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Kulkarni K, Stavrakis S, Elkholey K, Singh JP, Parks KA, Armoundas AA. Microvolt T-Wave Alternans Is Modulated by Acute Low-Level Tragus Stimulation in Patients With Ischemic Cardiomyopathy and Heart Failure. Front Physiol 2021; 12:707724. [PMID: 34366894 PMCID: PMC8343129 DOI: 10.3389/fphys.2021.707724] [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: 05/10/2021] [Accepted: 06/30/2021] [Indexed: 12/15/2022] Open
Abstract
Aims: Microvolt T-wave alternans (TWA), an oscillation in T-wave morphology of the electrocardiogram (ECG), has been associated with increased susceptibility to ventricular tachy-arrhythmias, while vagus nerve stimulation has shown promising anti-arrhythmic effects in in vivo and ex vivo animal studies. We aimed to examine the effect of non-invasive, acute low-level tragus stimulation (LLTS) on TWA in patients with ischemic cardiomyopathy and heart failure. Methods: 26 patients with ischemic cardiomyopathy (left ventricular ejection fraction <35%) and chronic stable heart failure, previously implanted with an automatic implantable cardioverter defibrillator (ICD) device with an atrial lead (dual chamber ICD or cardiac resynchronization therapy defibrillator), were enrolled in the study. Each patient sequentially received, (1) Sham LLTS (electrode on tragus, but no stimulation delivered) for 5 min; (2) Active LLTS at two different frequencies (5 and 20 Hz, 15 min each); and (3) Active LLTS, during concomitant atrial pacing at 100 bpm at two different frequencies (5 and 20 Hz, 15 min each). LLTS was delivered through a transcutaneous electrical nerve stimulation device (pulse width 200 μs, frequency 5/20 Hz, amplitude 1 mA lower than the discomfort threshold). TWA burden was assessed using continuous ECG monitoring during sham and active LLTS in sinus rhythm, as well as during atrial pacing. Results: Right atrial pacing at 100 bpm led to significantly heightened TWA burden compared to sinus rhythm, with or without LLTS. Acute LLTS at both 5 and 20 Hz, during sinus rhythm led to a significant rise in TWA burden in the precordial leads (p < 0.05). Conclusion: Acute LLTS results in a heart-rate dependent increase in TWA burden.
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Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, United States
| | - Stavros Stavrakis
- Heart Rhythm Institute, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Khaled Elkholey
- Heart Rhythm Institute, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA, United States
| | - Kimberly A Parks
- Cardiology Division, Brigham and Women's Hospital, Boston, MA, United States
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
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Kulkarni K, Walton RD, Armoundas AA, Tolkacheva EG. Clinical Potential of Beat-to-Beat Diastolic Interval Control in Preventing Cardiac Arrhythmias. J Am Heart Assoc 2021; 10:e020750. [PMID: 34027678 PMCID: PMC8483541 DOI: 10.1161/jaha.121.020750] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Life‐threatening ventricular arrhythmias and sudden cardiac death are often preceded by cardiac alternans, a beat‐to‐beat oscillation in the T‐wave morphology or duration. However, given the spatiotemporal and structural complexity of the human heart, designing algorithms to effectively suppress alternans and prevent fatal rhythms is challenging. Recently, an antiarrhythmic constant diastolic interval pacing protocol was proposed and shown to be effective in suppressing alternans in 0‐, 1‐, and 2‐dimensional in silico studies as well as in ex vivo whole heart experiments. Herein, we provide a systematic review of the electrophysiological conditions and mechanisms that enable constant diastolic interval pacing to be an effective antiarrhythmic pacing strategy. We also demonstrate a successful translation of the constant diastolic interval pacing protocol into an ECG‐based real‐time control system capable of modulating beat‐to‐beat cardiac electrical activity and preventing alternans. Furthermore, we present evidence of the clinical utility of real‐time alternans suppression in reducing arrhythmia susceptibility in vivo. We provide a comprehensive overview of this promising pacing technique, which can potentially be translated into a clinically viable device that could radically improve the quality of life of patients experiencing abnormal cardiac rhythms.
