[Vibration artefacts in the electrocardiogramm].
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Diagnosis, Differential↗
Biomedical subjects
D Pfeiffer
Publications and source records attributed to D Pfeiffer.
[Catheter ablation as an emergency treatment in Wolff-Parkinson-White syndrome with signs of acute infarct].
A 53-year-old man known to have Wolff-Parkinson-White syndrome suffered an acute posterior-wall myocardial infarction. Despite successful thrombolysis treatment with streptokinase he continued to have attacks of supraventricular tachycardia with angina. The ECG showed a short P-R interval and pre-excitation with positive delta waves in leads V1-6, as well as signs of re-infarction. The tachycardias could not be satisfactorily suppressed by drug treatment. Coronary angiography revealed triple vessel disease. During this investigation ventricular extrasystoles occurred which initiated orthodromic supraventricular tachycardia and angina, as well as monophasic S-T elevations in leads II, III and aVF. This provided the indication for immediate high-frequency catheter ablation left laterally at the mitral anulus after a left-lateral accessory conduction pathway had been identified. Three days later the stenoses of the circumflex and anterior interventricular branches were dilated. The patient has been free of symptoms for 3 months and can exercise up to 150 W. The tachycardias have not recurred.
Angina Pectoris↗
Prospective study of retrograde coronary venography in patients with posteroseptal and left-sided accessory atrioventricular pathways.
The morphologic features of the coronary vein system was prospectively studied with retrograde venography in 117 patients with left-sided (78 patients) and posteroseptal accessory pathway (39). Findings were compared with accessory pathway localization. A mean of 3.3 +/- 1.5 venous branches draining into the coronary sinus or the great cardiac vein could be visualized. The morphologic condition was described and classified. Incidence, morphologic condition, and distribution did not differ between left-sided and posteroseptal accessory pathway. Venous abnormalities including ectasy, diverticulum, narrowing, angulation, and hypoplasia occurred in 22.2%. Diverticulum and narrowing were present in posteroseptal accessory pathway only and always related to the successful ablation site. In patients with left-sided accessory pathway, ectasy, angulation, and hypoplasia were found. Anomalies were less frequent (9% vs 43.6%, p < 0.001) and had no relation to accessory pathway localization. However, the successful ablation site was in 42.3% located < 5 mm to an angiographically visualized venous branch. In conclusion, posteroseptal accessory pathways are often related to coronary sinus abnormalities. In patients with a left-sided accessory pathway venous malformation is uncommon, whereas a close anatomic relation exists between accessory pathway localization and venous ventricular branches.
Adolescent↗
Intravenous adenosine during atrioventricular reentrant tachycardia: induction of atrial fibrillation with rapid conduction over an accessory pathway.
Adenosine is considered to be a safe agent for termination of orthodromic atrioventricular reentrant tachycardia in patients with accessory pathways. A case with initially successful accessory pathway ablation and without preexcitation during sinus rhythm is presented, in which intravenous adenosine (6 mg) during orthodromic tachycardia was followed by atrial fibrillation and sudden onset of preexcitation with subsequent rapid ventricular response with moderate hemodynamic compromise.
Adenosine↗
Pacemaker function during radiofrequency ablation.
There are increasing numbers of radiofrequency current ablation procedures being reported. Selected patients have antitachycardia or antibradycardia pacemakers. The pacemaker behavior during and after ablation procedures differs widely. We report on the pacemaker reaction of 25 patients with 13 different devices, most with unipolar electrodes. Sensing failures were observed in 8 (32.0%) and pacing failures in 4 (16.0%) patients. Prolonged pauses and induction of tachyarrhythmias were observed. No pacemaker damage was seen although it is reported by other investigators. We recommend deactivation of implanted generators and an external bipolar pacing electrode. Manufacturers should focus their attention on this problem and protect the generators and their functions for 500 kHz radiofrequency current.
Adult↗
Echocardiographic imaging of coronary sinus diverticula and middle cardiac veins in patients with preexcitation syndrome: impact on radiofrequency catheter ablation of posteroseptal accessory pathways.
