[Cardiac arrhythmias in pregnancy]. / Herzrhythmusstörungen während der Schwangerschaft.

Atrial premature beats are frequently diagnosed during pregnancy (PR), supraventricular tachycardia (SVT; atrial tachycardia, AV nodal reentrant tachycardia, circus movement tachycardia) less frequently. For acute therapy, electrical cardioversion with 50-100 J is indicated in all unstable patients (pts). In stable SVT the initial therapy includes the vagal maneuver to terminate breakthrough tachycardias. For short-term management, when the vagal maneuver fails, intravenous adenosine is the first-choice drug and may safely terminate the arrhythmia. For long-term therapy, beta-blocking agents with beta 1 selectivity are first-line drugs; class Ic agents or the class III drug sotalol (sot) are effective and therapeutic alternatives. Ventricular premature beats are also frequently present during PR and benign in most pts; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia [VT], ventricular flutter [VFlut], ventricular fibrillation [VF]) were observed less frequently. Electrical cardioversion is necessary in all pts with a hemodynamically unstable situation and life-threatening ventricular tachyarrhythmias; in hemodynamically stable pts, initial therapy with ajmaline, procainamide or lidocaine is indicated. If prophylactic therapy is needed, beta-blocking agents with beta 1 selectivity are considered as first-choice drugs. If this therapy is ineffective, class Ic agents or sot can be considered. In pts with syncopal VT, VF, VFlut or aborted sudden death an implantable cardioverter-defibrillator is indicated. In pts with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of PR. The treatment of the pregnant patient with cardiac arrhythmias requires important modification of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered.

[Current aspects of defibrillator therapy in congestive heart failure]. / Aktuelle Aspekte der Defibrillatortherapie bei Herzinsuffizienz.

The beneficial effects of implantable cardioverter defibrillator (ICD) therapy in patients (pts) with life-threatening ventricular tachyarrhythmias and impaired left ventricular (LV) function is still unclear. We studied the follow-up of 410 pts (368 males, 42 females, mean age 57 +/- 11 years) after ICD implant. The LV function was assessed by the New York Heart Association functional class of heart failure (NYHA). Fifty pts (12%) were in NYHA I-II, 151 pts (37%) in NYHA II, 117 pts (29%) in NYHA II-III and 92 pts (22%) in NYHA III. Epicardial ICD implantation was performed in 209 pts (51%) and 201 pts (49%) received nonthoracotomy ICDs. Perioperatively (within 30 days after implant), 12 pts (3%) died, significantly more frequent after epicardial (11 of 209 pts, 5%) than after transvenous ICD implant (1 of 201 pts, < 1%) (p < 0.05). During a mean follow-up of 28 +/- 24 months (range < 1 to 114 months), 90 pts (23%) died: 9 pts (2%) died from sudden arrhythmic death and 5 pts (1%) suddenly, but probably not from arrhythmic causes; 55 pts (14%) died from cardiac causes (congestive heart failure, myocardial reinfarction) and 21 pts (5%) from noncardiac causes. The 3-year, 5-year and 7-year survival was 92% to 96% for arrhythmic mortality in NYHA class I, II and III compared to the 3-year survival of 94%, and a 5-year and 7-year survival of 84% in patients with NYHA class II-III. 338 pts (82%) received ICD shocks (mean incidence 21 +/- 43 shocks per pt); pts in NYHA class II (83%), class II-III (84%), class III (90%) received ICD discharges significantly more frequently than in class I-II (64%) (p < 0.05). Our data show that pts with LV dysfunction benefit from ICD therapy and that these pts survive for a considerable time after the first shock. However, survival is clearly influenced by the degree of left ventricular dysfunction and, in addition to ICD therapy, aggressive treatment of heart failure is necessary.

[Dual sensor-controlled rate adaptation in non-dynamical exercise]. / Dual-Sensor-gesteuerte Frequenzanpassung bei nicht-dynamischen Belastungen: Wie physiologisch sind frequenzadaptive Dual-Sensor-Schrittmacher wirklich?