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Affiliation(s)
- Kanchan Kulkarni
- IHU-LIRYC, Electrophysiology and Heart Modeling InstituteFondation Bordeaux Université Pessac, Bordeaux France.,Centre de Recherche Cardio-Thoracique de Bordeaux University of Bordeaux France.,Centre de Recherche Cardio-Thoracique de Bordeaux INSERM Bordeaux France
| | - Richard D Walton
- IHU-LIRYC, Electrophysiology and Heart Modeling InstituteFondation Bordeaux Université Pessac, Bordeaux France.,Centre de Recherche Cardio-Thoracique de Bordeaux University of Bordeaux France.,Centre de Recherche Cardio-Thoracique de Bordeaux INSERM Bordeaux France
| | - Antonis A Armoundas
- Cardiovascular Research Center Massachusetts General Hospital Boston MA.,Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA
| | - Elena G Tolkacheva
- Department of Biomedical Engineering University of Minnesota-Twin Cities Minneapolis MN
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Kulkarni K, Awasthi N, Roberts JD, Armoundas AA. Utility of a Smartphone-Based System (cvrPhone) in Estimating Minute Ventilation from Electrocardiographic Signals. Telemed J E Health 2021; 27:1433-1439. [PMID: 33729001 DOI: 10.1089/tmj.2020.0507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: We investigated the ability of a novel stand-alone, smartphone-based system, the cvrPhone, in estimating the minute ventilation (MV) from body surface electrocardiographic (ECG) signals. Methods: Twelve lead ECG signals were collected from anesthetized and mechanically ventilated swine (n = 9) using standard surface electrodes and the cvrPhone. The tidal volume delivered to the animals was varied between 0, 250, 500, and 750 mL at respiration rates of 6 and 14 breaths/min. MV estimates were determined by the cvrPhone and were compared with the delivered ones. Results: The median relative estimation errors were 17%, -4%, 35%, -3%, -9%, and 1%, for true MVs of 1,500, 3,000, 3,500, 4,500, 7,000, and 10,500 breaths*mL/min, respectively. The MV estimates at each of the settings were significantly different from each other (p < 0.05). Conclusions: We have demonstrated that accurate MV estimations can be derived from standard body surface ECG signals, using a smartphone.
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Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research Center, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Navchetan Awasthi
- Cardiovascular Research Center, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Jesse D Roberts
- Cardiovascular Research Center, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Antonis A Armoundas
- Cardiovascular Research Center, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge, Massachusetts, USA
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4
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Merchant FM, Sayadi O, Sohn K, Weiss EH, Puppala D, Doddamani R, Singh JP, Heist EK, Owen C, Kulkarni K, Armoundas AA. Real-Time Closed-Loop Suppression of Repolarization Alternans Reduces Arrhythmia Susceptibility In Vivo. Circ Arrhythm Electrophysiol 2020; 13:e008186. [PMID: 32434448 DOI: 10.1161/circep.119.008186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death. METHODS We have developed a real-time, closed-loop system to record and analyze RA from multiple intracardiac leads, and deliver dynamically R-wave triggered pacing stimuli during the absolute refractory period. We have evaluated the ability of this system to control RA and reduce arrhythmia susceptibility, in vivo. RESULTS R-wave triggered pacing can induce RA, the magnitude of which can be modulated by varying the amplitude, pulse width, and size of the pacing vector. Using a swine model (n=9), we demonstrate that to induce a 1 µV change in the alternans voltage on the body surface, coronary sinus and left ventricle leads, requires a delivered charge of 0.04±0.02, 0.05±0.025, and 0.06±0.033 µC, respectively, while to induce a one unit change of the Kscore, requires a delivered charge of 0.93±0.73, 0.32±0.29, and 0.33±0.37 µC, respectively. For all body surface and intracardiac leads, both Δ(alternans voltage) and ΔKscore between baseline and R-wave triggered paced beats increases consistently with an increase in the pacing pulse amplitude, pulse width, and vector spacing. Additionally, we show that the proposed method can be used to suppress spontaneously occurring alternans (n=7), in the presence of myocardial ischemia. Suppression of RA by pacing during the absolute refractory period results in a significant reduction in arrhythmia susceptibility, evidenced by a lower Srank score during programmed ventricular stimulation compared with baseline before ischemia. CONCLUSIONS We have developed and evaluated a novel closed-loop method to dynamically modulate RA in a swine model. Our data suggest that suppression of RA directly reduces arrhythmia susceptibility and reinforces the concept that RA plays a critical role in the pathophysiology of arrhythmogenesis.
