Electrocardiography

Surface Electrocardiography in Miniature Swine: Comparison of Limb and Nehb-Spörri Axial Lead Systems.

Individual swine (n= 16, 3-6 months, 6-16 kg) were comfortably positioned in a sling and standard veterinary ECG leads were positioned on the limbs (lead II).
In addition, adhesive leads were placed on the cardiac apex area, right mastoid process of the temporal bone, and sacrum using the Nehb-Spöerri axial lead system (axial).
ECG traces of 10 second duration were collected using a Cardiotest EK 53R (Hellige, Germany), and representative lead II and axial ECG's for each animal were analyzed manually; the results were (mean ± SEM):

Lead	HR(bpm)	RR(msec)	P(msec)	PR(msec)	QRS(msec)	QT(msec)
II	96±8	595±41	52±1	97±4	47±4	287±8
Axial	109±9	551±50	61±2	101±5	86±28	282±8

Lead	P(mV)	Q(mV)	R(mV)	S(mV)	STj(mV)	T(mV)
II	0.19±.01	-0.02±.02	0.38±.06	-0.14±.03	0±-0	-0.15±.06
Axial	0.16±.01	0±0	0.44±.07	-1.35±0.1	0±0	0.15±.12

Mean diastolic systolic quotients (DSQ) were 1.07±0.14 (II) and 0.93±0.16 (axial);
average modal QRS vector values were -9.3±11.8 (frontal plane) and -107±4 degrees (sagital plane). QRS duration tended to be slightly longer,
T-amplitude more positive, and modal vector more consistent using the Nehb-Spöerri axial lead system.
Because of the vertical axis of the base-apex cardiac vector in the chest of the miniature swine, traditional limb electrocardiography may be sub-optimal for evaluation of QT interval; an axial lead placement may be preferred.

From:
Abstract book 30th. Scand - LAS symposium, May 4-7, 2000, Sweden.