Single sensor and dual sensor systems are used to reach physiological rate adaptation in pacemaker therapy. The purpose of the present study was to examine the sensor-controlled heart rate reaction and adaptability of a dual sensor (QT + activity) with 3 different tests. Nine chronotropically incompetent patients (group 1), 3 females and 6 males, mean age 74.1±8.43 years, were implanted 5 VVIR and 4 DDDR pacemakers (Vitatron, The Netherlands). The control group included 10 chronotropically competent patients (group 2) (2 females, 8 males, mean age 58.2±12.6 years). Both groups underwent 3 different tests: 1) a mental test, 2) an isometric test and 3) an activity (=tap) test. Heart rate was measured every 30 seconds by the recorded surface ECG. We measured an unsatisfaying heart rate response of the pacemaker patients in all 3 tests: During isometric exercise the pacing rate decreased from 63±3.5bpm to 65±3.4bpm (-0.97±0.71bpm/min) (p=0.1829) in contrast to an increase of the heart rate in the control group: from 77.8±15.8bpm to 92.5±19.9bpm (3.76±1.29bpm/min) (p=0.0048). During mental stress testing the pacing rate increased from 63±3.5bpm to 65±3.4bpm (0.66±0.20bpm/min) (p=0.0199) in the pacemaker group, compared to an increase of the heart rate in the control group from 75.8±15.8bpm to 83.6±17.3bpm (2.04±0.74bpm/min) (p=0.0076). Tapping on the pacemaker case produced an increase of the pacing rate from 65.9±2.8bpm to 73.6±3.8bpm (2.83±0.73bpm/min) (p=0.0004), whereas the heart rate decreased from 76.8±13.0bpm to 75.0±1.9bpm (-0.19±0.61bpm/min) (p=0.7522) in the control group. Compared to the physiologically chronotropic function of the control group, the sensor-controlled heart rate response was inadaequate during these tests. The expectations of sensor cross checking could not be fulfilled with the previous sensor combination (QT + activity).

[Typical AV nodal reentry tachycardia in 4 anterograde AV nodal pathways. Successful high frequency ablation of slow AV nodal pathways]. / Typische AV-Knoten-Reentry-Tachykardie bei vier antegrad leitenden AV-Knoten-Bahnen. Erfolgreiche Hochfrequenzablation der langsamen AV-Knoten-Bahnen.

CASE REPORT: A 26-year-old patient was referred to our department for electrophysiologic evaluation of recurrent paroxysmal tachycardias with narrow QRS-complexes (< 120 ms). Three jumps in the AV-nodal conduction curve were detected during programmed atrial extrastimulation in sinus rhythm and at a cycle length of 600 ms indicating of 4 antegrade conducting AV-nodal pathways. After intravenous application of orciprenaline an AV-nodal re-entrant-tachycardia (AVNRT) of the common type was induced with a cycle length of 290 ms. During tachycardia, antegrade conduction occurred via one of the slow conducting pathways, retrograde conduction via the fast pathway ("slow-fast"-AVNRT). Application of radiofrequency energy was able to ablate all slowly conducting AV-nodal pathways at one site in the infero-posterior region of Koch's triangle. During control stimulation with and without orciprenaline no AH-jump or inducible tachycardia was found. CONCLUSION: This case shows the rare finding of 4 antegrade AV-nodal pathways in a patient with the common type of AVNRT. Application of radiofrequency current was able to ablate all slow conducting AV-nodal pathways successfully.

Single-chamber versus dual-chamber implantable cardioverter defibrillators: indications and clinical results.

The clinical benefit of standard (single-chamber) implantable cardioverter defibrillator (ICD) therapy in elderly patients or in subjects with moderate or severe heart failure who had ventricular tachyarrhythmias has been debated. We studied the follow-up of 450 patients who underwent standard ICD implantation at our institution in relation to the functional status of heart failure (New York Heart Association Class) or patient's age. During a mean follow-up of 24 +/- 28 months (range, < 1-114 months), 90 patients (23%) died: 9 patients (2%) from sudden arrhythmic death and 5 patients (1%) suddenly, but probably not from arrhythmic causes; 55 patients (14%) died from congestive heart failure and/or myocardial reinfarction and 21 patients (5%) from noncardiac causes. We could clearly demonstrate that ICD therapy was able to prevent sudden cardiac death, both in patients with severely depressed left ventricular function and in patients aged > or = 65 years. An important step forward in ICD technology was the introduction of dual-chamber pacing possibilities to improve left ventricular dysfunction and to allow a more individualized ICD therapy. At our institution, we have implanted a dual-chamber ICD in 15 patients. Preliminary results showed that heart failure improved in 5 patients (33%) and remained unchanged in 10 patients (67%, p = not significant). There were no patients who had a lesser degree of heart failure after implant. Based on our experience so far, in addition to the hemodynamic benefits of dual-chamber ICDs, dual-chamber sensing and wave-form storage capabilities are very helpful and promising diagnostic tools for the detection and handling of inappropriate ICD therapies.

