Predictors of sustained ventricular arrhythmia episodes in patients with primary ICD indication: male gender and AF in primary ICD prophylaxis.

AIMS: Implantable cardioverter-defibrillators (ICD) reduce mortality in patients with severely impaired left ventricular function. In randomized studies, female patients are underrepresented and data on ICD therapy is limited. Atrial fibrillation (AF) is a determinant of poor prognosis but has not been consistently evaluated. We evaluated the risk factors for the occurrence of ventricular arrhythmia episodes in patients with primary ICD prophylaxis. METHODS: Consecutive patients after ICD implantation for primary prophylaxis were followed. During follow-up, detected sustained episodes of ventricular arrhythmia were documented. Multivariate analysis controlled for propensity score was used to evaluate the correlation between gender, history of AF, and the occurrence of ventricular arrhythmia episodes. RESULTS: A total of 400 patients (19.8% female; n = 79) were included. During follow-up, 64 patients (16%) had appropriate ICD therapy episodes. Men (18%) had significantly more often episodes than women (8%; p = 0.025). Patients with a history of AF (102, 25.5%) had significantly more often episodes (30%) compared to patients without a history of AF (11%; p < 0.001). In a multivariate model, only gender (p = 0.02) and history of AF (p < 0.001) were significantly associated predictors of the occurrence of appropriate ICD therapies during follow-up. Based on the propensity score model, the adjusted hazard ratio for male gender was 2.7 (p = 0.02) and 2.6 (p = 0.0004) for history of AF. CONCLUSION: Male gender and history of AF are independent predictors for the occurrence of sustained ventricular arrhythmia in primary ICD prophylaxis. Further studies need to evaluate whether history of AF in female patients might be an indicator for higher risk of sudden cardiac arrhythmic death.

Gender differences in onset of symptoms in AV nodal re-entrant and accessory pathway-mediated re-entrant tachycardia.

PURPOSE: Is onset of symptoms in AV nodal re-entrant tachycardia (AVNRT) and accessory pathway-mediated re-entrant tachycardia (AVRT) patients gender-specific? METHODS: Intra- and inter-gender differences in onset of symptoms and mechanism of supraventricular tachycardia in adult patients undergoing catheter ablation for AVNRT or AVRT (N=230) were documented. RESULTS: Women with AVNRT were significantly younger at onset of symptoms compared to men (38+/-18, 51+/-18 years, p=0.01). Male AVNRT patients were significantly older at onset of symptoms compared to male AVRT patients (51+/-18, 25+/-11 years, p=0.04) but there was no difference in women. Symptoms beginning <30 years in men predicted AVRT in 73%, and beginning >or=30 years the predominant mechanism was AVNRT (85%). In women AVNRT was the most likely mechanism independent of symptom onset (>75%). CONCLUSIONS: Symptoms beginning in patients with AVNRT and AVRT prior to age 30 correlates with a 70% incidence of AVRT in men and a 80% incidence of AVNRT in women. Onset of palpitations >or= age 30 relates to AVNRT in 85% of patients.

[Optimized programming during cardiac resynchronization therapy]. / Optimierte Programmierung der atrio-ventrikulären und ventrikulo-ventrikulären Verzögerungszeiten bei Patienten unter biventrikulärer Stimulation - ein pragmatischer Ansatz.

Cardiac resynchronization (CRT) has evolved as a therapeutic add-on tool in patients with refractory heart failure. Additional pacing of the left ventricle leads to relevant clinical and hemodynamic improvement. Optimized programming of these pacing systems may modulate therapeutic efficacy. Optimal atrio-ventricular (AV) and ventriculo-ventricular (VV) delay programming is documented to increase invasively and non-invasively determined parameters of cardiac hemodynamics. In this manuscript different options for determining optimal AV and VV delay are discussed and a pragmatic approach to optimize CRT programming is detailed. VV delay needs to be optimized as a first step of programming. Different techniques may estimate the individual need for sequential ventricular pacing. Especially electrocardiographic criteria during right and left ventricular pacing may approximate the time-delay for pre-excitation. Delay between aortic and pulmonic valve ejection can be determined using Doppler echocardiography may identify patients who benefit from sequential pacing. Optimizing AV delay is a domain of Doppler echocardiography where using a simple formula the AV delay that produces the best diastolic resynchronization of left atrial contraction and left ventricular ejection can be calculated.Using the above mentioned techniques a pragmatic, easy and fast method for increasing CRT performance can be established. In cases of worsening heart failure or relevant changes of left ventricular dimensions adaptions (re-optimization) of VV and AV delay may be needed.

