The German National Pandemic Cohort Network (NAPKON): rationale, study design and baseline characteristics

The German government initiated the Network University Medicine (NUM) in early 2020 to improve national research activities on the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic. To this end, 36 German Academic Medical Centers started to collaborate on 13 projects, with the largest being the National Pandemic Cohort Network (NAPKON). The NAPKON’s goal is creating the most comprehensive Coronavirus Disease 2019 (COVID-19) cohort in Germany. Within NAPKON, adult and pediatric patients are observed in three complementary cohort platforms (Cross-Sectoral, High-Resolution and Population-Based) from the initial infection until up to three years of follow-up. Study procedures comprise comprehensive clinical and imaging diagnostics, quality-of-life assessment, patient-reported outcomes and biosampling. The three cohort platforms build on four infrastructure core units (Interaction, Biosampling, Epidemiology, and Integration) and collaborations with NUM projects. Key components of the data capture, regulatory, and data privacy are based on the German Centre for Cardiovascular Research. By April 01, 2022, 34 university and 40 non-university hospitals have enrolled 5298 patients with local data quality reviews performed on 4727 (89%). 47% were female, the median age was 52 (IQR 36–62-) and 50 pediatric cases were included. 44% of patients were hospitalized, 15% admitted to an intensive care unit, and 12% of patients deceased while enrolled. 8845 visits with biosampling in 4349 patients were conducted by April 03, 2022. In this overview article, we summarize NAPKON’s design, relevant milestones including first study population characteristics, and outline the potential of NAPKON for German and international research activities.

Trial registrationhttps://clinicaltrials.gov/ct2/show/NCT04768998.https://clinicaltrials.gov/ct2/show/NCT04747366.https://clinicaltrials.gov/ct2/show/NCT04679584

The Role of Rheology in Hemapheresis

Rheological therapy attempts to favorably influence the blood flow mechanics for the treatment of diseases, mainly of the microcirculation but also of the macrocirculation. Hemapheresis, originally used only for the elimination of an excess of cellular or plasmatic components, was shown to also influence the hemorheology favorably. As extracorporeal therapy affects the rheology much more than conventional hemorheotherapy, not only cellular or plasmatic hyperviscosity syndromes but also many more diseases associated with organ perfusion problems due to diseases of the micro- and macrocirculation, especially in the elderly, were and are increasingly considered to be indicated. Technical progress led away from plasma exchange as an unspecific and unselective procedure to plasma differential separation using precipitation. adsorption, and filtration. With our recent development, we demonstrated that rheohemapheresis is the most advanced technical procedure. The mechanism of action can well be related to a synergetic consideration of rheology. However. one has to keep in mind that the elimination of blood components such as lipids, immunoglobulins, and endothelial factors may well contribute to the explanation and understanding of the positive clinical effects observed. These speculative aspects need further investigation.

The current state of extracorporeal haemorheotherapy: from haemodilution via cascadefiltration to rheohaemapheresis

Rheological therapy aims at an improvement of organ perfusion however, it has to be stressed that the tonus of the blood vessels also plays an important role for both the blood distribution and the rheology in the micro- and the macrocirculation. Conventional rheotherapy consists of attempts to influence nutrition and life style, to apply drugs such as purin derivatives, vasodilatating or defibrinising substances and hypervolaemic (using infusion therapy), hypovolaemic, e.g., blood letting, erythrocytapheresis and--the most widely distributed- -isovolaemic haemodilution. With the introduction of centrifugal devices, and approximately 10 years later with the introduction of hollow fibre and flat sheet membrane techniques, a considerable increase of therapeutical efficacy was achieved. These technologies were successfully applied for the treatment of cellular and plasmatic hyperviscosity syndromes. The treatment of less severe diseases of the micro- and macrocirculation, vessel stenosis, vessel wall sclerosis, malformation of the blood vessel architecture, pathological clinical-chemical blood parameters and maldistribution have hardly been taken into consideration. Our group at Köln investigated different plasma differential separation techniques and demonstrated, that adsorption as well as filtration could be applied. These different techniques being 6-10 times more effective as conventional haemodilution techniques have in common high molecular weight proteins determining the viscosity of plasma and thus whole blood viscosity is removed, however differences among the different elimination techniques do exist. The rheological and clinical importance of such differences has to be determined. Applying filtration techniques for both primary and secondary separations, the concept of Rheohaemapheresis was developed. A corresponding quality program was also introduced into our clinical routine. Rheohaemapheresis is supported from the currently introduced concept of the synergetic consideration of the microcirculation. Age related macular degeneration, so far without generally accepted therapy, is a most advanced indication based on several pilot studies and a prospective, randomised controlled trial. Other diseases of the microcirculation have also successfully been treated.

