Abstract
Cardiac resynchronization therapy with atrioventricular and interventricular delay optimized biventricular pacing is an established therapy for symptomatic heart failure patients with prolongation of QRS duration, left bundle branch block and reduced left ventricular ejection fraction. The aim of the investigation was to evaluate right atrial, right ventricular and left ventricular electrical signals of implantable electronic cardiac devices with and without signal averaging technique with novel LabVIEW software. Electrical interatrial conduction delay and inter-ventricular conduction delay may be useful parameters to evaluate electrical atrial and ventricular desynchronization in heart failure patients.
1 Introduction
Cardiac resynchronization therapy with atrioventricular and interventricular delay optimized biventricular pacing is an established therapy for symptomatic heart failure patients with prolongation of QRS duration, left bundle branch block and reduced left ventricular ejection fraction 1, 2]. The aim of the investigation was to evaluate right atrial, left atrial far field, right ventricular and left ventricular electrical signals of implantable electronic cardiac devices with and without signal averaging technique. Electrical interatrial conduction delay and interventricular conduction delay may be useful parameters to evaluate electrical atrial and ventricular desynchronization in heart failure patients for evaluation of cardiac resynchronization therapy responder and non-responder.
2 Methods
Telemetric implant-based electrocardiography is a noninvasive technique for evaluation of right atrial, left atrial far field, right ventricular and left ventricular electrical signals of implantable cardioverter/defibrillators, cardiac pacemakers and cardiac resynchronization therapy with and without signal averaging technique with novel LabVIEW software. Spectral-temporal-mapping is a novel high resolution electrocardiography method for analyzing atrial and ventricular signals for evaluation of electrical cardiac desynchronization in heart failure patients.
3 Results
3.1 Analysis in time domain
Electrical interatrial conduction delay was measured between onset of P-wave in the surface ECG and offset of the atrial signal averaged signal in the right atrial pacemaker electrode ECG. Right atrial tachycardia or atrial flutter heart rate were measured between maximum amplitude of two bipolar right atrial pacemaker electrode signals (Fig. 1).
Example of right atrial flutter with 2:1 atrioventricular conduction with two-channel telemetric EKG of a Boston Scientific Insignia dual chamber pacemaker with bipolar right atrial ECG (upper curve) and bipolar right ventricular ECG (lower curve). The Atrial flutter heart rate was 252 beats per minute. X-axis in ms, Y-axis in mV.
Electrical interventricular conduction delay was measured between onset of QRS complex in the surface ECG and offset of ventricular signal averaged signal in the ventricular pacemaker electrode ECG. Electrical interventricular conduction delay of a cardiac resynchronization therapy device was measured between onset of the right ventricular ECG and onset of the left ventricular signal (Fig. 2).
Example of evaluation of electrical interventricular conduction delay of 81 ms in a Medtronic Concerto cardiac resynchronization therapy device between unipolar left ventricular ECG (upper curve) and bipolar right ventricular ECG (lower curve). X-axis in ms, Y-axis in mV.
3.2 Signal averaging ECG
QRS triggered signal averaging electrocardiography technique improves the signal-to-noise ratio in surface ECG and in right atrial, right ventricular and left ventricular ECG (Fig. 3). Fractionated high frequency electrical atrial and ventricular signals were evaluated with spectral-temporal-mapping electrocardiography with and without signal averaging technique.
Example of QRS triggered high resolution signal averaging electrocardiography of 12 heart beats of a left ventricular ECG with 188 ms atrioventricular conduction delay. X-axis in ms, Y-axis in mV.
3.3 Analysis in frequency domain
Spectral-temporal-mapping is a novel high resolution electrocardiography method for analyzing high frequency right atrial, left atrial, right ventricular and left ventricular signals. Fractionated high frequency electrical atrial and ventricular signals were evaluated with spectral-temporal-mapping electrocardiography with and without signal averaging technique (Fig. 4).
Demonstration of fractionated high frequency electrical atrial signals in a patient during right atrial flutter with fractionated signals at frequency of 70 Hz, time of 188 ms and amplitude of 625 nV.
4 Conclusion
Atrial and ventricular signal averaging electrocardiography with novel LabVIEW software can utilized to evaluate electrical atrial and ventricular conduction delays in heart failure patients with pacemaker, implantable cardioverter/defibrillator and cardiac resynchronization therapy. Interatrial conduction delay and interventricular conduction delay may be useful parameters to evaluate electrical left cardiac desynchronization in heart failure patients.
Author's Statement
Conflict of interest: Authors state no conflict of interest. Material and Methods: Informed consent: Informed consent is not applicable. Ethical approval: The research related to human use has been complied with all the relevant national regulations, institutional policies and in accordance the tenets of the Helsinki Declaration, and has been approved by the authors’ institutional review board or equivalent committee.
References
[1] Poller WC, Dreger H, Schwerg M et al (2014): Not left ventricular lead position, but the extent of immediate asynchrony reduction predicts long-term response to cardiac resynchronization therapy. Clin Res Cardiol 103(6): 456-6610.1007/s00392-014-0672-8Search in Google Scholar PubMed
[2] Heinke M, Ismer B, Kühnert H et al (2011): Transesophageal left ventricular electrogramm-recording and temporary pacing to improve patient selection for cardiac resynchronization. Med Biol Eng Comput 49: 851-85810.1007/s11517-011-0767-6Search in Google Scholar PubMed
© 2015 by Walter de Gruyter GmbH, Berlin/Boston
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