[Acute effects of cardiac resynchronization therapy on breathing during sleep in patients with severe chronic heart failure--a pilot study]. / Akuteffekte einer kardialen Resynchronisationstherapie auf die Atmung im Schlaf bei Patienten mit fortgeschrittener Herzinsuffizienz--Eine Pilotstudie.

BACKGROUND: Sleep-related breathing disorders (SDB), especially Cheyne-Stokes respiration (CSR), have prognostic relevance in patients with chronic heart failure (CHF). Thus, we investigated acute effects of cardiac resynchronization therapy on breathing during sleep. METHODS: Beside a cardiopulmonary investigation, breathing during sleep was analysed polygraphically/polysomnographically on the night before and during the second night after implantation of a biventricular pacemaker for cardiac resynchronization. PATIENTS: We investigated 16 consecutive patients with severe CHF (NYHA class III-IV) and widened QRS complexes (QRS > 150 ms) with the indication for cardiac resynchronization therapy independent of this study. RESULTS: Cardiac resynchronization therapy shortened the QRS time in each and every patient (QRS: 167.3 +/- 21.7 ms to 113.0 +/- 19.0 ms; p < 0.001) as a marker for successful resynchronization. Initially, SDB were diagnosed in 11 of the 16 patients studied (69 %), with 7 patients having CSR (44 %) and 4 patients (25 %) having CSR and obstructive sleep apnoea. With cardiac resynchronization therapy, no significant acute changes were seen regarding nocturnal breathing/breathing disorder, heart frequency, or oxygen saturation. CONCLUSIONS: The established positive effects of cardiac resynchronization therapy are rather due to a chronic improvement of cardiopulmonary interactions (remodelling, circulatory time, or chemosensitivity) than to acute effects, as investigated in this study.

[Angiographic assessment of functionally insignificant left main coronary artery stenoses: reliability compared to intracoronary pressure measurement]. / Angiographische Beurteilung funktionell nicht signifikanter Hauptstammstenosen--Zuverlässigkeit im Vergleich zur intrakoronaren Druckmessung.

BACKGROUND AND OBJECTIVE: Left main coronary artery disease (LMCA) is still a widely accepted indication for coronary artery bypass surgery. Intermediate LMCA disease, however, often cannot be evaluated reliably on the basis of clinical and angiographic information alone. The deferral of surgical revascularization based on fractional flow reserve (FFR) measurements has been shown to be safe and feasible when taking an FFR value of (3) 0.75 as cutoff. This study was performed to compare the accuracy of visual angiographic assessment of intermediate LMCA stenoses by experienced interventional cardiologists with functional assessment by FFR in a patient population with excellent long-term outcome after deferral of surgery on the basis of FFR measurements. PATIENTS AND METHODS: 24 of 51 consecutive patients with intermediate LMCA disease were deferred from surgery based on an FFR value of > or = 0.75. Each angiogram was retrospectively reviewed independently by three experienced interventional cardiologists. Reviewers were blinded to initial FFR results, clinical data, and clinical outcome and asked to classify each lesion as SIGNIFICANT (FFR < 0.75), NOT SIGNIFICANT (FFR > or = 0.75), or UNSURE if the observer was unable to make a decision based on the angiogram. RESULTS: Mean follow-up was 29 +/- 13.6 months. No death or myocardial infarction was observed, event-free survival was 69 %. When taking the "unsure" classifications into consideration the individual reviewers achieved correct lesion classification with respect to FFR results on average in 58 % to 82 % of cases. Interobserver variability resulted in only 46 % of cases in concordant lesion classification (3 agreements or 2 agreements and 1 "unsure" evaluation). The number of concordant agreements between the individual pairs of reviewers did not exceed the rate of coincidental agreements that could be expected to result from simple guessing (mean KAPPA coefficient 0.04). More than 50 % of patients with excellent long-term outcome after deferral of surgery would potentially have undergone operative revascularization if consensual decision making had been solely based on angiographic lesion assessment. CONCLUSION: The functional significance of intermediate or equivocal LMCA lesions should not be based on visual assessment alone, even when performed by experienced interventional cardiologists.

