[Defibrillation done by layman in Germany: particular conditions?].
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Biomedical subjects
Publications and source records attributed to Hans-Joachim Trappe.
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BACKGROUND: Initiation of effective cardiopulmonary resuscitation (CPR) at the earliest possible time is the most important determinant of prognosis for patients with prehospital cardiac arrest. Basic life support CPR, defibrillation by emergency medical systems or first responders as well as vasopressor drugs or antiarrhythmics are essential. RESULTS: Today, cardiocompression seems to be superior to ventilation. Defibrillation is the most effective treatment for ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). The effectiveness of defibrillation diminishes rapidly over time. The use of automated external defibrillators (AED) by first responders is very promising with excellent results caused by a short "call-to-arrival" time. Epinephrine and vasopressin are pressor drugs used in the treatment of cardiac arrest with similar success rates. Among antiarrhythmic drugs, lidocaine should no longer be used in patients with cardiac arrest, whereas amiodarone has high efficacy rates in VF or pulseless VT. CONCLUSION: Technique and methods of resuscitation are ranging from CPR to additional drugs. Fast and consequent work is essential. Among the "chain of survival" there is an increased value of first responders.
BACKGROUND AND PURPOSE: Vagus-induced atrial fibrillation is of particular clinical interest. The muscarinic potassium current I(K(ACh)) mediates the induction of vagus-induced atrial fibrillation. Selective inhibition of I(K(ACh)) seems to be an option to treat atrial fibrillation. The application of amiodarone, presently one of the most important antiarrhythmic agents in the parmacological treatment of atrial fibrillation, is limited by its adverse effects. KB130015, a new amiodarone derivative, and ibutilide are new class III antiarrhythmic agents. METHODS: In guinea-pig atrial myocytes the muscarinic potassium current (I(K(ACh))) was activated by acetylcholine and adenosine. The effect of KB130015 on I(K(ACh)) was measured using the whole-cell voltage-clamp method. RESULTS: KB130015 and ibutilide in a concentration of 50 microM effectively inhibited the muscarinic potassium current. The effect was concentrationdependent and reversible. The half-maximum effective concentration was 0.8 microM (KB130015) and 2.8 microM (ibutilide). The inhibition of I(K(ACh)) was independent of the mode of its activation. The adenosine-induced ion current was as well inhibited by both drugs as the acetylcholine-induced ion current. Via GTP-gamma-S irreversibly activated I(K(ACh)) was also inhibited by KB130015 and ibutilide, whereas intracellular application showed no effect on I(K(ACh)). CONCLUSION: KB130015 and ibutilide are potent inhibitors of IK(ACh). Their effect is most likely mediated by direct interaction with the extracellular part of the ion channel. Acute effects of KB130015 on ventricular myocardium are not known so far. Ibutilide on the other hand is known to inhibit I(kr). KB130015 is a promising antiarrhythmic agent for the pharmacotherapy of vagus-induced atrial fibrillation.
In contrast to Kawasaki syndrome the formation of coronary aneurysms caused by atherosclerosis has hardly been demonstrated. We report on a 56-year old patient, admitted to our hospital for cardiovascular evaluation before carotid surgery. He had no anginal pain, but a history of coronary artery disease with previous anterior myocardial infarction. Angiography revealed a collateralized LAD occlusion. Myocardial scintigraphy only demonstrated fixed perfusion defects. Surprisingly, MR imaging revealed large coronary aneurysms of the RCX and RCA. Angiographic follow up showed a rapid progression of ectatic towards aneurysmatic coronary lesions within 3 years. General pathophysiological mechanisms promoting ectatic coronary artery disease as a structural failure of the atherosclerotic remodelling process itself and chronic dilatatory stimuli due to endogenous and exogenous factors are discussed.
