Bronchoscopic method for measuring left atrial pressure; and aid to diagnosis in mitral disease.

The apparatus used was the same as that prexviouslv described by Allison and Linden.` 2 The manometer system was damped only by the puncturing needle and the degree of damping was 60 to 70 per cent of the critical value. It must be emphasized that in a system of this type no other damping is required. If, to eliminate artifacts, further damping is applied by electric or mechanical means, the amplitude of the recorded pressure pulse will be reduced, and inaccuracies of an unknown degree will occur. The Patient. At rapid heart rates the records of the left atrial pressure contours are less acemirate: (1) because the ratio of the frequency of the impressed force to the natural frequency of the manometer system is large and this causes distortion; and (2) because, in some patients with mitral disease and atrial fibrillation, re(,urcitation may occur when the heart rate is slow and iii.,y not be present when the rate is faster.1 In an investigation by this method the fact that the patient does not have a general anesthetic and is aware of the surroundings tends to increase the heart rate. To avoid tachycardia, therefore, it is advisable to give a vagal-stimulating drug such as morphia and withhold any vagal-paralyzing drug such as atropine. If the patient is apprehensive, additional sedation with a barbiturate may be necessary. The most important factors are adequate explanation and reassurance of the patient.3