[Anatomy, special features and angiographic assessment of the coronary sinus]. / Anatomie, Besonderheiten und angiographische Beurteilung des Sinus coronarius.

The endovenous approach for left ventricular lead implantation can be used in most patients. A complete angiography of the coronary vein will increase the success rate of lead implantation. From a technical point of view, attention should be focused on anatomical variation, which leads to a higher number of complications like dissection or perforation of the vessel. However, in a number of cases a left verticular lead must be implanted epimyocardial due to anatomical reasons.

Substrate-modification using electroanatomical mapping in sinus rhythm to treat ventricular tachycardia in patients with ischemic cardiomyopathy.

UNLABELLED: The treatment especially of frequent ischemic VT remains a challenge for medical and catheter ablation procedures. We evaluated the efficacy of a substrate-based procedure to eliminate clinical VTs in this patient collective. METHODS: In 25 consecutive patients (ejection fraction 37+/-12%) with frequent symptomatic medically refractory ischemic VT (with recurrent ICD-shocks), left ventricular anatomic scar mapping (Biosense Webster CARTO) was performed in order to modify the underlying myocardial substrate. Scar tissue was identified as having bipolar voltages <0.5 mV. Prior to the procedure an electrophysiological study (EPS) to determine number and morphology of inducible VTs was performed. Linear ablation procedures (8 mm tip, 70 Watts, 70 degrees C) were based on the findings of scar areas and proximity to anatomic obstacles. Correct location of ablation was documented by similarity of the morphology during pace-mapping. Follow-up included clinical evaluation, ICD holter interrogation plus holter ECG recording. RESULTS: The clinical VT was eliminated by linear catheter ablation in 23/25 patients (92%) (failure due to unstable catheter position during transaortic approach in 1 and epicardial origin of VT in 1). In 16/23 patients (70%) complete success could be produced with no VT inducible after substrate modification (1.7+/-1.0 lines per patient). In 7 patients (30%) only partial success was documented with further VTs inducible after ablation. No procedure-related complications occurred. During follow- up (10+/-4 months) 4 patients (16%) had occurrences of new VTs documented on ICD holter (3 patients with initially partial success and 1 with initial complete success) differing in cycle length and morphology from the clinical VT. Comparing patients with complete to those with partial success, there was a statistically significant difference of 93 vs. 48% freedom of arrhythmia (p=0.03). No difference in regard to baseline characteristics existed in these two patient subgroups. CONCLUSIONS: Ablation of frequent VTs in patients with ischemic cardiomyopathy can be safely performed using electro-anatomic scar mapping with a high procedural success of 90%. Based on the morphological findings, linear ablation can suppress inducibility of all VTs in 70% of patients with high mid-term efficacy. In patients with only partial ablation success, non-clinical VTs often occur early during follow-up (50%).

Normal angiogram in acute coronary syndrome-preangiographic risk stratification, angiographic findings and follow-up.

BACKGROUND: Coronary angiographies performed during acute coronary syndrome show different coronary morphologies-vessel occlusions, thrombi and various types of stenoses. In a few cases of acute coronary syndrome, angiography reveals normal coronary arteries. It is the purpose of this study to analyze this specific subset of patients who presented with an acute coronary syndrome but had a normal coronary angiogram with respect to the preangiographic diagnostics, risk stratification and clinical follow-up. METHODS AND RESULTS: A total of 897 coronary angiographies were performed as an emergency procedure in our institution. The majority of patients (n = 821) presented with coronary artery disease and the majority was treated by mechanical revascularization (86.3%). In 76 patients (8.5%), no coronary artery stenosis was documented. However, according to the preangiographic risk stratification, coronary artery disease was expected in these patients. Observations documented angiographically included coronary spasms (6.6%) and muscle bridges (5.3%). During a mean follow-up of 11.2 +/- 6.4 months, one patient developed an acute myocardial infarction requiring coronary intervention. All other patients were free of any cardiac event. CONCLUSIONS: In summary, we have to consider that coronary angiography may not always detect the cause of myocardial ischemia in every patient. There is a small group of patients with normal coronary angiograms during acute coronary syndrome. Additional diagnostic procedures like intravascular ultrasound (IVUS) or the assessment of intracoronary physiological parameters may increase the diagnostic value of angiography.

