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To the Editor- Alternate interpretation of left bundle branch potential. Heart Rhythm 2024; 21:505. [PMID: 38142833 DOI: 10.1016/j.hrthm.2023.11.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 11/08/2023] [Indexed: 12/26/2023]
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Ablation Versus Antiarrhythmic Drugs as First-Line Therapy for Treatment-Naive Atrial Fibrillation: A Systematic Review and Meta-Analysis. Am J Cardiol 2024; 213:63-68. [PMID: 38040282 DOI: 10.1016/j.amjcard.2023.11.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/12/2023] [Accepted: 11/21/2023] [Indexed: 12/03/2023]
Abstract
Evidence on the relative safety and efficacy of atrial fibrillation catheter ablation and antiarrhythmic drugs (AADs) as the first-line therapy for patients with treatment-naive atrial fibrillation (AF) remains disputed. Digital databases were queried to identify relevant randomized controlled trials. The incidence of recurrent AF, major adverse cardiovascular events, and its components (all-cause death, nonfatal stroke, and bleeding) were compared using the DerSimonian and Laird method under the random-effects model to calculate pooled unadjusted risk ratio (RR) with 95% confidence intervals (CIs). A total of 6 randomized controlled trials consisting of 1,120 patients (574 ablation and 549 AADs) were included in the final analysis. Over a median follow-up of 1 year, the risk of any AF recurrence (RR 0.54, 95% CI 0.39 to 0.75) was significantly lower in patients receiving ablation than in patients receiving AADs. However, there was similar risk of major adverse cardiovascular events (RR 2.65, 95% CI 0.61 to 11.46), trial-defined composite end point of adverse events (RR 0.71, 95% CI 0.28 to 1.80), stroke (RR 2.42, 95% CI 0.22 to 26.51), all-cause mortality (RR 1.98, 95% CI 0.28 to 13.90), and procedure/medication failure (RR 2.65, 95% CI 0.61 to 11.46) with both therapies. In conclusion, in patients presenting with treatment-naive AF, ablation as a first-line therapy lowers the risk of AF recurrence with no associated increase in major adverse events, stroke, and mortality compared with AADs.
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Single operator experience, learning curve, outcomes, and insights gained with conduction system pacing. Pacing Clin Electrophysiol 2024; 47:211-221. [PMID: 38265169 DOI: 10.1111/pace.14926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 12/29/2023] [Indexed: 01/25/2024]
Abstract
BACKGROUND Conduction system pacing (CSP) is increasingly utilized to prevent and correct dyssynchrony. Barriers to CSP adoption include limited training, methodologic variability, laboratory slot allocation, and few data on learning curves. We report learning curves/clinical outcomes from a single experienced electrophysiologist who was new to CSP, and share gained insights. METHODS Retrospective analysis of all patients who underwent attempted CSP implantation (2016-2023). Patient characteristics, ECGs, echocardiograms, fluoroscopy/procedure times, lead data were recorded at implant and follow-up. RESULTS CSP leads were implanted successfully in 167/191(87.4%) patients with a follow-up of 278 ± 378 days. His-bundle pacing (HBP = 59) and left-bundle-area pacing (LBAP = 108) had similar procedure/fluoroscopy times, QRS duration decreases, and ejection fraction improvements (all p > NS). Eight HBP lead revisions were required for high capture thresholds LBAP demonstrated lower pacing thresholds, higher lead impedances, and greater R-wave amplitudes at implant and follow-up. After 25 HBP cases, implant pacing thresholds, fluoroscopy, procedural times did not decrease. After 25 LBAP cases, there were significant decreases in all these parameters (p < 0.05). A separate analysis in LBAP patients with recorded Purkinje signals showed no differences in paced ECG characteristics between patients with pre- QRS Purkinje signals versus patients with Purkinje signals post-QRS onset. CONCLUSIONS Experienced implanters who are new to CSP can achieve steady-state procedural/fluoroscopy times after a learning curve of 25 implants. LBAP showed lower capture thresholds and higher success rates. Adequate depth of lead deployment (as determined by published parameters) does not require Purkinje potential to be pre-QRS. Operators new to CSP.can forego HBP and directly implement LBAP.
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Beyond biventricular pacing: Exploring the advantages of his-bundle pacing and left bundle branch pacing in heart failure-A systematic review and meta-analysis. Pacing Clin Electrophysiol 2024; 47:156-166. [PMID: 38071452 DOI: 10.1111/pace.14892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 10/23/2023] [Accepted: 11/17/2023] [Indexed: 01/11/2024]
Abstract
BACKGROUND This meta-analysis compares His-Purkinje system pacing (HPSP), a novel cardiac resynchronization therapy (CRT) technique that targets the intrinsic conduction system of the heart, with conventional biventricular pacing (BiVP) in heart failure (HF) patients with left ventricular (LV) dysfunction and dyssynchrony. METHODS We searched multiple databases up to May 2023 and identified 18 studies (five randomized controlled trials and 13 observational studies) involving 1291 patients. The outcome measures were QRS duration, left ventricular ejection fraction (LVEF) improvement, left ventricular end-diastolic diameter (LVEDD) change, HF hospitalization, and New York Heart Association (NYHA) functional class improvement. We used a random-effects model to calculate odds ratios (OR), and mean differences (MD) with 95% confidence intervals (CI). We also assessed the methodological quality of the studies. RESULTS The mean LVEF was 30.7% and the mean follow-up duration was 8.1 months. Among LBBP, HBP, and BiVP, HBP provided the shortest QRS duration [MD: -18.84 ms, 95% CI: -28.74 to -8.94; p = 0.0002], while LBBP showed the greatest improvement in LVEF [MD: 5.74, 95% CI: 2.74 to 7.46; p < 0.0001], LVEDD [MD: -5.55 mm, 95% CI: -7.51 to -3.59; p < 0.00001], and NYHA functional class [MD: -0.58, 95% CI: -0.80 to --0.35; p < 0.00001]. However, there was no significant difference in HF hospitalization between HPSP and BiVP. CONCLUSION LBBP as modality of HPSP demonstrated superior outcomes in achieving electrical ventricular synchrony and systolic function, as well as alleviating HF symptoms, compared to other pacing techniques.
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Evaluating Goldberger's triad as a marker of congestive heart failure: A systematic review and retrospective study. J Electrocardiol 2023; 81:207-213. [PMID: 37783013 DOI: 10.1016/j.jelectrocard.2023.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/19/2023] [Accepted: 09/14/2023] [Indexed: 10/04/2023]
Abstract
BACKGROUND In 1982, Drs. Barold and Goldberger described an ECG triad associated with left ventricular dysfunction (LVD) consisting of high precordial QRS voltage, low limb lead voltage, and poor precordial R wave progression. Studies have since attempted to replicate the originally reported sensitivity (70%), specificity (>99%), and positive predictive value (PPV, 100%) of Goldberger's triad (GT) with variable results. PURPOSE To assess sensitivity, specificity and PPV of GT as a screening tool for LVD in the current era. METHODS We performed: (1) A systematic review of the published studies; (2) Searched our hospital ECG database (GE MUSE) for diagnoses of "low limb-voltage" and "left ventricular hypertrophy" from 2017 to 2022; identified ECGs were analyzed for GT criteria and their medical records were screened for LVD. (3) ECG analysis of patients with known idiopathic LVD for the GT. RESULTS A total of 11,115 patients from 8 studies were included in the systematic review of published studies and showed widely varying sensitivity, specificity and PPV. A total of 4576 ECGs (in GE MUSE) from 372 patients met initial screening criteria of low limb lead voltage and LVH; only 12 patients had ECGs that satisfied GT. Of these 12, only 1 patient had evidence of LVD, yielding a PPV of 8%. Finally, of the 40 patients with known LVD, only 1 met the ECG criteria for GT, resulting in a sensitivity of 2.5%. CONCLUSION Our literature review does not support the original results of GT. ECGs from our database that met GT (searched by low limb-voltage and left ventricular hypertrophy) over a span of 5 years were rare. When present, the PPV of GT was 8%. In patients with established LVD, the sensitivity was 2.5%. These data do not validate GT as tool to identify LVD in the current era.