Oversensing in a cardioverter defibrillator system caused by interaction between two endocardial defibrillation leads in the right ventricle.

A 53-year-old male patient underwent implantable cardioverter defibrillator (ICD) implantation with a single lead (Endotak) transvenous system due to recurrent episodes of drug refractory ventricular tachycardia. After pulse generator replacement, inappropriate ICD shocks were observed due to muscle potential sensing. Intraoperatively, the old Endotak lead could not be extracted; therefore, it was transsected and capped. A new lead was inserted and tested without any problems. At the predischarge test, VF was induced and was followed by ICD shocks during sinus rhythm. In another surgical procedure, the old Endotak lead was explanted using a special instrument. The present report demonstrates that two endocardial Endotak leads should be avoided, because the leads may disturb each other and be followed by inappropriate ICD discharges.

Long-term follow up of patients with implantable cardioverter-defibrillators and mild, moderate, or severe impairment of left ventricular function.

OBJECTIVE: To determine whether patients with life threatening ventricular tachyarrhythmias, impaired left ventricular function, and severe heart failure will benefit from implantable cardioverter-defibrillator (ICD) treatment. DESIGN: 410 patients were followed up after ICD implant. Left ventricular function was assessed by the New York Heart Association (NYHA) functional class of heart failure: 50 patients (12%) were in NYHA I-II, 151 (37%) in NYHA II, 117 (29%) in NYHA II-III, and 92 (22%) in NYHA III. Epicardial ICD implantation was performed in 209 patients (51%) and 201 patients (49%) received non-thoracotomy ICDs. RESULTS: Perioperatively, 12 patients (3%) died, more often after epicardial ICD implant (11/209 patients, 5%) than after transvenous implant (1/201 patients, < 1%) (P < 0.05). During a mean (SD) follow up of 28 (24) months (range < 1 to 114 months), 90 patients (23%) died: nine (2%) died from sudden arrhythmia; five (1%) also died suddenly but probably not from arrhythmic causes; 55 (14%) died from cardiac causes (congestive heart failure, myocardial reinfarction); 21 (5%) died from non-cardiac causes. The three year, five year, and seven year survival was 92-96% for arrhythmic mortality in NYHA class I, II and III, compared to a three year survival of 94% and a five year and seven year survival of 84% for patients in NYHA class II-III. 338 patients (82%) received ICD shocks (21 (SD 43) shocks per patient); patients in NYHA class II (83%), class II-III (84%), and class III (90%) received ICD discharges more often than those in class I-II (64%) (P < 0.05). The mean (SD) time interval between ICD implant and the first ICD shock was shorter in NYHA class II (16 (17) months), class II-III (19 (27) months), and class III (16 (19) months) than in class 0-I (22 (24) months) (P < 0.05). CONCLUSIONS: Patients with mild, moderate, and severe left ventricular dysfunction benefit from ICD treatment and these patients survive for a considerable time after the first shock. Survival is influenced by the degree of left ventricular dysfunction; aggressive treatment of heart failure is necessary as well as ICD therapy.

Age dependent efficacy of implantable cardioverter-defibrillator treatment: observations in 450 patients over an 11 year period.

