This document discusses several methods for recording electrocardiograms (ECGs), blood pressure (BP), and heart rate in rats. It describes non-invasive methods like foot electrode apparatus and tail cuff plethysmography as well as invasive methods involving needle electrodes, intra-arterial catheters, and implantable radio telemetry devices. The document provides details on procedures for chronic BP monitoring in rats using indwelling tail arterial catheters and implanting radio telemetry devices in the peritoneal cavity or under the skin.

1. Recording of Rat ECG , BP and
Heart Rate
Shivanshu Bajaj
M .Pharmacy (Pharmacology)
SPER , Jamia Hamdard
Delhi

2. Different methods for ECG , BP and
Heart Rate
Non-Invasive
method
Invasive method
Foot
electrode
apparatus
Statham
pressure
transducer
6 channel ECG-
Needle
Electrodes
tail cuff
plethysmograph
y (noninvasive)
intra-arterial
catheters
Implantable
Radio
Telemetry

3. A SIMPLE METHOD FOR RECORDING THE
ELECTROCARDIOGRAM AND HEART RATE FROM
CONSCIOUS ANIMALS (Foot electrode method)
The small bioelectrical signals of the heart detected at
the body surface of animals are usually relayed to the
initial amplifier stage of the electrocardiograph by the
use of plate, needle or clip electrodes. Foot electrode
method has been used to obtain recordings from
conscious mice, rats, cats and dogs.

5.  Apparatus comprised four separate copper plate
electrodes mounted in either cork or blockboard, each
sealed with a waterproof mastic seal to prevent
leakage.
 The animal was placed on the apparatus so that each
foot was in contact with a separate plate electrode.
The front feet and left hind foot were used for
recording standard leads while the right hind foot was
grounded.
 Contact was facilitated by the use of gauze pads
damped with isotonic saline. The dimensions of the
apparatus were varied to suit the different animals.
 Heart rate was measured by a Neilson instantaneous
ratemeter (40-250 and 80-500 beats/min scales)
triggered from the QRS complex of the e.c.g

6. Neilson instantaneous
ratemeter

8. Hyperresponsivity of spontaneously
hypertensive rat to indirect
measurement of blood pressure

10. METHODS
• Chronic, indwelling, tail arterial catheters. Animals were anesthetized with
sodium pentobarbital (40-50 mg/kg ip), an incision (1.5 cm) was made on
the ventral surface of the tail about 1cm from its origin.
• Polyethylene tubing filled with sodium heparin was inserted into the
ventral tail artery for a distance of more than 1 cm. The tubing was fixed in
the artery and sutured to the tailskin, reflected dorsally and anteriorly, and
led subcutaneously through a 25-cm length of &gauge, hollow-needle
tubing to emerge at the back of the neck. The catheter was anchored to an
adhesive-tape collar around the neck and then threaded through a 20-cm
length of a thin wire spring
• The tail arterial catheter, with its spring guard, was passed through a hole in
the metal top and a plasticsyringe (1 ml) was connected to the catheter
with a 23- gauge hypodermic needle. The indwelling tail arterial catheter
was flushed twice daily with 0.5 ml of saline and animals were studied at
least 24 h after the insertion of the catheter.

11. Measurements of blood pressure
The blood pressure of the rats was directly through the
tailarterial catheter by using a Statham pressure
transducer and recorded by a Grass
Polygraph. The transducer was placed at the same level
as the rat. Heart rate was measured using the
fluctuations of the arterial blood pressure to trigger a
tachometer.