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Helping the hypertrophied (but nonobstructed) heart. Heart Rhythm 2023; 20:1314-1315. [PMID: 37247687 DOI: 10.1016/j.hrthm.2023.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 05/25/2023] [Indexed: 05/31/2023]
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Adverse Outcomes of Atrial Fibrillation Ablation in Heart Failure Patients with and without Cardiac Amyloidosis: A Nationwide Readmissions Database Analysis (2015-2019). EUROPEAN HEART JOURNAL OPEN 2023; 3:oead026. [PMID: 37065605 PMCID: PMC10098254 DOI: 10.1093/ehjopen/oead026] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/22/2023] [Accepted: 03/08/2023] [Indexed: 03/15/2023]
Abstract
Abstract
Atrial fibrillation (AF) in patients with cardiac amyloidosis (CA) has been linked with a worse prognosis. The current study aimed to determine the outcomes of AF catheter ablation in patients with CA. The National Readmission Database (NRD) 2015-2019 was used to identify patients with AF and concomitant heart failure (HF). Among these, patients who underwent catheter ablation were classified into two groups, patients with and without CA. The adjusted odds ratio (aOR) of index-admission and 30-day readmission outcomes were calculated using a propensity score matched (PSM) analysis. A total of 148,134 patients with AF undergoing catheter ablation were identified on crude analysis. Using PSM analysis, 616 patients (293 CA-AF, 323 no-CA-AF) were selected based on a balanced distribution of baseline comorbidities. At index admission, AF ablation in patients with CA was associated with significantly higher adjusted odds of net adverse clinical events (NACE) (aOR 4.21, 95% CI 1.7-5.20), in-hospital mortality (aOR 9.03, 95% CI 1.12-72.70), and pericardial effusion (aOR 3.30, 95% CI 1.57-6.93) compared with non-CA AF. There was no significant difference in the odds of stroke, cardiac tamponade, and major bleeding between the two groups. At 30-day readmission, the incidence of NACE, and mortality remained high in patients undergoing AF ablation in CA. Compared with non-CA, AF ablation in CA patients is associated with relatively higher in-hospital all-cause mortality and net adverse events both at index admission and up to 30-day follow-up.
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DIAGNOSIS-TO-ABLATION TIME AS A PREDICTOR OF RECURRENCE OF ATRIAL FIBRILLATION FOLLOWING CATHETER ABLATION: A SYSTEMATIC REVIEW AND META-ANALYSIS. J Am Coll Cardiol 2023. [DOI: 10.1016/s0735-1097(23)00501-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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Abstract
PURPOSE OF THE REVIEW Dyssynchrony occurs when portions of the cardiac chambers contract in an uncoordinated fashion. Ventricular dyssynchrony primarily impacts the left ventricle and may result in heart failure. This entity is recognized as a major contributor to the development and progression of heart failure. A hallmark of dyssynchronous heart failure (HFd) is left ventricular recovery after dyssynchrony is corrected. This review discusses the current understanding of pathophysiology of HFd and provides clinical examples and current techniques for treatment. RECENT FINDINGS Data show that HFd responds poorly to medical therapy. Cardiac resynchronization therapy (CRT) in the form of conventional biventricular pacing (BVP) is of proven benefit in HFd, but is limited by a significant non-responder rate. Recently, conduction system pacing (His bundle or left bundle branch area pacing) has also shown promise in correcting HFd. HFd should be recognized as a distinct etiology of heart failure; HFd responds best to CRT.
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A Novel Module Based Method of Teaching Electrocardiogram Interpretation for Emergency Medicine Residents. JOURNAL OF EDUCATION & TEACHING IN EMERGENCY MEDICINE 2022; 7:SG15-SG60. [PMID: 37465135 PMCID: PMC10332672 DOI: 10.21980/j8z06j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 10/01/2022] [Indexed: 07/20/2023]
Abstract
Audience This online learning module is designed for PGY 1-3 emergency medicine (EM) residents. Introduction Interpretation of the 12-lead electrocardiogram (ECG) is an essential skill for EM residents. The traditional approach to ECG interpretation in medical school is primarily didactic, teaching: "rate, rhythm, axis," etc. Throughout residency, EM residents continue to receive lectures and practical ECG teaching to independently interpret ECGs with accuracy and efficiency. In addition to basic rhythm interpretation, physicians must be able to identify cardiac ischemia, abnormal rhythms, and subtle ECG findings that could herald sudden death.1 Life-threatening diagnoses such as digitalis toxicity or hyperkalemia can be made promptly through ECG evaluation and catastrophic if missed. If correctly diagnosed through ECG, many channelopathies can be treated and cardiac events can be prevented.2,3 Lecture-based learning is a necessary part of medical education, but there is a need to supplement the traditional teaching approach with online learning modules. Online learning modules provide learners with an accessible and efficient tool that allows them to improve their ECG skills on their own time. Educational Objectives After completion of the module learners should be able to: 1) correctly recognize and identify ECG abnormalities including but not limited to abnormal or absent P waves, widened QRS intervals, ST elevations, abnormal QT intervals, and dysrhythmias that can lead to sudden cardiac death; and 2) synthesize findings into a succinct but accurate interpretation of the ECG findings. Educational Methods An online module was developed using Articulate 360 and was implemented with EM residents. The module covers common ECG findings seen in the emergency department including ischemia, atrioventricular blocks, and bundle branch blocks. The module uniquely emphasizes ECG findings of arrythmias that could lead to sudden cardiac death and highlights that diagnosing sudden cardiac death syndromes relies on both clinical presentation and specific ECG findings. Online modules have proven to be as effective as lecture-based learning at improving ECG interpretation among healthcare professionals and are convenient and easily accessible to the busy EM resident.4,5 Additionally, the module is self-paced, can be completed at any time, and includes elements of active learning by incorporating knowledge checks throughout. This allows learners in real time to see where individualized improvement is needed. The ease of embedment of self-paced questions into the module is one of the salient reasons why module-based learning can be superior to lecture-based learning. This allows for real time retrieval practice, feedback, and repetition, all of which can be powerful and effective tools for learning.6. Research Methods This module was offered at a single academic institution with a 3-year residency program. The investigation was reviewed and approved for exemption by the Institutional Review Board of Sydney Kimmel Medical College. The module was evaluated using survey data; before the module was disseminated, residents were given a pre-module survey. The survey was used to evaluate the methods residents used to interpret ECGs prior to completion of the module and to evaluate their baseline confidence in ECG interpretation. The residents were then given access to the module and had two weeks to complete it. After the two-week period, the post-module survey was used to evaluate resident satisfaction with the delivery of the module, the methods residents used to interpret ECGs after the module, and resident confidence in ECG interpretation. The objective efficacy of the educational content in the module was assessed using a pre- and post-module assessment. The assessments consisted of 15 ECGs.Residents were asked to provide a one-sentence interpretation for each of the 15 ECGs and the final answers were based on interpretation by an electrophysiologist. Results A group of 37 EM residents had two weeks to complete the module between pre- and post-tests. There was an 18.2% absolute increase in the mean percent correct after the module, a 42.5% relative increase from pre-test (t= -8.0, p < 0.001). Subjective data demonstrated that after completing the module, residents utilized the novel approach, were more confident in interpreting ECGs, and would use the module as a resource in the future. Discussion Most participants were not confident in their ability to interpret an ECG prior to completing the module, despite most of the participants having ECG training in the six months prior to the study. Almost all the participants reported using "rate, rhythm, axis" as their method of ECG interpretation. Even with recent training, and an understanding of "rate, rhythm, axis," there was a very low accuracy on the pre-test and lack of perceived baseline confidence in this skill. These findings highlight the need for a concise, effective supplemental ECG tool that can be incorporated into residency program curricula.The online learning module was effective at increasing confidence of ECG interpretation skills in residents as well as increasing accuracy of interpretation. Overall, participants were satisfied with the module as a resource for practicing their ECG interpretation, and most participants reported that they would use the module in the future as a reference. Implementation of the module as an additional resource in resident education is very simple. It can be accessed through any device that has internet and can be completed in a short period of time. Additionally, most experienced ECG readers will speak about "pattern recognition" as an important tool in ECG interpretation. This ability goes above and beyond the "rate, rhythm, axis" approach, but is acquired over time, often after many years of ECG interpretation. It is possible that the modular method may accelerate such pattern recognition abilities. Topics Electrocardiogram, online module, sudden cardiac death, ischemia.
