Toxicity of foreign sera for the isolated mammalian heart

Abstract

Seven per cent. to 10 per cent. goat serum in Locke's solution perfused under constant pressure and temperature through the coronary arteries of an isolated normal rabbit heart, usually produces the following series of phenomena:

1. An initial tachycardia, lasting about three minutes, succeeded by

2. A period of apparently normal heart action, lasting about five minutes, succeeded by

3. A secondary tachycardia, lasting about two minutes, ushering in

4. A period of decreasing rate and strength of heart action, increasing irregularities, etc., usually ending in inactivation of the heart in about ten minutes.

If goat serum is separated into diffusible and non-diffusible fractions by dialysis through a celloidin membrane, and the two fractions are tested independently, the following results are usually obtained:

1. The diffusible substances tested in 7 per cent. to 10 per cent. dilution usually produce an initial tachycardia indistinguishable from the tachycardia from the whole serum. This is succeeded by a period of regular rate and rhythm usually lasting for over an hour.

2. The non-diffusible substances (serum colloids) similarly tested usually give no initial tachycardia, the rate and rhythm continuing unchanged for about ten minutes. There is then usually a slight secondary tachycardia, ushering in a period of decreasing heart action, usually ending in inactivation in about fifteen minutes.

The secondary tachycardia is always accompanied by a progressively decreasing rate of perfusion through the coronary arteries, and beginning myocardial edema. We are therefore inclined to attribute the secondary tachycardia and subsequent heart-death to a breaking down of the capillary defenses (increased capillary permeability), allowing the foreign colloids to pass out of the capillaries into the tissue spaces, thus coming into direct contact with the essential myocardial cells.