham,
Jalal K Ghali,
Lynne Wagoner,
Philip C Kirlin,
Jerry D Kennett,
Satish Goel, Leslie A Saxon,
John P Boehmer,
David Mann,
Elizabeth Galle,
Fred Ecklund,
Patrick Yong,
Michael R Bristow
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ABSTRACT: A total of 405 participants in the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure trial were prospectively enrolled in an exercise sub-study designed to study the influence of cardiac resynchronization therapy (CRT) on measures of exercise capacity, functional capacity, and quality of life (QOL).
Substudy eligibility included New York Heart Association (NYHA) functional Class III or IV heart failure, left ventricular ejection fraction < or =0.35, QRS interval of > or =120 ms, normal sinus rhythm, a heart failure hospitalization (or equivalent) within 1 year, a peak VO2 < or =22 mL x kg x min, the ability to walk 150 to 425 meters in 6 minutes, forced expiratory volume in 1 second/forced vital capacity > or =50%, and no clinical indication for a pacemaker or implantable cardioverter-defibrillator. Patients were randomized in a 1:4 ratio to optimal medical therapy (OPT) or to OPT plus CRT. Cardiopulmonary exercise testing (peak VO2 and 6-minute walk distance [6MWD]) and assessment of NYHA functional class and QOL were assessed at baseline and at 3 and 6 months of assigned therapy. There was no significant improvement in peak VO2 at 6 months in the CRT group compared with the OPT group (+0.63 mL x kg x min) by unadjusted analysis (P = .05) or by analyses adjusted for missing data. Thus the primary end point of the study was not met. There was significantly greater improvement in the 6MWD in the CRT group compared with the OPT group at both 3 and 6 months by both statistical methods (P < or = .045). Likewise, a greater proportion of CRT patients improved by 1 or more NYHA functional classes (P < .01) at 3 months and had better QOL scores (P < .01) at 3 and 6 months compared with the OPT patients. Baseline peak VO2 predicted clinical events (time to death, time to death or first hospitalization, or time to death and first heart failure hospitalization: P < .05) in CRT participants.
CRT patients with moderate to advanced symptoms of systolic heart failure and prolonged QRS intervals benefit from the addition of CRT to OPT in terms of exercise capacity, functional status, and QOL. CRT should be considered standard therapy in this select group of heart failure patients.
Journal of cardiac failure 03/2008; 14(1):9-18. · 3.25 Impact Factor