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PO-618-08 IMPACT OF LEFT BUNDLE AREA PACING ON QRS DURATION IN PATIENTS WITH PREEXISTING RIGHT BUNDLE BRANCH BLOCK: INSIGHT INTO MECHANISM OF QRS SHORTENING. Heart Rhythm 2022. [DOI: 10.1016/j.hrthm.2022.03.819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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SERIAL TRENDS IN UNDERUTILIZATION OF IMPLANTABLE CARDIOVERTER DEFIBRILLATOR IN HYPERTROPHIC CARDIOMYOPATHY: 2002 TO 2018. J Am Coll Cardiol 2022. [DOI: 10.1016/s0735-1097(22)01583-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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An Unusual Case of Non-Reentrant Atrioventricular Nodal Tachycardia. J Cardiovasc Electrophysiol 2022; 33:1062-1066. [PMID: 35229370 DOI: 10.1111/jce.15426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/07/2022] [Accepted: 02/21/2022] [Indexed: 11/29/2022]
Abstract
Although uncommonly encountered, dual atrioventricular nodal non-reentrant tachycardia (DAVNNRT) is a well described arrhythmia that can manifest in patients with dual atrioventricular nodal pathways physiology. This arrhythmia is characterized on ECG by a single P wave followed by two conducted QRS complexes, and on intracardiac EGMs by a single atrial electrogram followed by two separate His deflections and ventricular electrograms. Our case demonstrates a rare case of "triple atrioventricular non-reentrant tachycardia" in which a patient was found to have 3 distinct AV nodal pathways and multiple "triple fire responses", both on surface ECG and intracardiac electrograms. This article is protected by copyright. All rights reserved.
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Implantation of cardiac electronic devices in active COVID-19 patients: Results from an international survey. Heart Rhythm 2022; 19:206-216. [PMID: 34710561 PMCID: PMC8547796 DOI: 10.1016/j.hrthm.2021.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/16/2021] [Accepted: 10/20/2021] [Indexed: 12/25/2022]
Abstract
BACKGROUND Cardiac implantable electronic device (CIED) implantation rates as well as the clinical and procedural characteristics and outcomes in patients with known active coronavirus disease 2019 (COVID-19) are unknown. OBJECTIVE The purpose of this study was to gather information regarding CIED procedures during active COVID-19, performed with personal protective equipment, based on an international survey. METHODS Fifty-three centers from 13 countries across 4 continents provided information on 166 patients with known active COVID-19 who underwent a CIED procedure. RESULTS The CIED procedure rate in 133,655 hospitalized COVID-19 patients ranged from 0 to 16.2 per 1000 patients (P <.001). Most devices were implanted due to high-degree/complete atrioventricular block (112 [67.5%]) or sick sinus syndrome (31 [18.7%]). Of the 166 patients in the study survey, the 30-day complication rate was 13.9% and the 180-day mortality rate was 9.6%. One patient had a fatal outcome as a direct result of the procedure. Differences in patient and procedural characteristics and outcomes were found between Europe and North America. An older population (76.6 vs 66 years; P <.001) with a nonsignificant higher complication rate (16.5% vs 7.7%; P = .2) was observed in Europe vs North America, whereas higher rates of critically ill patients (33.3% vs 3.3%; P <.001) and mortality (26.9% vs 5%; P = .002) were observed in North America vs Europe. CONCLUSION CIED procedure rates during known active COVID-19 disease varied greatly, from 0 to 16.2 per 1000 hospitalized COVID-19 patients worldwide. Patients with active COVID-19 infection who underwent CIED implantation had high complication and mortality rates. Operators should take these risks into consideration before proceeding with CIED implantation in active COVID-19 patients.
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Conduction system pacing versus biventricular pacing: Reduced repolarization heterogeneity in addition to improved depolarization. J Cardiovasc Electrophysiol 2021; 33:287-295. [PMID: 34911154 DOI: 10.1111/jce.15329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/01/2021] [Accepted: 11/15/2021] [Indexed: 11/26/2022]
Abstract
INTRODUCTION His-bundle pacing (HBP) and left-bundle-area pacing (LBAP) are conduction system pacing (CSP) modalities increasingly used as alternatives to conventional biventricular pacing (BiVP). While effects of CSP on ventricular depolarization have been reported, effects on ventricular repolarization have not. METHODS QRS duration (QRSd) and validated ECG parameters of ventricular repolarization associated with arrhythmic risk (T-peak-to-T-endTransmural , T-peak-to-T-endTotal , T-peak dispersion, QTc, QTc dispersion) were analyzed post-implant in 107 patients: 60 with CSP (HBP: n = 35, LBAP: n = 25) and 47 with BiVP. T-wave memory resolution and QTc shortening were analyzed on ECGs obtained ≥25 days post-implant. Twenty blinded measurements were obtained by both authors to assess Interobserver variability. RESULTS Although QRSd was shorter with HBP versus LBAP (119 ± 7 ms vs. 132 ± 9 ms, p = .02), there were no significant differences in any repolarization parameters between these methods of CSP. However, when comparing CSP (HBP + LBAP) to BiVP, both QRSd (125 ± 5 ms vs. 147 ± 7 ms, p < .0001) and repolarization parameters (T-peak-to-T-endTransmural : 83 ± 5 ms vs. 107 ± 8 ms; T-peak-to-T-endTotal : 110 ± 7 ms vs. 137 ± 10 ms; QTc: 470 ± 12 ms vs. 506 ± 12 ms; all p ≤ .0001) were significantly shorter with CSP. Improved T-peak-to-T-end values were unrelated to pre-implant QRSd or LV function. Interobserver variability was 4.6 ± 1.9 ms. Frontal QRS-T angle narrowing (132° to 104°, p = .001) and QTc shortening (483 ± 13 ms to 464 ± 12 ms, p = .008) were seen only with CSP. CONCLUSIONS In addition to improved depolarization, CSP reduced repolarization heterogeneity and provided greater T-wave memory resolution as compared to BiVP. Both modalities of CSP (HBP + LBAP) resulted in comparably reduced repolarization heterogeneity regardless of baseline QRSd and LV function. These observations may confer lower arrhythmogenic risk and warrant further study.
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Describing heart rate variability in patients with chronic atrial fibrillation during hospitalization for COVID-19. J Arrhythm 2021; 37:893-898. [PMID: 34386114 PMCID: PMC8339086 DOI: 10.1002/joa3.12569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/13/2021] [Accepted: 05/10/2021] [Indexed: 01/08/2023] Open
Abstract
INTRODUCTION Myriad cardiovascular manifestations have been reported with COVID-19. We previously reported that failure of PR interval shortening with increasing heart rate (HR) in patients with COVID-19 is associated with adverse outcomes. Here, we report on heart rate variability (HRV) and clinical outcomes in patients with chronic atrial fibrillation (cAF) hospitalized for COVID-19. METHODS A retrospective review of admitted COVID-19 patients with cAF between 1 March 2020 to 30 June 2020 was performed. HRV in cAF was compared during pre-COVID-19 and COVID-19 admissions; we selected pre-COVID-19 ECGs with HRs that were within 10 beats per minute of the COVID-19 ECGs. Mean HR and each RR interval were recorded. Time-domain measurements of HR variability were then calculated (SDSD, RMSSD, pNN50). Clinical outcomes during COVID-19 were correlated to indices of HRV. RESULTS A total of 184 ECGs (95 pre-COVID-19, 89 COVID-19) from 38 cAF in-patients were included. Mean age 78.6 ± 11.4 years, male 44.7%. The mean number of ECGs analyzed per patient pre-COVID-19 was 2.50 and during COVID-19 was 2.34. Comparing pre-COVID-19 versus COVID-19 ECGs showed: mean HR (95.9 ± 24.3 vs. 101.6 ± 22.8 BPM; P = .10), SDSD (109.0 ± 50.6 vs. 90.3 ± 37.2 ms; P < .01), RMSSD (184.1 ± 80.4 vs. 147.3 ± 59.8 ms; P < .01), pNN50 (73.8 ± 16.3 vs. 65.6 ± 16.6%; P < .01). Patients who had a smaller pNN50 during a COVID-19 admission had increased mortality (50.0% vs. 14.3%; log-rank test P = .02). CONCLUSION In patients with cAF, the HRV was reduced during COVID-19 compared with prior illnesses at similar average heart rates. Patients with the most depressed HRV as measured by pNN50 had an associated increase in mortality compared with patients whose HRV was preserved.
