Evaluation of antiarrhythmic drug effects with simultaneous analysis of single ventricular premature contractions, couplets and salvos.

To improve the clinical value of ambulatory Holter electrocardiographic (ECG) monitoring as a tool of antiarrhythmic therapy control, a new statistical model was developed. In a patient group at increased risk of sudden cardiac death, the spontaneous variability of ventricular arrhythmias was assessed, with simultaneous consideration of single ventricular premature complexes, couplets and salvos. The study included 100 patients who suffered from coronary heart disease or idiopathic dilated cardiomyopathy and for whom greater than 30 ventricular premature complexes/h and couplets had been demonstrated on the last Holter ECG before the study. Between 3 and 12 Holter recordings were made for each patient in a drug-free state; the mean follow-up period was 260 days (maximum 1,403). The mean hourly values of the ectopic events (EE) were assessed separately for ventricular premature complexes, couplets and salvos. The spontaneous variability (SV) was calculated for single ventricular premature complexes, couplets and salvos as SV = log (EEday 2 + 0.01/EEday 1 + 0.01) and linked in one, two and three dimensions. Compared with the consideration of only one type of arrhythmia (one-dimensional model), the simultaneous use of two or three types of arrhythmia (two- or three-dimensional model) resulted in considerably lower reduction and aggravation rates as sufficient proof of drug effects. With control intervals up to 1 week, the one-dimensional model yielded reduction rates for ventricular premature complexes, couplets and salvos of -63%, -90% and -95%, respectively. In contrast, with the three-dimensional model, the rates were -28%, -72% and -88%. The corresponding aggravation values were +370, +1,114% and +2,189% versus +38%, +256% and +747%.(ABSTRACT TRUNCATED AT 250 WORDS)

Body fat distribution in men with angiographically confirmed coronary artery disease.

Body fat distribution and its relationship to coronary artery disease and established cardiovascular risk factors have been studied in a cohort of 286 men aged between 30 and 74 years undergoing coronary angiography. 207 (72.4%) patients showed stenosis (greater than 30%) or occlusion of one or more coronary arteries. whereas the remaining 79 (27.6%) men were free of coronary lesions and served as a control group. 112 men with angiographically defined coronary artery disease had an additional history of myocardial infarction. Body fat distribution was assessed by determining the waist-to-hip circumference ratio. A stepwise logistic regression analysis revealed that in addition to LDL-cholesterol (P = 0.0001) and age (P = 0.0005) an abdominal type of body fat distribution (P = 0.0129) is also a significant risk indicator for the occurrence of coronary artery disease (CAD) independent of body weight and other factors such as total cholesterol, HDL-cholesterol, triglycerides, insulin, systolic and diastolic blood pressure. The results of this study suggest that an abdominal type of fat distribution is associated with an increased risk of coronary artery disease.

Measurement of myocardial fatty acid metabolism: kinetics of iodine-123 heptadecanoic acid in normal dog hearts.

To define the potential of iodine-123 heptadecanoic acid (IHA) for the noninvasive assessment of myocardial fatty acid metabolism with gamma camera imaging, the influence of myocardial oxygen consumption (MVO2) and blood flow (MBF) on extraction and half-times of IHA were investigated in dogs. Following IHA injection into the left circumflex coronary artery, extraction fraction and half-times were derived from the peak and slope of the IHA time activity curve, which consisted of a vascular, early, and late phase. Single-pass extraction fraction of IHA averaged 0.53 +/- 0.11 s.d. at control and was not influenced by MVO2 and MBF. The half-time of the early phase (T = 9.3 min +/- 2.8 s.d. in controls) as well as the ratio between the size of the early and late phase increased with MVO2 (r = 0.82, r = 0.87, respectively). Thus, early phase intracellular turnover of IHA increased, yet clearance of 123I activity was slowed by augmented cardiac work. Preliminary data of HPLC and electrophoretic analysis of myocardial arterial and venous blood samples over time indicate that the early phase is characterized by a decreasing washout of IHA and a relative increase of radioiodine washout. The half-time of the late phase (T = 245 min +/- 156 s.d. at control) was not related to MVO2 and MBF. In conclusion, myocardial fatty acid metabolism cannot be measured from the half-time of the early phase but might be analyzed from the ratio between the size of the early and late phase when using IHA.