To determine the value of echocardiography for identifying coronary sinus (CS) diverticula and middle cardiac veins (MCVs) in patients with posteroseptal accessory pathways (PAPs), transthoracic (TTE) and transesophageal echocardiography (TEE) were performed in 18 consecutive patients with PAP and in 15 control subjects with left lateral accessory pathway before CS angiography. The size, shape, and location of CS diverticula and MCV were described and compared to angiography. TEE and angiography were concordant for the identification of diverticula (n = 5) and agreed for depicting MCV in 22 of the 27 cases. TTE revealed 4 of 5 diverticula and identified 4 of 27 MCV (P < 0.001). Fourteen MCV but no diverticula were found in the control subject. There was no significant difference between transesophageal and angiographic measurements for the width (23.5 +/- 4.9 vs 26.8 +/- 6.6 mm) and height (13.5 +/- 3.8 vs 15.7 +/- 3.4 mm) of the diverticula, and the width (3.5 +/- 0.7 vs 3.7 +/- 0.6 mm) of MCV. TEE underestimated the length of the MCV (12.0 +/- 1.8 vs 27.2 +/- 6.0, P < 0.001). Delivery of radiofrequency energy within the neck of a diverticulum or within an MCV was successful in 5 of 5, and 6 of 13 cases in patients with PAPs, respectively. In conclusion, echocardiography was as reliable as angiography for detecting and describing CS diverticula and MCV in patients with preexcitation syndrome. Echocardiography is recommended prior to electrophysiological study because it may simplify radiofrequency catheter ablation.
Adult↗
Impact of the local atrial electrogram in AV nodal reentrant tachycardia: ablation versus modification of the slow pathway.
INTRODUCTION: The purpose of this study was to determine the predictors of successful ablation versus modification sites of the slow pathway in patients with AV nodal reentrant tachycardia. Complete elimination of slow pathway conduction ("ablation") is considered to be an appropriate endpoint during radiofrequency (RF) current delivery, whereas the persistence of residual slow pathway conduction with or without single echo beats ("modification") may be indicative of tachycardia recurrence. METHODS AND RESULTS: Of 131 patients, 71 consecutive patients were followed for 15.1 +/- 7.6 months. After elimination of inducible AV nodal reentrant tachycardia in all patients, residual slow pathway conduction (modification) persisted in 38 patients, whereas complete elimination of slow pathway conduction (ablation) was documented in 33 patients. Including electrophysiologic study after 5 to 7 days and after 3 to 6 months, 6 (8.4%) patients had recurrences: 5 with residual slow pathway conduction after the procedure and 1 with complete elimination of slow pathway conduction (P < 0.05). As compared with modulated sites, ablation sites of the slow pathway were characterized as follows: (1) duration of the local atrial electrogram (AEGM) (66.7 +/- 10.2 vs 54.1 +/- 12.6 msec, P < 0.01); (2) interval from the end of the AEGM to onset of His-bundle deflection (4.4 +/- 8.2 vs 16.1 +/- 9.3 msec, P < 0.01); and (3) number of peaks of the AEGM as an indicator of fractionation (4.1 +/- 0.7 vs 3.0 +/- 0.8, P < 0.01). The rate of junctional tachycardias (103.4 +/- 12.1 vs 102.1 +/- 16.9 per min), the AV ratio (0.4 +/- 0.5 vs 0.5 +/- 0.5), the number of RF current deliveries (4.1 +/- 4.4 vs 4.5 +/- 4.4), the duration of the procedure (124.1 +/- 45.3 vs 125.6 +/- 42.3 min), and the fluoroscopy time (15.5 +/- 10.8 vs 16.6 +/- 9.6 min) as well as power and total energy of RF current deliveries and the anatomically calculated catheter position at the successful site were not statistically different. A subset analysis in patients who received only a single RF application showed the same results for both groups. Patients without recurrence (n = 65) were found to have longer duration of the AEGM (61.9 +/- 14.6 msec) and a shorter interval from the end of AEGM to the onset of His-bundle deflection (10.1 +/- 12.2 msec) than patients with recurrence (n = 6) (47.5 +/- 7.5 msec and 20.8 +/- 12.8 msec, respectively). CONCLUSION: Complete ablation of the slow pathway resulted in a lower recurrence rate. The complete ablation approach is feasible using precisely analyzed local AEGMs to guide RF current in AV nodal reentrant tachycardia in a short procedure time.
