[Sub-pectoral implantation of defibrillators: intraoperative data and long-term outcome]. / Subpektorale Implantation von Defibrillatoren: Intraoperative Daten und Langzeitbeobachtung.

UNLABELLED: The present study examined the perioperative mortality and morbidity and lead-related complications in patients who had a defibrillator with a transvenous lead system and subpectoral implantation of the generator. Fifty-four out of 57 consecutive patients (95%) received a transvenous lead system. One patient had an acceptable defibrillation threshold with an additional subcutaneous patch whereas no sufficient defibrillation threshold was found in another 2 patients. Two patients died due to congestive heart failure after implantation. Perioperative complications were observed in 4 patients (7%) including pericardial effusion, pocket hematoma, injury of the plexus brachialis and a pneumothorax. None of these complications required surgical intervention. Fifty-five patients were discharged from the hospital. During 27 +/- 10 months none of these patients died. Lead-related complications were observed in 3 patients (5.5%) including microdislocation in two and a outer conductor fracture in one of the lead. CONCLUSION: Technical advancement such as a non-thoracotomy lead system and smaller devices have made the onc-incision approach and subpectoral implantation of the ICD generator clinical routine. Nevertheless complications related to the lead system can occur. Therefore frequent controls of patients with ICD are necessary.

Efficacy and safety of d,l-sotalol in patients with ventricular tachycardia and in survivors of cardiac arrest.

OBJECTIVE: The aim of this study was to assess the antiarrhythmic efficacy and safety of d,l-sotalol in patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) and in survivors of cardiac arrest and to identify the factors that are associated with arrhythmia suppression and therefore might be helpful in predicting drug efficacy. BACKGROUND: Despite increasing use of the class III antiarrhythmic agent d,l-sotalol, data on its short- and long-term efficacy in a large patient cohort are lacking. Information on its long-term tolerability and safety is limited. METHODS: A total of 396 patients with inducible sustained VT or VF (VT/VF) underwent programmed stimulation before and after receiving oral d,l-sotalol (240 to 640 mg/day). Patients in whom VT/VF was rendered either noninducible or more difficult to induce (more extrastimuli or faster drive cycle length needed for VT/VF induction) were discharged on a regimen of oral d,l-sotalol. RESULTS: d,l-Sotalol suppressed VT/VF in 151 patients (38.1%) and rendered the arrhythmia more difficult to induce in 76 patients (19.2%). The extent of drug-induced prolongation of right ventricular refractoriness and a shorter VT cycle length at baseline were independent predictors of immediate drug efficacy. Torsade de pointes developed in seven patients (1.8%). Two hundred ten patients (53%) continued to receive d,l-sotalol and were followed up for 34 +/- 18 months (mean +/- SD). The actuarial rates for the absence of arrhythmic recurrence (either VT/VF or sudden death) at 1 and 3 years were 89% and 77%, respectively. Actuarial rates for overall survival at 1 and 3 years were 94% and 86%, respectively. VT/VF suppression by d,l-sotalol was an independent discriminant variable that separated patients with and without arrhythmia recurrence. However, noninducibility of VT/VF did not predict freedom from sudden death. CONCLUSION: Oral d,l-sotalol is effective and safe in patients with VT/VF. However, sudden cardiac death develops in a significant proportion of patients, and programmed stimulation seems to be of limited value for its prediction.

Cardioverter discharges following sensing of electrical artifact due to fluid penetration in the connector port.

We report a unique case of fluid penetration, 3 months after implantation, in the connector port of an automatic implantable cardioverter defibrillator (ICD) with transvenous subcutaneous lead system. The patient had coronary artery disease and recurrent episodes of ventricular fibrillation, the fluid caused electrical signals interpreted as ventricular fibrillation by the device, which triggered shock delivery.

[Efficacy of the implantable cardioverter-defibrillator in patients on the waiting list for heart transplantation]. / Effizienz des implantierbaren Cardioverter-Defibrillators bei Patienten auf der Warteliste zur Herztransplantation.