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Tricuspid regurgitation associated with implantable electrical device insertion: A systematic review and meta-analysis. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2021; 44:1297-1302. [PMID: 34081789 DOI: 10.1111/pace.14287] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/28/2021] [Accepted: 05/30/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Implantable cardioverter defibrillator (ICD) and permanent pacemaker (PPM) lead placement may worsen or result in tricuspid regurgitation (TR). While the association between lead placement and the incidence of TR has been established, current understanding of this problem remains incomplete. This systematic review and meta-analysis sought to pool the existing evidence to better understand the occurrence and severity of TR associated with cardiac implantable electrical device (CIED) insertion. METHODS An electronic search was performed to identify all relevant studies published from 2000 to 2018. Overall, 15 studies were selected for the analysis comprising 4019 patients with data reported on TR development following ICD or PPM lead placement. Demographic information, perioperative clinical variables, and clinical outcome measures, including pre and postoperative echocardiographic TR grade changes, were extracted and pooled for systematic review. RESULTS Mean patient age was 69 years [95% CI: 64.62-73.59], and 63% [95% CI: 57-68] were male. Devices implanted included ICD in 57% [95%CI: 43-70] and PPM in 41% [95%CI: 31-52]. The most common indications for pacemaker implantation were sick sinus syndrome in 22% [95% CI: 22-37] and AV block in 21% [95%CI:12-34. The commonest indications for ICD implantation were primary and secondary prevention of sudden cardiac death. Atrial fibrillation was present in 37% [95%CI: 28-46] and congestive heart failure in 15% [95%CI: 2-57]. Baseline distribution of TR grades were as follows: grade 0/1 TR in 89% [95%CI: 82-93], grade 2 TR in 8% [95%CI: 5-13], grade 3 TR in 2% [95%CI: 0-7] and grade 4 TR in 2% [95%CI: 1-4]. Post-procedure, grade 0/ 1 TR decreased to 68% [95% CI: 51-81] (p < 0.01), grade 2 TR increased to 21% [15-28] (p < 0.01), grade 3 TR increased to 13% [95%CI: 5-32] (p = 0.02), and grade 4 TR increased to 7% [95%CI: 5-9] (p < 0.01). CONCLUSION ICD and PPM lead placement is associated with increased TR post-procedure. Further studies are warranted to evaluate changes in TR grade in the long term.
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A Shocking Case of Far-Field Atrial Oversensing in Giant-Cell Myocarditis. JACC Case Rep 2021; 3:603-609. [PMID: 34317586 PMCID: PMC8302787 DOI: 10.1016/j.jaccas.2021.02.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/21/2021] [Accepted: 02/05/2021] [Indexed: 11/25/2022]
Abstract
We report a unique case of delivery of inappropriate implantable cardioverter-defibrillator therapies related to a “perfect storm”: presence of an integrated lead, insufficient lead slack related to right heart dilation resulting in shock coil misplacement, myocarditis with loss of R waves, and the concomitant occurrence of an incessant atrial tachycardia. (Level of Difficulty: Advanced.)
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Ventricular tachycardia induced by a backup pacing stimulus in a patient with a dual chamber pacemaker with AutoCapture. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2021; 44:1130-1132. [PMID: 33590525 DOI: 10.1111/pace.14199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/04/2021] [Accepted: 02/14/2021] [Indexed: 11/29/2022]
Abstract
Manufacturers of cardiac implantable electronic devices have incorporated automatic features to allow for remote monitoring, improve device longevity, and additional safety. Algorithms to automatically measure capture threshold and adjust output to preserve battery life are one such feature. Automatic features may occasionally result in unexpected or undesirable clinical outcomes. We report on a patient who developed ventricular tachycardia inadvertently induced by the AutoCapture. feature of an Abbott/St. Jude Medical (SJM) pacemaker.
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Electromagnetic interference between implantable cardiac devices and continuous-flow left ventricular assist devices: a review. J Interv Card Electrophysiol 2021; 61:1-10. [PMID: 33433742 DOI: 10.1007/s10840-020-00930-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/27/2020] [Indexed: 11/30/2022]
Abstract
Many patients with continuous-flow left ventricular assist devices (CF-LVAD) have other, co-existing implantable cardiac devices. While such devices often function appropriately, there is potential for electromagnetic interference (EMI). A literature review was performed to identify cases of EMI between CF-LVAD and other implanted cardiac devices to better understand their etiology, outcomes, and the strategies used to overcome such interference. The cases identified included interference between CF-LVAD and pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy. The EMI reported in the current literature can be broken down into two general categories: interference leading to difficulty establishing telemetry and interference leading to impaired electrical signal sensing. Such interference led to inappropriate shock delivery in some cases. The type of interference, and thus treatments, differed and were device dependent. The strategies employed to reduce interference included metal shielding, physical manipulation to increase the distance between devices, and even exchange of the implanted device with another brand of the same class. To avoid such EMI in the future, physicians must be aware of the reported interference between certain devices, and manufacturers must work more closely to increase the compatibility of implanted cardiac devices.
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Differential Effects of Vagal Activation on the Sinus and Atrioventricular Nodes: Report of 2 Cases. JACC Case Rep 2020; 2:1748-1752. [PMID: 34317050 PMCID: PMC8311999 DOI: 10.1016/j.jaccas.2020.05.085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 11/17/2022]
Abstract
Vagal activation usually affects both sinus and atrioventricular (AV) nodes, manifesting as sinus slowing accompanied by varying degrees of AV block. AV block accompanying sinus acceleration as during treadmill testing is usually considered pathologic. We report 2 cases of vagally mediated reflex AV block accompanied by sinus tachycardia and acceleration. (Level of Difficulty: Intermediate.)
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Dual atrioventricular nodal pathways physiology and high-grade heart block. J Electrocardiol 2020; 62:138-141. [PMID: 32866914 DOI: 10.1016/j.jelectrocard.2020.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/11/2020] [Accepted: 07/29/2020] [Indexed: 10/23/2022]
Abstract
We report of case of an 87 year old lady with preexisting RBBB who developed LBBB after transcatheter aortic valve replacement (TAVR) for the treatment of severe aortic stenosis. She underwent pacemaker implantation, and subsequently developed high-grade atrioventricular (AV) block. Dual chamber pacing in the setting of complete heart block with a long programmed AV delay showed retrograde P waves. Ventricular pacing showed intact retrograde conduction. Shortening the programmed AV delay resulted in loss of retrograde P waves during dual chamber pacing. These findings are discussed.
