This study was undertaken to evaluate the effect of flecainie (Fle) and propafenone (Pro) on rest and exercise myocardial contractility after prolonged oral administration. Standardized, fully automated, gated radionuclide angiograms at rest and during maximum exercise were performed single blinded and prospectively in 19 patients before and after oral treatment with either 150 mg b.i.d. of Fle or 150 mg t.i.d. of Pro. The left ventricular ejection fraction (EF%) as a hemodynamic indicator presented as follows: (Table: see text) In general, there was no significant effect of either drug on resting ventricular function. In only one patient of the Fle group with decreased baseline function did the left ventricular EF fall from 40% to 29%. During exercise, ventricular performance showed deterioration in the Pro group, but, interestingly, improvement in the Fle group. As a result of these opposite changes, the effect of the two drugs on the exercise response of ventricular function was significantly different (P less than 0.05). This study thus gives first evidence that no significant cardiodepressive effects are to be expected after prolonged application of Fle or Pro in normal hearts. There might even be a mild beneficial effect on exercise performance after Fle.

The effect of a controlled-release formulation of isosorbide-5-mononitrate (IS-5-MN) was studied in patients with coronary heart disease (CHD), with the aim of comparing the acute effect with that after chronic administration on parameters of ischemia. To determine whether any tolerance developed, several aspects of ischemia were observed: ECG signs, clinical parameters, and left ventricular function. Fifteen patients with angiographically proven CHD were examined with 12-lead exercise ECG before, 2 h and 4 h after the first dose and after 10 days of therapy with 60 mg IS-5-MN (Coleb-Duriles) once daily. After 7 days, three radionuclide ventriculographies were performed: control, 2 h after nitrate and 2 h after 75 mg gallopamil. Plasma concentrations of IS-5-MN were measured before every exercise test. The results showed a reduction of total ST-segment depression from 0.59 mV to 0.29 mV after 2 h (NS) and 4 h (P < 0.05) on the Ist day and from 0.48 mV to 0.32 mV (P < 0.05) and 0.31 mV (NS) after 10 days. The severity of angina pectoris was diminished by about 50%. The effect on exercise duration and time to ST-segment depression by more than 0.1 mV remained unchanged after 10 days, whereas the effect on blood pressure, heart rate and time to onset of angina was attenuated. The mean decrease in ejection fraction (EF) from rest to exercise was reduced from —5.9% to — 1.9% (P < 0.05) after nitrate, while an increase of + 1.4% was seen after gallopamil (P < 0.01). Regional wall motion analysis revealed functional improvement especially in the ischemic segments of the left ventricle. Plasma concentrations of IS-5-MN were 14.7, 317 and 359 ng/ml on the first day, 94.2, 432 and 408 ng/ml after 7, and 104, 420 and 420 ng/ml after 10 days. We conclude that ST-segment depression and angina pectoris are reduced by 60 mg controlled-release IS-5-MN after the first dose and after a once-a-day therapy for 10 days to a comparable degree. Analysis of global and regional function after 7 days demonstrates an anti-ischemic effect of IS-5MN; gallopamil leads to further improvement. Plasma concentrations of IS-5-MN vary during 24 h, which prevents the development of tolerance. The plasma concentration 24 h after the last nitrate dose seems to exert a small anti-ischemic effect.