12. ECG measurement non-invasive in unconscious rat
Software used- LabScribe
6 channel ECG-
Needle
Electrodes

15. Tail cuff plethysmography (noninvasive)

16. Measurement of invasive blood pressure in rats
Blood pressure (BP) measurement is one of the basic procedures
in biomedical research.
MATERIALS AND METHODS
I. adult Wistar rats/Sprague Dawley rats
II. heparin, urethane/ketamine + xylazine/pentobarbital sodium
III. an intravenous cannula,
IV. 1 ml tuberculin syringe,
V. a bulldog clamp
VI. respiratory tubing (6′′ infant feeding tube/ pediatric Ryle's
tube may be used)

17. The materials used for recording the rat blood pressure. (a) bulldog clamp; (b)
6″ infant feeding tube [part of it used as respiratory tubing] for tracheostomy;
(c) PE tube [15–20 cm length] with a 26 G × 1/2″ needle for femoral vein
cannulation; (d) PE tube [15–20 cm length] with a 26 G × 1/2″ needle for carotid
artery cannulation; and (e) disposable clip-on BP domes

18. Steps
1) Intravenous
cannula
2) Tracheostomy
3) Cannulation of
carotid artery
4) Student
physiograph
5) Data acquisition
system
Cannulation of femoral vein. (a) experimental animal on
the surgical platform; (b-e) a small incision (1–2 cm) is
made in the epidermis of the right thigh, and the matrix
of collagen fibers interlaced with elastic fibers of the
dermis is cleaned and femoral vein is identified; (f–h)
femoral vein is cannulated using a femoral vein cannula

19. Procedure for tracheostomy. (a and b) a small incision (1.5–2 cm) is made in the neck of
the rat for tracheostomy and carotid artery cannulation; (c) slit incision is made on
platysma to identify the trachea; (d–f) trachea is identified and small incision made on
the cartilage tissue; (g and h) tracheostomy is performed using a piece of pediatric
Ryle's tube

20. Cannulation of carotid artery. (a) right side of the carotid artery is separated from
vagus nerve; (b and c) cephalic end of the blood vessel is tied to avoid the
bifurcation of blood pressure; (d) cardiac end of the blood vessel is clamped with a
bulldog clamp for cannulation; (e) small platform is placed in the canulation site;
(f–i) carotid artery is cannulated and tied; (j, k) The support platform and bulldog
clamp are removed and ensure there is no leakage in the cannulation site; and (l)
the carotid cannula is connected to pressure transducer through disposable clip-on
BP domes

21. Complete rat blood pressure experimental setup

22. Direct Blood Pressure Monitoring in Laboratory
Rodents via Implantable Radio Telemetry
 The ability to monitor and record precise blood pressure fluctuations in
research animals is vital to research for human hypertension.
 Direct measurement of blood pressure via implantable radio telemetry
devices is the preferred method for automatic collection of chronic,
continuous blood pressure data.
 Two surgical techniques are described for instrumenting the two most
commonly used laboratory rodent species with radiotelemetry devices. The
basic rat procedure involves advancing a blood pressure catheter into the
abdominal aorta and placing a radio transmitting device in the peritoneal
cavity. The mouse technique involves advancing a thin, flexible catheter from
the left carotid artery into the aortic arch and placing the telemetry device
under the skin along the animal’s flank. Both procedures yield a chronically
instrumented model to provide accurate blood pressure data from an
unrestrained animal in its home cage.

23. The rat blood pressure telemetry device is positioned in the peritoneal
cavity with the pressure sensing catheter advanced upstream
into the abdominal aorta .The catheter insertion site is sealed with tissue
adhesive and the transmitter body is sutured into the abdominal wall
closure. .With effective post-surgical analgesia, a typical outbred rat will
return to its pre-implantation body weight in 2–3 days and will return to
normal circadian behavior patterns in 5–7 days.
PA-C10 transmitter is used.

24. References
1. Cardiovascular Genomics Methods and Protocols Edited
byKeith DiPetrillo
2. Hyperresponsivity of spontaneously hypertensive rat to
indirect measurement of blood pressure
3. chuang c. chiueh and irwin j. kopin a simple method for
recording the electrocardiogram and heart rate from
conscious animals By j. b. farmer and g. p. levy Br. J.
Pharmac. Chemother. (1968), 32, 193-200.
4. Measurement of invasive blood pressure in rats
Subramani Parasuraman and Ramasamy Raveendran
5. A Simple Device for Invasive Measurement of Arterial
Blood Pressure and ECG in the Anesthesized Rat V. L.
Ordodi1, F. A. Mic1,3, A. A. Mic1, O. Toma2, D. Sandesc2, V.
Paunescu1