Simultaneous Electrocardiography Recording and Invasive Blood Pressure Measurement in Rats

Summary

Here, we describe a setup for simultaneous recording of electrocardiography and intra-arterial blood pressure (BP) in experimental rats, which can be done with standard equipment in animal facilities and can be applied to physiological or pharmacological studies to investigate pathogenic or therapeutic mechanisms in cardiovascular medicine.

Abstract

For studies related to cardiovascular physiology or pathophysiology, blood pressure (BP) and electrocardiography are basic observational parameters. Research focusing on cardiovascular disease models, potential cardiovascular therapeutic targets or pharmaceutical agents requires assessment of systemic arterial pressure and heart rhythm changes. In situations where radio telemetry systems are not available or affordable, the technique of femoral artery cannulation is an alternative way to obtain intra-arterial pressure waveform recordings and systemic BP measurements. This technique is economical and can be performed with standard equipment in animal facilities. However, invasive arterial pressure recording requires cannulation of small arteries, which can be a challenging surgical skill. Here, we present step-by-step protocols for femoral artery cannulation procedures. Key procedures include the calibration of the data acquisition system, tissue dissection and femoral artery cannulation, and setup of the arterial cannulation system for pressure recording. Surface electrocardiography recording procedures are also included. We also present examples of BP recordings from normotensive and hypertensive rats. This protocol allows reliable direct recordings of systemic BP with simultaneous electrocardiography.

Introduction

Blood pressure (BP) and electrocardiography (ECG) are basic parameters for cardiovascular physiology and medicine. Experimental animal models have been widely applied in biomedical research for various cardiovascular diseases such as hypertensive heart failure¹ and procedures for ECG recording and BP measurement can be performed in experimental rats.

There are three methods for BP measurement in rats: intra-arterial cannulation (invasive)², tail cuff plethysmography (noninvasive)³, and radio telemetry (invasive). The reliability of BP measurement by tail cuff plethysmog....

Protocol

All the animal experiments described were approved by the Institutional Animal Care and Use Committee of Kaohsiung Medical University.

1. Animal Care

1. To avoid difficult cannulation due to small arterial size, use rats with body weight over 200 g.
2. Remove chow from the cage and fast rats overnight.
3. Offer water ad libidum unless there is a special experimental design.

2. Experimental Preparation

1. Obtain the following materials: forceps with teeth (Figure 1A), surgical scissors (Figure 1B), forceps with fine ....

Results

We purchased SHR and normotensive Wistar-Kyoto WKY rats from the National Laboratory Animal Center (Taipei, Taiwan). All animals were housed in a temperature-controlled facility (20−22 °C) with free access to water and standard chow on a 12 h light/dark cycle.

We used six 47-week-old rats and they were weighed before the BP and ECG measurement. The representative tracings from simultaneous recording of ECG and BP in SHR and WKY .......

Discussion

Invasive arterial cannulation allows highly accurate measurement of BP. It can be done with a PE tube without requiring an expensive catheter. Invasive BP measurement can also be performed simultaneously with a recording of the surface ECG.

The major learning curve for this method is the experimental skill required to cannulate small blood vessels. In experienced hands, the successful rate for femoral artery cannulation can approach 100%. Practice is recommended before performing real exp.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Polyethylene tube	BECTON DICKINSON	427401	internal diameter of 0.5 mm, outer diameter of 0.9 mm
26 G x 1/2"" needle	TERUMO	160426D
Adson Forceps	TOP Line	12-540	12 cm (4.75") Long, Straight, 1 x 2 Teeth
Bulldog vascular clamp	Teleflex	357581	8 mm
Computer	AUSUS	X453M
Exernal analog signal recording device	iWorx	T5141538	This allows the recording of up to three channels of ECG, EMG or EEG as well as GSR (skin conductance) from a single iWire input on the recording Module.
Graefe Forceps	AESCULAP Surgical Instruments	BD312R	MICRO DRESSING FORCEPS, CURVED, SERRATED, 105 mm, 4 1/8
Mecury sphygmomanometer	Spirit	CK-101
Pressure transducer	iWorx	IworxBP100
Semken Forceps	MEDE TECHNIK	10-104	100 mm
Software	LabScribe3
Surgical scissors	HEBU	1714	14.5 cm long
Syringe (1 mL)	TERUMO	160426D
Three-way stopcocks	Cole-Parmer	EW-30600-23
Tipped forceps	World Precision Instruments	504506	11 cm long, 0.1 x 0.06 mm Tips
Vannas Scissors	World Precision Instruments	500086	8.5 cm long, Straight, 0.025 x 0.015 mm Tips, 7mm super fine Blades