Adult↗
[Prognostic value of signal averaged ECG in dilated cardiomyopathy with spontaneous and induced ventricular tachyarrhythmias].
UNLABELLED: Ventricular late potentials in signal-averaged ECG are a predictor of ventricular tachyarrhythmias in patients with coronary artery disease. The role of signal-average ECG in non-ischemic dilated cardiomyopathy has not been defined yet. We studied the prognostic impact of an abnormal signal-averaged ECG in 31 patients with non-ischemic dilated cardiomyopathy. All signal-averaged ECG recordings were analyzed by time-domain analysis as well as by frequency analysis with spectrotemporal mapping. RESULTS: In 13 (42%) patients time domain analysis and in 9 (29%) patients frequency analysis was found to be abnormal. During follow-up (13 +/- 7 months) seven (23%) patients developed spontaneous ventricular tachyarrhythmias. The mean ejection fraction and the results of programmed ventricular stimulation did not differ significantly between patients with and without clinical episodes. Abnormal time domain analysis was found in five (71%) patients with and in eight (33%) patients without spontaneous tachyarrhythmias (p = 0.07), and abnormal frequency analysis in 3 (43%) patients versus 6 (25%) patients (p = 0.36). The low-amplitude-signal duration was significantly increased in patients with tachyarrhythmias (p = 0.008). Ventricular tachyarrhythmias occurred in 38% of patients with abnormal time domain analysis and in 33% of patients with abnormal frequency analysis. In patients with normal signal-averaged ECG the incidence reached 11% and 18%. For time-domain analysis the sensitivity was 71%, specificity 67%, positive predictive value 38%, and negative predictive value 89%, for spectrotemporal mapping 43%, 75%, 33%, and 82%, respectively. The incidence of electrophysiologically inducible ventricular tachyarrhythmias in patients with abnormal signal-averaged ECG exceeded that in patients with normal findings. CONCLUSION: In patients with non-ischemic dilated cardiomyopathy a normal signal-averaged ECG is associated with a reduced occurrence of ventricular tachyarrhythmic events. Thus, signal-averaged ECG contributes to the evaluation of these patients. The negative predictive value exceeded the positive predictive value.
Adult↗
Complications of pacemaker-defibrillator devices: diagnosis and management.
Treatment of resuscitated patients with implantable cardioverter defibrillators has become increasingly more common as a method for the prevention of sudden cardiac death. Major complications such as perioperative death (incidence 2% to 8%), infection (2% to 11%); and lead-related problems (3% to 27%) have been described in previous trials. In our experience with 140 patients, problems were related to leads (n = 11), the device (n = 2), pacing (n = 1), sensing (n = 13), and defibrillation function (n = 5). Additional problems that occurred during the perioperative period included infection (n = 11), hematoma, and seroma (n = 2). Thrombus formation along endocardial leads was observed in 13 of 62 (21%) patients. Different arrhythmias (n = 10), such as sinus tachycardia, atrial fibrillation, and nonsustained, slow or incessant ventricular tachycardia with shock delivery, were also detected. Surgical management (predominantly for the major problems) was used in 31 (48%) patients, drug treatment in 25 (39%), and reprogramming of the device in 24 (38%) patients. All of these problems can result in an increase in mortality rates. This article provides an overview of the complications of cardioverter defibrillator treatment and is based on both published data and our series.
Arrhythmias, Cardiac↗
Predictors of outcome in patients with implantable transvenous cardioverter defibrillators.
