Auricular Fibrillation: Auricular Flutter

Disturbances of the Heart
by Oliver T. Osborne, M.D.

(Page 15 of 22)

Auricular fibrillation is at times apparently a clinical entity much as is angina pectoris, but it is often a symptom of some other condition. At times auricular fibrillation is only a passing symptom, and is rapidly cured by treatment. A real auricular fibrillation shows a semiparalysis of the auricles, and during this condition normal systolic contractions do not occur, although there are small rapid twitchings of different muscle fibers in the auricles. Although it was once thought that the auricle was paralyzed in this condition, it probably simply loses its coordinate activity. Auricular fibrillation and auricular flutter are probably simply different degrees of the same condition, and any contractions of the auricles over 200 per minute may be termed an auricular flutter, and below that the term auricular fibrillation may be used. When ventricular fibrillation occurs, the condition is serious and the prognosis bad. Both auricular fibrillation and auricular flutter may be temporary or permanent, and the exact number of fibrillations or tremblings of the auricular muscle can be noted only by electrical instruments.

Tallman, after examination of fifty-eight cases, classifies different types of auricular flutter: (1) such a condition in an apparently normal heart; (2) the condition occurring during chronic heart disease, and (3) an auricular flutter with partial or complete heart block.

The irregular pulse in auricular fibrillation is more or less distinctive, being generally rapid, from 110 upward. Occasionally the pulse rate may be much slower, if the heart is under the influence of digitalis. The irregularity of the pulse in this condition is excessive; the rate, strength and apparent intermittency during a half minute may not at all represent the condition in the next half minute, or in the next several minutes. If digitalis does not cure the irregularity, the condition has been termed the "absolutely irregular heart." Other terms applied to the condition have been "ventricular rhythm," "nodal rhythm" and "rhythm of auricular paralysis." The condition of the pulse has been Latinized as pulsus irregularis perpetuus.

While the condition is best diagnosed by tracings taken simultaneously of the apex beat, jugular and radial, still the jugular tracing is almost conclusive in the absence of the auricular systolic wave. The radial tracing is exceedingly suggestive, and if there is also a careful auscultation of the heart, a presumptive diagnosis may be made.

Occurrence

This condition of auricular fibrillation occurs occasionally in valvular disease, and perhaps most frequently in mitral stenosis; but it can occur without valvular lesions, and with any valvular lesion. If it occurs in younger patients, valvular disease is apt to be a cause; if in older patients, sclerosis or myocardial degeneration is generally present.

It may also follow infections such as diphtheria, or some infection which has caused a myocarditis. Rarely this fibrillation may be caused by some of the drugs used to stimulate the heart.

It is astonishing how few symptoms may be present with auricular fibrillation and an absolutely irregular heart action. The patient may be able to perform all of his duties, however strenuous, until coincident, concomitant or causative ventricular weakening and dilatation of the ventricles or broken compensation occurs, and then the symptoms are those due to the cardiac failure. Often in the first stage of this weakening and later fibrillation of the auricles the patient may recognize the cardiac irregularity and disturbances. Generally, however, he soon becomes accustomed to the sensations, and, unless he has cardiac pains or dyspnea, he becomes oblivious to the irregularity. At other times he may be conscious of irregular, strong throbs or pulsations of the heart, as such hearts often give an occasional extra sturdy ventricular contraction. These he notes. Real attacks of tachycardia may be superimposed on the condition. Sooner or later, however, if the condition is not stopped, cardiac weakness and decompensation, with all the usual symptoms, occur. It seems to be probable that more than half of all cases of heart failure are due to auricular fibrillation, or at least are aggravated by it.

As previously stated, ventricular fibrillation is a very serious condition, and may be a cause of sudden death in angina pectoris, and is probably then caused by disturbed circulation in one of the coronary arteries causing an irregular blood supply to one or other of the ventricles. Absorption of some toxins or poisons which could act on the blood supply of the ventricles could also be a cause of this condition. This irregular ventricular contraction sometimes displaces the apex beat.

Pathology

Schoenberg finds that in auricular fibrillation there are definite signs in the node, such as round cell infiltration, showing inflammation, a fibrosis of the tissue, and perhaps a sclerosis of the blood vessels of that region. He also found that compression of this nodal region of the auricle from some growth or other disturbance in the mediastinal region could cause auricular fibrillation.

Jarisch finds by personal investigations and by studying the literature that the node showed pathologic disturbance in less than half the cases. Consequently, although a pathologic condition of the node is a frequent, and perhaps the most frequent, cause of auricular fibrillation, other conditions, especially anything which dilates the right auricle, may cause it.

Diagnosis

If the pulse is intermittent and there is apparently a heart block. Stokes-Adams disease should be considered as possibly present, and digitalis would be contraindicated and would do harm.

A scientific indication as to whether a heart is disturbed through the action of the vagi or whether the disturbance is due to muscle degeneration may be obtained by the administration of atropin. Talley of Philadelphia shows the diagnostic value of this drug. It is a familiar physiologic fact that stimulation of the vagi slows the heart or even stops it. Stimulation of these nerves by the electric current, however, does not destroy the irritability of the heart; indeed, the heart may act by local stimulation after it has been stopped by pneumogastric stimulation. It is also a well known fact that anything which inhibits or removes vagus control of the heart allows the heart to become more rapid, since these nerves act as a governor to the heart's contractions. Under the influence of atropin the heart rate is increased by paralysis of the vagi. Talley states that a hypodermic injection of from 1/50 to 1/25 grain of atropin produces the same paralytic and rapid heart effect in man. He advises the use of 1/25 grain of atropin in robust males, and 1/50 grain in females and in less robust males, and he has seen no serious trouble occur from such injections. The throat is of course dry, and the eyesight interfered with for a day or more, but Talley has not seen even insomnia occur, to say nothing of nervous excitation or delirium. Theoretically, however, before such atropin dosage, an idiosyncrasy against belladonna should be determined.