[ARENA-Project atrial fibrillation in the Rhein-Neckar region]. / ARENA ­ Projekt Vorhofflimmern in der Rhein-Neckar-Region.

Atrial fibrillation (AF) is the most common form of cardiac tachyarrhythmia. It is estimated that in the Rhein-Neckar region approximately 40,000-50,000 out of 2 million people are affected. Due to demographic changes in the near future there will be a significant increase in the prevalence of AF within the next decades. The ARENA project was initiated by the Foundation Institute for Cardiac Infarction Research (IHF) Ludwigshafen in cooperation with cardiological and neurological departments of neighboring hospitals, resident doctors and pharmacies to improve the awareness and care of patients with AF. The particular aim is the prevention of stroke as one of the most dreaded complications. The project focusses on the following three subtopics: interventions, medication, migration. The aim of the intervention project is to raise awareness of AF as a risk factor for stroke and to improve the diagnostic work-up and care for patients with diagnosed or unknown AF. The subproject medication focusses on the adherence of patients with AF to the prescribed antithrombotic medication. To evaluate differences concerning patients with and without a migration background the subproject migration was initiated.

Critical analysis of dual-chamber implantable cardioverter-defibrillator arrhythmia detection : results and technical considerations.

BACKGROUND: One of the perceived benefits of dual-chamber implantable cardioverter-defibrillators (ICDs) is the reduction in inappropriate therapy due to new detection algorithms. It was the purpose of the present investigation to propose methods to minimize bias during such comparisons and to report the arrhythmia detection clinical results of the PR Logic dual-chamber detection algorithm in the GEM DR ICD in the context of these methods. METHODS AND RESULTS: Between November 1997 and October 1998, 933 patients received the GEM DR ICD in this prospective multicenter study. A total of 4856 sustained arrhythmia episodes (n=311) with stored electrogram and marker channel were classified by the investigators; 3488 episodes (n=232) were ventricular tachycardia (VT)/ventricular fibrillation (VF), and 1368 episodes (n=149) were supraventricular tachycardia (SVT). The overall detection results were corrected for multiple episodes within a patient with the generalized estimating equations (GEE) method with an exchangeable correlation structure between episodes. The relative sensitivity for detection of sustained VT and/or VF was 100.0% (3488 of 3488, n=232; 95% CI 98.3% to 100%), the VT/VF positive predictivity was 88.4% uncorrected (3488 of 3945, n=278) and 78.1% corrected (95% CI 73.3% to 82.3%) with the GEE method, and the SVT positive predictivity was 100.0% (911 of 911, n=101; 95% CI 96% to 100%). CONCLUSIONS: A structured approach to analysis limits the bias inherent in the evaluation of tachycardia discrimination algorithms through the use of relative VT/VF sensitivity, VT/VF positive predictivity, and SVT positive predictivity along with corrections for multiple tachycardia episodes in a single patient.

Ventricular arrhythmias initiated by programmed stimulation in four groups of patients with healed myocardial infarction.

Programmed electrical stimulation of the heart was prospectively used in 160 patients with healed myocardial infarction to study the incidence and characteristics of ventricular arrhythmias induced. Thirty-five patients had neither documented nor suspected ventricular arrhythmias (Group A); 37 patients had documented nonsustained ventricular tachycardia (Group B); 31 patients had been resuscitated from ventricular fibrillation (Group C); and 57 patients had documented sustained monomorphic ventricular tachycardia (Group D). No electrophysiologic differences were found between patients in Group A and Group B, but patients in both groups differed significantly from patients in Group C and Group D. In the last two groups, sustained monomorphic ventricular tachycardia was more frequently induced, the cycle length of the induced ventricular tachycardia was slower and a lesser number of premature stimuli was required for induction. No differences were found in the incidence, rate or mode of induction of nonsustained monomorphic ventricular tachycardia, but nonsustained polymorphic ventricular tachycardia and ventricular fibrillation were more frequently induced in Groups A and B. It is concluded that the substrate for sustained ventricular arrhythmia is present in at least 42% of patients after myocardial infarction. The electrophysiologic characteristics of the substrate for ventricular tachycardia seem to be the major determinant of the clinical occurrence of sustained ventricular arrhythmia. Changes in the electrophysiologic properties of the substrate of ventricular tachycardia, either spontaneously with time or induced by ischemia or antiarrhythmic drugs, can contribute to the clinical occurrence of sustained ventricular arrhythmias in patients with an old myocardial infarction.

