THE CARDIOGRAM. 6 1 



produced reflexly by gastric or intestinal irritation or dyspepsia. It also frequently results 

 from excesses of all kinds and the over-use of tobacco. The remedies to be used obviously 

 depend on the cause. Where the blood-pressure is low, as in anaemia, digitalis and iron will 

 do good ; the former by increasing the blood-pressure, and the latter by improving the general 

 nutrition of the body and the blood in particular. In neurotic cases cardiac sedatives are indi- 

 cated, while in cases due to indigestion hydrocyanic acid is useful (Brunton)]. 



[Fainting or Syncope. In fainting the person loses consciousness, owing to a sudden arrest 

 of the blood-supply to the brain, the face is pallid, the respiration is feeble or ceases, while the 

 heart beats but feebly or not at all. The defective supply of blood to the brain may depend 

 upon sudden arrest of the heart's action, caused, it may be, by a fright, or the heart's action 

 may be arrested reflexly. Any cause which suddenly diminishes the blood-pressure may pro- 

 duce it, or when pressure is suddenly removed from the large vessels, as in tapping the abdomen 

 in ascites, without at the same time giving sufficient support to the abdominal viscera. When 

 a person has been long in the recumbent position, on being rapidly set up in bed he may faint. 

 In some forms of heart disease, sudden exertion or change of posture may produce it. 



[Treatment. The object is to restore consciousness and the action of the heart. Place the 

 person in the horizontal position, keep the head low, even lower than the body, and do not 

 support it with pillows. Dashing cold water on the face, so as to stimulate the fifth nerve, 

 usually succeeds in causing the person to take a deep inspiration. In other cases a sniff of 

 smelling salts or ammonia, acting through the nasal branch of the fifth nerve, will excite the 

 cardiac and respiratory functions ( 368).] 



50. THE APEX-BEAT, CARDIOGRAM. Cardiac Impulse. By the term 

 " apex-beat " or " cardiac impulse " is understood under normal circumstances an 

 elevation (perceptible to touch and sight), in a circumscribed area of the fifth left 

 intercostal space, and caused by the movement of the heart. [The apex-beat is felt 

 in the fifth left intercostal space, 2 inches below the nipple, and 1 inch to its sternal 

 side, or at a point 2 inches to the left of the sternum.] The impulse is more rarely 

 felt in the fourth intercostal space, and it is much less distinct when the heart beats 

 against the fifth rib itself. The position and force of the cardiac impulse vary 

 with changes in the position of the body. 



[The cardiac impulse is synchronous with the systole of the heart, but although this name 

 and apex-beat are frequently used as synonymous terms, it is to be remembered that the 

 impulse may be caused by different parts of the heart being in contact with the chest-wall. 

 The cardiac impulse is usually higher than normal in children, while it is lower during inspira- 

 tion than expiration.] 



[Methods. To obtain a curve of the apex-beat or a cardiogram, we may use one or other of 

 the following cardiographs (fig. 36). Fig. 36, A, is the first form used by Marey, and it consists 

 of an oval wooden capsule applied in an air-tight manner over the apex-beat. The disc, p, 

 capable of being regulated by the screw, s, presses upon the region of the apex-beat, while t is a 

 tube which may be connected with a recording tambour (fig. 47). B is an improved form ot 

 the instrument, consisting essentially of a tambour, while attached to the membrane is a button, 

 p, to be applied over the apex-beat. The movements of the air within the capsule are com- 

 municated by the tube, t, to a recording tambour. Fig. 36, C, is the pansphygmograph of 

 Brondgeest, which consists of a Marej^'s tambour, in an iron horse-shoe frame, and adjustable 

 by means of a screw, s. Burdon-Sanderson's cardiograph is shown in D. The button, p, carried 

 by the spring, e, does not rest upon the caoutchouc membrane, but on an aluminium plate 

 attached to it. The apparatus is adjusted to the chest by three supports. Fig. 36, E, shows 

 a modified instrument on the same principle by Grummach and v. Knoll. In all these 

 figures the t indicates the exit-tube communicating with a recording tambour (fig. 47), D and 

 E may be used for other purposes, e.g., for the pulse, so that they are polygraphs. See also 

 % 76.] 



Fig. 39, A, shows the cardiogram or the impulse-curve of the heart of a healthy 

 man ; B, that of a dog, obtained by means of a sphygmograph. In both the follow- 

 ing points are to be noticed : ab, corresponds to the time of the pause and the 

 contraction of the auricles. As the atria contract in the direction of the axis of the 

 heart from the right and above towards the left and below, the apex of the heart 

 moves towards the intercostal space. The two or three smaller elevations are 

 perhaps caused by the contractions of the ends of the veins, the auricular appendices, 

 and the atria themselves. 



The portion be, which communicates the greatest impulse to the instrument, and 

 also to one's hand when it is placed on the apex-beat, is caused by the contraction 



