A novel pacing method to suppress repolarization alternans in vivo: Implications for arrhythmia prevention

Armoundas, Antonis A.; Weiss, Eric H.; Sayadi, Omid; Laferriere, Shawna; Sajja, Naveen; Mela, Theofanie; Singh, Jagmeet P.; Barrett, Conor D.; Heist, E. Kevin; Merchant, Faisal M.

doi:10.1016/j.hrthm.2012.12.026

Cited by 15 publications

(18 citation statements)

References 27 publications

(35 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Body surface ECG and intracardiac electrogram signals were recorded through a Prucka Cardiolab (Generic Electric) electrophysiology system that provided 16 high-fidelity analog output signals and front-end signal conditioning. Body surface signals were band-pass filtered 0.05-100 Hz, with a 60-Hz notch filter and gain of 2,500 V/V, and intracardiac signals were band-pass filtered 0.05-500 Hz, with a 60-Hz notch filter and gain of 250 V/V (3,30).…”

Section: Animal Preparationmentioning

confidence: 99%

See 1 more Smart Citation

An optimized method for estimating the tidal volume from intracardiac or body surface electrocardiographic signals: implications for estimating minute ventilation

Sayadi

Weiss

Merchant

et al. 2014

American Journal of Physiology-Heart and Circulatory Physiology

Self Cite

View full text Add to dashboard Cite

The ability to accurately monitor tidal volume (TV) from electrocardiographic (ECG) signals holds significant promise for improving diagnosis treatment across a variety of clinical settings. The objective of this study was to develop a novel method for estimating the TV from ECG signals. In 10 mechanically ventilated swine, we collected intracardiac electrograms from catheters in the coronary sinus (CS), left ventricle (LV), and right ventricle (RV), as well as body surface electrograms, while TV was varied between 0 and 750 ml at respiratory rates of 7–14 breaths/min. We devised an algorithm to determine the optimized respirophasic modulation of the amplitude of the ECG-derived respiratory signal. Instantaneous measurement of respiratory modulation showed an absolute error of 72.55, 147.46, 85.68, 116.62, and 50.89 ml for body surface, CS, LV, RV, and RV-CS leads, respectively. Minute TV estimation demonstrated a more accurate estimation with an absolute error of 69.56, 153.39, 79.33, 122.16, and 48.41 ml for body surface, CS, LV, RV, and RV-CS leads, respectively. The RV-CS and body surface leads provided the most accurate estimations that were within 7 and 10% of the true TV, respectively. Finally, the absolute error of the bipolar RV-CS lead was significantly lower than any other lead configuration ( P < 0.0001). In conclusion, we have demonstrated that ECG-derived respiratory modulation provides an accurate estimation of the TV using intracardiac or body surface signals, without the need for additional hardware.

show abstract

Section: Animal Preparationmentioning

confidence: 99%

“…Signals were sampled at 1,000 Hz by a multichannel 16-bit data acquisition card (National Instruments M-Series PCI6255), using a signal acquisition, display, and processing system consisting of custom software written in LabView 8.5 (National Instruments, Austin, TX) and MATLAB 7.6 (MathWorks, Natick, MA) (3,30).…”

Section: Animal Preparationmentioning

confidence: 99%

An optimized method for estimating the tidal volume from intracardiac or body surface electrocardiographic signals: implications for estimating minute ventilation

Sayadi

Weiss

Merchant

et al. 2014

American Journal of Physiology-Heart and Circulatory Physiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Experimental studies have demonstrated that stimulation during the absolute refractory period is capable of controlling APD, in part through modulation of cellular calcium transients 86,87 . Based on this premise, our group has recently developed a method for in situ dynamic control of MTWA in a large animal model 88 . In this model, the delivery of sub-threshold pacing stimuli during the absolute refractory period is capable of suppressing MTWA in a swine heart failure model, even when the pacing site (right ventricle) was located at a distance from the site of alternans genesis (left ventricle).…”