Ergebnisse der systemischen Lysetherapie mit ultrahoch dosierter Streptokinase bei tiefen Beinvenenthrombosen

Erfolgskriterien und Komplikationsraten sind in den publizierten Studien zur Lysetherapie von Beinvenenthrombosen (TVT) sehr unterschiedlich. Wir beschreiben unsere Ergebnisse mit ultrahoch dosierter Streptokinase (UHSK) bei standardisierter externer Erfolgsbewertung. Methoden: 90 Patienten (60 Männer, 30 Frauen, mittleres Alter 50,5 Jahre) mit TVT (Alter 4,0 ± 4,1 Tage, 1 Etage 4, 2 Etagen 12, 3 Etagen 61, 4 Etagen 13) erhielten täglich 9 Mio. E Streptokinase (SK) über im Mittel 3,1 Tage. Nach drei Zyklen und nach Abschluß erfolgten Kontroll-Phlebographien. Ergebnisse: Eine Vollrekanalisation ergab sich bei 41 (45,6%), eine Teilrekanalisation bei 24 (26,7%). Fieber (47,8%) und leichtere Hautblutungen (43,3%) waren häufig. Bei 7 Patienten wurde die Therapie wegen einer Blutung abgebrochen. Eine zerebrale Blutung oder ein tödlicher Ausgang wurden nicht beobachtet. Schlußfolgerung: Die UHSK-Lyse der TVT hat auch außerhalb von Studien und bei unabhängiger Bewertung der Ergebnisse eine Erfolgsrate von 72,3% bei einer relativ hohen Blutungsrate. Ob die geschätzte Reduktion des postthrombotischen Syndroms von 35% tatsächlich zu erreichen ist, müssen prospektive Studien zeigen.

[High-dose Crataegus extract WS 1442 in the treatment of NYHA stage II heart failure]

The efficacy and tolerance of the standardized hawthorn (crataegus) extract WS 1442 were tested in a multicenter utilization observational study. We monitored 1,011 patients with cardiac insufficiency stage NYHA II, treated with this extract (Crataegutt novo 450, 1 tablet b.i.d.) over a period of 24 weeks. During and at the end of the observation period a significant improvement in clinical symptoms (reduced performance in the exercise tolerance test, fatigue, palpitation and exercise dyspnea) was observed. Ankle edema and nocturia disappeared by 83%, and by half of the patients respectively manifesting these symptoms before treatment. The improvement and economization of cardiac performance were additionally shown by a reduction in blood pressure, an increased maximal exercise tolerance and a reduction in the difference in the pressure/heart rate product (PHRP). The positive effects of WS 1442 were further demonstrated by an improved ejection fraction and an increased percentile shortening fraction measured using M-mode echocardiography. The stabilizing effect of the hawthorn extract on the heart rate was shown by a slower rest pulse, as well as by an increase in the number of day and night normorhythmic patients, as documented by long-term ECG. The reduction in the number of patients showing ST depressions, arrhythmias and ventricular extrasystoles at the maximum exercise level is regarded as an indication for an improved myocardial perfusion. Fourteen side effects were noted. In two cases (abdominal discomfort and facial pains accompanied by tachycardia) a possible relationship with the hawthorn therapy, was postulated which however was considered unlikely by the treating physicians. Almost 2/3 of the patients felt better or much better following the 24 weeks of treatment. More than 3/4 of the participating physicians noted a good or a very good efficacy, and 98.7% noted a good or a very good tolerance. High-dose hawthorn therapy is an efficient, well-tolerated and easily regulated therapeutic alternative for patients suffering from cardiac insufficiency stage NYHA II.

