A recruitment maneuver followed by PEEP reduced atelectasis and improved oxygenation in morbidly obese patients, whereas PEEP or a recruitment maneuver alone did not.

Abstract. Dilated cardiomyopathy (DCM), characterized by chamber dilatation and myocardial systolic and diastolic dysfunction, is one of the most common heart diseases in dogs. The clinical diagnosis is based on findings on echocardiographic and Doppler examinations, with the active exclusion of other acquired or congenital heart diseases. However, the echocardiographic criteria for the diagnosis of DCM are not wholly specific for the disease, and histologic examination may be necessary for final diagnosis. Review of reports on histologic findings in dogs with clinically diagnosed DCM reveals two histologically distinct forms of DCM: 1) cardiomyopathy of Boxers and Doberman Pinschers, corresponding to the ''fatty infiltration-degenerative'' type and 2) the form seen in many giant, large-, and medium-sized breeds, including some Boxers and Doberman Pinschers, classified as the ''attenuated wavy fiber'' type of DCM. The histologic changes of the attenuated wavy fiber type of DCM may precede clinical and echocardiographic signs of heart disease, thus indicating an early stage of DCM.

The case records of 189 dogs (including 38 breeds) with congestive heart failure caused by dilated cardiomyopathy were studied retrospectively. Airedale terriers, boxers, Doberman pinschers, English cocker spaniels, Newfoundlands, St. Bernards, and standard poodles were over-represented. German shepherd dogs were under-represented. A male predominance was observed. Systolic murmurs were detected in 25% of the cases. Atrial fibrillation was the most common arrhythmia. Mild hyperglycemia and mild-to-moderate hypercholesterolemia were found in 38% and 33% of cases, respectively. Histopathological changes consisted of attenuated wavy fibers and interstitial fibrosis.

Summary Six horses with a history of recurrent exertional rhabdomyolysis (RER) (Horses A‐F) and 7 control horses performed a submaximal and later a near‐maximal treadmill exercise test. Blood samples were obtained before, during and after exercise and muscle biopsies were taken before and after exercise. At rest, plasma aspartate aminotransferase (AST) activities in horses with RER were above 95% confidence intervals for control horses. During submaximal exercise, 3 horses with RER (A, B and C) had much greater increases in plasma AST, creatine kinase (CK) and myoglobin concentrations than did Horses D, E and F and control horses. Clinical signs of muscle stiffness and pain were only obvious in Horse A. During near‐maximal exercise, only Horse C showed a substantial increase in CK activity and myoglobin concentrations without any associated clinical signs of rhabdomyolysis. Muscle biopsies from Horses A, B and C contained necrotic type II fibres which, on electron microscopic examination, contained disrupted myofibrils and swollen mitochondria. These results suggest that, in RER, subclinical episodes of muscle fibre necrosis and associated increases in plasma AST, CK and myoglobin occur with exercise more frequently than could be detected clinically. Furthermore, the pattern of increase in muscle enzymes and myoglobin concentrations in the 6 horses with RER suggested that the high plasma AST and CK activities commonly observed at rest in symptom‐free Standardbred horses are probably a result of repeated subclinical episodes of rhabdomyolysis after exercise, rather than leakage due to abnormal sarcolemmal permeability.

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