PATHOLOGICAL VARIATIONS IN THE HEART-BEAT. 



109 



Fig. E represents the apex-beat in a case of stenosis of the aortic orifice. 

 The auricular contraction (a b) is quite brief, the ventricular contraction is visibly 

 prolonged and after a short rise (b c) exhibits a series of indentations (c e) caused 

 by the mass of blood forcing its way through the stenotic and roughened entrance 

 to the aorta. 



Fig. F represents the apex-beat in a case of insufficiency of the mitral valve; 

 a b is well marked in consequence of the increased activity of the left ventricle; 

 the shock (d) caused by the closure of the aortic valves is slight on account of 

 the diminished tension in the arterial system. On the other hand, the shock of 

 the accentuated pulmonic second sound (e) stands like a huge accent high upon 

 the summit of the curve. In consequence of the tension in the pulmonary artery 



FIG. 33. Various Forms of Pathological Apex-beat Curves. In all of these curves a b indicates the auricular 

 contraction; b c, the ventricular contraction; d, the close of the aortic semilunar valves; e, that of the pul- 

 monary valves; e f, the time occupied by the relaxation of the ventricles. 



the pulmonary second sound may be so accentuated and it may follow so quickly 

 after the second aortic sound (d) that the two almost or quite coincide (H and K) . 



The curve in a case of stenosis of the left auriculo-ventricular orifice (G) 

 presents first of all a long, irregular, indented auricular contraction (a b) , due to 

 the fact that the blood is forced through the narrow orifice with considerable 

 agitation and friction. The ventricular contraction (b c) is feeble on account of 

 the imperfect filling of the left chamber. The closures of the two valves d and e 

 are separated by a comparatively long interval and the ear distinctly hears a 

 duplicated second heart-sound. The aortic valves close rapidly because the aorta 

 receives only a small amount of blood, while the more abundant flow of blood 

 into the pulmonary artery causes retarded closure of the pulmonary valves. 



When the heart-beats are rapid and weak and the tension in the aorta and 

 the pulmonary artery is low, the signs of closure of the valves in the latter 