Access-site complications after rescue percutaneous coronary intervention during thrombolysis for acute myocardial infarction.

Aggressive antithrombotic medical therapy may increase the rate of access-site complications after percutaneous coronary intervention. Frequently, emergency coronary interventions have to be performed in a situation when thrombolysis therapy was administered as the first-line therapeutic approach in acute myocardial infarction but failed to achieve stable conditions. We analyzed the rate of femoral bleeding complications after emergency coronary intervention in 76 consecutive patients with unsuccessful thrombolysis in acute myocardial infarction. All invasive procedures were performed in a time period no longer than eight hours after thrombolysis was administered. Additional antithrombotic therapy with heparin and glycoprotein IIb/IIIa-inhibitors was given during intervention in 100% and 38.2% of patients, respectively. In three patients (3.9%) femoral hematomas without therapeutic consequences were documented; one patient (1.3%) developed a hematoma requiring blood transfusion. A pseudoaneurysm, fistula or surgical vascular intervention did not occur. Coronary interventional procedures in rescue situations can be performed with excellent safety with respect to access-site bleeding complications even under conditions of ongoing thrombolysis therapy and aggressive antithrombotic medical regimens.

[Intraoperative cooled-tip radiofrequency ablation in patients with atrial fibrillation undergoing open heart surgery]. / Sicherheit und Effektivität der intraoperativen gekühlten linearen Hochfrequenzstromablation bei Patienten mit Vorhofflimmern während eines kardiochirurgischen Eingriffs.

METHODS: A total of 113 patients with chronic permanent (104) or paroxysmal (9) atrial fibrillation underwent open heart surgery plus an additional antiarrhythmic procedure using saline-irrigated cooled-tip radiofrequency ablation (SICTRA) for biatrial or left atrial linear lesions. Ablation was performed with steps of short (5 seconds) ablation around the pulmonary vein ostia and interconnecting lines. Postoperative complications and conversions to sinus rhythm were followed up (mean follow-up duration 17+/-14 months). RESULTS: Of the 113 patients, 16 died during follow-up (day 3 up to 33 months) resulting in a cumulative survival of 79% (2 sudden cardiac deaths, 2 gastrointestinal bleedings, 1 renal bleeding, 2 mediastinitis, 1 endocarditis, 1 hemorrhagic insult, 2 respiratory insufficiencies and 2 unknown). Three patients died between day 3 and 6 (30-day mortality 3%) due to low cardiac output. Complications occurred in 19% of the patients including 4% bleeding, 1% pneumothorax, 3% sternal dehiscence, 3% reversible low cardiac output, 6% reversible respiratory insufficiency, 2% TIAs and 1% intra aortal balloon pump implantation. Conversion to sinus rhythm usually occurred spontaneously within 6 months resulting in a cumulative percentage of 80% in sinus rhythm. In these patients, 85% showed biatrial contraction. CONCLUSIONS: SICTRA to treat atrial fibrillation can safely and effectively be combined with different surgical procedures. Mortality and complication rates are comparable to cardiac surgery without antiarrhythmic procedures. No severe procedure-related complications were noted when a stepwise ablation approach during open heart surgery was used. Antiarrhythmic surgical procedures are highly effective in restoring sinus rhythm in patients with atrial fibrillation. Is a modified approach using intraoperatively cooled-tip radiofrequency ablation to induce linear lesions safe and effective in the treatment of atrial fibrillation in cardiosurgical patients?