The value of the four main imaging tools: radiology, magnetic resonance imaging, echocardiography and nuclear cardiology depends in the first place on physical properties which determine the spatial, temporal and density resolution and second on the conditions under which the relevant information can be obtained with respect to the diagnostic or therapeutic problem, the comfort of the investigation, the degree of invasivity and the expenses. For several decades radiology was the only available method that allowed a look into the body. Thereby, all relevant information about diseases amenable to any surgical or conservative therapy could be attained. Parallel to the progress of cardiovascular surgery, angiocardiography could provide the anatomic and functional characteristics of congenital and acquired heart diseases. The basic principles for the measurement of total heart size, volume and shape were established already before contrast injection--initially by hand--showed the internal architecture of the heart cavities and the circulatory system. With the invention of film changers, the fundamental knowledge about all kinds of malformations of the heart and vessels was gained. Further technical progress made the procedures faster by cineangiocardiography, more comfortable by simultaneous biplane operation and easier to handle by videotechniques, allowing electronic data processing, storage and retrieval in bright operating theaters. Computer technology favored flexible image processing which, like digital subtraction and functional angiocardiography, could reduce the amount of contrast material to be injected and thereby improve the compatibility, due to better nonionic contrast material and shorter study times. Finally, computer tomography with cross sectional, or spiral data collection enabled a dynamic three-dimensional reconstruction and visualization of the beating heart and to display selected information in 'measures and numbers'. Inspite all these successes, the 'stain' of invasivity remains. Strong competition arose first in echocardiography, which--after some pioneering activities in Germany in the late 1950s--flourished in the 1970s, after being reimported from the US. Most of the rapidly increasing number of ultrasound technologies--from M-mode, via various 2D linear and sector scanning procedures in combination with continuous, pulsed and/or color Doppler methods, new contrast-echo modalities and finally 3D volume scanning procedures--can be applied without any harm in all age groups and from each competent practitioner with comparably small and cheap equipment. Only oesophageal and intravascular approaches retain a touch of invasivity. Consequently not much room remains for other techniques except those, like MRI, which can differentiate tissue properties better and with higher resolution and give unlimited access to all intrathoracic organs noninvasively. Under these conditions the indications for nuclear cardiology are restricted to the small field of myocardial perfusion and metabolic studies, whereas transit time measurements and radionuclide ventriculography are practically obsolete.

A data base of clinical studies is required for quality assurance of software used for analysis of radionuclide cardiac imaging procedures. Studies used must be rigorously validated in terms of both the clinical condition of the patient undergoing the procedure and the imaging protocol used. Selection protocols for the creation of a software phantom data base of normal studies and three typical patterns of cardiac disease--recent transmural myocardial infarction, isolated myocardial ischaemia and dilated cardiomyopathy--have been developed by the Cardiac Working Group of the European COST B2 project in association with the Cardiac Task Group of the European Association of Nuclear Medicine and the Working Group on Nuclear Cardiology of the European Society of Cardiology. These protocols include criteria for the interpretation of qualitative and quantitative non-radionuclide data. Compliance of the clinical data with the selection criteria will have to pass scrutiny by an international team for each study used as a software phantom. The radionuclide studies encompass stress and rest myocardial perfusion studies (planar and single photon emission tomography) using thallium-201 and technetium-99m methoxyisobutylisonitrile and rest gated blood pool studies. Methods for acquisition of data are defined for each type of study and for each individual study a portfolio of all clinical data is established. A pilot study is required to investigate the problems and logistics of distributing clinical radionuclide studies between a range of computers and institutes, and to ascertain the procedures necessary for analytical comparison of the results obtained.

A new tomographic technique combined with phase analysis was used to detect premature and ectopic ventricular contraction patterns in 15 patients with Wolff-Parkinson-White syndrome and during ventricular tachycardia in seven patients. Data generated by gated single-photon emission computed tomography (SPECT) were analysed by backprojection of the Fourier coefficients, double-angulation, and integration to thick slices containing the ventricles, thus allowing visualisation of the contraction patterns in three perpendicular views. The results were compared with those of catheter mapping. In nine patients with Wolff-Parkinson-White syndrome the site of initial contraction detected was identical with the site of the accessory pathway found by catheter mapping. The sites of origin of the ventricular tachycardias determined by catheter mapping were within 3 cm of the sites detected by the new technique. This new technique seems to be a promising non-invasive method for localising ectopic ventricular activity that will considerably shorten the time required for subsequent invasive procedures.