BACKGROUND: Acute chest pain is very frequent in medicine and caused by several cardiac disorders or disorders of the great vessels. In addition, chest pain is well known as "noncardiac chest pain" or due to functional abnormalities. For prognosis and long-term follow-up, acute coronary syndromes (ACS) and ascending aortic dissections are important disorders. RESULTS: The ACS represents a heterogeneous group of patients along a continuum of risk from unstable angina (UA) to non-ST segment elevation (NSTEMI) to ST segment elevation myocardial infarction (STEMI). In patients with NSTEMI/UA, beta-blockers, nitrates and calcium antagonists will improve chest pain, and invasive management of ACS is indicated in < 48 h, if risk factors are present. In patients without risk factors, stress studies and conservative treatment are mandatory. In patients with STEMI, nitrates, aspirin, heparin, and beta-blockers are required, and therapy of first choice is reperfusion with percutaneous coronary intervention (PCI). Acute ascending aortic dissection has a poor prognosis with mortality rates of 60% within 24 h, 75% within 1 week, and 90% within 3 months. Immediate surgical management of acute type A aortic dissection is necessary, whereas conservative treatment is preferred in acute type B aortic dissection. Both types require adequate therapy of hypertension. Acute pericarditis is caused by several factors; cardiac tamponade with pericarditis or pericardial effusion is associated with circulatory compromise and may be life-threatening. Acute pericarditis generally takes a benign course after empirical treatment with nonsteroidal or steroidal anti-inflammatory drugs. Immediate percutaneous pericardiocentesis is required, if cardiac tamponade is present. CONCLUSION: In many patients, chest pain is caused by functional abnormalities with impaired quality of life. In these, exclusion of an underlying organic heart disease and patient information on it are essential.
BACKGROUND AND PURPOSE: Vascular complications following transradial coronary angiography and coronary intervention could severely compromise perfusion of the hand. Drastic complications after cannulation of the radial artery (ischemia of the hand with occlusion of the digital arteries) are published only in brief reports. This study investigates whether percutaneous transradial artery coronary angiography/intervention results in vascular complications. PATIENTS AND METHODS: 93 patients were consecutively studied over a 4-month period. The following data were recorded before and after coronary angiography and/or intervention: diameter of the radial artery, blood volume, flow velocity, and occlusion pressure. Graduation of the stenosis after intervention was done according to the principle of the peak velocity ratio. RESULTS: A transradial coronary angiography/intervention was performed in 93 patients (75 men, mean age 62.5 years) in case of an unremarkable Allen test. Procedural success rate was 97.2%. The intervention could not be completed successfully in three patients (2.8%). Mean vessel diameter increased from 2.46 +/- 1.7 mm (standard deviation [SD]) before intervention to 2.78 +/- 0.69 mm (SD) after intervention; this increase was statistically significant (p = 0.002). Changes in blood flow, flow velocity and occlusion pressure did not reach significance. Vascular complications were seen in nine of 93 patients (10%) after the procedure. No patient mentioned discomfort. No perfusion deficit of the digital arteries was seen. CONCLUSION: The transradial coronary angiography and intervention is a safe method with a high procedural success rate.
PURPOSE: The aim of this study was to compare the visual and quantitative assessment for left ventricular ejection fraction (LVEF) in normal subjects and patients with impaired LV function. METHODS: One hundred subjects (40 normal subjects, 40 patients with ischemic cardiomyopathy, and 20 patients with nonischemic cardiomyopathy) were investigated using a 1.5-T cardiovascular magnetic resonance imager. Images were acquired by a fast gradient-echo sequence with steady-state free precession using the standard short-axis method. Left ventricular EF was calculated from the sums of the outlined areas using the Simpson rule. Interobserver variability between the calculated and the visual EF was assessed. Analyses were performed randomly and blinded by 2 independent observers. RESULTS: Left ventricular EF was significantly underestimated by the visual read in all 3 groups (mean difference: normal subjects -2.6% +/- 2.6%, ischemic cardiomyopathy -1.7% +/- 2.1%, and nonischemic cardiomyopathy -1.2% +/- 2.1%; P < or = .02). The difference was larger in normal subjects than in patients with cardiomyopathy (P = .04). The interobserver variability was smaller for the quantitative assessment than for the visual estimation. CONCLUSION: Left ventricular EF is underestimated by visual estimation compared with the quantitative assessment. The visual approach for EF assessment may be used for rapid assessment of left ventricular function in clinical practice where accuracy is of less concern. For most accurate analysis, the quantitative standard short axis approach is required.