[Recanalization by percutaneous coronary intervention in occlusion of all coronary vessels]. / Diabetiker mit Verschluss aller Koronarien. Gibt es Alternativen zum Bypass?

The utility of coronary intervention in the treatment of multivessel coronary disease with complex morphology and damage to the myocardium remains controversial. What is certain is that drug treatment is often not adequate and surgical revascularization not always possible. A patient with occlusion of all coronary vessels who underwent a multivessel intervention is presented. Multivessel intervention can improve the left ventricular function and appreciably increase the performance of the patient. In similar cases, consideration should be given to percutaneous coronary intervention as an alternative to bypass surgery.

Incremental programming of atrial anti-tachycardia pacing therapies in bradycardia-indicated patients: effects on therapy efficacy and atrial tachyarrhythmia burden.

AIMS: Efficacy of pace-termination of atrial arrhythmias (ATP) may depend on atrial cycle length and regularity. Whether device programming of ATP therapies can improve ATP efficacy and alter atrial tachyarrhythmia burden is unknown. METHODS AND RESULTS: ATP efficacy was evaluated in 61 patients (39 males; 66 +/- 10 years) with a standard indication for pacing, 95% with a history of AT/AF. Each patient was implanted with a novel DDDRP pacemaker capable of delivering ATP therapy. ATP efficacy and AT/AF frequency and burden were compared within each patient during a period of nominal ATP programming (NP) followed by a period of aggressive incremental programming (IP). Adjusted ATP-termination efficacy was higher during IP than during NP (54.8% vs 37.9%, P < 0.05). No differences in AT/AF frequency (3.3 +/- 5.9 vs 3.2 +/- 6.9 day(-1)) or burden (18 +/- 28% vs 18 +/- 29%) were observed comparing NP with IP. The majority of episodes during both the NP (81%) and IP (77%) periods terminated within 10 min. Episodes lasting 24 h or more accounted for only 0.4% of the episodes in both groups. but accounted for 38% of the average burden during NP and 51% during IP. CONCLUSIONS: Device programming of ATP therapies can influence the number of treated episodes and the efficacy of ATP therapies although arrhythmic frequency and burden may not change. Total atrial arrhythmia burden is disproportionately influenced by long (>24 h) episodes.

Coronary artery stenting in diabetes mellitus--unfavourable clinical outcome due to increased rate of myocardial ischemia and percutaneous interventions.

Diabetes mellitus is one of the major risk factors for cardiovascular diseases. The aim of this study was to analyze if diabetic patients, compared to nondiabetic patients, have a worse angiographic and clinical success rate and a reduced clinical and angiographic outcome at three-months follow-up after coronary artery stenting according to postprocedural complications, recurrent angina, myocardial ischemia, restenosis and revascularization. A total of 307 unselected patients with coronary artery disease and myocardial ischemia who underwent intracoronary stenting were included in this study. Diabetes was present in 49 patients. Morphological criteria, angiographic results and clinical in-hospital outcome did not differ significantly between both groups. At follow-up diabetics presented significantly more often recurrent angina and myocardial ischemia. The rate of restenosis and target lesion revascularization was not different. Among diabetics, the rate of percutaneous coronary interventions because of different lesions was significantly increased. Diabetes does not reduce the angiographic result initially and at follow-up after coronary artery stenting. Diabetes mellitus limits the clinical outcome because of recurrent angina, myocardial ischemia and the need of coronary interventions.

Efficacy of an additional MAZE procedure using cooled-tip radiofrequency ablation in patients with chronic atrial fibrillation and mitral valve disease. A randomized, prospective trial.