OBJECTIVE: To determine whether implantable cardioverter-defibrillator (ICD) treatment is beneficial in elderly patients with life threatening ventricular tachyarrhythmias. DESIGN: Since January 1984, ICDs were implanted in 450 patients to evaluate surgical risk, complications and mean survival in relation to patient age; 81 patients (18%) were < or = 50 years at the time of ICD implant, 254 patients (56%) were between 51 and 64 years, and the remaining 115 (26%) were > or = 65 years. Epicardial lead systems were implanted in 209 patients (46%), while transvenous lead systems were implanted in 241 (54%). RESULTS: 13 patients (3%) died perioperatively, more often after epicardial (11 of 209 patients, 5%) than after transvenous ICD implantation (one of 241 patients, < 1%) (p < 0.05). During a mean (SD) follow up of 28 (24) months (range < 1 to 114 months), 90 patients (20%) died. Of these, nine (2%) died from sudden arrhythmic death; five (1%) died suddenly, probably as a result of non-arrhythmic causes; 55 (12%) died from other cardiac causes (congestive heart failure, myocardial infarction); and 21 (5%) died from non-cardiac causes. The three, five, and seven year survival for arrhythmic mortality was 95% in patients < or = 50 years compared with a three year survival of 93% and a five and seven year survival of 91% in patients of 51 to 64 years, and a three, five, and seven year survival of 99% in patients > or = 65 years. 362 patients (80%) received ICD discharges (21 (43) shocks per patient), with a similar incidence among all three patient groups (< or = 50 years, 80%; 51 to 64 years, 81%; > or = 65 years, 79%). The time interval between ICD implant and the first ICD treatment was shorter in patients > or = 65 years (8 (8) months) than in patients between 51 and 64 years (11 (14) months) or < or = 50 years (11 (11) months) (p < 0.05). Survival time following first appropriate shock was 30 (24) months in patients < or = 50 years, 30 (26) months in patients of 51 to 64 years, and 19 (20) months in patients > or = 65 years. CONCLUSIONS: Elderly patients benefit from ICD treatment, and survive for a considerable time after the first treatment. Therefore, elderly patients should be considered candidates for ICD implantation if life threatening ventricular tachy-arrhythmias are present.

Transvenous defibrillation leads: is there an ideal position of the defibrillation anode?

A potential benefit of two-lead transvenous defibrillation systems is the ability to independently position the defibrillation electrodes, changing the vector field and possibly decreasing the DFT. Using the new two-lead transvenous TVL lead system, we studied whether DFT is influenced by SVC lead position and whether there is an optimal position. TVL leads and Cadence pulse generators were implanted in 24 patients. No intraoperative or perioperative complications were observed. In each patient, the DFTs were determined for three SVC electrode positions, which were tested in random order: the brachiocephalic vein, the mid-RA, and the RA-SVC junction. The mean DFTs in the three positions were not statistically different, nor was any single lead position consistently associated with lower DFTs. However, an optimal electrode position was identified in 83% of patients, and the DFT from the best lead position for each patient was significantly lower than for any one of the electrode positions (P < 0.01). The mean safety margin for the best SVC lead position was approximately 27 J. These results demonstrate the advantage of a two-lead system, as well as the importance of testing multiple SVC lead positions when the patient's condition permits. Both of these factors can decrease the DFT and maximize the defibrillation safety margin. This will become increasingly important as pulse generator capacitors become smaller (as part of the effort to decrease generator size) and the energy output of the generators consequently decreases.