Arrhythmogenic substrate diagnosis has been achieved by electrophysiological studies and best localized by successful radiofrequency ablation. Pre-invasive localization procedures have been based on surface ECGs and more recently on biomagnetism, but in addition to these electric and magnetic signals a mechanical signal may be utilized: the initial site of contraction may be detected by phase analysis during radionuclide ventriculography. Generation of three-dimensional data set of phases is achieved by incorporating the new emission tomography technique. The performance of this modified phase analysis has been investigated for the detection of the normal contraction pattern during sinus rhythm, the arrhythmogenic substrate of the WPW syndrome and ventricular tachycardia, and further, to define the limitations of the method in experimental studies on pigs. In 30 out of 44 patients with normal sinus rhythm and no ventricular lesion, a characteristic phase pattern was found. Physiologically, the initial site of contraction appeared to be paraseptal and in the anterior wall of the right ventricle close to the apex. In 13 patients with WPW syndrome and in seven with ventricular tachycardia, the phase data were compared to the electrophysiological study. In 14 of 20 there was a complete match, in 3 of 20 a mechanical focus was found in the area adjacent to the electric focus. From experimental pig studies with simulated stimulation, a spatial precision of at least 20 mm was found at a pre-excitation of 20 ms.(ABSTRACT TRUNCATED AT 250 WORDS)

Since catheter or surgical techniques for ablating the arrhythmogenic substrate in patients with SVT due to accessory pathways or those with VT are now available, exact localization of the substrate is mandatory. We report preliminary results of two new non-invasive techniques for localizing either the site of earliest ventricular contraction using ISPECT, or the site of initial ventricular depolarization by magnetocardiography (MCG) in WPW syndrome and in VT patients.

Currently the images of nuclear medicine institutions are stored on magnetic media. The documentation is done with hardcopies. Officially magnetic media are not accepted for documentation purpose and hardcopies do not allow further processing. The access to the original data is time consuming and personal intensive. There is a demand to store at least the original information cheaply, safely and direct accessibly. The appearence of the optical disks together with a jukebox facilitates digital archives at least for nuclear medicine. As a prerequisit it is necessary to connect all imaging devices through its data systems within a nuclear medicine institution to a local area net (LAN) forming a PACS (Picture Archiving and Communication System) Data compatibility must be fulfilled as well as a positive patient identification. Quality controls must provide for data security and reliability. An effective retrieval system must serve for fast access to the archives. PACS and RIS (Radiological Information System) must built a unified system. Such a local net in addition should be connected to the HIS (Hospital Information System) in order to reduce the administration work in nuclear medicine. A prototype of a nuclear medicine system is in use at the University of Ulm since 1988, wich will be hooked to the HIS in 1990. Since PACS currently is developed mainly for the other modalities (CT, MR, DSA, DR) through the industry, nuclear medicine should participate in this development with its particular needs.

The quantification of myocardial perfusion abnormalities is necessary to allow comparison of repeated studies, especially in the evaluation of the success of medical, interventional or combined treatment in stable coronary artery disease or in evolving myocardial infarction. The purpose of this study was to assess inter-observer reproducibility of tomographic study processing using a semi-automatic quantitative programme. Technetium 99m hexakis-2-methoxyisobutylisonitrile (99mTc-Sestamibi) was chosen for tomographic imaging of repeated rest-stress studies in patients with stable coronary artery disease. The quantification was performed using a modification of the Cedars polar coding and comparison with the normal data base. The perfusion defects were quantified separately for each standard perfusion area [left anterior descending (LAD), right coronary (RCA) and left circumflex (LCX) arteries] and total area of hypoperfused myocardium. The inter-observer variability for 40 tomographic studies was accomplished. The defects were the largest in the LAD perfusion area (average 19.7% of the normalized LAD supply area) with an inter-observer correlation of 0.84 for this region. The greatest variability was found for the LCX region (r = 0.55) and is attributed to a small average perfusion defect (7.1%), only 18 studies having abnormal perfusion in this area. In total, an average 14.3% of the left ventricular myocardium was significantly hypoperfused, and the inter-observer correlation was 0.87. These results show good inter-observer reproducibility using semi-automatic quantitation of perfusion defects. Careful interpretation of smaller defects in the evaluation of treatment results is advised when repeated 99mTc-Sestamibi single photon emission tomography studies are processed by more than one observer.