AIMS: This study is the first prospective randomized trial evaluating the efficacy of an antiarrhythmic surgical procedure in patients with chronic atrial fibrillation undergoing mitral valve replacement. METHODS AND RESULTS: Thirty consecutive patients with chronic atrial fibrillation undergoing mitral valve replacement were randomized for an additional modified MAZE-operation using intra-operatively cooled-tip radiofrequency ablation (group A) or mitral valve replacement alone (group B). Biatrial contraction was studied and functional capacity was evaluated in spiro-ergometry 6 months after surgery. Thirty-day mortality was 0% in both groups. After 12 months, sinus rhythm was reinstituted significantly more often in patients of group A (cumulative rate of sinus rhythm 0.800) compared to patients in group B (0.267) (P<0.01). 66.7% of patients in sinus rhythm of group A had documented biatrial contraction. Electrocardioversion showed long-term success in only 17% of patients in group A and 0% in group B. Maximal aerobic uptake at the 6-month spiro-ergometry revealed no significant difference (9.3 vs 8.5 ml x min(-1) kg(-1), P=0.530). CONCLUSIONS: A modified MAZE operation using cooled-tip radiofrequency ablation can be safely combined with mitral valve surgery and is highly effective in restoring sinus rhythm. Biatrial contraction is found in 66.7% of patients with sinus rhythm undergoing mitral valve replacement plus the MAZE operation.

Pace-termination and pacing for prevention of atrial tachyarrhythmias: results from a multicenter study with an implantable device for atrial therapy.

INTRODUCTION: Patients with bradycardia requiring permanent pacing frequently suffer from additional atrial tachyarrhythmias (ATs). This study evaluated the safety and efficacy of atrial antitachycardia pacing (ATP) and the performance of pacing for AT prevention implemented into a new pacemaker. METHODS AND RESULTS: In patients with conventional indications for permanent pacing, an investigational DDDRP pacemaker (Medtronic AT500, model 7253) was implanted. The primary study objectives were to determine the safety of overall device functioning and its efficacy in terminating spontaneous AT. A secondary endpoint was to determine the reliability of AT detection. Pacemaker memory functions were used to analyze the impact of dedicated pacing algorithms on AT prevention. In 33 European and Canadian centers, 325 patients were enrolled (mean follow-up 2.3+/-1.3 months). Complication-free survival at 3 months was 88%. In 2,145 episodes stored with atrial electrograms, AT detection was confirmed in 97%. The algorithm for continuous overdrive pacing increased the percentage of atrial pacing to 97%. After ATP activation, 16,683 of 52,468 AT episodes were treated (120 patients). Of these, 8,903 episodes (53%) were terminated successfully by ATP. No proarrhythmic effect of preventive pacing or atrial ATP was observed. Preventive pacing algorithms increased the median percentage of atrial pacing from 62% to 97%. However, the number of AT/AF (atrial fibrillation) episodes (4.1 vs 4.1 per patient per day) and the time in AT/AF (13.7% vs 12.8%) was not significantly different before and after activation of preventive pacing. CONCLUSION: DDDRP pacing with a new system for AT therapy was safe and associated with successful pace-termination of AT in 53% of episodes. Preventive pacing and atrial ATP algorithms represent two new functions that can be implemented safely into pacemaker systems for nonpharmacologic treatment of ATs in patients requiring pacemaker therapy.

Prevalence, characteristics and clinical implications of regular atrial tachyarrhythmias in patients with atrial fibrillation: insights from a study using a new implantable device.

OBJECTIVES: This study prospectively analyzed atrial tachyarrhythmia (AT) organization and antitachycardia pacing (ATP) success in patients with an implanted device for AT therapy. BACKGROUND: In patients with atrial fibrillation (AF), the incidence of regular, slow ATs amendable by ATP is unknown. METHODS: Forty patients with previously documented AT (70% with AF) received a new pacemaker with atrial electrogram (AEG) storage and atrial ATP capabilities for standard pacing indications. The AEGs acquired during the first month (study phase 1) were classified into high (type I), intermediate (type II) and low (type III) degrees of organization. Atrial ATP was then activated, and treated AT episodes were retrieved three and six months after implantation (study phase 2). RESULTS: Of 824 AEGs retrieved before ATP activation (study phase 1), 351 (43%) were classified as type 1, 47% as type II and 10% as type III. Episodes of AT starting as type I (35%) and type II or III (65%) maintained their type over 1 min in 73%. All patients with an exclusive history of AF also showed type I AEGs. In 361 subsequently treated AT episodes (study phase 2), ATP was successful in 62% of type I and 34% of type II episodes, but not in type III (p < 0.0001). CONCLUSIONS: The majority of patients with a history of AF show not only disorganized but also highly organized AT episodes, which can be successfully terminated by ATP.