[Conversion rate and prevention of recurrence of paroxysmal and sustained atrial fibrillation or atrial flutter with verapamil/quinidine]. / Konversionsrate und Rezidivprophylaxe bei paroxysmalem und anhaltendem Vorhofflimmern oder Vorhofflattern mit Verapamil/Chinidin.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia, occurs in 0.4% of the adult population and in as many as 2% to 4% of those 60 years of age or older. PATIENTS AND METHODS: We studied retrospectively 102 patients, 76 males, 26 females, mean age 56 +/- 12 years, with paroxysmal or sustained atrial fibrillation or atrial flutter (AFlut) treated with verapamil/quinidine (Cordichin) (dosage 3 to 5 times 1 tablet/day). Coronary artery disease was present in 39 patients, dilated cardiomyopathy in 8 patients, valvular disease in 16 patients and various etiologies were present in 13 patients. Twenty-six patients had no discernable heart disease ("Jone atrial fibrillation"). Patients with long QT-syndrome (QT-duration > or = 500 msec; QTc > or = 440 ms) were excluded from this study. RESULTS: Using verapamil/quinidine conversion to sinus rhythm (SR) was possible in 64 patients (63%) within 2 +/- 1 day (range 1 to 6 days). The mean given dosage of quinidine was significantly higher in patients converted to sinus rhythm (762 +/- 129 mg) compared to those without successful conversion (638 +/- 161 mg) (p < 0.001). Diameter of left atrium and left ventricle as well as the degree of heart failure did not influence cardioversion rate significantly. During a mean follow-up of 34 +/- 32 months (range < 1 to 129 months), sinus rhythm remained constant in 28/64 patients (44%) with verapamil/quinidine in whom conversion to sinus rhythm was successful. During follow-up, side effects were present in 20/64 patients who were discharged with verapamil/quinidine: in 2 patients (2%) a torsade de pointes tachycardia was observed (1 patient died suddenly); gastrointestinal side effects were observed in 5 patients (5%); 4 patients had sinuatrial and 3 patients atrioventricular conduction disturbances. An increase in ventricular ectopic beats were present in 3 patients and allergic reactions occurred in 3 patients. CONCLUSIONS: The present data show that verapamil/quinidine is effective in conversion of atrial fibrillation and atrial flutter to sinus rhythm and is associated with an acceptable efficacy rate in preventing recurrences of atrial fibrillation or flutter. Final conclusions concerning side effects are only possible in prospective studies that are ongoing at the present time.

First experience with a new nonthoracotomy defibrillation lead system.

The clinical efficacy and safety of a new nonthoracotomy defibrillation lead system (TVL lead system, Ventritex, inc., Sunnyvale, Calif.) was studied in patients with ventricular tachycardia or fibrillation. Implantation of the TVL lead system and a Cadence pulse generator (Ventritex, Inc.) was attempted in 27 patients. A subcutaneous patch lead was added if required to achieve adequate defibrillation energy. Patients were monitored for an average of 6 +/- 4 months (range 1 week to 14 months). Implantation was successful in 26 patients (96%). Twenty-three of those patients (88%) were implanted in a lead-alone configuration; the remaining three (12%) required a subcutaneous patch lead. The mean defibrillation threshold was 401 +/- 120 V (12 +/- 7 J) at implantation, 467 +/- 134 V (15 +/- 8 J) at predischarge testing, and 452 +/- 151 V (14 +/- 9 J) at 4-month follow-up. The mean defibrillation threshold at 4 months was not significantly different from that at implant. No deaths, sensing anomalies, infections, lead fractures, or lead dislodgments occurred. One patient required addition of a subcutaneous patch 4 months after device implantation because of an elevated defibrillation threshold. Eight patients (31%) experienced 545 spontaneous arrhythmic episodes, and all episodes were successfully terminated by the device. In conclusion, the TVL lead system combined with Cadence tiered-therapy defibrillator has a high success rate and low complication rate, and it can be recommended for treatment of patients with life-threatening ventricular tachyarrhythmias.

[Permanent ventricular tachycardia in a 12-year-old boy: curative therapy by high frequency current ablation]. / Permanente ventrikuläre Tachykardie bei einem 12 Jahre alten Jungen: kurative Therapie durch Hochfrequenzstromablation.

UNLABELLED: A 12-year old boy from Armenia presented with chronic permanent ventricular tachycardia (150/min) and reduced left ventricular shortening fraction (< 30%). Tachycardia was present > 20 h/day on several 24-h Holter monitorings. Diagnosis of ventricular tachycardia could be established on surface ECG by identification of atrioventricular dissociation and a right bundle branch block pattern with a R/S ratio < 1 in lead V6. Antiarrhythmic therapy with mexiletine and sotalol alone or in combination did not influence the presence of the dysrhythmia. During electrophysiological study, the dysrhythmia could not be terminated by administration of adenosine, ventricular extrastimuli, overdrive stimulation or direct current cardioversion. Endocardial mapping identified a region on the left ventricular surface of the anterior upper interventricular septum as the origin of the dysrhythmia. At this location stimulation at a cycle length shorter than the tachycardia produced a QRS complex nearly identical to the tachycardia QRS complex. Local ventricular electrogram preceded the onset of the tachycardia QRS complex on surface ECG by 23 ms. Radiofrequency current application with 30 W for 30 s resulted in permanent termination of the tachycardia. No complications occurred. Six months after the intervention, the boy is still in normal sinus rhythm. Left ventricular function normalized. CONCLUSION: Radiofrequency catheter ablation should be considered in young patients with drug-refractory chronic permanent ventricular tachycardia.

