Three-dimensional (3-D) images of the human left ventricle were reconstructed from 2-dimensional echocardiographic pictures. All images were recorded at held end-expiration from an optimal point where a high-quality parasternal long-axis view maximally visualizing the left ventricle could be obtained. Multiple short-axis views were obtained from the same reference point. Interactive computer techniques were used to reconstruct 3-D shells of endocardium and epicardium. End-diastolic and end-systolic outlines were superimposed after correcting for motion during the cardiac cycle to demonstrate wall motion. Images were displayed from different perspectives and regional wall thickness, thickening, and motion were then demonstrated using surface map displays. Volumes and derived indices of left ventricular function were calculated. The ejection fraction of normal patients was 69 +/- 9%, compared to 57 +/- 7% in infarct patients; the latter results correlated well with contrast angiography. 3-D echocardiographic reconstruction provides the observer with a spatial appreciation of left ventricular wall motion and thickness, as well as useful quantitative information. The system requires only a standard echocardiographic recorder and simple computer hardware.

Echocardiography↗

PubMedDate not supplied

Computer processing of artifact and arrhythmias in heart rate variability analysis.

Analysis of heart rate variability (HRV) with Holter monitoring is often difficult due to excessive artifacts and arrhythmias. While short sudden surges are treated successfully by most methods, slow heart rate (HR) variations, nocturnal trapezoidally-shaped HR increases and special types of arrhythmias which are similar to normal HRV fluctuations may distort further time domain and spectral analysis. This paper examines the advantages and disadvantages of different methods for preprocessing of HR data. We have developed the following approach to the analysis of HRV. (1) A combination method based on the absolute difference between HR values and both the last normal HR value and an updated mean is used for removal of artifacts and arrhythmias. This method can detect both sudden surges in HR values as well as longer periods of noise combined with slow normal variations. An additional stage of wild point removal is then optionally applied. (2) Certain special problems such as large T-waves, bigeminal rhythm, slow HR variations and nocturnal trapezoidally-shaped HR increases are also identified. Although none of the algorithms can be applied successfully to all cases, the final computer analysis for preprocessing described in the present study has proved to be superior to the simplified methods which are usually used and provides more suitable data for HRV analysis.

Algorithms↗

PubMedDate not supplied

Age- and gender-related differences in success, major and minor complication rates and the duration of hospitalization after percutaneous transluminal coronary angioplasty.

This report describes the effect of age and gender on the results of balloon angioplasty using current technique and indications. A consecutive group of 2,067 patients who underwent angioplasty at a single institution after 1990 is described. Angioplastic success was 92.2% and similar among men and women and the various age groups. Sixteen patients (0.8%) died, and mortality among women was significantly higher (1.4 vs. 0.6%, p < 0.001). There were no age or gender differences in the rate of Q-wave myocardial infarction and the need for coronary artery bypass. Minor complications such as groin complications (10.5% women, 5.0% men; p < 0.001) and infections (6.4% women, 3.7% men; p < 0.05) were more common in women, and as a result the duration of hospitalization after angioplasty was longer. The length of hospitalization after angioplasty was longer with advanced age, mainly as a result of higher groin complications (p < 0.001), infections (p < 0.01) and renal failure (p < 0.05). We conclude that using current indications and technique, angioplasty can be performed safely with a high success rate. Mortality is higher among women. The length of hospitalization after angioplasty is longer in women and, at advanced age, due to higher rate of minor complications.

Age Factors↗

PubMedDate not supplied

Power spectrum analysis of spontaneous fluctuations in the photoplethysmographic signal.

Direct measurement of variability in the peripheral circulation was performed by means of photoplethysmography, which provides assessment of blood volume in tissue and systolic blood volume increase. Both parameters showed oscillations at a relatively low frequency, about 0.02 Hz, and a relatively high frequency, about 0.3 Hz, which is related to respiration. These frequencies are similar to those found in measurements of heart rate variability--which is also obtained by measuring the photoplethysmographic period variability--but the powers of the different frequencies are different. The low frequency oscillation, which is attributed to the activity of the sympathetic nervous system, is more pronounced in the measurements of tissue blood volume and of systolic blood volume increase than in the measurement of heart rate.

Adult↗

PubMedDate not supplied

Capillary and myofiber ultrastructure in endomyocardial biopsies from cyclosporine-treated heart transplant patients.

This study focuses on the ultrastructure of microvessels and myofibers in 54 endomyocardial biopsy specimens from 16 patients treated with cyclosporine after heart transplantation. Although the capillary and myofiber pathologic condition was significantly correlated with the degree of rejection, ultrastructural changes sometimes occurred in biopsy specimens with little or no histologic cellular infiltration. Immunocytochemical studies of some biopsy specimens showed that all microvessels were positive for IgM, whereas concentrations of IgG, complement, and fibrin varied. The microvascular and myofiber changes appeared to be reversible and correlated (Pearson's coefficient of correlation of myofiber vacuoles and microangiopathy, R = 0.67, p less than 0.00001). The vacuoles in myofibers resembled those in subendocardial regions of ischemic myocardium. They could, however, be related to cyclosporine toxicity because similar vacuoles have been described in kidneys of transplant patients receiving cyclosporine. We conclude that in cases of unclear graft failure in the absence of classic signs of rejection, electron microscopy could be helpful in detecting microvascular and myofiber pathologic situations that may influence myocardial function.

Adult↗

PubMedDate not supplied

The application of photoplethysmography to the recording of Valsalva maneuver responses.

Explore the source record for details and available documents.

Blood Pressure↗