[Fibrinolytic therapy of deep vein thrombosis]

BACKGROUND

The most important complications of deep vein thrombosis are pulmonary embolism and postthrombotic syndrome. While the medicine of lethal pulmonary embolism is reduced to less than 2% by conventional anticoagulation, fibrinolytic therapy aims at a reduction of the greater than 50% incidence of postthrombotic syndrome. The optimal therapeutic regimen concerning risks and effect has not been established yet.

RESULTS

A review of 26 studies involving ultrahigh-dose streptokinase (UHSK), urokinase (UK), and tissue-type plasminogen activator (rt-PA) shows the highest success rate for UHSK (45% complete and 40% parital patency), whereas there are lower rates for UK (25% and 40%) and low-dose locoregionally applied rt-PA (22% and 44%). The studies were not directly comparative, however. Published data concerning complications range from 1.7% mortality for UHSK to 0.9% for UK and 0.0% for rt-PA. Success criteria, however, are varying and not well defined. The influence of fibrinolytic therapy on the incidence of postthrombotic syndrome has not been established prospectively, but a reduction by 40 to 50% can be assumed. Calf vein thromboses are not indication for lytic therapy. In patients with iliacal vein thromboses there is an increased risk of pulmonary embolism using UHSK.

CONCLUSIONS

UHSK can be regarded the standard concerning success rate in deep vein thromboses. DATA involving locoregional therapy with rt-PA are inconsistent and worse, but bleeding complications might be less frequent. Large prospective studies evaluating the impact on incidence and severity of the postthrombotic syndromes, which involve a controlled application of compression therapy are needed.

[Congenitally corrected transposition of the great vessels in adulthood. The value of noninvasive study methods]

A 57-year-old man with a cough and increasing exertional dyspnoea for the past 6 weeks was found on examination to have a loud systolic murmur and cardiomegaly with pulmonary congestion. Echocardiography revealed congenitally corrected transposition of the great arteries (cTGA: atrioventricular and ventriculoarterial discordance): a morphologically right ventricle with a tricuspid valve on the left, a morphologically left ventricle with bicuspid a-v valve on the right, the aorta arising ventrally from the left-sided (morphologically right) ventricle. The tricuspid valve showed an Ebstein-like anomaly with obvious regurgitation. Transoesophageal and contrast echocardiography defined valvar anatomy, attachment of the great arteries and cardiac chambers to the venous and arterial circulations, as well as absence of a left to right shunt. Angiography revealed a coronary anatomy typical for cTGA. The exertional dyspnoea responded to diuretics and low doses of ACE inhibitor. Follow-up monitoring of the valvar regurgitation and appropriate endocarditis prophylaxis were recommended. As the haemodynamics in cTGA is normal, in the absence of additional anomalies, it is a congenital cardiac defect which can, though rarely, present first in adulthood. Life expectancy depends on the nature of any additional defects and the degree of commonly associated tricuspid valve regurgitation. As this case demonstrates, echocardiography can largely define the anomalies.

Slow release isosorbide-5-mononitrate therapy in angina pectoris. Effects of exercise performance and hemodynamics

The possibility of maintaining preload reduction and enhancement of exercise tolerance during an interval treatment with 100 mg/day of slow-release isosorbide-5-mononitrate (IS-5-MN) was investigated in 12 patients (aged 57 +/- 5.0 years) with angiographically confirmed coronary artery disease and chronic stable angina pectoris. The effects of a single dose (acute test) were compared with those following an 8-day (chronic) regimen of mononitrate administration. Two hours after administration of 100 mg sustained-release IS-5-MN, mean resting pulmonary artery pressure (PAP), measured with a Swan-Ganz catheter, was reduced by 32% (p less than 0.001) and at submaximal exercise level (50 W, 3 min) by 37% (p less than 0.001). At individually highest comparable work loads mean PAP was reduced by 37% (p less than 0.001), and at maximal work load the PAP reduction was 14% (p less than 0.05). At the end of 1 week of therapy with sustained-release IS-5-MN a slight, clinically irrelevant reduction of hemodynamic effect was recorded. Work capacity increased after 1 h by 79% (264 +/- 154 vs. 472 +/- 180 W x min, p less than 0.01), still significantly above base-line 10 h after nitrate administration. No difference from baseline was demonstrable 24 h after medication. During interval therapy the improved work capacity was fully maintained (chronic, 1 h: 280 +/- 119 vs. 532 +/- 160 W x min, p less than 0.001). There was no significant difference between the plasma IS-5-MN levels at acute and chronic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemodynamics and differentiated CO transfer following fulminant lung embolism and pulmonary artery embolectomy and following recurrent lung embolism]