PURPOSE: Most MRI centers currently use prospective ECG triggering and fast gradient-echo sequences for image acquisition. Retrospectively gated sequences allow the coverage of the entire cardiac cycle. There is concern about whether ventricular volumes and ejection fraction (EF) differ according to the gating method used for image acquisition. We sought to evaluate the impact of the gating method on measurements of right and left ventricular volumes and EF in normal subjects. MATERIALS AND METHODS: Fifteen subjects with no cardiovascular disease were investigated by MRI using a 1.5 Tesla scanner. Images were acquired with a gradient-echo sequence with steady-state free precession (SSFP) using the standard short-axis method for volume and EF measurements. Images were acquired with 6-mn-thick slices using both prospective triggering and retrospective gating. Left and right ventricular volumes (EDV, ESV, SV) and EF were determined with a commercially available software package (Argus, Siemens). RESULTS: EDV and SV calculated from short-axis images were significantly smaller with the prospectively triggered SSFP sequence (mean difference: EDV left: 13.9 +/- 4.4 mL, p < 0.0001; SV left: 13.5 +/- 4.8 mL, p < 0.0001; EDV right: 14.2 +/- 3.9 mL, p < 0.0001; SV right: 14.7 +/- 5.9 mL, p < 0.0001). EF was significantly smaller for the right ventricle (mean difference -3.6 +/- 3.3%, p = 0.0008) and the left ventricle (mean difference -2.3 +/- 3.3%, p = 0.02). ESV remained unchanged (mean difference: ESV left: 0.47 +/- 3.5 mL, p = 0.6179; right ESV: 0.5 +/- 3.7 mL, p = 0.6083). CONCLUSION: The gating method has a significant impact on volume and EF measurements. The global ventricular EF is underestimated by using the prospective triggering technique. However, the difference in the left ventricle is small and might not be of clinical relevance.
PURPOSE: Most magnetic resonance imaging (MRI) centers currently use prospective electrocardiographic (ECG) triggering for image acquisition. Retrospectively gated sequences allow the coverage of the entire cardiac cycle. It has been recently shown that ventricular volumes and ejection fraction (EF) differ according to the gating method used for image acquisition. The authors sought to evaluate how much measurements of atrial volumes and EF differ depending on the gating method. MATERIALS AND METHODS: Eighteen subjects with no cardiovascular disease were investigated by MRI using a 1.5 Tesla scanner. Images were acquired with a gradient-echo sequence with steady-state free precession (SSFP) using the standard short-axis method for volume and EF measurements. Images were acquired with 6 mm thick slices using both prospective triggering and retrospective gating. Left and right atrial volumes (end diastolic volume [EDV]; end systolic volume [ESV]; stroke volume [SV]) and EF were determined with a commercially available software package. RESULTS: ESV was significantly smaller with the retrospectively gated SSFP sequence than with the prospectively triggered sequence (mean difference: ESV left 3.97 +/- 1.3 ml, p < 0.0001; ESV right 4.34 +/- 1.8 ml, p < 0.0001). EF and SV were significantly smaller with prospective triggering (mean difference: EF left -5.94 +/- 0.9%, p < 0.0001; EF right -5.52 +/- 1.3 %, p < 0.0001; SV left -3.99 +/- 1.3 ml, p < 0.0001; SV right -4.32 +/- 1.9 ml, p < 0.0001). EDV remained unchanged (mean difference: EDV left -0.03 +/- 0.8 ml, p = 0.902; right EDV 0.04 +/- 0.7 ml, p = 0.882). CONCLUSION: The gating method has a significant impact on atrial volume and EF measurements. Atrial EF is underestimated by using the prospective triggering technique.
