Definition.—Tachycardia is a rapid action of the heart, either constant or paroxysmal. It is usually associated with palpitation, though it may be entirely independent. There are generally no subjective symptoms of forcible action in tachycardia.
Etiology.—Occasionally we meet with a physiological tachycardia, the normal pulse running a hundred or more per minute, and still more rarely is found a patient who can increase the pulse-rate at will.
The rapid heart seen in all fevers is not usually considered under the head of tachycardia, but is limited to that form which is paroxysmal in character. It is generally due to a neurosis, though it sometimes occurs as the result of a growth or clot in or about the medulla. Also pressure of the- pneumogastrics by growths or tumors may give rise to it. The peripheral neuritis of the pneumogastrics produced by the toxins of the various infectious fevers may be attended by heart hurry.
The more frequent causes, however, are reflex, and may be due to wrongs of the rectum, the uterus, ovaries, bladder, or urethra. Fright, grief, and emotional excitement are frequently the exciting causes of a rapid heart. Severe physical or mental exertion may be followed by a rapid heart-beat, which may continue for days. Sexual excesses and masturbation will also give rise to this condition, some cases being especially stubborn in yielding. Often associated with palpitation, the same causes may give rise to it. Anemic and chlorotic females are subject to rapid heart, while the victim of hysteria or neurasthenia may suffer with paroxysms of tachycardia. It sometimes occurs in females during the menopause.
Pathology.—No characteristic lesions are found, though neuritis of the pneumogastric and myocardial degenerations have been discovered post-mortem.
Symptoms.—Where tachycardia is permanent, there are few pronounced symptoms aside from rapid pulse-beat; but in the paroxysmal form, true tachycardia, the symptoms are more varied and pronounced.
As a rule, the attacks come on suddenly and often without any premonitory symptoms. In other cases an attack is announced by vertigo, ringing in the ears, and a sense of danger impending.
The subjective symptoms also vary. Sometimes there is almost an entire absence of unpleasant sensations, the patient being unaware of the increased movement of the heart; in fact, he is inclined to believe that the heart-beat is not sufficiently rapid. At first the face is pale, but it soon becomes flushed and sometimes turgid.
The pulse is small, weak, easily compressed, and sometimes irregular. At the beginning of an attack the pulse rapidly increases to one hundred and fifty or two hundred beats per minute, and has been known to reach three hundred per minute.
The respiration may remain normal in frequency, though it is usually somewhat increased. There may be dyspnea and sometimes a feeling of uneasiness, or even pain. in the precordial region. It is not infrequently associated with palpitation, and the patient becomes extremely anxious as to his condition. Vertigo, headache, and ringing in the ears may continue through an attack. An attack may last for but a few minutes, or it may last for hours or sometimes days.
Physical Signs.—If the chest-walls be thin, the rapid, diffuse, and irregular impulse may be perceptible on inspection. Palpation but confirms the visible signs. There may be no enlargement of the heart, and nothing is learned by percussion.
Auscultation may show the heart-beats somewhat modified. Since a less amount of blood is thrown into the aorta with each ventricular systole, the first sound will be slightly accentuated, while the second sound will be diminished. The second pulmonic sound may sometimes be increased, as may also the first systolic sound. Murmurs are seldom heard.
Diagnosis.—The diagnosis is readily made unless complications exist. The great rapidity of the hearts action, with an absence of subjective symptoms; is characteristic. Dyspnea, pre-cordial oppression, pain, and a sense of impending danger are generally associated with palpitation, and where present in tachycardia, are much milder than in the former.
Prognosis.—The prognosis depends somewhat on the causes giving rise to it, though at best it yields but slowly. It seldom proves fatal, though in elderly patients there may be rupture of the cerebral vessels, or death may result from heart exhaustion.
Where the tachycardia is due to reflexes, a cure may result in a removal of the cause. The various orifices should be carefully examined for sources of irritation, and when found they should be promptly removed.
Treatment.—A successful treatment will necessarily be the one which corrects the wrongs that give rise to this disease. In one, it will be wrongs of digestion that need attention, and the patient will need to have his diet restricted and fluids prohibited at meal-times. The bitter tonics will assist in bringing about a cure in these cases. Another will need to have hemorrhoids, pockets, fistulas, fissures, and papilla removed, or a uterus curretted or urethra dilated, before the trouble is overcome. To overlook these points is to court defeat.
During a paroxysm, the patient should be put to bed, his mind quieted as to the result of his case, and such remedies given as are especially indicated.
Gelsemium, if there be undue excitement, may be administered in full doses, a half dram or a dram to a half glass of water, and a teaspoonful every hour.
Aconite, in the small dose, is indicated where the pulse is small and rapid, and as this is the most characteristic symptom, we will find this remedy often beneficial.
Pulsatilla will be used where there is a sense of impending danger. The patient will have an anxious and frightened appearance.
Passiflora.—Where the patient is sleepless and uneasy, passiflora in half or teaspoonful doses will give good results.
Morphia.—Where the rapidity is extreme, and the patient alarmed, a hypodermic of morphia will give the quickest relief. As a rule, the bromides and opiates had better be omitted.