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Atrial fibrillation post central retinal artery occlusion: Role of implantable loop recorders. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2020; 43:992-999. [PMID: 32567072 DOI: 10.1111/pace.13990] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/03/2020] [Accepted: 06/14/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE This study evaluated the risk of subclinical atrial fibrillation (AF) in patients with central retinal artery occlusion (CRAO) compared to those with cryptogenic stroke using implantable loop recorders (ILR). METHODS We conducted a retrospective analysis of 273 consecutive patients who had ILRs inserted at our institution for either cryptogenic stroke (n = 227) or CRAO (n = 46). Our primary endpoint was a time to event analysis for the new diagnosis of AF by ILR. Univariable and multivariable Cox proportional hazard models were used to determine the predictors of time-to-AF. RESULTS A total of 64 patients were found to have newly diagnosed AF by remote monitoring of the ILR. AF was detected in 57 of 227 (25%) cryptogenic stroke patients by the end of a maximum 5.1 years follow-up and in seven of 46 (15%) CRAO patients by the end of a maximum 3.6 years follow-up (P = .215, log-rank test). The Kaplan-Meier estimates for freedom from AF was 59.4% for CRAO and 66.6% for cryptogenic stroke (P = NS, log-rank test). Baseline variables predicting AF included older patients, higher CHADS2 VASC score, longer PR interval on initial EKG evaluation, and mitral annular calcification on transthoracic echocardiogram. CONCLUSIONS Patients with CRAO are at risk for subclinical AF, similar to those with cryptogenic stroke. Long-term monitoring to detect AF may lead to changes in pharmacotherapy to reduce the risk for subsequent stroke.
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The diagnostic yield of implantable loop recorders stratified by indication: "real-world" use in a large academic hospital. J Interv Card Electrophysiol 2020; 61:303-311. [PMID: 32621215 DOI: 10.1007/s10840-020-00815-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/29/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE To report on the clinical utility of implantable loop recorders (ILRs) in a large academic hospital setting over a 4-year period. METHODS Retrospective study (2013-2016) of patients receiving ILRs for any indication including syncope, cryptogenic stroke (CrS), atrial fibrillation (AF) burden, palpitations, ventricular arrhythmias (VA), and other. Remote checks, symptomatic transmissions, and in-person checks were reviewed. Time to diagnosis was documented. RESULTS A total of 263 patients (54% male, mean age 63 ± 15 years, mean follow-up 601 (range 9-1714) days) received ILRs for 324 indications; multiple indications were noted in 53/263 (20.2%) patients. ILR indications were 126 (39%) syncope, 81 (25%) CrS, 46 (14%) AF, 37 (11%) palpitations, 10 (3%) VA, and 24 (7%) other. Diagnostic yield for each indication was compared to the overall yield for all other indications. Three indications showed a significantly higher yield: AF (65% vs. 22%, p < 0.002), palpitations (60% vs. 24%, p < 0.001), and VA (70% vs. 28%, p < 0.004). For all other indications, there were no significant differences. Syncope had nearly half the diagnostic yield of previously published trials (28% vs. 43-56%). We observed a fourfold increase in ILR implant rate over the study duration. CONCLUSIONS In a "real-world" academic hospital setting, the diagnostic rate of ILRs was highest for AF, palpitations, and VA; however, these high yield indications comprised only 29% of all indications. The diagnostic yield for the commonest indication (syncope) was approximately half that reported in the previously published trials. With increasing implantation rates, additional studies are required to refine guideline-based indications for ILR implantation to improve diagnostic yield.
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Behavior of the PR interval with increasing heart rate in patients with COVID-19. Heart Rhythm 2020; 17:1434-1438. [PMID: 32535142 PMCID: PMC7289083 DOI: 10.1016/j.hrthm.2020.06.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/05/2020] [Accepted: 06/07/2020] [Indexed: 12/29/2022]
Abstract
Background Myriad manifestations of cardiovascular involvement have been described in patients with coronavirus disease 2019 (COVID-19), but there have been no reports of COVID-19 affecting the cardiac conduction system. The PR interval on the electrocardiogram (ECG) normally shortens with increasing heart rate (HR). The case of a patient with COVID-19 manifesting Mobitz type 1 atrioventricular (AV) block that normalized as the patient’s condition improved prompted us to investigate PR interval behavior in patients with COVID-19. Objective The purpose of this study was to characterize PR interval behavior in hospitalized patients with COVID-19 and to correlate that behavior with clinical outcomes. Methods This study was a cross-sectional cohort analysis of confirmed COVID-19 cases (March 26, 2020, to April 25, 2020). We reviewed pre–COVID-19 and COVID-19 ECGs to characterize AV conduction by calculating the PR interval to HR (PR:HR) slope. Clinical endpoints were death or need for endotracheal intubation. Results ECGs from 75 patients (246 pre–COVID-19 ECGs and 246 COVID-19 ECGs) were analyzed for PR:HR slope. Of these patients, 38 (50.7%) showed the expected PR interval shortening with increasing HR (negative PR:HR slope), whereas 37 (49.3%) showed either no change (8 with PR:HR slope = 0) or paradoxical PR interval prolongation (29 with positive PR:HR slope) with increasing HR. Patients without PR interval shortening were more likely to die (11/37 [29.7%] vs 3/38 [7.9%]; P = .019) or require endotracheal intubation (16/37 [43.2%] vs 8/38 [21.1%]; P = .05) compared to patients with PR interval shortening. Conclusion Half of patients with COVID-19 showed abnormal PR interval behavior (paradoxical prolongation or lack of shortening) with increasing HR. This finding was associated with increased risk of death and need for endotracheal intubation.
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Underdiagnosis of VT due to cycle length variation among cardiac sarcoidosis patients having ICD: Problem with stability discriminator. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2020; 43:573-582. [PMID: 32320087 DOI: 10.1111/pace.13923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 04/14/2020] [Accepted: 04/19/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Implantable cardioverter defibrillator (ICD) is recommended for patients with ventricular tachycardia (VT) due to cardiac sarcoidosis (CS). Programming supraventricular tachycardia (SVT) discriminators (onset, stability, and morphology/template match) is generally recommended to minimize inappropriate therapies. However, VT in patients with CS is known to show cycle length variability (CLV) and pleomorphism. OBJECTIVE To determine whether the stability criterion, designed to prevent inappropriate therapy during atrial fibrillation with rapid ventricular rates, could potentially lead to incorrect classification of VT as SVT and inappropriately delay or inhibit ICD therapy. METHODS Cases of biopsy-proven CS with VT were analyzed. For patients with implanted devices, all recorded electrograms of tachycardia episodes and ICD therapies were analyzed at last follow up. RESULTS A total of 142 patients were included (mean age 38 years, 87 males). One hundred and three of 142 patients had implanted devices (ICD or CRT-D). Thirty eight of 103 (36.9%) patients received appropriate ICD therapies over 3 ± 2.2 years follow up. Four of 38 (10.5%) of patients experienced delayed-detection or underdetection of VT related to CLV, resulting in VT counters being repeatedly "reset" (classified as "unstable" rhythms). Retrospective analysis of other VT episodes in 70 of 103 (68%) patients revealed that 25 of 80 (31.3%) episodes had > 50 ms cycle length oscillations. CONCLUSION Among CS patients with VT, CLV is a common occurrence seen in two-thirds of VT episodes. Routine programming of the stability criterion may result in underdetection of VT in a subset of such patients. We recommend that the stability criterion should be programmed "OFF" for patients with CS, unless the patient has documented atrial fibrillation.
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Sudden death and its risk factors after atrioventricular junction ablation and pacemaker implantation in patients with atrial fibrillation. Clin Cardiol 2016; 40:18-25. [PMID: 27748530 DOI: 10.1002/clc.22600] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 08/25/2016] [Accepted: 08/31/2016] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Although sudden death (SD) is a rare complication after atrioventricular junction (AVJ) ablation and permanent pacemaker implantation, the risk factors leading to this SD remain unknown. The purpose of this study was to investigate SD and its risk factors after ablate-and-pace strategy for rate control in atrial fibrillation (AF) patients during long-term follow-up. HYPOTHESIS METHODS: From January 2005 to December 2009, we enrolled into this study 517 AF patients with AVJ ablation and right ventricular pacemaker implantation. Patients were divided into 2 groups, SD and non-SD. Cox proportional hazards models were used to assess potential risk factors for overall mortality and SD. RESULTS During a mean follow-up of 25.8 ± 18.6 months (range, 3 days to 63.8 months), 53 patients died (15 with SD). Cox proportional hazards models showed that the presence of congestive heart failure, New York Heart Association functional class, chronic renal failure, and nonsustained ventricular tachycardia were risk factors that predicted overall mortality. For SD, the presence of dilated cardiomyopathy and mitral stenosis were associated risk factors. SD was exclusively seen in patients who had narrow QRS complex or right bundle branch block prior to AVJ ablation and pacemaker implantation; SD was not seen in any patient with preexisting complete left bundle branch block. CONCLUSIONS Dilated cardiomyopathy, mitral stenosis, and baseline QRS morphology should be examined as potential risk factors for SD after AVJ ablation and pacemaker implantation.