The identification of patients who benefit most from implantable cardioverter defibrillator (ICD) therapy is of great interest. To find out if clinical variables, the signal-averaged electrocardiogram, and electrophysiologic study predict occurrence of appropriate ICD discharges and death, we followed-up on 76 patients after implantation of a transvenous ICD. During a mean follow-up period of 18.2 +/- 6.4 months, 29 patients (38.6%) experienced at least one appropriate episode. When these patients were compared with those who had either no therapy or inappropriate episodes, three variables were found to be significant in the identification of patients who experienced appropriate discharges: (1) The mean ejection fraction of patients who received appropriate discharges was 35.4% +/- 13.5% versus 45.1% +/- 15.3% in the other group (p < 0.05); (2) patients with appropriate therapy had sustained monomorphic ventricular tachycardia that was more likely to be inducible (75.9% vs 21.2%, p < 0.01); and (3) in patients with appropriate therapy ventricular fibrillation was less likely to be inducible (10.3% vs 25.5%, p < 0.05). The signal-averaged electrocardiograms were more often abnormal, but the differences were not significant. The total mortality rate in our patient group was 7.8%, with nonsudden cardiac death in four patients, noncardiac death in one patient, and sudden death in one patient. In our patient group a lower ejection fraction and inducible sustained monomorphic ventricular tachycardia were predictors of future ICD discharge after implantation. The survival rate after transvenous ICD implantation is excellent; a longer follow-up period is necessary to further define predictors of total mortality rate.
Cardiac Pacing, Artificial↗
Intraoperative laser photocoagulation of ventricular tachycardia.
Mapping-guided laser photocoagulation was used as an intraoperative technique to treat ventricular tachycardia (VT) in patients with ischemic heart disease. Laser irradiation was delivered during VT to sites identified with local diastolic activation or, if VT was not inducible, to sites identified with delayed potentials during sinus rhythm. The group consisted of 12 male and two female patients who ranged in age from 41 to 74 years (mean, 59.9 years). All of the patients had experienced myocardial infarction before surgery; in eight cases myocardial infarction was associated with an anterior wall aneurysm, and in one case it was associated with a posterior wall aneurysm. Identified sites for laser irradiation were restricted to the endocardium in only four patients, whereas six patients showed endocardial and epicardial foci and four of them without circumscript aneurysm were subjected only to epicardial laser photocoagulation. Resection of an aneurysm was performed in nine patients, and additional bypass grafting (one to four grafts) has been performed in 10 patients. There were two perioperative deaths. Laser photocoagulation has proved to be an efficacious method for the surgical treatment of VT. It gives access to epicardial sites and, in particular, allows limited surgery in patients with restricted left ventricular function and no circumscript aneurysm.
Cardiopulmonary Bypass↗
Loss of late potentials after radiofrequency catheter ablation of recurrent ventricular tachycardia in a patient with right bundle branch block.
The case of a patient with a history of myocardial infarction and recurrent ventricular tachycardia undergoing attempted radiofrequency catheter ablation with loss of late potentials is described. Prior to energy delivery fractionated, late activation could be found using the signal-averaged ECG despite the presence of a right bundle branch block. After successful catheter ablation, the clinical ventricular tachycardia was no longer inducible and the signal-averaged ECG, recorded the next day, showed marked changes indicating loss of late potentials. Our report emphasizes the possibility of late potential recordings despite the presence of bundle branch block.
Aged↗
[Methods, topography and mechanisms of radiofrequency ablation of AV-nodal reentry tachycardia].
Three different methods of radiofrequency catheter ablation of AV nodal reentrant tachycardia were investigated in 128 patients. Results, relapses, and complications using anterior approach (n = 15), moved catheter (n = 20), and posterior-inferior approach (n = 93) were compared. Eight mechanisms of ablation of AV nodal reentrant tachycardia were distinguished: 1) Ablation of fast pathway (n = 8), 2) of slow pathway (n = 22), 3) modification of fast (n = 12), 4) slow (n = 54), or 5) both pathways (n = 13), 6) Ablation of fast and modulation of slow pathways (n = 4), 7) ablation of slow and modulation of fast pathways (n = 12), and 8) ablation of both pathways (n = 3). The criteria of diagnosis of these mechanisms and a mapping grid of Koch's triangle were proposed. The fast pathway is located in the anterior septum in a region with identical amplitudes of atrial and ventricular deflections and the slow pathway could be found posteriorly in a more ventricular location. The anatomical location of the slow pathway differed more widely than the location of the fast pathway. The best method with lowest risk could be recommended as the ablation of the slow pathway. This method implicated the lowest incidence of complications. We observed relapses in 12 patients during control studies 30 min, 3-5 days, and 3-6 months after first ablation procedure. These arrhythmias could be ablated in a second attempt in eight and in a third procedure in four patients. With increasing experience the radiofrequency catheter ablation of AV nodal reentrant tachycardia will be the method of first choice in patients with recurrent tachycardia.