BACKGROUND: Because cardiovascular magnetic resonance imaging (CMR) is becoming increasingly available in clinical practice, there is a need to establish normal values for left atrial dimensions as determined by this method to allow accurate assessment of cardiac dimensions and to provide standardization for follow up studies. For clinical purpose measurements of the left atrial end diastolic diameter (LAEDD) are most appropriate to assess left atrial size. We aimed to establish normal values for LAEDD using CMR and a fast gradient-echo sequence with steady-state free precession (SSFP). METHODS: A total of 111 healthy subjects (52 women and 59 men, mean age 51.5 +/- 14.5 years) were examined by CMR. Images were acquired using SSFP in the horizontal (HLA) and vertical (VLA) long axis planes and the left ventricular outflow tract plane (LVOT) to measure the LAEDD. RESULTS: Age between men and women was not different (p = 0.7050). CMR yielded the following normal ranges for LAEDD: HLA 4.5 +/- 0.4 cm for men and 4.2 +/- 0.5 for women, VLA 4.5 +/- 0.5 cm for men and 4.2 +/- 0.4 for women, and LVOT 2.8 +/- 0.3 cm for men and 2.8 +/- 0.4 for women. LAEDD were significantly larger in HLA and VLA than in LVOT (p < or = 0.0001). There was no significant difference in the measurements between HLA and VLA (p = 0.4617). Gender-related differences for LAEDD were found in HLA (p = 0.0087) and VLA (p = 0.0015) but not in LVOT (p = 0.5281). LAEDD were not found to be age-related (p > or = 0.0994). CONCLUSIONS: LAEDD differ significantly according to the image plane. We provide reference values for CMR using prospective triggering in the evaluation of left atrial diameters to identify patients with enlarged left atria and for follow-up studies.
BACKGROUND AND PURPOSE: Pharmacological treatment of atrial fibrillation (AF) is limited by induction of malignant ventricular arrhythmias. Developing new drugs, a promising strategy is a more specific treatment of the atria. Muscarinic potassium current (IK[ACh]) is predominantly expressed in supraventricular tissue and mediates the induction of vagus-induced AF. The authors investigated the profile of representative class III drugs in respect to their effect on IK(ACh). METHODS: In rat atrial myocytes, IK(ACh) was activated by acetylcholine (ACh) measured with the whole-cell voltage clamp method. Drugs used: selective IKs blocker chromanole 293B (Cro); IKr blockers sotalol (Sot), dofetilide (Dof), ibutilide (Ibu), and terikalant (Ter). Data are expressed as mean values +/- standard deviation (SD). RESULTS: ACh-induced IK(ACh) density was 73 +/- 9 pA/pF (n= 9). IK(ACh) was almost completely desensitized in the presence of 50 micro M Ter, Ibu, or Dof. IC(50) of IK(ACh) inhibition by the three drugs was 0.9, 2.8, and 4.2 micro M (Dof, Ibu, and Ter, respectively). Receptor-independent GTP-gamma-S-induced IK(ACh) was sensitive to Ter, Ibu, and Dof as well. Sot is known to be a weak inhibitor of IKr. Inhibition of IK(ACh) by Sot was much less potent (IC(50) = 35.5 micro M) than inhibition by the high-affinity IKr blockers Ter, Ibu, and Dof. Superfusion of the cells with the IKs blocker Cro showed no desensitization of IK(ACh). Applied via the patch pipette (< 40 min) none of the class III drugs were effective. CONCLUSION: The results indicate inhibition of IK(ACh) and IKr but not IKs to be of similar mechanism (direct ion channel inhibition from the external side of the membrane). Potent desensitization of muscarinic potassium current could be of clinical relevance especially in patients with vagus-induced AF.