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Affiliation(s)
- Faisal M Merchant
- Cardiology Division, Emory University School of Medicine, Atlanta, GA (F.M.M.).,Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Omid Sayadi
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Kwanghyun Sohn
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Eric H Weiss
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge (E.H.W., A.A.A.)
| | - Dheeraj Puppala
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Rajiv Doddamani
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service (J.P.S., E.K.H.), Massachusetts General Hospital, Boston
| | - E Kevin Heist
- Cardiology Division, Cardiac Arrhythmia Service (J.P.S., E.K.H.), Massachusetts General Hospital, Boston
| | - Chris Owen
- Neurosurgery Division (C.O.), Massachusetts General Hospital, Boston
| | - Kanchan Kulkarni
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Antonis A Armoundas
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge (E.H.W., A.A.A.)
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Kulkarni K, Merchant FM, Kassab MB, Sana F, Moazzami K, Sayadi O, Singh JP, Heist EK, Armoundas AA. Cardiac Alternans: Mechanisms and Clinical Utility in Arrhythmia Prevention. J Am Heart Assoc 2019; 8:e013750. [PMID: 31617437 PMCID: PMC6898836 DOI: 10.1161/jaha.119.013750] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | | | - Mohamad B. Kassab
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Furrukh Sana
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Kasra Moazzami
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Omid Sayadi
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Jagmeet P. Singh
- Cardiology DivisionCardiac Arrhythmia ServiceMassachusetts General HospitalBostonMA
| | - E. Kevin Heist
- Cardiology DivisionCardiac Arrhythmia ServiceMassachusetts General HospitalBostonMA
| | - Antonis A. Armoundas
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
- Institute for Medical Engineering and ScienceMassachusetts Institute of TechnologyCambridgeMA
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6
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Sohn K, Dalvin SP, Merchant FM, Kulkarni K, Sana F, Abohashem S, Singh JP, Heist EK, Owen C, Isselbacher EM, Armoundas AA. Utility of a Smartphone Based System (cvrPhone) to Predict Short-term Arrhythmia Susceptibility. Sci Rep 2019; 9:14497. [PMID: 31601824 PMCID: PMC6787075 DOI: 10.1038/s41598-019-50487-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 09/10/2019] [Indexed: 01/27/2023] Open
Abstract
Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death. We developed a 12-lead, blue-tooth/Smart-Phone (Android) based electrocardiogram (ECG) acquisition and monitoring system (cvrPhone), and an application to estimate RA, in real-time. In in-vivo swine studies (N = 17), 12-lead ECG signals were recorded at baseline and following coronary artery occlusion. RA was estimated using the Fast Fourier Transform (FFT) method using a custom developed algorithm in JAVA. Underlying ischemia was detected using a custom developed ischemic index. RA from each lead showed a significant (p < 0.05) increase within 1 min of occlusion compared to baseline (n = 29). Following myocardial infarction, spontaneous ventricular tachycardia episodes (n = 4) were preceded by significant (p < 0.05) increase of RA prior to the onset of the tachy-arrhythmias. Similarly, the ischemic index exhibited a significant increase following myocardial infarction (p < 0.05) and preceding a tachy-arrhythmic event. In conclusion, RA can be effectively estimated using surface lead electrocardiograms by analyzing beat-to-beat variability in ECG morphology using a smartphone based platform. cvrPhone can be used to detect myocardial ischemia and arrhythmia susceptibility using a user-friendly, clinically acceptable, mobile platform.