The upward creep of the heart during myocardial single photon emission tomography (SPET) acquisition has been reported as a frequent source of false-positive results. The aim of this study was to simplify the detection and correction of this upward creep and to estimate its clinical relevance during routine patient care. To recognize the upward heart motion a straight line was fitted to the upper and lower border of consecutively displayed tomographic projection images. In this way, vertical translation of at least 1 pixel in size could be detected easily. On the assumption of a slow but continuous upward motion a fast interpolation correction method was developed. From 100 consecutive, supine, ergometric exercise studies, 1, 2 or 3 pixels of upward creep were found in 16, 4 or 3 patients, respectively. It was found that an upward creep of at least 2 pixels (7/100 cases) led to evident, mostly antero-septal defects on quantitative bull's-eyes, whereas only upward creeps of 3 pixels or more (3/100 cases) produced false-positive diagnostic results. The simple correction method offered a sufficient compensation of image and/or bull's-eye artefacts. These clinical findings could be reproduced in a computer model. Thus, it can be stated that clinically significant upward creep of the heart during stress SPET acquisition is relatively rare; it may have been overestimated in the past, and its artificial effects can be corrected by a quick and simple algorithm.

Timing of aortic valve replacement (AVR) in chronic aortic regurgitation (AR) remains a difficult problem in clinical practice. Radionuclide ventriculography (RNV) yields information on the extent of valvular regurgitation, the enlargement and the systolic function of the left ventricle. A “well-timed” AVR is defined by 1) postoperative improvement of clinical symptoms, decrease in left ventricular enddiastolic volume (EDV) and normalization of ejection fraction (EF) as well as by 2) greater improvement under surgical therapy as compared to conservative management. In “too early” AVR the latter condition is not fulfilled, while in “too late” AVR the first condition is not accomplished. In this study 54 patients with chronic aortic incompetence were evaluated by RNV to see whether these three groups (“too early”, “well-timed”, “too late” AVR, resp.) can be separated by the relation between EDV and regurgitant volume (RV), the level of the EDV and the clinical status. The examination was based on pre- and postoperative RNV studies as well as on follow-up studies. A good postoperative result can be expected in cases with a preoperative EDV/RV- ratio similar to that observed in 30 patients with AR in whom AVR was not indicated. In contrast, in the majority of those cases with an EDV/RV-ratio exceeding this normal range the postoperative outcome will be unsatisfactory. If the EDV/RV-ratio is normal, AVR should be performed in cases with an EDV exceeding 400 ml, while in cases with an EDV between 300 and 400 ml AVR is only indicated in the presence of additional symptoms (NYHA > II). In general, AVR is not required in AR patients with an EDV below 300 ml. In cases with an EDV > 300 ml and an EDV/RV-ratio exceeding the normal range, AVR should not be deferred though the postoperative result may be unsatisfactory especially in cases with long-standing left ventricular dysfunction.

A carbon-14 (14C) urea breath test for detecting Helicobacter pylori with multiple breath sampling was developed. Carbon-14-urea (110 kBq) administered orally to 18 normal subjects and to 82 patients with Helicobacter infection. The exhaled 14C-labeled CO2 was trapped at 10-min intervals for 90 min. The total 14C activity exhaled over 90 min was integrated and expressed in %activity of the total dose given. In normals, a mean of 0.59% +/- 0.24% was measured, resulting in an upper limit of normal of 1.07%. In 82 patients, a sensitivity of 90.2%, a specificity of 83.8%, and a positive predictive value of 90.2% was found. The single probes at intervals of 40-60 min correlated best with the integrated result, with r ranging from 0.986 to 0.990. The test's diagnostic accuracy did not change at all when reevaluated with the 40-, 50-, or 60-min sample data alone. Thus, the 14C-urea breath test can be applied routinely as a noninvasive, low-cost and one-sample test with high diagnostic accuracy in detecting Helicobacter pylori colonization.