Detection of myocardial injury during transvenous implantation of automatic cardioverter-defibrillators.

OBJECTIVES: The present study was designed to assess the extent of myocardial injury in patients undergoing transvenous implantation of an automatic implantable cardioverter-defibrillator (ICD) using cardiac troponin I (cTNI), which is a highly specific marker of structural cardiac injury. BACKGROUND: During ICD implantation, repetitive induction and termination of ventricular fibrillation (VF) via endocardial direct current shocks is required to demonstrate the correct function of the device. Transthoracic electrical shocks can cause myocardial cell injury. METHODS: Measurements of total creatine kinase (CK), CK-MB, myoglobin, cardiac troponin T (cTNT) and cTNI were obtained before and after ICD implantation in 49 consecutive patients. Blood samples were drawn before and 2, 4, 8, and 24 h after implantation. RESULTS: Elevations of CK, CK-MB, myoglobin, cTNT and cTNI above cut-off level were found in 25%, 6%, 76%, 37% and 14% of patients, respectively, with peak cTNI concentrations ranging from 1.7 to 5.5 ng/ml. Cumulative defibrillation energy (DFE), mean DFE, cumulative VF time, number of shocks as well as prior myocardial infarction (MI) were found to be significantly related to a rise of cTNI. Mean DFE > or = 18 J and a recent MI were identified as strong risk factors for cTNI rise. CONCLUSIONS: During transvenous ICD implantation myocardial injury as assessed by cTNI rise occurs in about 14% of the patients. Peak cTNI concentrations are only minimally elevated reflecting subtle myocardial cell damage. Patients with a recent MI and a mean DFE > or = 18 J seem to be prone to cTNI rise.

Mechanisms for spontaneous termination of monomorphic, sustained ventricular tachycardia: results of activation mapping of reentrant circuits in the epicardial border zone of subacute canine infarcts.

OBJECTIVES: The objective of this study was to determine why sustained ventricular tachycardias (VT) sometimes stop without outside intervention. BACKGROUND: Sustained, monomorphic VT in patients with ischemic heart disease is often caused by reentrant excitation. These tachycardias can degenerate into rapid polymorphic rhythms or occasionally terminate spontaneously. METHODS: Sustained VT was induced by programmed stimulation in dog hearts 4 to 5 days after ligation of the left anterior descending coronary artery. Activation in reentrant circuits in the epicardial border zone of the infarct was mapped using 192 to 312 bipolar electrodes. RESULTS: Spontaneous termination of sustained VT always occurred when the reentrant wave front blocked in the central common pathway in reentrant circuits with a figure-of-eight configuration. Two major patterns of termination were identified from activation maps of the circuits that were not distinguishable from each other on the surface electrocardiogram: 1) Abrupt termination was not preceded by any change in the pattern of activation or cycle length. It could occur at different locations within the central common pathway, was not related to the directions of the muscle fiber orientation and was not caused by a short excitable gap. 2) Termination caused by premature activation (after a short cycle) either resulted from shortening of the functional lines of block around which the reentrant impulse circulated or was caused by wave fronts originating outside the reentrant circuit. In only one episode were oscillations of cycle length associated with termination. CONCLUSIONS: The mechanisms for termination of reentry in functional circuits causing VT are different from those in anatomic circuits where oscillatory behavior precedes termination.

Long-term follow-up after direct percutaneous transluminal coronary angioplasty for acute myocardial infarction.