Adult↗
[Adenosine in prediction of the success of radiofrequency ablation in Wolff-Parkinson-White syndrome].
Rapid bolus injection of adenosine has been shown to produce transient atrioventricular (AV) nodal block while having almost no direct effect on accessory pathway conduction. The aim of this study was to determine the efficacy of adenosine for prediction of success of catheter ablation in WPW syndrome in 31 patients (23 with preexcitation; 8 with concealed conduction) before and 30 min, 5-7 days, and 3-6 months after attempted radiofrequency catheter ablation. Before ablation 6 mg adenosine produced maximal preexcitation (QRS duration increased from 100 +/- 15 ms to 123 +/- 18 ms) in patients with manifest preexcitation, while AV block occurred in all patients (100%) with concealed conduction for 1.5 +/- 0.5 s. No patient had accessory pathway conduction unmasked by adenosine. In 30/31 (96%) of patients retrograde conduction was unchanged prior to ablation. Immediately after ablation adenosine induced AV and VA block in 29 (93%) patients. These results were also present 5-7 days and 3 months later and were confirmed by electrophysiologic study. The positive and negative predictive values are 96% and 100%, respectively. Adenosine is reliable and useful to predict short- and long-term success following radiofrequency catheter ablation.
Adenosine↗
Radiofrequency catheter ablation of a posteroseptal accessory pathway within a coronary sinus diverticulum.
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Catheter Ablation↗
Enhancing biosensor performance using multienzyme systems.
Enhancing the performance of biosensors, in terms of increasing the range of analytes that may be detected, and the sensitivity and specificity of the detection event, would improve the prospects for commercializing this technology. Coupling the catalytic activities of several enzymes is one approach being used to address these issues. Sequences of enzymes, where ligand binding triggers the activation of enzymes, or where biocatalytic pre-concentration of intermediates permits augmentation of the signal, may be used. In addition, enzymatic recycling of the analyte can be used to increase the sensitivity by several orders of magnitude.
Animals↗
Effects of antiarrhythmic drugs on epicardial defibrillation energy requirements and the rate of defibrillator discharges.
Antiarrhythmic drugs are commonly used with the implantable cardioverter/defibrillator to treat recurrent ventricular tachyarrhythmias. Since various antiarrhythmic drugs have been reported to alter defibrillation threshold, an important question is whether the device will provide adequate energy for defibrillation during long-term follow-up and to what extent antiarrhythmic drug treatment will affect defibrillation energy requirements. To answer these questions, the defibrillation thresholds were determined in 20 patients using an epicardial patch-patch lead configuration at the time of implantation and at the time of pulse generator replacement. During a mean follow-up period of 24 +/- 6 months, the defibrillation threshold increased significantly from 14.2 +/- 3.7 joules to 18.3 +/- 5.5 joules in the entire group (P < 0.05). This increase in defibrillation threshold was due to a marked elevation of defibrillation energy requirements in the subgroup of patients taking amiodarone compared with patients receiving mexiletine. Based on these results it is mandatory to retest defibrillation threshold at any time of pulse generator replacement to guarantee continued effectiveness. In particular, if amiodarone treatment is initiated after implantation of a defibrillator, it is recommended to reevaluate defibrillation threshold to ensure an adequate margin of safety.
Amiodarone↗
[Multiparametric flow cytometry determination of the EGF receptor and DNA cell cycle distribution in cervix cancer].
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Cell Cycle↗