Acute heart failure
The acute heart failure is characterized by sudden loss of consciousness and falling with or without convulsions. The mucous membranes become pale followed by either recovery or death.
Etiology: Acute heart failure results from (i) filling disorders due to severe tachycardia or severe bradycardia or (ii) when there is more work load on the heart, seen in anaphylaxis and rupture of valves, (iii) myocarditis as seen in peracute form of foot-and-mouth disease (FMD) especially in young dairy animals, (iv) myopathies associated with deficiency of selenium and copper, (v) intravenous rapid calcium therapy, (vi) xylazine administration, (vii) occlusion of coronary artery (myocardial infarction).
Pathogenesis: In tachycardia, the diastolic period is short and ventricular filling is not adequate, thus reducing the cardiac output. When heart rate is slow to a critical point, the cardiac output is also reduced. There is severe degree of anoxia in the tissues. Brain is affected and nervous signs are shown by the animal. Due to reduced arterial blood flow, the mucosa becomes pale.
Clinical signs: Due to respiratory distress animal is dyspnoeic. There is staggering and falling down followed by death. There may be sporadic convulsions. Clinical findings also comprise pale mucosa, absence of palpable pulse or absence of heart sounds. Pulmonary edema is evident on the auscultation of the lungs. When the animal survives longer then hydrothorax or ascites develop.
Treatment: It is not successful due to the shorter course of the disease.