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Impact of baseline PR interval on cardiac resynchronization therapy outcomes in patients with narrow QRS complexes: an analysis of the ReThinQ Trial. J Interv Card Electrophysiol 2015; 43:145-9. [DOI: 10.1007/s10840-015-9999-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 03/20/2015] [Indexed: 11/29/2022]
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Pleomorphism during Ventricular Tachycardia: A Distinguishing Feature between Cardiac Sarcoidosis and Idiopathic VT. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2015; 38:694-9. [PMID: 25754130 DOI: 10.1111/pace.12626] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 02/23/2015] [Accepted: 03/01/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Ventricular tachycardia (VT), a common manifestation of cardiac sarcoidosis (CS), is associated with high morbidity and mortality. It could be mistaken for idiopathic VT (IVT) in the absence of systemic manifestations and overt cardiac structural abnormality. We studied the electrocardiogram (ECG) characteristics of VT in CS that may distinguish from IVT and also explored the relationship of the ECG characteristics with imaging findings in patients with CS. METHODS AND RESULTS Twelve-lead ECG characteristics of VT in CS patients (Group I = 37) were compared with IVT (Group II = 49). QRS duration, axis, morphology, VT cycle length, and cycle length variation (CLV) were analyzed. In Group I, 18 (49%) had pleomorphic VT (PLVT) and none in Group II. CLV was seen only in Group I (24%). Mean QRS duration (milliseconds) and cycle length (milliseconds) were greater in Group I (QRSd 152.49 [39.3] vs 140.9 [19.2]) and (332.2 [136.5] vs 312.9 [56.2]), the differences not statistically significant. In Group I, myocardial scar was present in 22 of 25 patients and myocardial inflammation in 28 of 29 patients as assessed by cardiac magnetic resonance imaging (delayed enhancement) and 18-fluorodeoxyglucose positron emission computed tomography, respectively. PLVT was seen more commonly in patients with involvement of >1 myocardial region than focal involvement (58% and 30%, respectively, with myocardial scar and 50% and 40%, respectively, with myocardial inflammation). CONCLUSION Pleomorphism and CLV during VT may be distinguishing features between IVT and VTs of CS origin.
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Changes in left ventricular synchrony and systolic function in dilated cardiomyopathy patients with fragmented QRS complexes. Europace 2015; 17:1712-9. [PMID: 25825459 DOI: 10.1093/europace/euu408] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 12/24/2014] [Indexed: 11/13/2022] Open
Abstract
AIMS Fragmented QRS (f-QRS) complexes are associated with adverse cardiovascular events in patients with coronary heart disease; however, the effects on patients with dilated cardiomyopathy (DCM) remain elusive. This study is to investigate the changes of left ventricular (LV) synchrony and systolic function in DCM patients with f-QRS complexes. METHODS AND RESULTS Twenty DCM patients with f-QRS complexes and 29 DCM patients without f-QRS (n-QRS) complexes were enrolled. The LV segmental longitudinal, radial and circumferential time to peak strain and general longitudinal systolic strain, radial strain, circumferential strain were measured, respectively, by speckle tracking imaging. The LV segmental standard deviations and maximal differences were also calculated. The LV dyssynchrony was defined as the time in peak anteroseptal wall to posterior wall strain >130 ms or longitudinal strain delay index >25%. The mean QRS durations in f-QRS and n-QRS groups were not different (P = ns). The incidence of LV dyssynchrony was 15/20 (75%) vs. 5/29 (17%) in two groups (P < 0.01). Two patients died of sudden death in f-QRS group during 2 years follow-up; however, no death in n-QRS group (P < 0.05). Patients in f-QRS group showed worsening LV dyssynchrony in f-QRS group after 2 years follow-up (P < 0.05). Overall, LV function was comparable at baseline (P = ns), but had significantly worsened only in the f-QRS group (P < 0.05). CONCLUSION The f-QRS complex is significantly associated with LV dyssynchrony in DCM patients and can be used as a reliable index to evaluate ventricular synchrony and predict the prognosis in DCM patients with narrow QRS complexes.
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Abrupt increase in impedance measurements as detected via remote monitoring: What is the cause? HeartRhythm Case Rep 2015; 1:51-53. [PMID: 28491510 PMCID: PMC5418532 DOI: 10.1016/j.hrcr.2014.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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T WAVE SLOPES: A NOVEL METHOD FOR ASSESSMENT OF REPOLARIZATION DISPERSION FROM SURFACE ECGS WITH PROLONGED QT AS COMPARED TO NORMAL ECGS. J Am Coll Cardiol 2014. [DOI: 10.1016/s0735-1097(14)61641-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Superiority of automatic remote monitoring compared with in-person evaluation for scheduled ICD follow-up in the TRUST trial - testing execution of the recommendations. Eur Heart J 2014; 35:1345-52. [PMID: 24595864 PMCID: PMC4028610 DOI: 10.1093/eurheartj/ehu066] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Aims To test recommended implantable cardioverter defibrillator (ICD) follow-up methods by ‘in-person evaluations’ (IPE) vs. ‘remote Home Monitoring’ (HM). Methods and results ICD patients were randomized 2:1 to automatic HM or to Conventional monitoring, with follow-up checks scheduled at 3, 6, 9, 12, and 15 months post-implant. Conventional patients were evaluated with IPE only. Home Monitoring patients were assessed remotely only for 1 year between 3 and 15 month evaluations. Adherence to follow-up was measured. HM and Conventional patients were similar (age 63 years, 72% male, left ventricular ejection fraction 29%, primary prevention 73%, DDD 57%). Conventional management suffered greater patient attrition during the trial (20.1 vs. 14.2% in HM, P = 0.007). Three month follow-up occurred in 84% in both groups. There was 100% adherence (5 of 5 checks) in 47.3% Conventional vs. 59.7% HM (P < 0.001). Between 3 and 15 months, HM exhibited superior (2.2×) adherence to scheduled follow-up [incidence of failed follow up was 146 of 2421 (6.0%) in HM vs. 145 of 1098 (13.2%) in Conventional, P < 0.001] and punctuality. In HM (daily transmission success rate median 91%), transmission loss caused only 22 of 2275 (0.97%) failed HM evaluations between 3 and 15 months; others resulted from clinic oversight. Overall IPE failure rate in Conventional [193 of 1841 (10.5%) exceeded that in HM [97 of 1484 (6.5%), P < 0.001] by 62%, i.e. HM patients remained more loyal to IPE when this was mandated. Conclusion Automatic remote monitoring better preserves patient retention and adherence to scheduled follow-up compared with IPE. Clinical trial registration NCT00336284.
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Tools for risk stratification of sudden cardiac death: a review of the literature in different patient populations. Indian Heart J 2014; 66 Suppl 1:S71-81. [PMID: 24568833 DOI: 10.1016/j.ihj.2013.12.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 12/14/2022] Open
Abstract
While various modalities to determine risk of sudden cardiac death (SCD) have been reported in clinical studies, currently reduced left ventricular ejection fraction remains the cornerstone of SCD risk stratification. However, the absolute burden of SCD is greatest amongst populations without known cardiac disease. In this review, we summarize the evidence behind current guidelines for implantable cardioverter defibrillator (ICD) use for the prevention of SCD in patients with ischemic heart disease (IHD). We also evaluate the evidence for risk stratification tools beyond clinical guidelines in the general population, patients with IHD, and patients with other known or suspected medical conditions.