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Cardiovascular magnetic resonance (CMR) using contrast enhancement allows exact determination of the site and transmural extent of myocardial infarction (MI). We evaluated whether 12-lead electrocardiography can differentiate transmural from non-transmural MI or determine the site of MI by comparing the findings with those of contrast-enhanced CMR. A total of 27 patients (59.5+/-12.9 years) with a history of MI (6.4+/-2.9 months) underwent CMR (Magnetom, Siemens, Erlangen, Germany). Cine images were acquired in the horizontal and vertical long axes and short axis by TrueFISP. Contrast-enhanced CMR images were acquired in the same axes by segmented FLASH 15 min after administration of gadolinium-DTPA (0.15 mmol/kg). This showed the MI to be transmural in 11 patients and non-transmural in 16. An electrocardiogram (ECG) was recorded in all patients before CMR. T-wave alterations, descending ST-depression, pathological Q-waves and absent R waves were more frequent in non-transmural MI than transmural MI, as defined by contrast-enhanced CMR (p> or =0.618). However, none of the differences were statistically significant. R-wave reduction, q waves and horizontal ST-depression were more frequent in transmural than in non-transmural MI (p> or =0.157). Again, the differences were not significant. The sensitivity of the ECG for MI localization was highest in inferior infarctions (85.71%), the specificity was highest in anterior infarctions (100%), the best positive predictive value (80%) was achieved for anterolateral infarctions, and the best negative predictive value for lateral infarctions (95.83%). Transmural and non-transmural MI cannot be differentiated by ECG. The ECG is most accurate in detecting anterolateral MI.
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Cardiovascular magnetic resonance (CMR) is an accurate tool for the determination of right and left ventricular volumes and ejection fractions. However, the current standard short-axis technique is time-consuming and thus, often not practicable for routine daily use, because papillary muscles and trabeculations have to be marked and their volumes subtracted from the total ventricular volume. To reduce calculation time we evaluated the volumetric data that included papillary muscle and trabecular volumes and compared the outcome with the results of the standard technique. Thirty patients (17 healthy, 13 with coronary heart disease) were examined by CMR using TrueFISP (Magnetom, Siemens, Erlangen, Germany). Right and left ventricular volumes and ejection fractions were calculated using the standard short-axis technique and then again without subtracting papillary and trabecular volumes. The two methods were compared by determining the differences in results for ventricular volumes and ejection fractions. Statistically significant differences were found between the two methods for right and left ventricular stroke volumes and end-systolic volumes, and left ventricular end-diastolic volumes (EDV) (p < or = 0.011). No significant difference was found for right ventricular end-diastolic volumes (p > or = 0.149) or left or right ventricular ejection fraction (p > or = 0.130). Except in the case of left ventricular EDV, the deviations in the results of method 1 and method 2 did not vary significantly with the presence or absence of heart disease. Measurements were obtained considerably more quickly with the modified method than with the standard short-axis method (25 +/- 4 min vs. 13 +/- 3 min, p = 0.000). Although systematic differences were found when papillary and trabecular volumes were not subtracted, these differences are small and may not be of clinical relevance in healthy subjects or patients with coronary heart disease. Not subtracting the volumes of these structures enables faster determination of right and left ventricular volumes and ejection fractions without loss of the accuracy associated with the standard short-axis technique.
INTRODUCTION: Cardiovascular magnetic resonance (CMR) allows very accurate, but time-consuming, volume assessment by the short-axis slice summation technique. The single and biplane methods of volume assessment are used less, partly because FLASH cine imaging provides poor blood-myocardium contrast in long-axis views. TrueFISP gives excellent blood-myocardium contrast, even in patients with heart failure. We hypothesized that the single plane and biplane methods of volume assessment in TrueFISP images might provide an acceptable degree of accuracy and be quicker than the short axis method, and that single and biplane left ventricular volume assessment would be more accurate with TrueFISP than with FLASH in patients with impaired ventricular function. METHODS: Short- and long-axis CMR images were obtained by FLASH and TrueFISP with a 1.5-T scanner. We determined the accuracy of both single and biplane long-axis methods for left ventricular volume and ejection fraction (EF) measurements compared with the conventional short-axis method in 10 heart failure patients using both FLASH and TrueFISP and in 9 healthy subjects using TrueFISP. RESULTS: No difference in volumes and EF was found between the single plane method, the biplane method, and the short-axis method using TrueFISP for image acquisition, in both patients and healthy subjects. The same was true of the results obtained by FLASH in the patients with heart failure. CONCLUSIONS: The single and biplane methods, regardless of whether TrueFISP or FLASH is used, are a reasonable and rapid alternative to the conventional short-axis approach for left ventricular volume and EF assessment in patients with heart failure and impaired ventricular function.
