Color superposition: a new modality for contrast echocardiography.

To improve the estimation of endocardial borders in echocardiography, a technique has been developed to combine images from contrasted and noncontrasted echocardiograms of the same heart-phase using a color superposition mode. This method allows both experienced as well as less experienced examiners to define the endocardial borders more reproducibly and objectively. This is achieved by displaying tissue structures as gray level images while the ventricular cavity is marked selectively by the color display of the contrast material zone. Results of volume estimations of the left ventricle by different examiners using several imaging modes including color superposition display are presented.

Methods for non-invasive detection of ventricular late potentials--a comparative multicenter study.

To evaluate the methodological problems of the non-invasive registration of late potentials the results obtained with four different averaging devices in the same 109 patients were compared. The high-resolution ECG was obtained from the body surface, high-gain amplified and filtered. With the averaging technique, the improved signal-to-noise ratio was able to detect low-amplitude cardiac activity. The incidence of late potentials detected with the four averaging systems, whose characteristics are described, ranged between 12% and 21%. Corresponding positive results were obtained in 5.5%, corresponding negative results in 68.8%. The reasons for differing results were mainly due to differences in visual or automatic interpretation of the registered fractionated electrical cardiac activity. Additionally, the determination of the end of QRS using the QRS width, obtained from reference leads, may influence the specificity of the methods.

New balloon catheter for prolonged percutaneous transluminal coronary angioplasty and bypass flow in occluded vessels.

A new balloon catheter was developed for continuous perfusion of coronary arteries during angioplasty (CPC catheter). Steerable Grüntzig balloon catheters (3.7 mm) with two lumina were formed. The first lumen was used for balloon inflation. Side holes to the second lumen proximally and distally to the balloon were created for coronary perfusion even during inflation phase. At a perfusion pressure of 120 mmHg, a flow rate of 63 +/- 3 ml/min with 0.9% saline and 43 +/- 1 ml/min with plasma expander were measured. In experiments on five dogs, dilation time until appearance of signs of ischemia could be prolonged in three of five dogs from 30 to 40 s, 120 to 203 s, and 180 to 420 s comparing conventional and CPC balloon catheters. In 11 patients with proximal lesions, dilation time could be increased from 39.5 +/- 23.9 s to 81.1 +/- 36.3 s (p less than 0.01) until appearance of angina pectoris. ST segment changes were observed in 10/11 patients using conventional catheters. Using CPC catheters, no ST segment changes were observed in four patients; time until appearance of ST segment changes was delayed in the other seven patients. The CPC catheter seems to be an alternative catheter in proximal lesions of the left and right coronary artery, allowing the possibility of prolonged dilation and increased safety to the patient. In case of dissection or perforation, the CPC catheter can be used for perfusion of the distal part of the coronary vessel until emergency bypass surgery.

[Improved occlusion tolerance time by continuous coronary perfusion with a modified Grüntzig coronary angioplasty catheter]. / Verbesserte Okklusionstoleranzzeit durch kontinuierliche Koronarperfusion mit einem modifizierten Grüntzig-Koronarangioplastiekatheter.

We evaluated the modified Grüntzig coronary angioplasty catheter, which allows for continuous antegrade coronary perfusion during balloon occlusion without the use of an external pump. During in vitro tests the flow rates for effective pressure differences between aorta and distal coronary vessel in the range between 25 and 100 mm Hg were determined. During in vivo tests in 10 dogs the effect of balloon occlusion with continuous perfusion (OM) was compared with conventional occlusion without perfusion (OC). The occlusion tolerance time (OTZ) as determined by the appearance of unequivocal signs of ischemia in the ECG, was 486 +/- 77 s for OM versus 256 +/- 82 s for OC with a relative, individual increase of 191 +/- 54% (p less than 0.01, data are given +/- SEM). Observed ST-elevation was less with OM than with OC (0.22 +/- 0.05 versus 0.33 +/- 0.06, p less than 0.05). Occlusion related pressure difference between aorta and occluded coronary vessel was less with OM than with OC (31 +/- 8 mm Hg versus 40 +/- 10 mm Hg, p = 0.05). In selected cases such a prolongation of the intracoronary balloon occlusion time may represent a distinct advantage.

[Normal values for two-dimensional echocardiography]. / Normalwerte für die zweidimensionale Echokardiographie.

In 51 normal subjects (26 men, 25 women, age range 15-38 years), normal values for longitudinal axis and diameters of left and right ventricle and left and right atrium were determined by 2-D echocardiography. Both left parasternal longitudinal and cross-sectional cuts were used. Tolerance values to determine normal range were recorded, in addition to mean values and standard deviations. Diastolic and systolic diameters (DD/DS) in the left parasternal longitudinal and cross-sectional cuts gave similar results to those in the 4-chamber view from the apex: DD 2.7 +/- 0.4 (2.3-3.1) cm/m2, DS 1.8 +/- 0.4 (1.4-2.2) cm/m2, and DD 2.7 +/- 0.4 (2.3-3.1) cm/m2, DS 1.7 +/- 0.3 (1.4-2.0) cm/m2, respectively. Sizes of the right ventricle (1.8 +/- 0.4/1.4-2.2 cm/m2) and right atrium (2.4 +/- 0.5/1.9-2.9 cm/m2) could only be obtained in the 4-chamber view. Values for the left atrium (2.3 +/- 0.7/1.6-3.0 cm/m2) were obtained also in the left parasternal cross-section. Correcting for body surface, differences between males and females were reduced to the extent that there was no significant difference between them. These normal values make it possible to standardize the measurement of intracardiac dimensions by 2-D echocardiography and classify individual values.