High-dose streptokinase therapy with three million units in one hour significantly improves early coronary patency rates in acute myocardial infarction.

In a prospective, randomized open trial, significantly higher patency rates were observed 60 minutes after beginning fibrinolytic therapy for acute myocardial infarction after administration of 3 million U streptokinase as compared to 1.5 million U (Thrombolysis in Myocardial Infarction [TIMI] grade 2 and 3 in 52% vs 26%; p = 0.04). Adverse events were observed with similar frequency in both groups.

Beneficial effects of a single dose of quinapril on left ventricular performance in chronic mitral regurgitation.

To evaluate the effect of a single dose of the angiotensin-converting enzyme inhibitor quinapril on left ventricular (LV) performance and size in patients with moderate to severe chronic mitral regurgitation (MR), 12 patients with angiographically proven isolated MR grade II to III and no evidence of coronary artery disease were studied. In all patients a baseline right heart catheterization and simultaneous radionuclide angiogram were performed at rest and during supine exercise (maximum 100 W) as well as 2 hours after oral administration of 10 mg of quinapril. Quinapril reduced heart rate slightly and lowered mean blood pressure at rest and during maximal exercise (p < 0.05). Systemic vascular resistance at rest was decreased from 1,484 +/- 505 to 1,150 +/- 427 dynes s cm-5 and with maximal exercise from 999 +/- 455 to 734 +/- 395 dynes s cm-5 (p < 0.005). Pulmonary capillary arterial pressure at rest decreased from 13 +/- 6 to 10 +/- 4 mm Hg (p = 0.01) and during maximal exercise from 29 +/- 10 to 20 +/- 7 mm Hg (p = 0.001). LV end-diastolic volume at rest (146 +/- 26 ml/m2) decreased after administration of quinapril to 128 +/- 24 ml/m2 (p = 0.001) and was also reduced during exercise (p = 0.001). LV end-systolic volume decreased from 63 +/- 43 to 49 +/- 35 ml/m2 at rest (p = 0.001) and with maximal exercise from 56 +/- 49 to 44 +/- 39 ml/m2 (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis of constrictive pericarditis by pulsed Doppler echocardiography of the hepatic vein.

The diagnostic value of hepatic venous flow patterns was evaluated for constrictive pericarditis by pulsed Doppler. A characteristic flow pattern was assumed to be associated with the well-known atrial pressure curve. Thirteen patients with constrictive pericarditis were compared to 13 control subjects and to 25 patients with right ventricular pressure overload including 13 patients with tricuspid regurgitation. The characteristic finding in constrictive pericarditis was a W-wave pattern of flow velocities in the dilated hepatic veins, with abrupt reversal of flow late in systole and diastole before the A wave (100% specificity, 68% sensitivity). This depends, however, on the absence of tricuspid regurgitation (for its systolic component) or fast sinus rhythm (for its diastolic component). Additional diagnostic markers were systolic deceleration time of forward flow (40 to 130 ms) and systolic integral of flow velocities (4.3 to -4.0 cm) (sensitivity and specificity greater than or equal to 92%). In the presence of tricuspid regurgitation, diastolic deceleration time less than 150 ms and diastolic integral of flow velocities less than 6 cm were useful diagnostic signs. If combined, these criteria had 100% sensitivity and specificity for the diagnosis. Thus, pulsed Doppler assessment of flow velocities in the hepatic vein facilitates the diagnosis of constrictive pericarditis in clinical routine, using an auxiliary site with unlimited diagnostic access to the characteristic flow velocity pattern, which reflects right atrial pressure curve and filling abnormalities.

Control of pacemaker rate by impedance-based respiratory minute ventilation.

Several studies have shown that the capability for exercise can be increased in patients with pacemakers by means of adjusting the rate. Respiration is one of the parameters considered for rate control. The aim of our study was to determine how respiratory parameters such as ventilation, tidal volume, and respiratory rate are capable of controlling the pacemaker rate, especially when measured indirectly by means of impedance plethysmography. We examined four volunteers and eight patients with implanted cardiac pacemakers using bicycle ergometry at increasing work loads. We recorded heart rate, uptake of oxygen, and ventilation directly (by pneumotachygraphy) and indirectly (by chest wall impedance plethysmography). A good correlation of directly to indirectly measured ventilation (r = 0.8687) was found. Our study suggests that respiratory minute volume is more appropriate for rate control of physiologic pacemakers than tidal volume or respiratory rate alone. Measurement by means of impedance plethysmography is sufficiently precise to be used for this purpose. Further studies must be conducted as to the optimum realization within an implantable device.