8 of 122 patients receiving an implantable cardioverter defibrillator (ICD) in our department since 1985 for the treatment of ventricular tachyarrhythmias were considered candidates for cardiac transplantation. In 6 of 8 patients, at least one successful ICD discharge (range 1-378 discharges) was documented in the follow up time until transplantation. These therapies included cardioversions/defibrillations as well as overdrive stimulation in sustained monomorphic ventricular tachycardia. 1 patient died shortly before receiving a compatible organ. The remaining 7 patients survived successful heart transplantation undertaken 7-34 months after implantation of the cardioverter defibrillator. Cardiac transplantation was not complicated in any of these patients by the previous ICD management. Our results show the high efficacy of ICD as "bridge to transplant" therapy unit cardiac transplantation.

[The value of tilt-table examination in diagnosis of syncope: studies of 24 patients]. / Der Stellenwert der Kipptischuntersuchung in der Synkopendiagnostik: Untersuchungen an 24 Patienten.

Sudden hypotension, alone or combined with bradycardia is a major cause of syncope. 24 consecutive patients with a history of > 1 syncope of unknown aetiology were exposed to vagal provocation by the head-up tilt test. The clinical symptoms were reproduced in 11 patients under the given protocol, representing a sensitivity of 46%. The patients were followed up for 13.2 +/- 5.3 months. 7 of the 11 patients (64%) with a positive result on tilting versus 2 of the 13 patients (15%) with a negative result had a relapse of syncope. There was no statistical difference between the groups with regard to the number of syncopal episodes before patients were included in the study. Syncope in the head-up tilt test is, thus, a pointer towards identifying with a higher incidence of syncope on follow-up.

Efficacy of ajmaline and propafenone in patients with accessory pathways: a prospective randomized study.

In a prospective randomized study, we assessed the electrophysiologic effects and the efficacy of ajmaline versus propafenone in patients with accessory pathways (APs). During initiated atrioventricular (AV) reentrant tachycardia or atrial fibrillation (AF), ajmaline (1 mg/kg as bolus followed by infusion of 15 micrograms/kg/min) or propafenone (2 mg/kg, followed by infusion of 30 micrograms/kg/min.) were randomly administered intravenously (i.v.) in 40 patients with APs. AV reentrant tachycardia terminated in 15 of 16 patients (94%) on ajmaline and in 12 of 15 patients (80%, NS) on propafenone. AF ceased in 4 of 4 patients receiving ajmaline and in 3 of 5 patients receiving propafenone (n.s.). During continuous infusion of drugs, AV reentrant tachycardia became noninducible in 10 (50%) patients receiving ajmaline, as compared with 6 (32%) receiving propafenone (NS). Both drugs significantly prolonged the anterograde and retrograde effective refractory periods (ERPs) of the AP. There were no significant differences in changes in electrophysiologic parameters between the two drugs. Ajmaline and propafenone are highly effective and safe in terminating and preventing reinitiation of AV reentrant tachycardia or AF in patients with APs. Both drugs significantly prolonged the anterograde and retrograde ERPs of the APs.

[Complications in transvenous and transvenous-subcutaneous implantable defibrillator systems]. / Komplikationen bei transvenös bzw. transvenös-subkutan implantierbaren Defibrillatorsystemen.

Due to technical improvement using the transvenous-subcutaneous approach for lead fixation for cardioverter-defibrillator implantation, the incidence of device implantation has extended enormously. While a significant lower perioperative mortality in transvenously implanted systems compared to epicardially fixed implantable cardioverter-defibrillator (ICD) has been proven, perioperative as well as complications during follow-up are not analyzed systematically. In 59 patients, in whom transvenous-subcutaneous ICDs had been implanted, 3 patients showed bleeding complications in the subcutaneous patch area, 1 patient showed a bleeding in the device pocket, and in 1 patient a seroma in the subcutaneous patch region was observed necessitating surgical revisions. During follow-up of 10 +/- 7 months, lead dislocations were observed in 6 patients, in another 6 patients patch crinkling was observed. There was 1 patient with a lead fracture as well as 1 patient with a bleeding in the subcutaneous patch region. Despite the high efficacy of this therapy used in patients with life-threatening ventricular arrhythmias, these potential complications have to be considered.

Hemodynamics during ventricular tachyarrhythmias.