AIM: To evaluate right ventricular wall motion abnormalities in healthy subjects using a new segmental model for the right ventricle. METHODS AND RESULTS: 29 healthy subjects (9 female, 20 male, mean age 48.9+/-15 years) underwent cardiovascular magnetic resonance imaging (CMR; 1.5-Tesla Sonata, Siemens, Erlangen, Germany) for the evaluation of cardiac function and right ventricular wall motion. A steady-state free precession gradient-echo sequence (TrueFISP) was used. Right ventricular wall motion was analyzed, and the site of areas of disordered motion was classified according to the new segmental model. Such areas were seen in 27 (93.1%) of the 29 subjects. Dyskinesia was found in 22 subjects (75.9%), hypokinesia in 11 (37.9%), and bulging in 8 (27.6%). The number of wall motion abnormalities diagnosed was significantly higher in the transverse plane (86.2%) than in the short-axis plane (13.8%) and the horizontal longitudinal plane (41.4%; p = 0.000). CONCLUSION: Right ventricular wall motion abnormalities are one of the criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy. However, our findings indicate that they may also be seen around the insertion of the moderator band in healthy subjects, so that the significance of their presence at this site in patients undergoing diagnostic investigations for this disease should be interpreted with caution.
OBJECTIVES: To determine whether the biplane area-length method can be used for the evaluation of left atrial volumes and ejection fraction with cardiovascular magnetic resonance imaging (CMR) by TrueFISP in normal subjects and patients with atrial fibrillation. BACKGROUND: Atrial fibrillation is the most common arrhythmia in elderly patients. Left atrial size and volumes play an important role in predicting short and long-term success after cardioversion. METHODS: Fifteen healthy subjects (mean age 65.6+/-6.4 years) and 18 patients (mean age 67.2+/-8.8 years) with atrial fibrillation were examined by CMR (Magnetom, Siemens, Erlangen, Germany). Images were acquired by TrueFISP using the horizontal and vertical long-axis plane to measure left atrial end-diastolic and end-systolic areas and longitudinal dimensions. Volumes were determined with commercially available software. Left atrial end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) were determined by the biplane area-length method and compared to findings obtained by the standard short-axis method. Images were acquired and analyzed a second time in the patients with atrial fibrillation. RESULTS: There was no difference in age between men and women (p=0.147) and healthy subjects and patients (p=0.128) included in the study. EDV and ESV were significantly higher and SV and EF significantly lower in patients with atrial fibrillation than in healthy subjects (p < or = 0.009), regardless of the method used. The values obtained for EDV and ESV by the biplane area-length method were significantly higher in both healthy subjects (p<0.001) and patients with atrial fibrillation (p<0.001) than those obtained by the standard short-axis approach, whereas SV (p> or = 0.057) and EF (p> or = 0.118) did not differ significantly. In the second investigation in patients with atrial fibrillation, ESV, SV, and EF did not differ significantly between the two methods (p> or =0.481). Assessment of interobserver variability revealed good agreement in the findings of the two observers, both in normal sinus rhythm and atrial fibrillation (overall variability 0.8+/-6.5%). CONCLUSIONS: The biplane area-length method can be used in CMR images obtained by TrueFISP to assess left atrial volumes and ejection fraction in normal subjects and patients with varying cardiac cycle length, as in atrial fibrillation.