Pulmonary embolectomy as an emergent surgical treatment after massive pulmonary embolism often is necessary in cardiogenic shock (CS) and even without previous diagnostic. If complete dissolution of the thromboembolus is possible or spreading of microemboli may occur is unknown. Therefore we studied 21 patients surgically treated by embolectomy, ten of these with consecutive cardiogenic shock (CS) and twelve patients after repetitive microembolism and cava-blocking. Besides lung-functional parameters for special CO-diffusion capacity (DLCO), differentiated in membrane (DM) and vascular (VC) component (Roughton and Forster), we measured mean pulmonary artery pressure (PAP) at rest and at exercise. Patients after repetitive embolism showed considerably more diminution of DLCO (-31%) than those after single massive embolic event (-15%) even concomitant by CS (-10%). Repetitive microembolism lowered VC by 21%. Slight decrease of DM was found after CS. Mean pulmonary artery pressure was elevated at rest (26 mm Hg) and exercise (33 mm Hg) after repetitive microembolism and normal after massive embolism or CS. Pulmonary embolectomy may prevent disturbances of DLCO or PAP even after CS. Damage of vascular integrity (VC) was found after microembolism. Pulmonary embolectomy seems to remove total embolic material and therefore seems to be optimal.

Interval treatment of coronary artery disease with sustained-release isosorbide-5-mononitrate

The possibility of maintaining preload reduction and enhancement of exercise tolerance during an interval treatment with 50 mg/day of sustained-release isosorbide-5-nitrate (IS-5-N) was investigated in 13 patients (aged 54.4 +/- 7.9 years [mean +/- standard deviation]) with angiographically confirmed coronary artery disease and chronic stable angina pectoris. The effects of a single dose (acute test) were compared with those following an 8-day (chronic) regimen of mononitrate administration. Two hours after administration of 50-mg sustained-release IS-5-N, mean resting pulmonary arterial pressure (PAP), measured with a Swan-Ganz catheter, was reduced by 27% (p less than 0.01), and at submaximal exercise level (50 W, 3 minutes) by 34% (p less than 0.001). At individually highest comparable work loads mean PAP was reduced by 28% (p less than 0.01), and at maximal work load the PAP reduction was 21% (p less than 0.05). At the end of 1 week of therapy with sustained-release IS-5-N a slight, clinically irrelevant reduction of hemodynamic effects was recorded. Work capacity increased after 1 hour by 60% (408 +/- 104 vs 653 +/- 147 W x min, p less than 0.001)--still significantly above baseline 10 hours after nitrate administration. No difference from baseline was demonstrable 24 hours after medication. During interval therapy the improved work capacity was fully maintained (chronic, 1 hour: 417 +/- 93 vs 679 +/- 160 W x min, p less than 0.001). During interval therapy with sustained-release IS-5-N, hemodynamics and exercise tolerance were durably improved.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute effect of various doses of isosorbide-5-mononitrate on hemodynamic and exercise performance in coronary artery disease

The optimal dose of nitrates is still controversial, as chronic usage of too high a dose may result in a decrease in vascular response. The dose should be determined to reduce preload acutely, and not to decrease the activity during chronic therapy. To determine this dose, 50 patients with angiographically confirmed coronary artery disease were studied. The effects on heart rate and mean systemic and pulmonary arterial pressures at rest and during exercise, and work capacity and duration were measured. The patients were classified into 5 groups, receiving placebo or isosorbide-5-mononitrate, 5, 10, 20 and 50 mg, respectively, as a single oral dose. Placebo had no effect on the measured parameters. All doses of isosorbide-5-mononitrate reduced mean pulmonary arterial pressure: 10 mg--by 16% at rest and 24% during exercise; 20 mg--24% and 34%, respectively (a near maximal effect); and 50 mg--27% and 38%. Similar results were found also for work capacity: 10 mg increased work capacity by 33%; 20 mg--79%; and 50 mg--56%. Thus, the therapeutically optimal single dose is about 20 mg. Higher doses produce no additional benefit and increase the risk for tolerance development.

