Diseases of the chest and the principles of physical diagnosis . •EAD % GoMPLSTE Block Fig. 156.—Auriculo-ventricular heart block. Complete block. Note that the P wavenow occurs quite independently of the ventricular complexes, , there is no simple ratiobetween auricular and ventricular rate. Intraventricular. A. Bundle Branch Block.—A fairly common typeof heart block, that is only detectable by the electrocardiograph, is thatoccurring in one of the branches of His Bundle. If one or other is de-ficient in conductivity, an anomalous complex results, which resemblesthat of right or left vent
Diseases of the chest and the principles of physical diagnosis . •EAD % GoMPLSTE Block Fig. 156.—Auriculo-ventricular heart block. Complete block. Note that the P wavenow occurs quite independently of the ventricular complexes, , there is no simple ratiobetween auricular and ventricular rate. Intraventricular. A. Bundle Branch Block.—A fairly common typeof heart block, that is only detectable by the electrocardiograph, is thatoccurring in one of the branches of His Bundle. If one or other is de-ficient in conductivity, an anomalous complex results, which resemblesthat of right or left ventricular hypertrophy {), except that the QRSdeflection time is considerably lengthened (more than seconds),the initial deflections aie of high amplitude, bizarre shape and BiaJeK \U HjChT BsAfVCH af H|V ^^H\ Fig. 157.—Intraventiicular heart block. Right branch of Hiss bundle. From acase of decompensated myocarditis, which has been for two weeks on large doses ofdigitalis. Note the notching of <S and the prolonged deflection time of the R-S group(more than second). The P-R interval is prolonged to second. As both thesesigns continued after the cessation of digitalis, they were presumably due to deficient con-ductivity caused by organic changes. Note also the small U wave that is occasionally seenin normal records. There is usually a high T wave, in the opposite direction to the largerof the initial deflections. If the right branch is deficient and .the im-pulse reaches the ventricle through the left branch, the picture resemblesthat of left ventricular hypertophy; and vice versa if the left branch isdeficient. This condition may be a permanent result of organic diseaseor a temporary result of digitalis. THE ELECTROCARDIOGRAPH 195
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectdiagnos, bookyear1920
