Chapter 142 Auscultation and Physical Diagnosis
Physical examination follows the obtaining of a complete history and the consideration of the species, age, breed, and sex (see Chapter 1). Diagnosis, or at the very least a number of plausible diagnoses, may be made in many instances by history and signalment; however, following a thorough physical examination, a single, “most likely” diagnosis can be made with reasonable assurance in most patients with cardiac problems.
Physical examination is best performed in a systematic manner, initially conducting those portions that are least likely to aggravate or to cause discomfort to the patient. Physical examination of the cardiovascular system can be separated into four steps: inspection, palpation, percussion, and auscultation. What separates the physical examination from the remainder of the cardiac examination is the close relationship between the veterinarian and the patient, and, with the exception of the stethoscope, the absence of elaborate instrumentation such as radiography, electrocardiography, or echocardiography.
Inspect the patient while obtaining the history. Perform the inspection while the animal enters the room; while the pet stands, sits, or walks; while the owner supports the pet; and while the pet stands alone.
Cyanosis indicates the finding of dark-blue to purple colored mucous membranes caused by poorly oxygenated (desaturated) hemoglobin. The main reasons for cyanosis are respiratory disease and right-to-left shunting due to congenital heart disease.
Analysis of the jugular vein (Fig. 142-1) is simpler if the hair is clipped from around the jugular furrow or if it is moistened with 70% alcohol. Look for pulsations in the vein and estimate the pressure distending it.
Figure 142-1 Analysis of venous pulses. A normal pulse is shown for reference (N), as are systemic arterial pressure (AP), phonocardiogram (PCG), and electrocardiogram (ECG). Abnormal pulses shown are those produced by tricuspid regurgitation (TR) and constrictive pericarditis (CP); also shown are two types of cannon, or giant, a waves.