["Circumscribed defibrillator erythema": a differential diagnostic and therapeutic problem in differential occult defibrillator infection diagnosis]. / "Zirkumstriptes Defibrillator-Erythem": ein differentialdiagnostisches und -therapeutisches Problem in der Abgrenzung zur okkulten Defibrillatorinfektion.

We report about three out of 452 patients (pts) (< 1 %) with circumscribed erythema (E) after implantation of an automatic cardioverter defibrillator (ICD). ICD-E occurred in two pts after pulse generator replacements and in one pt after initial ICD implantation. There were no clinical signs of inflammation and laboratory and technical finding were completely normal. Allergic reactions could be ruled out in all pts. Local or systemic drug treatment did not influence the ICD-E. During a follow-up of 28, 10 or 9 months, the ICD-E is still present in two patients and much improved in one pt without any treatment. We did not observe an infection in any of the pts. Our data show that the ICD-E occur rarely after ICD implantation and no special treatment is necessary if an infection or allergic reaction has been excluded. Nevertheless, it is sometimes difficult to exclude in those pts an atypical infection.

[Pelvic symptoms 6 months after implantation of an automatic cardioverter-defibrillator]. / Unterbauchbeschwerden 6 Monate nach Implantation eines automatischen Kardioverterdefibrillators.

Very few complications after implantation of an automatic cardioverter defibrillator (ICD) have been observed. Most complications are caused by infections, electrode problems and inappropriate ICD shocks caused by supraventricular tachyarrythmia. We report on a 64-year-old patient who received an ICD after successful resuscitation due to ventricular fibrillation. Six months after ICD implant the patient suffered from abdominal pain. Abdominal X-ray and ultrasound revealed perforation of the ICD into the pelvis. After operative revision and implantation into a new pulse generator pouch, the patient was fine up to 7 months later. Then incarceration of an epigastric hernia was present without any signs that the defibrillator pouch was involved.

[Cardioverter-defibrillator implantation in the heart catheterization laboratory--observations with 105 patients]. / Kardioverter-Defibrillator-Implantation im Herzkatheterlabor--Beobachtungen bei 105 Patienten.

Today, we are facing an exponential increase in implantation of cardioverter defibrillators (ICD). The intraoperative and follow-up results are reported in 105 patients (pts) with ventricular tachyarrythmias who underwent ICD implantation in the catheterization laboratory. Fifty-seven pts (54%) hat their first ICD implant (G 1), whereas 46 pts (44%) underwent pulse generator replacement or electrode revision (2 pts, 2%) (G 2). In all pts, ICD implant or pulse generator replacement was performed under general anesthesia from the beginning. In 57/58 pts (98%) in G 1, ICD implantation was possible with a mean defibrillation threshold (DFT) of 13 +/- 8 joules. One patient hat a DFT of > 25 joules and ICD implantation was not achieved. This patient underwent epicardial lead implantation 1 day later. One patient in G 1 had a vessel rupture (v. subclavia) intraoperatively. During a mean follow-up of 5 +/- 2 (< 1-13) months, three pts (3%) died from congestive heart failure, 2, 4 and 6 months after device implantation. An infection occurred in 1 patient in G 2, 3 months after generator replacement. Our data show that in the majority of patients ICD implantation in the cath-lab is possible, safe, and the complication rate is low. Therefore, ICD implantation in the cath-lab can generally be recommended.

Implantation and follow-up of a third-generation cardioverter defibrillator: comparison of epicardial and nonthoracotomy defibrillation lead system.