Efficacy and safety of ticlopidine monotherapy versus ticlopidine and aspirin after coronary artery stenting: follow-up results of a randomized study.

A combined antiplatelet treatment with ticlopidine and aspirin has been accepted as standard pharmacological regimen after coronary artery stenting. No data of a randomized trial are available on ticlopidine monotherapy. This prospective, randomized monocenter trial investigates the role of ticlopidine monotherapy versus combined antiplatelet therapy with ticlopidine and aspirin in unselected patients undergoing coronary artery stenting. After successful placement of 378 coronary artery stents, two hundred and forty-three consecutive patients were randomly assigned to receive antiplatelet therapy with 2 x 250 mg ticlopidine (121 patients) or a combination of 2 x 250 mg ticlopidine plus 100 mg aspirin (122 patients) daily. The primary endpoint included the absence of death, cardiac events and vascular access-site complications during the in-hospital phase. Angiographic and clinical assessment was repeated at the 3-month follow-up exam. Two hundred and thirty-seven patients (97.5%) were free from cardiac and non-cardiac events. Stent thromboses were seen in 2 patients of the combined treatment group, while none were observed in the monotherapy group. No statistically significant differences were found between the 2 groups regarding the primary endpoint. Angiography performed in 210 patients (86.4%) at follow-up revealed a restenosis rate of 29.4% in the combined treatment group and 27.8% in the monotherapy group. Monotherapy with ticlopidine is as safe and effective as a combined regimen of ticlopidine plus aspirin after coronary artery stenting in an unselected patient population. These results need to be confirmed in a larger multicenter trial.

[Sensor-induced rate adaptation: sensor systems and tuning. Manual versus automatic tuning]. / Frequenzadaptation durch Sensorerkennung: Sensorsysteme und Einstellung. Manuelle Einstellung versus Automatik.

BACKGROUND: Rate adaptive stimulation represents an established therapeutic option in the management of cardiac rhythm disturbance. To realize a physiologic heart rate in patients with chronotopic incompetence several different sensor systems were developed. Due to the requirements of a physiologic pacemaker with all algorithms and therapeutic functions complex pacemaker systems were created. The realization of an automatic rate optimization was given by self adjusting algorithm or new sensor systems (closed loop systems). Comparing data respecting automatic vs manual sensor adjustment are not present. The automatic sensor adjustment was examined only in small patient groups. CONCLUSION: This studies indicated that most patients could be adjusted by the automatic function. Nevertheless, out of technical reasons a small group of patients could not be adjusted. The verification of the correct individual rate response in all patients treated with rate response pacemakers belongs to the physicians obligation.

Atrial pacing in the prevention of paroxysmal atrial fibrillation: first results of a new combined algorithm.

UNLABELLED: Pacing algorithms for prevention of atrial tachyarrhythmia (AT) are under clinical evaluation. The present study prospectively evaluated the efficacy of three simultaneously active algorithms for AT prevention and aimed at identifying patients in whom atrial preventive pacing (APP) may be particularly successful. METHODS: In 31 patients with conventional pacing indications and paroxysmal AT, a DDDRP pacing system was implanted, which stores 35 AT episodes with atrial electrograms and marker annotations. Counters and stored AT episodes were retrieved 30 days after implant. APP algorithms (atrial preference pacing, atrial rate stabilization, postmode switching overdrive) were activated. Counters and stored AT episodes were again retrieved 60 days later. The number and duration of AT episodes was measured. Several clinical variables were examined with respect to their ability to identify candidates for APP. RESULTS: During APP, the mean number of AT episodes/patient/day decreased from 7.67 to 1.68 (P = 0.04). However, time in AT was not significantly reduced (9.45% versus 10.41%). APP decreased the number of episodes/day in 11 patients and increased it in 9 patients. No clinical parameters predicting APP success was identified. CONCLUSIONS: APP using three algorithms significantly reduced the mean number of AT episodes/patient/day. However, the time during which patients were in AT was not reduced. No clinical variable predicted the success or failure of APP.