[Stress echocardiography with physical burden using step-climbing for the diagnosis of ischemia]. / Stress-Echokardiographie mit körperlicher Belastung an der Kletterstufe zur Ischämiediagnostik.

OBJECTIVE: To ascertain the reliability of stress echocardiography (SEG) with a standardized step-climbing test in predicting significant coronary heart disease (CHD) in patients suspected of having CHD, subsequently verified by coronary angiography. PATIENTS AND METHODS: 174 consecutive patients (116 men, 58 women; average age 60 years) suspected of having CHD or with suspected progression of known CHD were included. RESULTS: Compared with coronary angiography SEG had a sensitivity of 81% for the recognition of ischaemia in patients with coronary artery stenosis of 50% or more, with a specificity of 74%. The positive and negative predictive values were 81% and 73%, respectively. Multi-vessel disease was better recognized then single-vessel involvement. Abnormal perfusion in the region supplied by the left anterior descending artery (LAD) was diagnosed with a higher sensitivity than those of the circumflex branch (CXB) and the right coronary artery (RCA/CXB). For 50% stenoses in the LAD distribution the sensitivity was 76%, specificity 79%; for the combined RCA/CXB and CXB areas the sensitivity was 52%, specificity 84%. When comparing the SEG findings with coronary stenoses of 50%, the sensitivity for diagnosing ischaemia rose to 86%, specificity 70%. Positive and negative predictive values were 83% and 75%, respectively. Ischaemia in the LAD distribution area was recognized with a sensitivity of 79%, specificity 72%, ischaemia in the combined RCA/CXB and CXB areas with a sensitivity of 56%, specificity 82%. CONCLUSION: Stress echocardiography with stair-climbing can achieve acceptable results in the diagnosis of coronary heart disease.

Diagnosis of patent foramen ovale by transesophageal echocardiography and association with cerebral and peripheral embolic events.

This study compares the value of transthoracic (TTE) and transesophageal (TEE) color Doppler and contrast echocardiography for detecting a patent foramen ovale (PFO). A total of 238 patients were studied: 74 patients with a history of otherwise unexplained ischemic stroke, transient cerebral ischemic attacks or peripheral embolic events (group A), 48 with a history of similar episodes explained by other cardiac abnormalities (group B), and 116 with no embolic events (group C). A PFO was detected by contrast TEE in 50 of 238 patients (21%) compared with 45 patients (19%) by color Doppler TTE. In a subgroup of 198 patients, TEE results could be compared with TTE findings. No patient had a PFO identified by color Doppler TTE. Contrast TTE detected a PFO in 15 patients (8%) compared with contrast TEE which demonstrated a PFO in 44 of 198 patients (22%) (p less than 0.001). Prevalence of PFO by TEE was 22, 21 and 22% in groups A, B and C, respectively. A PFO was present in 50% of patients aged less than 40 years and otherwise unexplained ischemic stroke; this percentage was higher (p less than 0.05) than corresponding values found in all other groups. Thus, contrast and color Doppler TEE are significantly superior to TTE for detecting PFO. The prevalence of PFO is significantly increased in young adults with otherwise unexplained ischemic stroke.

Risk of bacteremia induced by transesophageal echocardiography: analysis of 100 consecutive procedures.

The incidence of bacteremia induced by transesophageal echocardiography (TEE) and, consequently, the need for an antibiotic prophylaxis before TEE is still controversial. Therefore, we studied the incidence of bacteremia associated with TEE prospectively in 100 consecutive patients without clinical or laboratory signs of bacterial infection. Blood samples were drawn immediately before and at 0, 5, and 15 minutes after TEE. In addition, swabs were taken from the pharyngeal region before TEE and from the distal part of the TEE-probe before and after TEE. All blood cultures taken before TEE remained sterile. After TEE, three positive blood cultures were found in two patients: the first patient had two different species of coagulase-negative staphylococci in cultures taken at 0 minutes (Staphylococcus capitis) and 15 minutes (Staphylococcus cohnii) after TEE, whereas the sample taken after 5 minutes remained sterile. In the second patient, Propionibacterium species appeared after 7 days of processing in a culture taken immediately after TEE, but not in the samples taken after 5 and 15 minutes. None of the three microorganisms found in the blood were simultaneously isolated in pharyngeal specimens or TEE-probe specimens of the same patient. Thus positive blood cultures in both patients were considered contaminated. This study demonstrates that TEE, when performed by an experienced investigator, is not associated with an increased risk of bacteremia. Accordingly, it is justified to perform TEE examinations (also in high-risk patients) without antibiotic prophylaxis.