OBJECTIVES: The purpose of this study was to analyze long-term follow-up information over several years from consecutive, unselected patients treated with direct percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (MI). BACKGROUND: Direct PTCA is often used in patients with acute MI. Short-term results are favorable. However, there is less information available on long-term observations over several years in these patients. METHODS: A total of 416 consecutive and unselected patients with acute MI underwent direct PTCA. Survival of the acute infarct phase was 94.2%; the remaining 392 patients--the study population-were discharged and followed for 3.3+/-1.4 years. Mortality as well as cardiac events and reinterventions are reported. Clinical variables assessed at the time of discharge are submitted to statistical analysis to detect potential risk factors. RESULTS: Total cumulative mortality in the first year was 10% for the entire group and 6% for patients not presenting in cardiogenic shock. Mortality after discharge was 4.6% in the first year and dropped to <4% per year thereafter. Reinterventions after discharge were required in 16% in the first year and in <4% per year in years 2 to 4. Poor left ventricular ejection fraction (<35%), three-vessel disease and advanced age (> or =75 years) were long-term risk factors for total mortality after direct PTCA. CONCLUSIONS: The clinical benefit of direct PTCA for acute MI is maintained during follow-up with respect to mortality. However, reinterventions for restenosis or de novo stenosis are often required (10% to 20%). Although few in number (<10%), patients with severely impaired left ventricular function continue to have a poor prognosis.

Automatic pacemaker termination of two different types of supraventricular tachycardia.

A new antitachycardia pacemaker system was used in a 58 year old woman to terminate two different types of supraventricular tachycardia by a single automatic pacing mode. During the invasive electrophysiologic study before pacemaker implantation (in the absence of medication), sustained episodes of atrioventricular (AV) nodal reentrant tachycardia and two short-lasting episodes of nonsustained atrial tachycardia were induced. After implantation, sustained episodes of both AV nodal tachycardia and atrial tachycardia were initiated. Both arrhythmias could be terminated reproducibly by a single pacing mode.

Effects of early reperfusion in acute myocardial infarction on arrhythmias induced by programmed stimulation: a prospective, randomized study.

This study compares inducibility of ventricular tachyarrhythmias by programmed electrical stimulation of the heart in patients with myocardial infarction with and without reperfusion after streptokinase therapy. Sixty-two consecutive patients admitted with an acute myocardial infarction were randomized to either combined intravenous and intracoronary streptokinase (streptokinase group) or to standard coronary care unit treatment (control group). Thirty-six of the 62 patients (21 patients from the streptokinase and 15 from the control group) with a first myocardial infarction were studied by programmed ventricular stimulation after a mean of 26 +/- 14 days. No patient had a history of antiarrhythmic drug use or documentation of a ventricular arrhythmia before the initial admission. A sustained ventricular arrhythmia was induced in 10 (48%) of the 21 patients randomized to streptokinase therapy and in all 15 (100%) control patients (p less than 0.001). Sustained monomorphic ventricular tachycardia was induced in 6 (29%) and 10 (67%) patients, respectively (p less than 0.05). To terminate an induced arrhythmia, direct current countershock was required in 33% of patients in the streptokinase group and 73% of patients in the control group (p less than 0.02). Seventeen of the 21 patients treated with streptokinase and no control patient had evidence of early reperfusion 200 +/- 70 minutes after the onset of pain. In comparison with patients without early reperfusion, patients in the reperfused group had a lower maximal serum creatine kinase value (p less than 0.01), a shorter time to peak creatine kinase value (p less than 0.001) and a higher angiographic left ventricular ejection fraction (62 versus 45%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

[CT-guided steroid injection into disc herniation: a causative therapy for lower back pain due to disc herniation]. / CT-gesteuerte Prolaps-Steroidinjektion: Eine kausale Therapie des bandscheibenprolapsassoziierten Schmerzsyndroms.