OBJECTIVE: The intraoperative and follow-up results were compared in 67 patients with ventricular tachyarrhythmias who underwent implantation of the Ventritex Cadence defibrillator with either epicardial patch (EPI, 25 patients) or nonthoracotomy CPI Endotak (ENDO, 42 patients) defibrillation lead systems. RESULTS: There was no significant difference between groups in age, sex, structural heart disease, ejection fraction, arrhythmia history, or drug therapy. Successful implantation was accomplished in all patients using either lead system. In the ENDO group, 35 patients (83%) had a defibrillation threshold < or = 550 V and did not require a subcutaneous patch. Intraoperatively, the defibrillation threshold was 453 +/- 139 V (13 +/- 9 J) for EPI and 490 +/- 113 V (15 +/- 8 J) for ENDO (P = NS). There were no perioperative deaths in either group. At predischarge testing, the defibrillation threshold was 445 +/- 183 V (14 +/- 12 J) for EPI and 439 +/- 133 V (13 +/- 7 J) for ENDO (P = NS). During a mean follow-up of 16 +/- 8 months, there were no sudden deaths, and four patients died from congestive heart failure (3 EPI, 1 ENDO). During follow-up, 916 spontaneous arrhythmia episodes occurred in 16 of 25 EPI patients (64%) and 967 episodes occurred in 31 of 42 ENDO patients (74%) (P = NS). The number of episodes detected as ventricular fibrillation were 192 for EPI (21%) and 232 for ENDO (24%), with first shock success in 76% and 75%, respectively; all episodes were successfully terminated by the device. In the remaining episodes detected as ventricular tachycardia, antitachycardia pacing was attempted and was successful in 672 of 724 episodes (93%) with EPI and 666 of 735 episodes (91%) with ENDO lead systems (P = NS). Acceleration of ventricular tachycardia with antitachycardia pacing occurred in 21 episodes (3%) with EPI and in 37 episodes (5%) with ENDO leads (P = NS). CONCLUSIONS: A nonthoracotomy approach using the third generation cardioverter defibrillator Cadence V-100 is safe and effective and has clinical results that are not significantly different from epicardial defibrillation lead systems.

[Experiences with the new cardioverter-defibrillator Ventak PRxII]. / Erfahrungen mit dem neuen Kardioverter-Defibrillator Ventak PRxII.

Clinical safety and efficacy of the new third-generation implantable cardioverter defibrillator (ICD) Ventak PRxII was studied in 50 patients (pts) with ventricular tachycardia (VT) and/or fibrillation (VF). In 23 pts (46%) the ICD was implanted with a transvenous lead system as first implant and 27 pts (54%) received the Ventak PRxII as generator replacement. Intraoperatively, the mean defibrillation threshold (DFT) was 13 +/- 8 joules and 12 +/- 8 joules, respectively. One pt died perioperatively. During a follow-up of 5.3 +/- 3.8 months 3 patients died due to heart failure. During follow-up 1060 arrhythmia episodes (AE) occurred and were terminated primarily by countershock in 121 AE (11%). Antitachycardia pacing (ATP) was tried in 939 AE (89%) and was successful in 878 AE (94%). Acceleration was present in 6 AE (< 1%). We conclude that there is a high efficacy rate in AE termination by the Ventak PRxII, using ATP or countershock. Therefore, the Ventak PRxII allows a flexible approach to cardiac rhythm management.

[10 years of therapy with implantable defibrillators--observation in 353 patients]. / 10 Jahre Therapie mit implantierbaren Defibrillatoren--eine Beobachtung bei 353 Patienten.

Since January 1984, the cardioverter-defibrillator (ICD) has been implanted in 353 patients (pts). Epicardial ICD implantation was performed in 207 pts and 146 pts underwent non-thoracotomy ICD implant. Overall operative mortality was 3% (12/353 pts) and was significantly higher in pts with epicardial ICD implantation (11/207 pts, 5%) than in patients who received non-thoracotomy ICDs (1/146 pts, < 1%) (p < 0.05). During a mean follow-up of 25 +/- 23 months, 63 pts (19%) died: 8 pts (0.8% per year) from sudden arrhythmic death and 6 pts (0.8% per year) suddenly without an underlying arrhythmia. Cardiac death was observed in 36 pts (4% per year) and 13 pts (2% per year) died from other causes. Appropriate ICD discharges were observed in 245 pts (72%) with a mean incidence of 22 +/- 44 IC discharges per pt. In pts with third-generation ICDs, 3,542 ventricular tachyarrhythmias (VTA) were observed and terminated by primary ICD shocks in 778 VTA (22%). Antitachycardia pacing was attempted in 2,764 VTA (78%) and was successful in 2,484 VTA (90%).