title: Mouse ECG findings in aging, with conduction system affecting drugs and in cardiac pathologies: Development and validation of ECG analysis algorithm in mice.
abstract: Mouse models are extremely important in studying cardiac pathologies and related electrophysiology, but very few mouse ECG analysis programs are readily available. Therefore, a mouse ECG analysis algorithm was developed and validated. Surface ECG (lead II) was acquired during transthoracic echocardiography from C57Bl/6J mice under isoflurane anesthesia. The effect of aging was studied in young (2-3 months), middle-aged (14 months) and old (20-24 months) mice. The ECG changes associated with pharmacological interventions and common cardiac pathologies, that is, acute myocardial infarction (AMI) and progressive left ventricular hypertrophy (LVH), were studied. The ECG raw data were analyzed with an in-house ECG analysis program, modified specially for mouse ECG. Aging led to increases in P-wave duration, atrioventricular conduction time (PQ interval), and intraventricular conduction time (QRS complex width), while the R-wave amplitude decreased. In addition, the prevalence of arrhythmias increased during aging. Anticholinergic atropine shortened PQ time, and beta blocker metoprolol and calcium-channel blocker verapamil increased PQ interval and decreased heart rate. The ECG changes after AMI included early JT elevation, development of Q waves, decreased R-wave amplitude, and later changes in JT/T segment. In progressive LVH model, QRS complex width was increased at 2 and especially 4 weeks timepoint, and also repolarization abnormalities were seen. Aging, drugs, AMI, and LVH led to similar ECG changes in mice as seen in humans, which could be reliably detected with this new algorithm. The developed method will be very useful for studies on cardiovascular diseases in mice.
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Mari
authors.initials: M
authors.lastname: Merentie
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
authors.forename: Jukka A
authors.initials: JA
authors.lastname: Lipponen
authors.affiliation: Heart Center, Kuopio University Hospital, Kuopio, Finland Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Marja
authors.initials: M
authors.lastname: Hedman
authors.affiliation: Heart Center, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Hedman
authors.affiliation: Heart Center, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Hartikainen
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Jenni
authors.initials: J
authors.lastname: Huusko
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Line
authors.initials: L
authors.lastname: Lottonen-Raikaslehto
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Viktor
authors.initials: V
authors.lastname: Parviainen
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Laidinen
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
authors.forename: Pasi A
authors.initials: PA
authors.lastname: Karjalainen
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland Science Service Center, Kuopio University Hospital, Kuopio, Finland Gene Therapy Unit, Kuopio University Hospital, Kuopio, Finland seppo.ylaherttuala@uef.fi.
authors.forename: Seppo
authors.initials: S
authors.lastname: Ylä-Herttuala
keywords: Aging; left ventricular hypertrophy; mouse ECG; myocardial infarction