The hemodynamic consequences of ventricular tachycardias are caused by cardiac and peripheral reactions. As a result, cardiac output and arterial pressure decrease. Even if the decrease is related to the tachycardia rate and left ventricular function, clinical symptoms do not in each case correlate with the degree of hemodynamic compromise. The explanation for this phenomenon is the different cardiac and peripheral reaction of patients to an immediate rise in heart rate. In this regard, it is questionable if pressure monitoring is superior to heart rate monitoring as a sensor for implantable antitachycardia devices.

[Therapy monitoring in cardiac arrhythmias: guidelines for evaluation of anti-arrhythmia effects]. / Therapiekontrolle bei Herzrhythmusstörungen: Richtlinien zur Prüfung antiarrhythmischer Wirkungen.

The incidence of avoidable or unavoidable, cardial and extracardial side effects is a risk in the drug treatment of supraventricular and ventricular tachyarrhythmias. Therefore the indication of antiarrhythmic drug therapy has to be considered critically. The patient has to be controlled close-meshed, especially at the beginning of the drug treatment. In patients with life threatening ventricular tachyarrhythmias, which can not be suppressed by drug therapy, nonpharmacological therapy--implantable cardioverter/defibrillator, catheterablation and heart-transplantation--has to be discussed.

[Electrocardiography and electrophysiologic findings in patients with myotonic muscular dystrophy]. / Elektrokardiographische und elektrophysiologische Befunde bei Patienten mit myotoner Muskeldystrophie.

Myotonic dystrophy is associated with diffuse cardiac conduction disturbances. Seven consecutive patients, all asymptomatic with respect to cardiac abnormalities, were investigated by means of ECG, Holter monitoring, and invasive electrophysiologic studies (EPS). During Holter monitoring, no abnormalities were found in any patient, except for one patient who showed single monomorphic VEBs. During EPS three patients showed conduction disturbances in the AV-node (AVN) as well as in the His-Purkinje-system (HPS) in another three patients. Except for two patients ventricular vulnerability was normal during programmed ventricular stimulation. A considerable number of asymptomatic patients with myotonic dystrophy reveals AVN- and HPS-conduction disturbances as shown during EPS.

[Implantation of defibrillators with transvenous-subcutaneous electrode systems]. / Implantation von Defibrillatoren mit transvenös-subkutanem Elektrodensystem.

In 23 patients an integrated pacemaker-defibrillator-system with transvenous-subcutaneous lead system was implanted. Two transvenous electrodes were positioned, one in the right ventricle for sensing, pacing and defibrillation and one in the superior vena cava for defibrillation alone. Another electrode was positioned subcutaneously near the ventricular apex for defibrillation. In 22 patients (96%) the lead system could be implanted without a major complication. The defibrillation threshold for ventricular fibrillation was 16 +/- 5 joules. During follow up of 6 +/- 4 months all spontaneous tachyarrhythmias were successfully terminated. There were three complications during follow up. In 2 patients the transvenous electrode dislocated and one patient showed a sensing malfunction. In conclusion the non-thoracotomy approach is effective, reduces the perioperative risk and represents therefore a great advantage compared to peri-/epicardial lead system.

[Value of a provocation test with diprafenone in patients with bifascicular block]. / Stellenwert eines Provokationstestes mit Diprafenon bei Patienten mit bifaszikulärem Block.

The significance of provocative tests in patients with bifascicular block is not established. We studied 14 patients with bifascicular block, syncope and documented episodes of high degree AV-block. 1.5 mg/kg Diprafenon was given after a period of at last 12 hours 1:1 AV-conduction. Electrophysiologic evaluation was performed before and after diprafenon. AV-block III could be provoked in 1 of 14 patients with Diprafenon. Therefore a total AV block occurred in 7% of patients. The low sensitivity of provocative test with Diprafenon even in patients with documented high degree AV-block prevents its application in clinical practice.

Catheter ablation of ventricular tachycardia using radiofrequency current.

