Blood pressure in the finger was measured by a servo-plethysmomanometer constructed after the design of Penàz, which uses the principle of the unloaded arterial wall. The device contains a photoelectric plethysmograph mounted in an inflatable cuff and an electro-pneumatic transducer to control air pressure in the cuff via a servosystem. Comparison of simultaneous measurements of intra-arterial pressure in the brachial artery was performed on 33 patients suspected of having hypertension. In 12 patients evaluation of the technique could not be carried out due to technical failures or distorted blood pressure wave forms. Results of the remaining 21 patients show a mean underestimation of intra-arterial blood pressure by finger cuff blood pressure of 0.8 kPa (6 mm Hg), both for systolic and diastolic levels. The scatter range of the difference is from 1.9 to -3.5 kPa for systolic and 0.1 to -2.5 kPa for diastolic values. It appears that, although not all technical problems are solved, the Penàz servo-plethysmo-manometer is potentially an elegant method by which to arrive at the fully calibrated wave form of blood pressure in a finger in a non-invasive and continuous fashion.

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Esophageal phonocardiography (ePCG) has the advantage that certain heart sounds are picked up near their sites of origin, whereas in conventional surface phonocardiography (sPCG) attenuation of the vibration occurs in the pathway to the microphone. The disadvantage of directional sensitivity of an accelerometer-type microphone has been eliminated by constructing biaxial microphones; with the aid of an electronic axes rotation, optimal recording of heart vibrations in the horizontal plane is achieved. ePCG has clinical value because of diagnosing mitral valve regurgitation (MR) better than conventional PCG, especially in patients having prosthetic valves in both mitral and aortic orifices where left ventricular angiography is not easily accomplished. Regarding the level of the microphone in the esophagus it has been established that various significant vibration patterns can be recorded at different heights. This variety of patterns is also explained by the distance to specific sources: heart sounds generated in the vicinity of the microphone are better detected with respect to others having a more distant origin. In this way the method contributes to the discussion about valvular components contained in the first heart sound. In the investigation simultaneous recordings with M-mode echocardiogram and pulsation curves have been obtained. More than 60 patients and normal subjects were examined. In 9 patients with prosthetic valves in both mitral and aortic orifices and 8 patients with mitral valve prolapse, MR was proved by ePCG in respectively 4 and 2 cases while sPCG failed to do so.

In an effort to clarify the genesis of the opening snap (OS) of mitral stenosis (MS), the frequency versus amplitude spectra of OS of 30 patients were obtained using the FFT algorithm together with mono- and twodimensional échocardiographie parameters. Each echo parameter was correlated with the relative energy contained in each of the 20-Hz bands in which the normalized average spectrum of OS of each subject was divided. Out of these echo parameters, only left atrial volume, mitral valve area, septal and posterior left ventricular diastolic slopes showed significant correlations with the phonocardiographic signal. Besides the role of the valvular apparatus, the size of the left atrium seems to be the most important factor. The left atrium with the blood it contains appears to represent the mass of a mass-spring system which is maximally decelerated rendering manifest the forces generating the vibrations when the stenotic valve suddenly blocks the blood flow.

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