Diseases of the heart and arterial system : designed to be a practical presentation of the subject for the use of students and practitioners of medicine . eft ventricle found in cases of free and un-combined mitral insufficiency. This enlargement seems rather re-markable at first thought, since one would naturally think thechamber ought to be smaller rather than larger in size. At onetime this condition of hypertrophic dilatation was explained onthe hypothesis that in consequence of venous and capillary stasisblood-pressure was increased in the arterial system, and that hencethere was augmente
Diseases of the heart and arterial system : designed to be a practical presentation of the subject for the use of students and practitioners of medicine . eft ventricle found in cases of free and un-combined mitral insufficiency. This enlargement seems rather re-markable at first thought, since one would naturally think thechamber ought to be smaller rather than larger in size. At onetime this condition of hypertrophic dilatation was explained onthe hypothesis that in consequence of venous and capillary stasisblood-pressure was increased in the arterial system, and that hencethere was augmented intraventricular pressure which resulted indilatation, with increased demand for work which led to hyper-trophy. This theory is now known to be incorrect, and has been re-placed by the following: Owing to the abnormal volume of blood 220 DISEASES OF THE HEART contained by the left auricle at the close of its diastole, thischamber, which has become hypertrophied, discharges with greatforce an unnatural amount of blood into the ventricle. This Cyanosis of face Cyanosis, and clubbinof fingers Congestion and cedemaof kings Engorgement of portalsystem. Congestion and oedemaof lower limbs. Fig. 35.—Diagram showing Effects on the Circulation of a Mitral Leak. MITRAL REGURGITATION 221 cavity is in a state of diastole when it receives tliis inrush, and, being relaxed, becomes after a time dilated. At the same timeit is forced to handle a larger volume of blood, which it can onlydo by undergoing hypertrophy, and thus at last this ventricleconies in its turn to feel the secondary effects of the circulatorydisturbance. In time, moreover, when stasis has become everywhere appar-ent, the left ventricle undergoes still further dilatation, for whichit has become prepared by certain structural changes within itsmyocardium. Its myocardium is flabby and of a brown insteadof the normal beefy red colour, while its fibres are found micro-scopically to be reduced in size and to contain granules o
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