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Twelve clinically normal pigs were anesthetized with fentanyl citrate and sodium pentobarbital and placed in left lateral recumbency. M-mode echograms were recorded from the area of the 4th intercostal space with a 3.5 mmHz transducer. Changes in the internal minor axis diameter %deltaD were measured at 44.8 +/- 3.3 cm. An index of contractility (Vcf) was 1.12 +/- 0.16 cm/s. The caudal wall thickness dimension measured 0.61 +/- 0.04 cm and the aortic root dimension was 1.9 +/- 0.11 cm. To corroborate the echocardiographic findings, echocardiographic, cineangiographic, and postmortem studies were conducted on a 2nd group of 3 pigs. Aortic root, diastolic lumenal dimensions, and wall thickness were compared and the results never differed more than 2 mm. Echograms can conveniently be acquired from restrained, mature swine, and they provide useful, reliable structural and hemodynamic information, without the hazards or expense of invasive techniques.

Echocardiographic examinations were performed on 25 normal healthy cats placed in left lateral recumbency. The cats were representative of serveral breeds, consisted of 12 males and 13 females, and weighed between 2 and 6.5 kg. Twelve measurements from the echocardiograms of each cat were made for the purpose of compiling a small data base (reference values). These measurements included wall thicknesses, luminal dimensions, and contractile indices. Left ventricular wall thickness averaged 0.37 +/- 0.08 cm, and the septal wall thickness averaged 0.45 +/- 0.09 cm. The average left ventricular lumen in diastole was 1.48 +/- 0.26 cm, and in systole, it was 0.88 +/- 0.24 cm, which resulted in an average shortening fraction of 41 +/- 7.3%. Velocity of circumferential shortening, an index of contractility, averaged 2.86 +/- 0.78 cm. In eight additional cats, both ventricles were catheterized for echographic chamber identification and then cineangiographic procedures. Then these cats were euthanatized, and postmortem measurements were compared with echocardiographic and cineangiographic measurements. According to the three methods of determining wall thickness, differences were less than 15%, where the range of deviations was between 0 and 0.5 mm and the average deviation was -0.01 +/- 0.26 mm.