Catheter ablation techniques have evolved as an alternative to map-guided surgery and proven effective in a variety of supraventricular tachyarrhythmias. Direct current catheter ablation has been shown to be effective in about 50 to 70% of cases. Approximately, 60% of patients with structural heart disease and monomorphic ventricular tachycardia were successfully treated using direct current ablation techniques. This overall success rate and possible risks associated with the use of direct current have stimulated the search for other energy sources appropriate for catheter ablation. Presently, only a few preliminary reports on the clinical efficacy of radiofrequency energy for the treatment of ventricular tachyarrhythmias in man exist. 23 patients with identifiable heart disease at a mean age of 52 +/- 17 years underwent radiofrequency catheter ablation. 16 patients had coronary artery disease, one patient dilative cardiomyopathy and six patients had arrhythmogenic right ventricular disease. All patients presented with chronic current sustained ventricular tachycardia. After detailed endocardial catheter mapping radiofrequency energy was applied at the site of earliest ventricular activation during ventricular tachycardia which could be entrained during fixed rate ventricular pacing at the site of origin of ventricular tachycardia. At all ablation sites a long latency between the stimulus and QRS complex was noted. Of 23 patients 18 were treated with radiofrequency alone whereas in five patients a second ablation procedure using direct current was performed. Following the ablation procedures, 14 patients (61%) remained free of ventricular tachycardia. One patient died due to congestive heart failure 21 months following ablation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Non-drug therapy of ventricular tachycardia/ventricular fibrillation]. / Nichtmedikamentöse Therapie von Kammertachykardie/Kammerflimmern.

In the majority of patients with ventricular tachycardia/fibrillation drug treatment is not effective. The non-pharmacological treatment of this high-risk patients is of increasing importance. In Austria about 900 patients per year need non-pharmacological treatment of malignant ventricular arrhythmias. For this purpose 4 or 5 specialized centers would be necessary.

Effects of enflurane on inducibility of ventricular tachycardia.

The effects of enflurane on cardiac electrophysiologic parameters and on inducibility of ventricular tachycardia (VT) by programmed stimulation were studied in 12 patients (11 men, 1 woman, mean age +/- standard deviation 55 +/- 8 years) with drug refractory sustained monomorphic VT who underwent transcatheter ablation with high-energy direct-current shocks. One catheter ablation procedure was performed in 10 patients, whereas 2 ablation sessions were necessary in 2 patients. Programmed ventricular stimulation was performed on 2 separate days (mean interval 19). There were 2 baseline studies, 1 several days before ("baseline study I") and the second at the beginning of the ablation procedure ("baseline study II") while the patient was awake and nonsedated. The third programmed stimulation study was done 15 to 30 minutes after administration of anesthesia with enflurane, oxygen and nitrous oxide ("enflurane study"). Rate of sinus rhythm, QRS duration, PQ interval and ventricular effective refractory period were unaltered, whereas QTc interval increased significantly after initiation of anesthesia. Before and after induction of general anesthesia, clinical VT was inducible in all patients. However, in 1 patient, induction of VT was only possible by pacing in the left ventricle after enflurane administration. Based on these data, it is concluded that general anesthesia with enflurane, oxygen and nitrous oxide has no marked influence on inducibility of clinical VTs. Therefore, this type of anesthesia may be useful for nonpharmacologic, ablative procedures requiring general anesthesia.

Acute and long-term efficacy of propafenone in patients with sustained ventricular tachyarrhythmias: assessment with programmed ventricular stimulation.

To determine the electrophysiological properties of oral propafenone, 50 patients (39 male and 11 female, aged 31 to 80 years) with sustained ventricular tachycardia or ventricular fibrillation underwent serial electrophysiological drug testing, using propafenone (750 to 900 mg daily) as the anti-arrhythmic regimen of first choice. During baseline study, all patients had inducible sustained ventricular tachyarrhythmias. After oral loading of propafenone, 37 patients (74%) remained inducible whereas 13 were rendered non-inducible. Among the still inducible patients, the mean VT rate decreased from 223 +/- 38 b.min-1 (baseline) to 172 +/- 32 b.min +/- 1 (P less than 0.001). Four patients showed an increase of VT rate during propafenone compared to the VT rate at control. Non-inducible patients were discharged on propafenone. During a mean follow-up period of 20 +/- 15 months, there were three non-fatal VT recurrences among the responders, two of them due to non-compliance. Thus, propafenone used as the anti-arrhythmic agent of first choice among patients undergoing serial electrophysiological drug testing for ventricular tachyarrhythmias proved effective in suppressing VT induction in 26%. With regard to arrhythmic events, these patients have a favourable outcome.