Acute and chronic effects of molsidomine on pulmonary artery pressure and work capacity in patients with coronary heart disease

To test the clinically supposed development of tolerance during chronic molsidomine therapy we studied a total of 11 patients with angiographically-proven coronary heart disease at rest and during ergometric exercise (supine position; submaximal, i.e. 50 W for 3 min, and maximal exercise). Pulmonary arterial pressure (PAPmean, floating catheter), arterial blood pressure (RR, cuff method), work capacity (W x min) and duration of exercise loading (sec) were measured at rest and on exercise before and during chronic (4 weeks) oral therapy with 3 x 4 mg day-1 of molsidomine. Acute administration of 4 mg molsidomine reduced the mean arterial resting pressure by 12% and under submaximal exercise loading by 8%. After molsidomine, the PAPmean was reduced by 35% at rest; following a period of treatment of 4 weeks no significant decrease in efficacy could be discerned (PAPmean reduction by 31%). Under submaximal and maximal exercise the PAPmean dropped by 44% and 37%, respectively (35.5 +/- 6.7 cf. 19.9 +/- 4.5 mmHg; 39.2 +/- 6.5 cf. 24.8 +/- 7.0 mmHg), whilst simultaneously the work capacity increased by 93% (281 +/- 108 cf. 545 +/- 254 W x min). After 4 weeks treatment with 12 mg day-1 of molsidomine, the PAPmean of 22.4 +/- 6.6 mmHg and 30.1 +/- 9.9 mmHg under identical exercise loading conditions, remained significantly below the exercise load value prior to the onset of medication. The molsidomine-induced increase in the exercise tolerance was maintained throughout the long-term medication (537 +/- 268 W x min). With a four-week treatment with daily doses of molsidomine there was a persistent effect on the pulmonary arterial pressure and the work capacity. Thus development of tolerance during high dose, long-term molsidomine therapy is not to be expected.

Beneficial effects of intracoronary nifedipine during percutaneous transluminal coronary angioplasty

In twelve patients with coronary heart disease and hemodynamically significant coronary artery stenoses (LAD: 11, LAD plus RCA: 1) the effect of intracoronary nifedipine, 0.2 mg, on PTCA-related myocardial ischemia was evaluated. The severity of angina pectoris during balloon inflation was not significantly reduced by nifedipine, whereas the sum of ST segment alterations in Einthoven and Goldberger leads on inflation was significantly decreased by the drug. Before inflation intracoronary nifedipine lowered the systolic arterial blood pressure significantly, whereas diastolic and mean aortic pressure and heart rate remained unchanged. At the end of the inflation period heart rates were significantly faster after nifedipine, and the heart rate-blood pressure product higher with nifedipine. No significant correlations could be calculated between the extent of ST segment alterations and any of the hemodynamic parameters. From our results we conclude that, besides the possibility of ventricular afterload reduction, the beneficial cardioprotective effect of intracoronary nifedipine may mainly be attained by the local "cardioplegic" action of this substance.

[Endocardial cardioversion--a new method for treating recurrent ventricular tachycardia]

The effect of endocardial cardioversion was investigated in 17 patients (aged 26-76 years), ten of them with ventricular tachycardia, either spontaneous or initiated by programmable stimulation. During a total of 14 days of observation there were 33 episodes of spontaneous or induced ventricular tachycardia. A special cardioverter catheter had been placed into the right ventricle and endocardial microshocks were given ranging from 0.05-2.0 J. All patients could feel the shock, but in most instances it was mild to moderate, in only one painful. The tachycardia was slowed in 20% of all microshocks, moderate acceleration occurred in 6%, while in 71% the tachycardia rate remained unchanged. In 7 out of 65 microshocks sinus rhythm occurred spontaneously, after an interval in which the tachycardia slowed. Atrial fibrillation was induced in 6% of cases, but there was no instance of ventricular fibrillation. Reversion directly to sinus rhythm after endocardial cardioversion occurred in 26 of 33 episodes of ventricular tachycardia, while in 7 episodes the tachycardia rate slowed. In no case was it necessary to use external DC cardioversion to terminate a ventricular tachycardia. Threshold values for successful cardioversion of ventricular tachycardia averaged 0.77 (+/- 0.63) J. In one patient, atrial flutter with a relatively high A-V conduction rate was converted into atrial fibrillation by an intra-atrial microshock of 5.0 J. Thus endocardial cardioversion proved effective and safe in terminating ventricular tachycardia, even in patients in whom anti-tachycardic ventricular pacemaker stimulation had failed. The method is apparently not suitable for the conversion of supraventricular tachy-arrhythmias to sinus rhythm.