PURPOSE: To evaluate the therapeutic benefit of CT-guided steroid injection into disc herniations. MATERIALS AND METHODS: In 64 patients, 2.5 mg Dexamethasone was injected into a symptomatic disc herniation under CT-guidance. Conservative treatment 3 to 12 months before injection was unsuccessful. Classified as "complete relief", "strong relief", "mild relief" and "no relief" of pain, the change of discomfort and pain was registered at 14 days, 3 months and 6 months after injection while the conservative regimen continued. RESULTS: At 14 days after injection, 36 patients (56 %) showed complete relief, 5 strong relief (8 %), 12 mild relief (19 %) and 11 no relief (17 %). At 6 months after injection, 25 patients showed complete relief (39 %), 16 strong relief (25 %), and 23 no relief (36 %). One complicating spondylodiscitis was observed. CONCLUSION: CT-guided steroid injection into symptomatic disc herniation represents a therapeutic alternative with good therapeutic results. It can be recommended as an alterative to other minimal invasive therapeutic regimens. The disc material acts as reservoir for the drug with good long term depot effect.

Type 2 diabetes and acute myocardial infarction. Angiographic findings and results of an invasive therapeutic approach in type 2 diabetic versus nondiabetic patients.

OBJECTIVE: Mortality in diabetic patients with acute myocardial infarction (MI) is high. The significance of the pretreatment coronary status in type 2 diabetic patients with acute MI, as well as the effect of mechanical revascularization using percutaneous transluminal coronary angioplasty (PTCA), has not been established. RESEARCH DESIGN AND METHODS: All patients with type 2 diabetes and acute MI (n = 54) were prospectively enrolled into a study of immediate coronary angiography to guide PTCA of the occluded infarct vessel. Hospital and long-term course were assessed and compared with an unselected control group of nondiabetic patients (n = 358) who were enrolled in the same study. RESULTS: Angiography showed that sites of occlusion and acute coronary flow were similar in both groups. Multivessel disease and shock were more common in type 2 diabetic versus nondiabetic patients: 69 vs. 51% and 21 vs. 10% (P < 0.02), respectively. Direct PTCA was successful in > 90% in both groups. Mortality after 30 days was 13% in type 2 diabetic patients versus 5% in patients without diabetes (P < 0.04). Left ventricular (LV) ejection fraction before discharge was lower in diabetic patients (48 +/- 17 vs. 55 +/- 15%, P < 0.05). Mortality 1 year after discharge was 11 vs. 4% in diabetic versus nondiabetic patients (P < 0.02). Multivariate analysis identified type 2 diabetes as an independent risk factor for acute, but not for late, mortality. CONCLUSIONS: Direct PTCA is safe and effective in type 2 diabetic patients with acute MI. Mortality after 30 days in unselected diabetic patients is < 15% with this approach. Advanced disease and shock contribute to an increased mortality in type 2 diabetic patients with acute MI versus nondiabetic patients.

Dysrhythmias after direct-current cardioversion.

The success rate of direct-current (DC) countershocks and postshock arrhythmias are of concern for the design of automatic devices. Results of 112 DC shocks for induced ventricular tachycardia/fibrillation (VT/VF) (n = 99) or atrial fibrillation (AF) were analyzed. Clinical and arrhythmia characteristics were related to the success rate of DC shocks as well as postshock arrhythmias. Sixty-one patients were men and 14 were women; mean age was 52 +/- 15 years. Coronary artery disease was present in 56 patients and cardiomyopathy in 4. The other patients had no apparent structural heart disease. The success rate of transchest DC shocks for VT and VF were identical. The first DC shock interrupted 80% of VT and VF episodes. All episodes were terminated by 4 or fewer DC shocks. A single DC shock changed morphologic pattern or rate of 4 episodes of VT. Asystole after VT/VF (1,900 +/- 960 ms) was longer than after atrial fibrillation (1,150 +/- 470 ms, p less than 0.01). VT/VF recurred (within 3 minutes) after 26 of 99 initially successful DC shocks, requiring repeat shocks in 2 cases. Sinus bradycardia (n = 18) or high degree atrioventricular block (n = 11) necessitated rate support pacing in 10 patients. Antiarrhythmic drugs did not prevent postshock tachycardias, but facilitated the development of bradycardias. In conclusion, reliable and continuous analysis of cardiac rhythm after discharge is mandatory to enable automatic devices to correct unsuccessful discharges or recurring VT/VF. In addition, demand pacing capability is desirable to prevent severe bradycardia after DC shocks in patients receiving antiarrhythmic drugs.