[The implantable automatic cardioverter-defibrillator]. / Der implantierbare automatische Kardioverter-Defibrillator (AICD)]

In addition to medical treatment for ventricular tachyarrhythmias which has not proven to be sufficient, nonmedical modes of treatment are available such as electrophysiologically-guided surgical measures and catheter ablation, both of which are restricted to only a relatively small patient population and require further technical refinement. In 1980, Mirowski introduced the automatic implantable defibrillator and, to date, world-wide, this device has been implanted in 8000 patients. CHARACTERISTICS AND IMPLANTATION OF THE AUTOMATIC IMPLANTABLE CARDIOVERTER/DEFIBRILLATOR (AICD): The AICD continuously monitors the electrical activity of the heart, recognizes the onset of threatening ventricular tachycardias and terminates these according to the respectively programmed mode by delivering direct current shocks or stimuli. The currently used defibrillators consist of an impulse generator with lithium batteries and an electrode system. The batteries can charge a capacitor with about 700 volts in five to eight seconds which produces a current with an energy up to 30 Joules on discharge. The current is delivered either by two plate electrodes on the right and left ventricles or a plate electrode on the left ventricle and a spiral electrode inserted in the superior vena cava. The electrodes also serve the purpose of tachycardia detection by means of an electrical signal, the probability density function (PDF), that is, a significant decrease in the potentials to isoelectric. With this, it is only possible to terminate ventricular fibrillation. Additional electrical detection criteria are obtained and analyzed by two adjacently positioned epicardial screw electrodes or a bipolar endocardial electrode, enable identification of ventricular tachycardia as well. If the tachycardia detection criteria are fulfilled, the capacitor is discharged according to its programmed shock energy. In 1988, programmable defibrillators were introduced. Current defibrillator treatment also incorporates the possibility for antitachycardia stimulation. Attempts to use, instead of the monophase, square-wave impulse, a biphasic defibrillation impulse, to achieve a sequential impulse and to make use of the bidirectional impulse extension have rendered improved reliability for tachycardia termination and energy savings. After median sternotomy, the plate electrodes are usually sutured to the epicardium and the spiral electrode for the bipolar ECG is positioned at the anterior aspect of the right ventricle. The generator is implanted on the left side para-umbilically in subcutaneous or subfascial tissue. With the subxyphoid approach to avoid sternotomy, the plate electrode is sutured extrapericardially over the left ventricle and the spiral electrode is positioned at the epicardium. Alternatively, for those in whom prior cardiac surgery has been carried out, a lateral thoracotomy can be used. The defibrillation threshold, that is the lowest possible energy for defibrillation of ventricular fibrillation or ventricular tachycardia, should be determined intraoperatively after stimulation of the arrhythmia. The energy required for termination of a stable ventricular tachycardia is usually less than that for termination of ventricular fibrillation and can be determined postoperatively. A margin of security should be taken into consideration which, for defibrillation thresholds of up to 10 Joules, is about twice the amount of the defibrillation threshold itself.(ABSTRACT TRUNCATED AT 400 WORDS)

[Syncope in patients with Wolff-Parkinson-White syndrome: clinical data, electrophysiologic substrate and prognostic value]. / La sincope in pazienti con Wolff-Parkinson-White: rilievi clinici, substrato elettrofisiologico e valore prognostico.

Syncope in Wolff-Parkinson-White (WPW) patients might be considered a premonitory event heralding the future development of sudden death. Therefore, we reviewed the clinical and electrophysiologic data of 91 WPW patients referred for invasive evaluation of known arrhythmias, in order to assess the incidence and clinical relevance of syncope. Thirty-four patients (37%, Group I) reported the occurrence of 1 or more syncopal episodes, while 57 patients (63%, Group II) had no syncope. These 2 groups did not differ significantly with regard to age, sex, incidence and characteristics of arrhythmias, clinical history and frequency of arrhythmic events, presence of associated cardiac diseases. Eleven patients in Group I and 9 in Group II were resuscitated from a cardiac arrest. The sensitivity (40%), the specificity (64%) as well as the positive predictive value (32%) and the negative predictive value (71%) of syncope vs a cardiac arrest were not significant. There were no statistical differences in the effective refractory period of the right atrium, atrioventricular node, accessory pathway and right ventricle between the 2 groups. Furthermore, no differences were noted in the cycle length of tachycardia (327 +/- 60 ms in Group I and 335 +/- 46 ms in Group II) and in the minimum RR interval during atrial fibrillation (248 +/- 49 ms and 244 +/- 43 ms, in Group I and II, respectively) as well as in the number of patients who had a minimum RR interval during atrial fibrillation less than or equal to 250 ms (15 patients--65%--in Group I and 21 patients--62%--in Group II).(ABSTRACT TRUNCATED AT 250 WORDS)

Purification of human plasma lipoprotein lipase.

Human plasma lipoprotein lipase was purified in a highly active form. Addition of the non-ionic detergent Triton X-100 led to stabilization of enzyme activity during the purification procedure. Antithrombin III, the major contaminant after affinity chromatography with heparin-Sepharose 4B, could be removed by gel filtration on Bio-Gel A-5m. The application of Tris-glycine buffer in the absence of denaturating agents allowed identification of the protein band corresponding to lipoprotein lipase activity on polyacrylamide gels.