[Long-term therapy with nitrates. Relation between dosage and tolerance effect]

In 56 patients with angiographically-documented coronary artery disease, the longterm effects of isosorbide dinitrate (ISDN) and isosorbide 5-mononitrate (5-ISMN) on exercise hemodynamics and exercise capacity were assessed. The hemodynamic and antianginal acute and longterm effects of the respective agents were objectively analyzed on the basis of the tested parameters of mean pulmonary artery pressure and work capacity (watts X minutes). These parameters are unaffected by placebo and show reproducible changes at rest and during exercise after drug administration. After the standard 20 mg dose of ISDN or 5-ISMN, both at rest and during exercise, there was a marked decrease in pulmonary artery pressure as well as an increase in exercise capacity. The acute effects of 60 mg ISDN or 50 mg 5-ISMN were not substantially more marked than those of the 20 mg doses. During longterm treatment with 20 mg ISDN or 5-ISMN three times daily there was no attenuation of the hemodynamic effects, that is, no tolerance development; the increase in exercise capacity was maintained. In contrast, at the end of the four-week treatment period with 60 mg ISDN or 50 mg 5-ISMN three times daily there was a marked attenuation of the hemodynamic effects as well as the associated exercise capacity. The results of this study do not enable delineation of the mechanism responsible for the attenuated effect during high-dose treatment. Most probably, it is due to a complex process, in which, in addition to pharmacokinetics and pharmacodynamics, alterations in various reflex and adaptive mechanisms also play a role.

[Effect of nitroglycerin plasters on hemodynamics and stress tolerance of patients with coronary heart disease]

The haemodynamic and antianginous efficacy of percutaneous nitroglycerin was evaluated in 24 patients with coronary heart disease. Groups of 8 patients each received one, two or four patches (nitroglycerin liberation 5 mg per patch within 24 hours). Prior to application and after 1 and 2 hours cardiac frequency, arterial and pulmonary arterial pressures and exercise tolerance were assessed. Cardiac frequency and arterial pressure showed no relevant changes after application of patches. The mean pulmonary arterial pressure decreased after application of one or two plasters by 18.5 and 22.2% at rest and by 12.7 and 21.1%, respectively, during exercise. The working capacity showed a trend towards improvement only. With four nitroglycerin patches the mean pulmonary arterial pressure at rest was lower by 26.2% and during exercise by 39.1%. The working capacity rose significantly by 48.7%. Comparison of these effects with oral single dosage of 20 mg 5-isosorbide mononitrate (ISMN) showed that two simultaneously administered plasters did not achieve efficacy of 20 mg 5-ISMN, four plasters, however, were more effective.

[Value of the dipyridamole test in the diagnosis of coronary heart disease. Comparison with the stress ECG and coronary angiogram]

In 500 patients suffering from angina pectoris (454 males, 46 females) in whom coronary angiography had been performed a dipyridamole test was carried out. The test was positive in 319 of 396 patients with stenosing coronary heart disease (sensitivity 80%); ECG changes typical of ischaemia were demonstrated in 51%. The exercise ECG test was positive in only 68% of 229 patients with coronary heart disease. Among 104 patients without stenosing coronary heart disease the dipyridamole test was false-positive in 47, giving a specificity of 55%, while in 17 (16%) there were false-positive ECG-changes. The exercise test was falsely positive in 20 of 38 patients without stenosing coronary heart disease (specificity of 47%). Coronary blood flow was measured with the argon technique in 19 of 47 with a false-positive dipyridamole test and three with a false-positive exercise ECG. Maximal pharmacologically induced coronary blood flow was significantly reduced in all so that the diagnosis of "atypical coronary heart disease" or "small vessel disease" was made. The dipyridamole test or the exercise ECG test were falsely positive in these patients only with regard to the coronary arteriogram, correctly positive, however, in relation to angiographically non-demonstrable coronary blood flow abnormalities. The dipyridamole test is complementary to the exercise ECG test and has comparable accuracy. The same precautions must be observed for both tests.

