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Biomedical subjects

R Vas

Publications and source records attributed to R Vas.

15 recordsLinked to original sources
PubMed1979

Photokymography: a noninvasive method of detecting ischemic segmental myocardial wall motion abnormalities.

The photokymograph is a new and simple noninvasive device for assessing epicardial segmental myocardial wall motion utilizing cardiac fluoroscopy and image intensification. The validity of this technique in detecting wall motion changes occurring with ischemia was assessed in seven closed chest dogs undergoing acute balloon occlusion of the left circumflex coronary artery. Acute occlusion resulted in a prompt change in the analog signal of the photokymogram, characterized first by a decreased systolic inward motion and late systolic outward movement that later became akinetic and dyskinetic. Systolic amplitude decreased 18 +/- 7 percent (mean +/- standard error of the mean) within 5 seconds of occlusion and progressed to systolic outward motion (- 106 +/- 24 percent) at 2 minutes. The time course and type of morphologic changes observed after occlusion were similar to those previously described using invasive methods. Furthermore, such changes preceded electrocardiographic S-T segment elevation. These data suggest that photokymography is a sensitive technique for noninvasive detection of acute ischemic segmental wall motion abnormalities and holds promise as a simple method of detecting ischemic heart disease in man.

Animals↗
PubMed1979

Analysis of regional ischemic left ventricular dysfunction by quantitative cineangiography.

The ability of left ventricular angiography to detect regional ischemic dysfunction was assessed in 10 closed-chest dogs during the course of acute balloon occlusion of the anterior descending coronary artery. During the 2-minute period of occlusion, serial cineangiography revealed a sequence of wall motion abnormalities over the anteroapical region almost identical to that observed using directly implanted gauges. This sequence consisted of progressive reduction in regional systolic shortening with eventual replacement by systolic expansion. These changes preceded both electrocardiographic ST-segment and hemodynamic alterations, and were readily observed by gross subjective inspection of the cineangiograms, but with an intraobserver variability of 22%. Frame-by-frame motional analysis of the ventricular perimeter relative to its centroid of mass allowed more precise characterization of regional dysfunction. These data are consistent with previous studies demonstrating that regional wall motion abnormalities are both sensitive and specific markers of acute ischemia, and support the use of computerized left ventricular angiography for the quantitative assessment of clinical ischemic dysfunction.

Animals↗
PubMed1978

[Cardiokymography: noninvasive assessment of the regional myocardial wall motion in the detection of coronary artery disease (author's transl)].

Cardiokymography is a technique to assess myocardial wall motion by means of an electromagnetic field induced over the left precordium. The normal cardiokymogram (CKG) is characterized predominantly by systolic inward movement. An abnormal contraction pattern--either at rest or provoked by a stress test--reveals a different tracing with decreased or absent systolic inward motion and/or systolic outward motion (bulging). In 50 patients with suspected coronary artery disease (CAD) the CKG was recorded before and after treadmill exercise test and the results compared to coronary angiography. Out of 33 patients with angiographically documented CAD (more than 50% luminal narrowing) 25 showed an abnormal CKG after exercise. There was one false positive postexercise CKG in the group of 17 patients without angiographically documented CAD. The CKG allows the qualitative assessment of regional myocardial wall motion, which is a sensitive and specific marker of ischemia. In conjunction with an ECG-stress test the CKG helps to detect the evolving ischemic abnormalities of myocardial contraction. The CKG represents a marker of ischemia independent of the ECG and helps to improve the diagnostic accuracy of stress testing for detection of CAD. The stress CKG is especially advantageous in those cases in which the interpretation of the stress ECG is difficult or even not possible. Its simple and inexpensive technique makes it a useful adjunct to the stress ECG in the diagnosis of CAD.

Aged↗
PubMed1977

Noninvasive analysis of regional myocardial wall motion: cardiokymography.

The validity of a new noninvasive device, the cardiokymograph, was assessed as to its ability to detect regional myocardial wall motion by direct comparison of the analog tracing with that of an epicardial length gauge in 11 open-chest dogs. The correlation of the two methods was excellent both during control conditions and following changes induced by acute coronary occlusion. The average difference between the methods in timing of various cardiac events was only 6.2 +/- 1.9 ms at rest and 6.8 +/- 1.5 ms following ischemia (P = NS). Relative amplitude ratio correlations, determined for the four portions of the cardiac cyele (isovolumic systole, ejection, isovolumic relaxation, and diastole), were also excellent. The average correlation of the kymograph to the length gauge was r = 0.896 +/- 0.018 at rest (K = 0.977 LG + 0.033) and r = 0.932 +/- 0.013 following occlusion (K = 1.071 LG + 0.101). Thus, the cardiokymograph is a sensitive and accurate noninvasive method for detection of regional ischemic dysfunction and produces an analog tracing essentially identical to that of the epicardial length gauge.

Animals↗
PubMed1976

The displacement cardiograph. A noninvasive technique for recording myocardial wall motion.

The displacement cardiograph (DCG) is a noninvasive device employing an electromagnetic field to record tissue motion within the body. The sensing coil need not be in contact with the patient since the field penetrates air and stationary tissue without significant distortion. Disturbances in the field with result from ventricular wall motion are electronically converted to an analog output and a pattern inscribed on the paper of a physiological recorder. In an attempt to determine the reliability of the DCG in detecting regional areas of abnormal left ventricular wall motion, displacement cardiograms were obtained from 70 patients who underwent cardiac catheterization and left ventriculography. The DCG interpretations were in agreement with the ventriculographic picture of left ventricular wall motion in 67 of the 70 patients. There were two false positive and one false negative DCG diagnoses. The results indicate that the DCG can be employed as a reliable noninvasive method for repetitive assessment of the pattern of contraction of the anterior, anterolateral and posterior left ventricular wall.

Cardiomyopathies↗