Timing of aortic valve replacement (AVR) in chronic aortic regurgitation (AR) remains a difficult problem in clinical practice. Radionuclide ventriculography (RNV) yields information on the extent of valvular regurgitation, the enlargement and the systolic function of the left ventricle. A "well-timed" AVR is defined by 1) postoperative improvement of clinical symptoms, decrease in left ventricular end-diastolic volume (EDV) and normalization of ejection fraction (EF) as well as by 2) greater improvement under surgical therapy as compared to conservative management. In "too early" AVR the latter condition is not fulfilled, while in "too late" AVR the first condition is not accomplished. In this study 54 patients with chronic aortic incompetence were evaluated by RNV to see whether these three groups ("too early", "well timed", "too late" AVR, resp.) can be separated by the relation between EDV and regurgitant volume (RV), the level of the EDV and the clinical status. The examination was based on pre- and postoperative RNV studies as well as on follow-up studies. A good postoperative result can be expected in cases with a preoperative EDV/RV-ratio similar to that observed in 30 patients with AR in whom AVR was not indicated. In contrast, in the majority of those cases with an EDV/RV-ratio exceeding this normal range the postoperative outcome will be unsatisfactory. If the EDV/RV-ratio is normal, AVR should be performed in cases with an EDV exceeding 400 ml, while in cases with an EDV between 300-400 ml AVR is only indicated in the presence of additional symptoms (NYHA greater than or equal to II).(ABSTRACT TRUNCATED AT 250 WORDS)

Gated SPECT (GASPECT) during radionuclide ventriculography (RNV) is a time-consuming procedure requiring extended hard- and software. Furthermore, the procedure suffers from poor count statistics. Our method tries to overcome these difficulties by exploiting the count summation effect of Fourier analysis. The sine and cosine coefficients of the first harmonic are extracted from the gated views and reconstructed. This, in fact, results in an improvement of the count statistics by a factor of four combined with a tremendous reduction of disc space requirements. Using short-axis slices, bull's-eye plots of the amplitude and phase of the left ventricle are calculated. Cardiac functions and localization and extent of any malfunction are documented three-dimensionally without superposition.

The suitability of a 3-dimensional filter in diminishing the statistical noise of left ventricular volume curves without any systematical error in the left ventricular ejection fraction (EF) was investigated. The EF values were compared in 50 studies on 24 patients. There was no significant systematical difference between the EFs before and after filtering. The filter diminishes the statistical uncertainty of the EF by a factor of 0.47. Therefore, the method may possibly be employed in processing the left ventricular volume curves.

The suitability of a 3-dimensional filter in diminishing the statistical noise of left ventricular volume curves without any systematical error in the left ventricular ejection fraction (EF) was investigated. The EF values were compared in 50 studies on 24 patients. There was no significant systematical difference between the EFs before and after filtering. The filter diminishes the statistical uncertainty of the EF by a factor of 0.47. Therefore, the method may possibly be employed in processing the left ventricular volume curves.

Die Vielzahl der nuklearmedizinischen Geräte hat sich heute im Wesentlichen auf die vielseitig einsetzbare Gammakamera reduziert. Das Spektrum der Untersuchungen reicht von einfachen statischen Szintigrammen bis zu höchst komplizierten Methoden wie bei einer gegateten SPECT-Untersuchung [1]. Unerlässlich ist dabei das nuklearmedizinische Datensystem, welches nach wie vor praktisch nur zur Bilderfassung, -verarbeitung und -dokumentation herangezogen wird. Es handelt sich meistens um Single-User-Systeme eventuell mit Foreground/Background-Betrieb. Sie sind für ihre Aufgaben, der Echzeitbilderfassung und -verarbeitung ausgelegt. Werden mehrere Gammakameras in einer Abteilung verwendet, so wird meistens ein Rechner pro Kamera eingesetzt, was oft zu einer heterogenen DV-Ausstattung führt.

In planar radionuclide ventriculography (RNV) identification of the site of initial contraction is possibly by the Fourier phase. First clinical experiences will be presented with a new integrated tomographic technique--ISPECT--in noninvasively assessing the site of ectopic or premature ventricular depolarization. In six patients Fourier phases of RNV and ISPECT were performed and compared in five with results from the corresponding electrophysiologic study. It was possible to exactly localize the beginning of mechanical contraction in the two orthogonal planes: during pacemaker stimulation at the apex of the right ventricle, at the lateral border of a large aneurysm during ventricular tachycardia, and at the site of three of five WPW bundles. In the other two bundles the site of first contraction was near the area found during invasive mapping procedure. Thus, this new ISPECT approach together with planar radionuclide imaging may help in noninvasively localizing the site of ectopic and premature depolarization in addition to surface ECG.