[Echinococcosis involvement of the heart]

A case report is given of a 37-year-old patient who had echinococcus infestment the heart. Diagnosis was established after drainage of the pericardium, when cysts of a diameter between 0.5 and 3 cm were evacuated. During this procedure the pericardium and the left ventricle were searched and revised extensively and drug therapy with Mebendazole was instituted. In spite of that a new cyst developed in the pericardium and a big cyst in the abdomen, was found which had practically transformed the whole left lobe of the liver into a cyst. Both lesions were removed surgically. It must be emphasized 1) that a very careful search of all organs liable to harbour echinococcus should be performed in patients who have cardiac involvement of the disease, 2) that chemotherapy will not prevent with necessity the development of fertile elements which could not be removed during surgery and 3) that patients have to be followed through several years in order to evaluate the success of therapy.

[5-isosorbide mononitrate at rest and on exercise in coronary heart disease: acute and long-term effect]

Haemodynamic effects of 5-isosorbide mononitrate (5-ISMN) were studied at rest and on exercise in 31 patients with angiographically confirmed coronary heart disease. A decrease in arterial blood pressure and mean pulmonary artery pressure without significant change in heart rate, cardiac output and stroke volume occurred both at rest and on exercise after 20 mg of 5-ISMN to 12 patients. Administration of 50 mg 5-ISMN to 19 patients achieved greater decrease in mean pulmonary artery pressure; cardiac output and stroke volume were highly significantly reduced at rest, while on exercise both cardiac output and stroke volume remained unchanged. Ten patients, in whom after a single dose of 50 mg 5-ISMN the mean pulmonary artery pressure at rest and on exercise had decreased 28% and 45%, respectively, with a definite rise in exercise tolerance, repeat acute administration of a single dose of 50 kmg 5-ISMN produced a fall in mean pulmonary artery pressure at rest by 20% after 50 mg three times daily for four weeks. On exercise the fall was only 14% below the control levels before treatment. In addition, exercise tolerance was reduced. These results indicate that acute administration of 5-ISMN at rest and on exercise decreases cardiac work load. But on chronic administration of high doses, tolerance to the drug may develop.

[Valve replacement for mitral in incompetence in a patient with osteogenesis imperfecta (author's transl)]

Reports on aortic and mitral valve alterations in patients with osteogenesis imperfecta, a congenital connective tissue disorder, are sparse in the literature. Aortic valve incompetence is more common than mitral valve dysfunction. Though the clinico-pathological and histological features of valve alterations are very similar to those seen in Marfan's Syndrome, valve dysfunctions in osteogenesis imperfecta are rarer than in Marfan's Syndrome. In a 23-year-old patient with typical clinical feature of osteogenesis imperfecta, mitral incompetence was detected by echo- and angiography. Patient was provided with a St.-Jude-Medica prosthesis and postoperative course was without any complications.

Electrophysiological effects of cardioselective and non-cardioselective beta-adrenoceptor blockers with and without ISA at rest and during exercise