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Electrophysiological Features Differentiating the Atypical Atrioventricular Node–Dependent Long RP Supraventricular Tachycardias. Circ Arrhythm Electrophysiol 2013; 6:597-605. [DOI: 10.1161/circep.113.000187] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Same-day discovery of implantable cardioverter defibrillator dysfunction in the TRUST remote monitoring trial: influence of contrasting messaging systems. Europace 2012; 15:697-703. [PMID: 23258817 PMCID: PMC3636999 DOI: 10.1093/europace/eus410] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aims Assess whether automatic remote home monitoring (HM) permits same-day evaluation of implantable cardioverter defibrillator (ICD) system dysfunction. Methods and results Compromised ICD system integrity (generator/lead) demands prompt evaluation. Home monitoring promises earlier discovery but may be limited by technological differences and follow-up mechanism. We tested whether HM enabled event review within 24 h, and contrasted differing messaging mechanisms. Nine hundred and eight patients in the TRUST prospective multicentre trial were followed by HM for 15 months. ICD system problems automatically triggered notifications: repeatedly (‘redundant’) for impedance deviations and elective replacement indication (ERI), but only a single transmission for ‘30 J ineffective’. Detection time from event onset to physician evaluation was measured. Forty-three system-related alerts occurred; 42% were asymptomatic, 42% were actionable, and 22 of 43 (51%) were viewed within 24 h. Redundant notifications were: 1 ERI, 9 shock impedance, 2 ventricular and 6 atrial pacing impedance. Most (11/18; 61%) were detected in <24 h. Others elicited daily notifications without interruption until resolution. For single transmissions, 11 of 25 (44%) events were detected on the same day. Most (56%, 14/25) were detected between 1 and 39 days (mean 10.0 ± 13.0 days). Ten of 14 events were detected by HM and 4 at the time of office visits. These observations suggest single transmissions were vulnerable to detection failure. Mean detection time of redundant events was 1.1 ± 1.8 vs. single transmission 5.6 ± 10.9 days (P = 0.05). Hence, redundant notification avoided late detection. Conclusion Same-day discovery of ICD dysfunction, even if asymptomatic, was achievable. For those events not evaluated within 24 h, repetitive messaging promoted earlier discovery. Reorganization of clinical follow-up methods may maintain early reaction ability. Clinical Trials registration information ClinicalTrials.gov; NCT00336284.
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Abstract
Background—
We evaluated the viability of I
Kur
as a target for maintenance of sinus rhythm in patients with a history of atrial fibrillation through the testing of MK-0448, a novel I
Kur
inhibitor.
Methods and Results—
In vitro MK-0448 studies demonstrated strong inhibition of I
Kur
with minimal off-target activity. In vivo MK-0448 studies in normal anesthetized dogs demonstrated significant prolongation of the atrial refractory period compared with vehicle controls without affecting the ventricular refractory period. In studies of a conscious dog heart failure model, sustained atrial fibrillation was terminated with bolus intravenous MK-0448 doses of 0.03 and 0.1 mg/kg. These data led to a 2-part first-in-human study: Part I evaluated safety and pharmacokinetics, and part II was an invasive electrophysiological study in healthy subjects. MK-0448 was well-tolerated with mild adverse experiences, most commonly irritation at the injection site. During the electrophysiological study, ascending doses of MK-0448 were administered, but no increases in atrial or ventricular refractoriness were detected, despite achieving plasma concentrations in excess of 2 μmol/L. Follow-up studies in normal anesthetized dogs designed to assess the influence of autonomic tone demonstrated that prolongation of atrial refractoriness with MK-0448 was markedly attenuated in the presence of vagal nerve simulation, suggesting that the effects of I
Kur
blockade on atrial repolarization may be negated by enhanced parasympathetic neural tone.
Conclusions—
The contribution of I
Kur
to human atrial electrophysiology is less prominent than in preclinical models and therefore is likely to be of limited therapeutic value for the prevention of atrial fibrillation.
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Abstract
BACKGROUND Implantable cardioverter-defibrillators (ICDs) often have clinically useful battery life remaining when explanted because of upgrades, infection, or patient death. OBJECTIVE To show that explanted ICDs can be resterilized and reused. DESIGN Retrospective cohort study. SETTING Multicenter ICD acquisition and single-center ICD reimplantation. PATIENTS Indigent persons in India who had class I indications for cardiac resynchronization therapy with an ICD and were unable to afford such a device. MEASUREMENTS Device longevity after reimplantation, device-related complications, number of appropriate therapies, patient clinical characteristics, and deaths. RESULTS Eighty-one consecutive consenting patients (mean age, 52.6 years; 66 male patients) received 106 explanted devices. Twenty-two patients received a second device and 3 patients received a third device after the prior one reached replacement voltage. Mean time to ICD replacement was 1287.4 days. Follow-up data were available for 75 of 81 (92.6%) patients. Mean follow-up duration for all devices was 824.9 days. No infectious complications occurred; 1 lead dislodgement and 1 lead fracture required repeated surgery. Appropriate therapy (shocks or antitachycardia pacing) was delivered by 64 of 106 (60.4%) devices in 44 of 81 (54.3%) patients. Nine of 81 (11.1%) patients died; mean time from implantation to death was 771.3 days. LIMITATIONS This is a retrospective report of a single-center experience with a modest number of patients and devices. Follow-up data were missing for 6 patients. No records were kept of the number of devices obtained through postmortem versus antemortem explantation or whether explantation was due to infection or upgrade. Complete data were not available on exact battery voltage at the time of reimplantation, left ventricular ejection fraction, or number of inappropriate shocks. A control group was not possible. CONCLUSION Explanted ICDs with 3 or more years of estimated remaining battery life can be reused after they are cleaned and resterilized. These devices functioned normally and delivered life-saving therapies, without an increased risk for complications. These preliminary data deserve further validation and, if confirmed, could have important societal and economic implications. PRIMARY FUNDING SOURCE None.
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Pacemaker Malfunction Induced by a Pharmaco-Metabolic “Perfect storm”: A Brief Report. J Clin Pharmacol 2011; 51:107-9. [DOI: 10.1177/0091270010365546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Abstract
A 10-year-old girl developed life-threatening recurrent polymorphic ventricular tachycardia following surgical closure of a simple secundum atrial septal defect. Post hoc analysis of a Holter recording suggested Brugada syndrome. After managing the acute phase, a dual chamber defibrillator was implanted. One week later she experienced VF storm, needing 96 appropriate shocks within a few hours. Quinidine, by virtue of its I(to) blocking property, is the only drug reported to be useful in managing VF storm in Brugada syndrome. Nonavailability of quinidine led us to try its diastereomer, intravenous quinine, which succeeded in controlling the ventricular tachycardia. Arrhythmia storm in the setting of ion channelopathy can be difficult to manage, and sometimes requires innovative therapies.
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Combined heart failure device diagnostics identify patients at higher risk of subsequent heart failure hospitalizations: results from PARTNERS HF (Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure) study. J Am Coll Cardiol 2010; 55:1803-10. [PMID: 20413029 DOI: 10.1016/j.jacc.2009.11.089] [Citation(s) in RCA: 279] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 11/13/2009] [Accepted: 11/18/2009] [Indexed: 11/29/2022]
Abstract
OBJECTIVES We sought to determine the utility of combined heart failure (HF) device diagnostic information to predict clinical deterioration of HF in patients with systolic left ventricular dysfunction. BACKGROUND Some implantable devices continuously monitor HF device diagnostic information, but data are limited on the ability of combined HF device diagnostics to predict HF events. METHODS The PARTNERS HF (Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure) was a prospective, multicenter observational study in patients receiving cardiac resynchronization therapy (CRT) implantable cardioverter-defibrillators. HF events were independently adjudicated. A combined HF device diagnostic algorithm was developed on an independent dataset. The algorithm was considered positive if a patient had 2 of the following abnormal criteria during a 1-month period: long atrial fibrillation duration, rapid ventricular rate during atrial fibrillation, high (> or =60) fluid index, low patient activity, abnormal autonomics (high night heart rate or low heart rate variability), or notable device therapy (low CRT pacing or implantable cardioverter-defibrillator shocks), or if they only had a very high (> or =100) fluid index. We used univariate and multivariable analyses to determine predictors of subsequent HF events within a month. RESULTS We analyzed data from 694 CRT defibrillator patients who were followed for 11.7 +/- 2 months. Ninety patients had 141 adjudicated HF hospitalizations with pulmonary congestion at least 60 days after implantation. Patients with a positive combined HF device diagnostics had a 5.5-fold increased risk of HF hospitalization with pulmonary signs or symptoms within the next month (hazard ratio: 5.5, 95% confidence interval: 3.4 to 8.8, p < 0.0001), and the risk remained high after adjusting for clinical variables (hazard ratio: 4.8, 95% confidence interval: 2.9 to 8.1, p < 0.0001). CONCLUSIONS Monthly review of HF device diagnostic data identifies patients at a higher risk of HF hospitalizations within the subsequent month. (PARTNERS HF: Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure; NCT00279955).