[Evaluation by means of ECG-gated cardiac blood pool scintigraphy of global and regional left ventricular function at rest and during exercise in patients with coronary artery disease (author's transl)]. / Die Beurteilung der globalen und regionalen linksventrikulären Funktion in Ruhe und während Ergometerbelastung bei Patienten mit koronarer Herzkrankheit mit der EKG-getriggerten Herzbinnenraumszintigraphie.

ECG-gated cardiac blood pool scintigraphy permits a non-invasive determination of the end-diastolic and end-systolic ventricular volumes and of the ejection fraction as well as a qualitative description of regional ventricular wall motion at rest and during excercise. In 6 healthy persons a significant increase of the ejection fraction from 66 +/- 7% at rest to 78 +/- 3% during exercise (p less than 0.01) was observed. In contrast, the ejection fraction decreased in 15 out of 18 patients with coronary artery disease, with a significant (p less than 0.01) difference between patients with and without angina pectoris. Thus, the ejection fraction fell in 12 patients without angina during excercise from 60 +/- 11% to 52 +/- 11% (p less than 0.05) whereas in 6 patients with angina a decrease from 61 +/- 7% to 30 +/- 8% (p less than 0.01) was observed. This non-invasive technique makes it possible to demonstrate in a simple and safe manner changes of cardiac function during excercise in patients with coronary artery disease.

Central venous blood temperature for rate control of physiological pacemakers.

In 17 pacemaker patients and 14 volunteers we studied the behaviour of central venous blood temperature and heart rate under different kinds of exercise. Data were recorded by means of 5F catheter placed at the right ventricle. Temperature was measured with a thermistor incorporated in the lead. We found the increase in central venous blood temperature to be dependent on the individual exercise capacity and work load performed. The maximum temperature increase seen was 1.7 degrees Celsius. Subjects with lower physical fitness showed a more pronounced increase in temperature and heart rate compared to more physically fit subjects at the same work load. Due to its close relationship to metabolic and circulatory parameters, central venous blood temperature represents an appropriate signal to control the rate of physiological pacemaker systems. A special algorithm also using the initial dip for rate control has been incorporated into a pacemaker system, that is currently under clinical investigation (Intermedics NOVA MR).

Myocardial salvage prior to emergency coronary bypass surgery for PTCA-induced coronary occlusion.

The possibility of prolonged, selective coronary perfusion via angioplasty catheters was evaluated. A pump was developed featuring minimal hemolysis even at high pump pressures. Pressure requirements differed greatly between various catheter types. Catheter-induced hemolysis did not correlate with pump pressure and was mainly due to a turbulent jet effect through sideholes. In 20 of 22 closed-chest dogs, myocardial ischemia could be greatly reduced or completely prevented for over 2 hours after proximal LAD or Cx occlusion. With flow rates between 1 and 2.5 ml/min/kg body weight and using the ECG and coronary venous O2 saturation for rate adjustment, pressure within the selectively perfused vessel never reached critical values. Thus, with the appropriate equipment, prolonged coronary perfusion is feasible. In some cases of percutaneous transluminal coronary angioplasty-(PTCA) induced coronary occlusion, it may prevent ischemic myocardial damage between PTCA-induced acute coronary occlusion and subsequent surgical revascularization.

[Cardiological aspects of chest pain (author's transl)]. / Brustschmerz aus kardiologischer Sicht.

Of all chest pains, the differential diagnosis of angina pectoris is without doubt prominent. The later life of a person is permanently affected by it. Angina pectoris is a complex of complaints which can only be recognized with great reliability through specific questioning of the patient, whereas practically all objective findings such as direct examination of the patient, radiographic and laboratory findings, even the resting ECG are usually negative. Pointers to the presence of a coronary heart disease can only be found after effort in the ECG or cardioscintigram. In the matter of chest pain particularly, the great importance of medical discussion which is, in fact, able to differentiate the clinical picture with great reliability is underlined here.

