ETIOLOGY.—Rheumatism with its attendant complications—that is, disease of the valves, and especially of the aortic valve, atheroma of the coronary artery and possibly cardiac or other thrombosis—forms the chief cause of embolism, a small fragment of tissue being borne away by the current of blood.
SYMPTOMS.—These are acute paralysis of the heart's movements, pain, feeling of impending annihilation, retained consciousness, and regular respiration. Nausea and vomiting have been observed. The lips are livid, extremities cold and covered with a clammy sweat. In one case there was inability to lie down. No pulse could be felt in any of the accessible arteries, and neither apex-beat nor heart-sounds could be detected. The ear applied to the cardiac region could hear only a kind of cardiac tremor, which was very like the sound of a vibrating steel plate. There was no loss of consciousness. The respiration was regular and rhythmical, not exceeding eighteen or twenty in the minute. The patient died twenty hours after the first symptoms.
DIAGNOSIS.—Although a positive diagnosis is impossible, the negative pulmonary physical signs, the regular and rhythmic character of the respiration, and the enfeeblement of the heart's action may lead to a very strong suspicion of embolism of the coronary artery.
PATHOLOGY.—A small coagulum may stop up the main branch, usually the left anterior, of one artery, or both arteries may be occluded by a larger coagulum. In one instance an atheromatous softened patch ruptured into the anterior portion of the left coronary artery, and filled up the lumen with a soft putty-like mass (the sculptor Thorwaldsen). A fatal issue is likely to occur in a very short time, as the anastomosis cannot be sufficient for the sudden demand.
PROGNOSIS and TREATMENT need hardly be considered, as the affection is necessarily fatal in cases which can be made out.
THROMBOSIS.
The same causes which give rise to thrombosis elsewhere are operative in this case. They are chiefly arterio-sclerosis and rheumatism.
SYMPTOMS.—There have been observed slight tightness in the cardiac region, lasting a few days, or a sense of oppression or constraint at the back of the sternum. The pulse has been quickened, but is usually very much slowed and very feeble; it has been observed as low as eight beats in the minute. There is a sense of great lassitude and feebleness of all the limbs. The respiration is normal in rhythm and frequency. Auscultation reveals nothing but ordinary respiration till near a fatal issue, when moist râles indicative of oedema of the lungs are heard. Percussion gives at all times a normal resonance. There is no dyspnoea. The heart-tones are clear, though weak, if occlusion is not complete or anastomosis is perfect. (West was able to inject the arterial system of the heart completely from one coronary artery, the other having been tied.) If there is complete obstruction, we may expect to hear a fremitus such as is produced by muscular spasm instead of normal heart-sounds (observed in two cases). The skin of the body and face is cool, pallid, and covered with sweat. The visible mucous membranes are anæmic and pale. The mind is clear.
DIAGNOSIS.—The cardiac feebleness and progressive slowness, together with the absence of symptoms connected with the lungs, might lead one to suspect the presence of thrombus.
PROGNOSIS.—If a large branch of the artery is affected a fatal termination is probable. If, on the other hand, the affection occurs in a small branch, there is reason to believe that the circulation is sometimes re-established through anastomosis.