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Affiliation(s)
- Kwanghyun Sohn
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Steven P Dalvin
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Faisal M Merchant
- Cardiology Division, Emory, University School of Medicine, Atlanta, GA, USA
| | - Kanchan Kulkarni
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Furrukh Sana
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Shady Abohashem
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA, USA
| | - E Kevin Heist
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA, USA
| | - Chris Owen
- Neurosurgery Division, Massachusetts General Hospital, Boston, MA, USA
| | - Eric M Isselbacher
- Healthcare Transformation Lab, Massachusetts General Hospital, Boston, MA, USA
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA. .,Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge, MA, USA.
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Martin-Yebra A, Monasterio V, Cygankiewicz I, Bayes-de-Luna A, Caiani EG, Laguna P, Martinez JP. Post-Ventricular Premature Contraction Phase Correction Improves the Predictive Value of Average T-Wave Alternans in Ambulatory ECG Recordings. IEEE Trans Biomed Eng 2018; 65:635-644. [PMID: 29461965 DOI: 10.1109/tbme.2017.2711645] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We proposed and evaluated a method for correcting possible phase shifts provoked by the presence of ventricular premature contractions (VPCs) for a better assessment of T-wave alternans (TWA). Methods: First, we synthesized ECG signals with artificial TWA in the presence of different noise sources. Then, we assessed the prognostic value for sudden cardiac death (SCD) of the long-term average of TWA amplitude (the index of average alternans, ) in ambulatory ECG signals from congestive heart failure (CHF) and evaluated whether it is sensitive to the presence of VPCs. RESULTS The inclusion of the phase correction after VPC in the processing always improved estimation accuracy of the under different noisy conditions and regardless of the number of the VPCs included in the sequence. It also presented a positive impact on the prognostic value of with increased hazard ratios (from 17% to 29%, depending of the scenario) in comparison to the noninclusion of this step. CONCLUSION The proposed methodology for estimation, which corrects for the possible phase reversal on TWA after the presence of VPCs, represents a robust TWA estimation approach with a significant impact on the prognostic value of for SCD stratification in CHF patients. SIGNIFICANCE An accurate TWA estimation has a potential direct clinical impact on noninvasive SCD stratification, allowing better identification of patients at higher risk and helping clinicians in adopting the most appropriate therapeutic strategy.
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Goya-Esteban R, Barquero-Pérez O, Blanco-Velasco M, Caamaño-Fernández AJ, García-Alberola A, Rojo-Álvarez JL. Nonparametric signal processing validation in T-wave alternans detection and estimation. IEEE Trans Biomed Eng 2014; 61:1328-38. [PMID: 24658256 DOI: 10.1109/tbme.2014.2304565] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Although a number of methods have been proposed for T-Wave Alternans (TWA) detection and estimation, their performance strongly depends on their signal processing stages and on their free parameters tuning. The dependence of the system quality with respect to the main signal processing stages in TWA algorithms has not yet been studied. This study seeks to optimize the final performance of the system by successive comparisons of pairs of TWA analysis systems, with one single processing difference between them. For this purpose, a set of decision statistics are proposed to evaluate the performance, and a nonparametric hypothesis test (from Bootstrap resampling) is used to make systematic decisions. Both the temporal method (TM) and the spectral method (SM) are analyzed in this study. The experiments were carried out in two datasets: first, in semisynthetic signals with artificial alternant waves and added noise; second, in two public Holter databases with different documented risk of sudden cardiac death. For semisynthetic signals (SNR = 15 dB), after the optimization procedure, a reduction of 34.0% (TM) and 5.2% (SM) of the power of TWA amplitude estimation errors was achieved, and the power of error probability was reduced by 74.7% (SM). For Holter databases, appropriate tuning of several processing blocks, led to a larger intergroup separation between the two populations for TWA amplitude estimation. Our proposal can be used as a systematic procedure for signal processing block optimization in TWA algorithmic implementations.
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