Conversion of sustained into nonsustained ventricular tachycardia during therapy assessment by programmed ventricular stimulation: criterion for a positive drug effect?

Serial electropharmacologic testing using up to 11 different antiarrhythmic drugs was performed in 130 consecutive patients (107 men, 23 women, ages 56 +/- 12) with inducible sustained ventricular tachycardia (VT). After 4 +/- 2.3 drug tests, complete suppression of VT inducibility (defined as less than 6 consecutive beats, mean 1.4 +/- 1.6) was achieved in 86 patients (66%), whereas in 44 patients (34%) nonsustained VTs (greater than or equal to 6 consecutive beats, less than 30 seconds in duration) were still inducible. There was no statistical difference between both groups regarding age, sex, underlying heart disease, ejection fraction or entry arrhythmia. After a mean follow-up period of 19 +/- 17 months, 24 patients (18%) had died, 8 (6%) suddenly. Eight patients (6%) experienced recurrent sustained VT. Symptomatic recurrences (sudden death or VT) occurred in 10 (11%) and 6 patients (13%, difference not significant), respectively. Probability of arrhythmia-free survival was comparable for patients with 0 to 5, 6 to 10, 11 to 15 and 16 to 32 inducible ventricular complexes with discharge medication. The negative predictive value of electropharmacologic drug testing was about 89%, irrespective of the maximal number of inducible complexes used for the definition of a negative test result. It is therefore concluded that conversion of sustained into nonsustained VT during therapy assessment by programmed ventricular stimulation indicates a positive drug effect.

Reverse use-dependent effects of sotalol demonstrated by recording monophasic action potentials of the right ventricle.

In 22 patients referred for electrophysiologic study, monophasic action potentials (MAP) were recorded from the right ventricular aspect of the ventricular septum. The duration of MAP at 90% (MAP90) and 30% (MAP30) repolarization was measured in sinus rhythm, at a constant atrial paced cycle length of 600 ms for 3 minutes and at constant ventricular paced cycle lengths of 600, 500, 400 and 300 ms for 20 beats. Programmed ventricular stimulation from the apex of the right ventricle was performed at a basic drive cycle length of 400 ms and MAP90 and MAP30 of premature beats was determined. Changes of MAP duration were assessed 20 minutes after administration of intravenous sotalol 1.5 mg/kg. Sotalol significantly increased MAP90 and MAP30 in sinus rhythm. This was independent from sinus cycle length prolongation as evidenced by a significant prolongation of MAP90 and MAP30 with constant atrial pacing after sotalol. With slow ventricular stimulation frequencies and with long coupling intervals at programmed ventricular stimulation, sotalol significantly prolonged MAP90 and MAP30; with high stimulation frequencies and at short coupling intervals the action potential-prolonging effect of sotalol was diminished, indicating a reverse use-dependent effect of sotalol on repolarization of the right ventricle in humans.

Programmed electrical stimulation in healed myocardial infarction using a standardized ventricular stimulation protocol.