Section: Emerging Clinical Applications Of Ramentioning

confidence: 99%

T-Wave Alternans as an Arrhythmic Risk Stratifier: State of the Art

et al. 2013

Self Cite

View full text Add to dashboard Cite

Microvolt level T-wave alternans (MTWA), a phenomenon of beat-to-beat variability in the repolarization phase of the ventricles, has been closely associated with an increased risk of ventricular tachyarrhythmic events (VTE) and sudden cardiac death (SCD) during medium- and long-term follow-up. Recent observations also suggest that heightened MTWA magnitude may be closely associated with short-term risk of impending VTE. At the sub-cellular and cellular level, perturbations in calcium transport processes likely play a primary role in the genesis of alternans, which then secondarily lead to alternans of action potential morphology and duration (APD). As such, MTWA may play a role not only in risk stratification but also more fundamentally in the pathogenesis of VTE. In this paper, we outline recent advances in understanding the pathogenesis of MTWA and also the utility of T-wave alternans testing for clinical risk stratification. We also highlight emerging clinical applications for MTWA.

show abstract

“…Intracardiac and body-surface (leads II and V4) electrocardiographic signals as well as arterial blood pressure were recorded through a Prucka Cardiolab (General Electric) electrophysiology system that provided 16 high fidelity analog output signals, as previously described 10,14 . We used a previously developed signal acquisition, analysis and display system, consisting of custom software written in LabView 8.5 (National Instruments, Austin, TX) and MATLAB 7.6 (Mathworks, Natick, MA) 10 .…”

Section: Methodsmentioning

confidence: 99%

“…In aggregate, the clinical and experimental data suggest that the heart either passes through a state of heightened T-wave alternans on the way to VT/VF or heightened TWA occurs in close conjunction with developing VTE 12, 13 . In either scenario, these findings suggest that detecting significantly elevated levels of TWA may serve as an important short -term predictor of impending arrhythmias and also raise the possibility for a therapeutic role where TWA suppression therapies are delivered upstream to suppress the arrhythmogenic substrate and abort VT/VF prior to arrhythmia onset 214 .…”

Section: Introductionmentioning

confidence: 99%

A Novel Method for Determining the Phase of T-Wave Alternans

Sayadi

Merchant

Puppala

et al. 2013

Circ: Arrhythmia and Electrophysiology

Self Cite

View full text Add to dashboard Cite

Background T-wave alternans (TWA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death (SCD). However, in order to effectively estimate and suppress TWA, the phase of TWA must be accurately determined. Methods and Results We developed a method that computes the beat-by-beat integral of the T-wave morphology, over time points within the T-wave with positive alternans. Then, we estimated the signed derivative of the T-wave integral sequence which allows the classification of each beat to a binary phase index. In animal studies, we found that this method was able to accurately identify the T-wave phase in artificially induced alternans (p<0.0001). The coherence of the phase increased consistently after acute ischemia induction in all body-surface and intracardiac leads (p<0.0001). Also, we developed a phase resetting detection algorithm that enhances the diagnostic utility of TWA. We further established an algorithm that employs the phase of TWA in order to deliver appropriate polarity pacing pulses (all interventions compared to baseline, p<0.0001 for alternans voltage; p<0.0001 for Kscore), to suppress TWA. Finally, we demonstrated that using the phase of TWA we can suppress spontaneous TWA during acute ischemia; 77.6% for alternans voltage (p<0.0001) and 92.5% for Kscore (p<0.0001). Conclusions We developed a method to quantify the temporal variability of the TWA phase. This method is expected to enhance the utility of TWA in predicting ventricular arrhythmias and SCD and raises the possibility of using upstream therapies to abort a ventricular tachyarrhythmia prior to its onset.

show abstract

A novel pacing method to suppress repolarization alternans in vivo: Implications for arrhythmia prevention

Cited by 15 publications

References 27 publications

An optimized method for estimating the tidal volume from intracardiac or body surface electrocardiographic signals: implications for estimating minute ventilation

An optimized method for estimating the tidal volume from intracardiac or body surface electrocardiographic signals: implications for estimating minute ventilation

T-Wave Alternans as an Arrhythmic Risk Stratifier: State of the Art

A Novel Method for Determining the Phase of T-Wave Alternans

Contact Info

Product

Resources

About