[Electrocardiographic and phonocardiographic findings in Ebstein's anomaly with special regard to its severity (author's transl)]. / Elektrokardiographische und phonokardiographische Besonderheiten beim Ebstein-Syndrom unter besonderer Berücksichtigung des Schweregrades

Electrocardiographically, the combination of the P-dextro-atriale and the RBBB without right ventricular overload almost certainly constitutes a pathognomonic finding in Ebstein's anomaly. The height of the P wave and the duration of the QRS complex are related the the severity of the anomaly. So the higher the P wave, the wider the QRS complex, the more severe is the Ebstein'ngs are detectable in the phonocardiogram. In the mild form, however, a loud systolic click and occasionally a low systolic murmur are present, while in severe forms, there is only a loud systolic murmur, and no systolic click.

[Heart valve surgery without heart catheter study]. / Herzklappenchirurgie ohne Herzkatheteruntersuchung.

The development of new non-invasive diagnostic techniques in cardiology and their validisation has questioned the up-to-now performed preoperative heart-catheterization for evaluation of valvular heart disease. Although all these methods--2-dimensional echocardiography, Doppler-sonography and nuclear techniques--offer a reliable judgement in regard to classification and operative indications, coronary heart disease can only be ruled out by coronarography--except in younger patients without risk-factors and angina. Also in acute valvular disease the invasive diagnostic measures give the heart surgeon more security as regards additional morphologic changes such as intimatears, fistulas or abscesses near the valve. The sensitivity of invasive methods is higher than that of 2-dimensional echocardiography. The expanding application of non-invasive diagnostic tools and with increasing experience it can be assumed that heart-catheterizations prior to surgical valvular repair can be done with more accuracy and not only as a routine.

[Thoracic pain from the cardiologic viewpoint]. / Der Thoraxschmerz aus kardiologischer Sicht.

Differential diagnosis of chest-pain as seen by the cardiologist consists of a broad spectrum from pericarditis, mitral valve prolaps to dissecting aneurysm which requires an urgent treatment. The main interest however concentrates on coronary heart disease which threatens the life of a patient with sudden death. Proper treatment in time--medically or surgically--is of greatest importance. Especially the anamnesis as obtained by proper questioning the patient gives the best results and leads to further investigations. The doctor's interrogation plays the most important role even in times of great apparative and technical equipment. This disease requires engagement and time-spending at the doctor's is of utmost importance. In dubious cases the decision for invasive investigations should be made early since the risk of a misdiagnosis of coronary heart disease has more severe consequences than that of an invasive diagnostic work-up.

[Physiopathology of angina pectoris]. / Pathophysiologie der Angina pectoris.

The concept of blood flow limited fixed coronary artery stenosis holds true for most of the patients with stable, e.g. exercise-dependent angina pectoris. In this condition exists a disproportion between oxygen demand and oxygen consumption. On the other hand the unstable angina pectoris (angina pectoris at rest) is explained by a variable transient reduction of oxygen supply due to vasoconstriction ("dynamic stenosis"). In addition to the fixed stenosis and vasoconstriction the rheological behaviour plays a further role in the pathogenesis.

[Platelet suppressant therapy and oral anticoagulants in the secondary prevention of acute myocardial infarction (authors transl)]. / Aggregationshemmer und Antikoagulantien zur Sekundärprophylaxe des Herzinfarkts.

First positive results with platelet suppressant drugs in the secondary prevention of acute myocardial infarction have engendered optimism in the medical and lay community alike. A review of the subject therefore seems appropriate. In the same context a critical reappraisal of the value of long-term anticoagulant therapy after acute myocardial infarction appears also warranted. Results with platelet suppressant therapy reported so far are favorable; however, they fall short from establishing definite proof of the value of such therapy after myocardial infarction. Accordingly, limited clinical use of platelet suppressants may be justifiable by now; it should be borne in mind, however, that such use at the present time still has to be considered experimental. In contrast, there has been statistically well-founded evidence that long-term anticoagulant therapy lowers the mortality after myocardial infarction. It is true, however, that the profit is rather small and that it can be achieved only under rigid control of anticoagulant therapy. Therefore the pros and the cons have to be weighed very carefully for every individual patient, before long-term therapy with oral anticoagulants is started after an acute myocardial infarction. Several large clinical studies are close to completion. It is to be hoped that their outcome will decide, whether platelet suppressant drugs will entirely replace oral anticoagulants in the secondary prevention of acute myocardial infarction.