Implantable cardioverter/defibrillators (ICD): a new lead-system using transvenous-subcutaneous approach in patients with prior cardiac surgery.

The current approach in cardioverter-defibrillator implantation requires placement of epicardial leads which may lead to pericardial and/or pleural effusion and pneumonia during the perioperative period. Although ICD implantation is less invasive than other surgical techniques for the treatment of rhythm disturbances, the perioperative mortality must be considered. Minimizing the operative procedure could lead to a reduction in perioperative mortality. Therefore, we investigated an approach without the need for thoracotomy using a transvenous/subcutaneous lead system. In nine patients with prior cardiac surgery, defibrillator implantation was performed by a transvenous/subcutaneous approach. There was no perioperative mortality. In all patients, a sufficient defibrillation threshold was achieved. The defibrillation pulses were delivered as two sequential pulses between a right ventricular electrode (cathode) and a coronary sinus or superior caval vein electrode (anode 1) and a subcutaneous patch electrode (anode 2). Intubation of the coronary sinus was necessary in 4 patients in order to obtain satisfactory defibrillation thresholds. These data demonstrate that a transvenous/subcutaneous approach is feasible in patients with prior cardiac surgery obviating the need for thoracotomy. Sensing function of the RV-electrode, intubation of the coronary sinus and the intraoperative use of an epicutaneous patch electrode are current problems of this new technique.

Thermal catheter disruption during closed-chest radiofrequency ablation of the atrioventricular conduction system.

Radiofrequency ablation of the atrioventricular conduction system was attempted in a 63-year-old man with drug refractory atrial fibrillation. A total of 5 radiofrequency pulses (750 kHz, power setting: 25-50 W, pulse duration: 9-20 sec) were delivered in a unipolar fashion via the distal electrode of a 7 Fr bipolar electrode catheter without induction of permanent AV block. No direct measurements of current (I) and voltage (U) were made. During the fifth pulse catheter disruption occurred at the interface of the shaft and the proximal electrode. Inspection of the catheter shaft revealed carbonized insulation material indicating overheating of the catheter tip. Overheating was presumably due to an impedance rise with unrecognized clot formation on the distal electrode. This led to progressive melting of insulation material during repeated radiofrequency applications and short circuiting of current flow to the proximal ring electrode that resulted in catheter disruption. This case report is the first to describe a serious complication of radiofrequency ablation. The complication might have been prevented by measurements of U and I, reflecting changes in impedance or by measurements of catheter tip temperature (T). It is concluded that measurements of U, I, and/or T are necessary to control the coagulation process thereby reducing the risk of serious complications during transcatheter radiofrequency ablation.

[Patient behavior and length of the prehospital phase in myocardial infarction]. / Patientenverhalten und Dauer der Prähospitalphase bei Myokardinfarkt.

120 of 272 consecutive patients (44%) with confirmed myocardial infarction reached hospital within three hours of onset of symptoms. Important delays were caused by the patients "treating" themselves with drugs (delay of 6.8 +/- 14.9 h) and/or other measures (11.1 +/- 15.7 h), and in 50 of 144 (35%) patients, who consulted a doctor, time-consuming diagnostic tests and therapeutic measures (10.9 +/- 12.6 h). On the other hand, severity of pain shortened the prehospitalization phase significantly (P less than 0.025). Age, time of day, infarct site or whether first-time or recurrent infarct had no influence on the time elapsed until admission to the intensive care unit. Thus advice to patients and instruction to doctors may be the most effective means of shortening the prehospital phase in patients with myocardial infarction.

[Transvenous high frequency current ablation of atrioventricular conduction in therapy refractory tachycardic atrial fibrillation]. / Transvenöse Hochfrequenzstromablation der AV-Uberleitung bei therapieresistentem tachykardem Vorhofflimmern.

We present a case of radiofrequency ablation of the atrioventricular conduction system by means of intravenous catheter technique in a patient with drug-refractory paroxysmal atrial fibrillation. Total AV block was produced. Since the ablation and implantation of a pacemaker this female has had no recurrences. The advantages of this method compared with electrical fulguration are better control of delivered energy and reduction of complications (catheter perforation, thromboembolism). The disadvantage of radiofrequency ablation is the difficulty in positioning the catheter so as to give the most precise contact with the tissue, which is a very time-consuming procedure.