1 In 46 patients (16 female and 30 male), aged between 18 and 73 years and effect of acute beta-adrenoceptor blockade with i.v. pindolol, acebutolol and atenolol has been studied at rest and during ergometric exercise, during routine intracardiac His bundle investigations. 2 At rest the functional parameters of the sinus node were impaired most markedly by atenolol. A-V nodal conduction was more depressed with acebutolol and atenolol than with pindolol. The His-Purkinje system conduction remained unaffected by all three beta-adrenoceptor blocking agents. 3 During ergometric exercise the depressant action of beta-adrenoceptor blockade on sinus nodal function with lower heart rates and on A-V nodal conduction with slower conduction velocities was equieffective with pindolol, acebutolol and atenolol. His-Purkinje system conduction again remained unchanged with one exception that after administration of pindolol, conduction rate during exercise was faster than before beta-adrenoceptor blockade. 4 It may be concluded that, in patients with low heart rates, an antagonist such as pindolol with relatively pronounced intrinsic sympathomimetic activity can be considered to be the drug of choice. In contrast, patients with higher heart rates at rest should be treated with a cardioselective betablocker without ISA. Patients with overt Sick Sinus Syndrome should not be given beta-adrenoceptor blockers at all. 5 Physical activity may change (improve or impair) the antiarrhythmic potency of beta-adrenoceptor blockers used in the treatment of supraventricular tachycardias or tachyarrhythmias.

Antiarrhythmic effects of acute betablockade with atenolol on supraventricular tachycardias at rest and during exercise

In a total of 18 patients, 7 females and 11 male patients with ages ranging from 23 to 70 years (mean: 45.5 +/- 14.5) diagnostic His bundle studies incorporating programmed atrial and ventricular pacing for the induction of tachycardias was performed before and after betablockade with the cardioselective betablocking agent atenolol, in a dose of 5 mg given iv. over 3 to 5 minutes. In 7 patients the pacing procedure could be repeated following ergometric exercise in order to evaluate the influence of a raised sympathetic tone on the conditions initiating paroxysmal tachycardias. At rest, atenolol prevented the pacing induced tachycardias (20 dysrhythmias in 18 patients) in 3/5 individuals with Wolff-Parkinson-White (WPW)-syndrome, in 4/6 cases with atrial tachycardias, in 4/6 patients presenting atrial flutter, in 2/2 cases developing AV-nodal tachycardias and in 1/1 individual with ventricular tachycardia. Thus, in 13 out of 19 (68%) supraventricular dysrhythmias patients benefitted from atenolol by preventing or controlling the tachycardia. Ergometric exercise changed the tachycardia or echo zone in 5/8 arrhythmias after betablockade when compared to the controls before administration of atenolol (3/5 improvement by narrowing of the tach- or echo zone, 1/5 prevention of tachycardia, 1/5 impairment due to widening of the tachycardia zone). Considering only the prevention of tachycardias, the antiarrhythmic potency of atenolol was improved in one patient with pacing induced flutter and impaired in one individual with a WPW syndrome, by ergometric exercise. These results suggest that atenolol seems to provide a good antiarrhythmic action, especially in supraventricular tachycardias, and that an increased sympathetic tone during exercise may modify the antidysrhythmic strength of betablockade.

[Non-invasive derivation of potential of the bundle of His from the body surface (author's transl)]

In 17 of the 28 patients a surface potential of the bundle of His could be differentiated. Pharmacological tests with verapamil and ajmaline raised the number of positive body surface recordings of the bundle of His to 22 out of 30 (=73%). In 11 of the 30 subjects (=37%) depolarizations of the Tawara bundle branches were recorded in addition. Two possible applications of this method are discussed: follow-up of patients with AV-block and supervision of negative dromotropic cardiac medication.

An approach to direct detection of sinus nodal activity in man

We are reporting a series of 13 out of a total of 16 patients in whom sinus nodal activity was recorded with the use of intra-atrial electrodes, during diagnostic His-bundle electrocardiography investigations. The protocol consisted of the simultaneous monitoring of the following intra-atrial points: high right atrium, low lateral right atrium, left atrium and the His-bundle electrogram (HBE), which accompanied the detecting sonde placed as a loop in the superior vena cava, with the electrodes facing the sinus nodal area. This permitted an adequate assessment of the sequence of the depolarizing activity. All patients showed sinus nodal potentials preceding the initiation of the P-wave in the surface-EKG or the atrial potential in the high right atrial lead, respectively, in the range of 60 to 270 msec depending upon the functional status of the sinus node in each patient. Such waves were clearly separated from the initiation of the atrial potential by an isoelectric line and showed functional traits compatible with the S-A nodal functions, as many authors have previously reported in experimental animal models. The text contains a review of the relevant literature and discussion upon the diagnostic significance of this method in the assessment of sinus nodal disease.