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Implantation Trends and Patient Profiles for Pacemakers and Implantable Cardioverter Defibrillators in the United States: 1993-2006. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2010; 33:705-11. [PMID: 20059714 DOI: 10.1111/j.1540-8159.2009.02670.x] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Changes in Intrathoracic Fluid Index predict subsequent adverse events: Results of the Multi-site Program to Access and Review Trending INformation and Evaluate CoRrelation to Symptoms in Patients with Heart Failure (PARTNERS HF) Trial. J Card Fail 2008. [DOI: 10.1016/j.cardfail.2008.10.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
BACKGROUND The planar QRS-T angle can be easily obtained from standard 12-lead ECGs, but its predictive ability is not established. We sought to determine the predictive ability of the planar QRS-T angle in patients with nonischemic cardiomyopathy and to assess QRS-T angle behavior over time. METHODS AND RESULTS Baseline QRS-T angles from 455 patients in the Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial were measured. All patients had nonischemic cardiomyopathy, New York Heart Association class I to III heart failure, and nonsustained ventricular tachycardia or frequent ventricular ectopy. The primary end point (a composite of total mortality, appropriate implantable cardioverter-defibrillator shock, or resuscitated cardiac arrest) occurred in 25 of 172 patients (14.5%) with a QRS-T angle < or =90 degrees and in 72 of 283 patients (25.4%) with a QRS-T angle >90 degrees (hazard ratio, 1.93; 95% confidence interval, 1.23 to 3.05; P=0.002). A QRS-T angle >90 degrees remained a significant predictor of the primary end point (P=0.039) after adjustment for treatment group, age, gender, QRS duration, left bundle-branch block, left ventricular ejection fraction, New York Heart Association class III, atrial fibrillation, and diabetes mellitus. The secondary end point (total mortality) occurred in 17 of the 172 patients (9.9%) with a QRS-T angle < or =90 degrees and in 49 of the 283 patients (17.3%) with a QRS-T angle >90 degrees (hazard ratio, 1.79; 95% confidence interval, 1.03 to 3.10; P=0.016). A sample of 152 patients with multiple follow-up ECGs was analyzed to assess temporal QRS-T angle behavior. Changes in the QRS-T angle correlated with changes in left ventricular ejection fraction and QRS duration over time (P<0.001). CONCLUSIONS A planar QRS-T angle >90 degrees is a significant predictor of a composite end point of death, appropriate implantable cardioverter-defibrillator shock, or resuscitated cardiac arrest in nonpaced, mild to moderately symptomatic patients with nonischemic cardiomyopathy with frequent or complex ventricular ectopy. QRS-T angles changed predictably with left ventricular ejection fraction and QRS duration.
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Cardiac resynchronization therapy: from creation to evolution--an evidence-based review. CONGESTIVE HEART FAILURE (GREENWICH, CONN.) 2007; 13:84-92. [PMID: 17392612 DOI: 10.1111/j.1527-5299.2007.888126.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the past decade, cardiac resynchronization therapy (CRT), achieved by simultaneous left and right ventricular pacing, has emerged as a potent therapeutic option for patients with congestive heart failure. Electrical dyssynchrony, most often manifested by left bundle branch block on the surface 12-lead electrocardiogram, results in mechanical dyssynchrony of the left ventricular septum and free wall, which decreases cardiac efficiency. In patients with ejection fractions <30%, New York Heart Association (NYHA) class III or IV, and QRS width >120 ms, CRT improves clinical parameters such as 6-minute walk distances, quality-of-life scores, and NYHA functional class. Long-term reverse remodeling of the failing ventricle results in reductions in congestive heart failure hospitalizations and mortality independent of defibrillator therapy. While most patients show significant improvement, a small proportion fail to respond. Appropriately identifying patients who will benefit most from CRT and timing the initiation of resynchronization therapy remain areas of intense investigation.
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Cardiac resynchronization therapy in patients with right bundle branch block: Analysis of pooled data from the MIRACLE and Contak CD trials. Heart Rhythm 2005; 2:611-5. [PMID: 15922268 DOI: 10.1016/j.hrthm.2005.03.012] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Accepted: 03/15/2005] [Indexed: 11/25/2022]
Abstract
BACKGROUND Clinical trials of cardiac resynchronization therapy (CRT) have not included many patients with right bundle branch block (RBBB). OBJECTIVES We pooled data from two randomized controlled trials of CRT (Multicenter InSync Randomized Clinical Evaluation [MIRACLE] and Contak CD) in order to assess outcomes of patients with RBBB. METHODS A total of 61 patients with RBBB were identified, 34 of whom were randomized to the CRT group and 27 to the control group. The data from these patients were entered into a new database and analyzed. RESULTS Baseline demographics were not different between the two groups (mean age 65.5 +/- 11.3 years vs 69.5 +/- 9.6 years; male gender 91% vs 85%; patients with coronary disease 76.5% vs 88%; QRS duration 167 ms vs 164 ms; all P = NS). Outcome variables (New York Heart Association [NYHA] class, 6-minute hall walk distance, peak oxygen consumption (VO2), Minnesota Living with Heart Failure quality-of-life scores, left ventricular ejection fraction, and norepinephrine levels) were analyzed at randomization, 3 months, and 6 months. CONCLUSIONS (1) With the exception of NYHA class, patients with RBBB as the qualifying wide QRS did not derive significant benefit from CRT in any of the other parameters studied at 3 or 6 months. (2) RBBB patients who received active CRT showed significant improvements in NYHA class by 6 months and trends toward improvement in 6-minute walk distance, quality-of-life scores, and norepinephrine levels. However, control patients also showed significant improvement in NYHA class by 6 months but showed no improvement in objective measurements (VO2, 6-minute walk distance, left ventricular ejection fraction, and norepinephrine levels), consistent with a placebo effect. Analysis of a larger cohort of patients with RBBB undergoing CRT may demonstrate significant benefit, but the current analysis does not support the use of CRT in patients with RBBB.
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Recurrent paroxysmal atrioventricular block triggered paradoxically by a pacemaker. Heart Rhythm 2005; 2:185-7. [PMID: 15851296 DOI: 10.1016/j.hrthm.2004.09.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Accepted: 09/28/2004] [Indexed: 10/25/2022]
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Unique self-perpetuating cycle of atrioventricular block and phase IV bundle branch block in a patient with bundle branch reentrant tachycardia. Heart Rhythm 2004; 1:493-6. [PMID: 15851205 DOI: 10.1016/j.hrthm.2004.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2004] [Accepted: 06/01/2004] [Indexed: 11/16/2022]
Abstract
Bundle branch reentrant tachycardia (BBRT) is an uncommon form of ventricular tachycardia involving diseased bundle branches. Phase IV bundle branch block also accompanies severe His-Purkinje disease. We present an unusual case of BBRT in a patient who also manifests a unique self-perpetuating cycle of AV block and phase IV left bundle branch block following aortic valve surgery. BBRT was treated successfully by ablation of the right bundle.
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