Studying intracardiac electrophysiology with PowerLab
As part of their research into the pathophysiological processes that trigger ventricular arrhythmia, a group of French researchers are using PowerLab to study cardiac electrophysiology. The research group, headed by Dr Sylvain Richard and led by principal investigator Jérôme Thireau, use a single PowerLab system to simultaneously record intracardiac electrical activity and surface ECG signals in small rodents.
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The researchers’ experimental models are a surgical mouse model of heart failure after ligature of the left coronary artery, and transgenic mice overexpressing the human β2-adrenergic receptor in the heart. The transgenic model spontaneously develops dilated cardiomyopathy with a high mortality rate related to progressive ventricular dysfunction. The researchers compare data acquired from these mice with data acquired from age and sex matched wild-type mice.
Right: LabChart recording of surface ECG (blue signal), ventricular intracardiac electrogram (green signal) and tricuspid valve intracardiac electrogram (pink signal), recorded in wild-type mice.
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Recording intra-cardiac electrical activity
The researchers use a Millar Instruments Mikro-Tip catheter to study their subjects’ intracardiac electrophysiology. Millar’s electrophysiology catheters are ultra-miniature (1.1F or 1.6F), so can be used with very small mice or rats, and include eight gold electrodes. Each electrode can be used for both pacing and recording. This means the researchers can use a single catheter to:
- record electrical activity in different parts of the heart simultaneously (for example, in the atria, ventricles, or the tricuspid valve) via connection to an ADInstruments Bio Amp and PowerLab system
- apply intracardiac pacing to induce arrhythmia in both the atria and ventricles via connection to an STG stimulator
Above: The Millar EPR-800 electrophysiology catheter
Data Analysis in LabChart
The researchers use the intra-cardiac data to analyse the atrial-His interval (approximating the AV node conduction time) and the His-ventricular interval (the time between the His-bundle potential and ventricular depolarization).
“What I like best about LabChart is that you can analyse raw data online or offline, with tools like the digital filters, channel calculations and power spectrum,” says Dr Thireau. “I also find the ability to create personalised, custom macros very useful”.
Exploring sex differences in heart failure
Recently, the researchers used this technique as part of a study investigating the sex differences in cardiomorbidity in heart failure. The study was published in Endocrinology, and found evidence of differences in the cardiac electrophysiology of male and female mice overexpressing ß2-adrenergic receptor, including the prolongation of the infra-Hisian conduction time with a longer QRS interval in male mice.
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Read the full article:
Jérôme Thireau, Franck Aimond, Denise Poisson, BeiLi Zhang, Patrick Bruneval, Veronique Eder, Sylvain Richard, and Dominique Babuty
Endocrinology 151: 1837–1845, 2010
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06 October 2011
Tagged as: labchart, france, powerlab, mice, electrophysiology