The diagnostic accuracy of programmed electrical stimulation was prospectively assessed in 111 patients with myocardial infarction (MI) with or without a history of spontaneous ventricular arrhythmias. In 29 patients neither ventricular tachycardia (VT) nor episodes of 10 premature ventricular depolarizations per hour was documented. Fifty patients had documented nonsustained VT and 32 had sustained monomorphic VT. One and 2 extrastimuli (twice diastolic threshold, 2 ms in duration) were given during sinus rhythm and ventricular pacing at 100, 120 and 140 beats/min in the right ventricular apex (part I). When this protocol failed to induce a sustained monomorphic VT, a third extrastimulus was introduced (part II). Repetitive ventricular responses were induced in all patients, and in 15 (14%) polymorphic ventricular arrhythmias requiring DC shock were induced. Incidence of initiation of sustained monomorphic VT and polymorphic ventricular arrhythmias requiring DC shock was related to the clinical arrhythmia and the stimulation protocol. In patients with documented sustained monomorphic VT, a third extrastimulus only increased the incidence of sustained monomorphic VT (68% to 94%), whereas in patients with documented nonsustained VT and without VT the incidence of both polymorphic and monomorphic arrhythmias increased by 7 to 12%. Sustained monomorphic VTs induced in patients without such a history were faster (p less than 0.01), depended on site of MI (p less than 0.05) and were more often preceded by nonsustained polymorphic VT (p less than 0.01) than in patients with documented sustained monomorphic VT.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of modes of electrical termination of ventricular tachycardia for the selection of implantable antitachycardia devices.

Different implantable systems for electrical treatment of ventricular arrhythmias are available. Information about mode of termination of ventricular tachycardia (VT) helps to select the most appropriate electrical treatment for drug-resistant VT. During 158 electrophysiologic studies, the mode of termination of 215 episodes of VT was analyzed in 2 groups of patients. Group 1 consisted of 54 patients with documented monomorphic VT and group 2 of 46 patients with other documented or suspected ventricular arrhythmias. Eighty-two patients had coronary heart disease, 8 had other structural heart disease and 10 had idiopathic VT. Termination of VT was attempted using extrastimuli and overdrive pacing; direct-current (DC) shocks were given in case of syncopal VT. During 33 of 96 studies (34%) in group 1, DC shock was required to interrupt VT, compared with 45 of 62 studies (73%) in group 2 (p less than 0.001). This difference was a result of less frequent induction of immediately syncopal VT in group 1 (14 of 129 VTs, vs 40 of 86 in group 2, p less than 0.001). Non-syncopal VT could reliably and safely be terminated by pacing in 61%, irrespective of the clinical arrhythmia. Pacing-induced acceleration of VT occurred in 6% (single extrastimuli) to 36% (over-drive pacing) (mean 26%) of attempts. Subsequent DC shock was required in half of these cases. Immediate collapse after induction of VT was not related to the presence of heart disease, but was related to a combination of VT cycle length (shorter than 260 ms) and left ventricular ejection fraction (less than 40%). Antiarrhythmic drugs reduced the need for DC shock.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiologic characteristics of ventricular tachycardia or fibrillation in relation to age of myocardial infarction.

Evaluation of ventricular myocardium after the onset of acute myocardial infarction (AMI) suggests that the substrate for ventricular arrhythmias changes as the substrate for ventricular arrhythmias changes as the AMI heals. To determine if the ability of programmed stimulation to initiate ventricular tachycardia (VT) varies according to the interval between AMI and electrophysiologic testing, the clinical and electrophysiologic data of 42 patients with spontaneous sustained VT and 12 patients with ventricular fibrillation (VF) more than 3 days after a single AMI were analyzed. For patients with VT, there were no significant differences in the incidence of initiation of sustained monomorphic VT among those evaluated 1 to 3 weeks (100%), 3 to 8 weeks (75%), 2 to 6 months (100%), 6 to 18 months (80%) or more than 18 months (81%) after AMI, and the mean number of extrastimuli required for initiation did not differ among the groups. Patients evaluated more than 4 weeks after the initial episode of VT had a lower incidence of inducible VT than those studied earlier (14 of 21 [71%] vs 21 of 21 [100%], p less than 0.05), although this appeared to be a result of earlier termination of the stimulation protocol owing to initiation of polymorphic arrhythmias in those studied later. The 14 patients evaluated within 8 weeks of AMI had significantly faster VT rates (mean cycle length 269 +/- 45 ms) than the 28 patients studied later (320 +/- 75 ms, p less than 0.01), possibly because of more out-of-hospital presentations of VT in patients studied later.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias induced during termination of supraventricular tachycardia.

