White found that about half of his cases of pulsus alternans showed an increased blood pressure of 160 mm. or more; 62 percent. were in patients over 50 years of age, and 69 percent. were in men. Necropsics on patients who died of this condition showed coronary sclerosis and arteriosclerotic kidneys.
The onset of dyspnea, with a rapid pulse, should lead one to suspect pulsus alternans when such a condition occurs in a person over 50 with cardiovascular-renal disease, arid with signs of decompensation, and also when such a condition occurs with a patient who has a history of angina pectoris.
While the forcefulness of the varying beats of an alternating pulse may be measured by blood pressure instruments by the auscultatory method, White and Lunt [Footnote: White, P. D. and Lunt, L. K.: The Detection of Pulsus Alternans, THE JOURNAL A. M. A., April 29, 1916, p. 1383.] find that in only about 30 percent. of the cases, the graver types of the condition, is this a practical procedure.
Pulsus alternans, except when it is very temporary, Gordinier finds to be of grave import, as it shows myocardial degeneration, and most patients will die from cardiac insufficiency in less than three years from the onset of the disturbance.
The treatment is rest in bed and digitalis, but White found that in only four patients out of fifty-three so treated was the alternating pulse either "diminished or banished." In a word, the only treatment is that of decompensation and a dilated heart, and when such a condition occurs and is not immediately improved, the prognosis is bad, under any treatment.
BRADYCARDIA
The first decision to be made is what constitutes a slow pulse or slow heart. A pulse below 58 or 60 beats per minute should be considered slow, and anything below 50 should be considered abnormally slow and a condition more or less suspicious. A pulse from 45 to 50 per minute occasionally occurs when no pathologic excuse can be found, but such a slow rate is unusual. Before determining that the heart is slow, it must of course be carefully examined to determine if there are beats which are not transmitted to the wrist; also whether a slow radial rate is not due to intermitence or a heart block. Auricular fibrillation, while generally causing a rapid pulse (though by no means all beats are transmitted to the peripheral arteries), tray cause a slow pulse because some of the contractions of the heart are not transmitted.
While any pulse rate below 50 should be considered abnormal and more or less pathologic, still a pulse rate no lower than 60 may, be very abnormal for the individual. For athletes and those who work hard physically, a slow pulse is normal. Such hearts are often not even normally stimulated by high fever, so that the pulse is unusually slow, considering the patient's temperature, unless inflammation of the heart has occurred.
Some chronic diseases cause a slow pulse; this is especially true of chronic interstitial nephritis. In fact, it may be stated that any disease or condition which increases the blood pressure generally slows the pulse, unless the heart itself is affected. This is true of hypertension, of arteriosclerosis, of nicotin unless the heart has become injured, and often of caffein, unless it acts in the individual as a nervous stimulant. Chronic lead poisoning causes a slow pulse on account of the increased blood pressure.
A slow pulse may occur during convalescence from acute infections, such as typhoid fever and pneumonia, and sometimes after septic processes. While it may not be serious in these conditions, it should always be carefully watched, as it may show a serious myocarditis.