Pacing is being used frequently for the treatment of drug-resistant, paroxysmal supraventricular tachycardias (SVT). SVT can usually be terminated by pacing, but arrhythmias may be induced which interfere with the safety of antitachycardia pacing. To quantify these pacing-induced arrhythmias, 453 attempts to terminate SVT in 111 patients were analyzed. The patients were 6 to 73 years old (mean 41); 62 were male. Seventy-six patients had SVT using an accessory atrioventricular bypass, and 35 patients had intranodal SVT. Single and then, if required, multiple ventricular and atrial premature beats and overdrive pacing were delivered from the atrium and ventricle. A pacing-induced arrhythmia occurred in 9% of all attempts (34% of patients). Atrial flutter or fibrillation (AF) was the most frequent arrhythmia (in 8% of all attempts and sustained in 75%). Atrial vs ventricular pacing resulted in a 12% vs 2% incidence of AF. AF was unrelated to age, sex, atrial size and SVT type, and was predominantly induced by multiple premature beats. In 6 patients a different SVT and in 2 patients a nonsustained ventricular tachycardia was induced. In 6 patients SVT could only be terminated by initiating another arrhythmia. Thus, AF is frequently induced during attempted pacing termination of SVT. To limit the risk of AF, a single premature beat should preferentially be used to terminate SVT. In 6% of patients, SVT can only be terminated by inducing another arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS)

Results and significance of Holter monitoring after direct percutaneous transluminal coronary angioplasty for acute myocardial infarction.

Whether acute and direct percutaneous transluminal coronary angioplasty improves the incidence of nonsustained ventricular tachycardia in patients surviving acute myocardial infarction is not known. In 400 consecutively studied patients, Lown classification IVb on Holter monitoring was only associated with arrhythmia morbidity, whereas reduced ejection fraction was related to total and cardiac mortality and arrhythmia morbidity.

Clinical performance of a specific algorithm to reconfirm self-terminating ventricular arrhythmias in current implantable cardioverter-defibrillators.

Inappropriate shock therapy is a frequent problem in patients with implantable cardioverter-defibrillators (ICDs), caused mostly by supraventricular rhythms. Self-terminating ventricular arrhythmias (STVAs), however, may also lead to inappropriate shock discharges even in ICDs with abortive shock capabilities. The aim of this study was to evaluate the clinical performance of a specific ventricular tachycardia/ventricular fibrillation (VT/VF) reconfirmation algorithm implemented in current ICD devices from Medtronic to prevent inappropriate shock discharges due to STVAs. A total of 161 STVA episodes were documented in 59 of 150 patients (39%) within a mean follow-up of 30 +/- 20 months and resulted in 25 inappropriate shock discharges in 15 of 150 patients (10%) despite activation of the reconfirmation algorithm. The first synchronization interval of the algorithm was met in 92% of STVA episodes with and even 38% of STVA episodes without shock delivery. A reduced incidence of inappropriate shocks due to STVAs was found with tachycardia/fibrillation detection intervals (TDI/FDI) programmed to shorter cycle lengths < or =280 ms or the use of the first 2 cycles after the end of charging to be considered for reconfirmation only. Thus, inappropriate shocks due to STVAs still occur in 10% of patients with ICDs despite activation of a specific VT/VF reconfirmation algorithm, and are mainly caused by meeting the first synchronization interval that therefore should be shortened in cycle length. Moreover, to reduce the likelihood of inappropriate shocks, the VF reconfirmation algorithm should be optimized by basing the synchronization intervals exclusively on the FDI with short cycle lengths or using the first 2 cycles for reconfirmation only.

[Initial experiences with nuclear spin tomography of bone diseases]. / Erste Erfahrungen mit der Kernspintomographie bei Knochenerkrankungen.

The results of MRT in 41 patients with bone diseases are reported. MRT proved to be a sensitive method in evaluating localised bone lesions. MR provided definite advantages in comparison with computed tomography and plain films in the determination of the intramedullary and extraosseous extent of circumscribed bone lesions. A better characterisation of the nature and histology of bone changes was not possible with MRT. Diffuse bone marrow disease are well demonstrable via MRT.