Search

Die Risikostratifizierung von Patienten mit koronarer Herzerkrankung (KHK) und nicht anhaltenden ventrikularen Tachykardien (NSVTs) stellt weiterhin ein klinisches Problem dar. Die Induzierbarkeit monomorpher ventrikularer Tachykardien (MVT) wahrend programmierter ventrikularer Stimulation (PVS) wurde bei 211 Patienten mit angiographisch gesicherter KHK und NSVTs untersucht, wobei eine Unterteilung in verschiedene Gruppen erfolgte: Patienten mit einer, 2–5 oder >5 Salven innerhalb von 24 h; Patienten mit einer Frequenz der Salven ≥150/min oder 10 konsekutiven Extrasystolen. Es fand sich eine signifikant hohere Induktionsrate von MVTs bei Patienten mit schnellen (≥150/min) NSVTs als bei Patienten mit langsamen NSVTs (

The effects of intravenous ethmozine (3 mg.kg-1) on electrophysiological parameters of ischaemically damaged myocardium and induced ventricular tachyarrhythmias were studied by programmed stimulation in 17 conscious dogs with 4 to 8 day-old ligation of the left anterior descending coronary artery. Ethmozine showed a beneficial effect on sustained ventricular tachycardia by suppressing its inducibility in five of 14 animals or by slowing its rate in six of 14 animals. Ethmozine prolonged the ventricular effective refractory period in normal and infarcted myocardium, and impaired depressed conduction in ischaemically damaged tissue. The latter was indicated by significant lengthening of late potentials recorded from the infarction zone. The QT interval was only slightly increased with ethmozine. Our findings indicate an antiarrhythmic action of ethmozine in the late stage of myocardial infarction. Major mechanisms accounting for its efficacy may predominantly be associated with marked depression of slow conduction in the infarction zone, as well as with prolongation of ventricular refractoriness without significant changes of ventricular repolarization.

The effects of prenylamine (PNL) and AQ-A 39 on sustained ventricular tachycardia (SVT) were studied by programmed stimulation in conscious dogs 4-10 days after ligation of the left anterior descending (LAD) coronary artery. In 8 of 16 dogs developing SVT in the control, PNL (3 mg/kg intravenously, i.v.) suppressed inducibility of SVT and slowed the rate of tachycardia in 6 other animals. In a separate group of 10 dogs with inducible SVT, AQ-A 39 (4 mg/kg i.v.) abolished elicitation of tachycardia in 3 dogs and decreased its rate in 6 other dogs. Neither drug affected normal conduction significantly, but PNL impaired slow conduction in the infarct zone, as indicated by prolongation of late potential. Both agents increased the effective refractory period (ERP) of infarcted and normal ventricular myocardium and prolonged the corrected QT interval. PNL and AQ-A 39 exert notable efficacy in preventing infarcted heart from severe ventricular arrhythmias. Prolongation of ventricular refractoriness and repolarization, as well as decreased slow conduction in ischemically damaged myocardium, are major mechanisms accounting for the effectiveness of these drugs against ventricular arrhythmias.

There is extensive experimental and clinical experience concerning the antiarrhythmic potency of DL-sotalol, a beta-adrenergic antagonist that lengthens the cardiac action potential duration. More recently, its dextrorotatory isomer, D-sotalol, has been evaluated in experimental studies and preliminary clinical trials. Whereas the isomer is almost free of beta-blocking activity, both experimental and clinical data demonstrate that potent class III activity of D-sotalol. Further investigations, particularly in patients with life-threatening arrhythmias, are needed to delineate the clinical usefulness of this compound.

Congestive heart failure (CHF) is a complex clinical syndrome with autonomic dysbalance and increased plasma levels of inflammatory cytokines, which further worsen the syndrome. Experimental data have shown that stimulation of certain acupoints decreases autonomic dysbalance.To test the therapeutic potential of acupuncture for life-threatening diseases such as CHF.17 stable patients with CHF (New York Heart Association class II-III, ejection fraction40%) receiving optimised heart failure medication were randomised into a verum acupuncture (VA) and placebo acupuncture (PA) group. Cardiopulmonary function, heart rate variability and quality of life were explored.No improvements of the cardiac ejection fraction or peak oxygen uptake were observed, but the ambulated 6 min walk distance was remarkably increased in the VA group (+32+/-7 m) but not the PA group (-1+/-11 m; p0.01). Accordingly, post-exercise recovery after maximal exercise and the VE/VCO(2) slope, a marker of ventilatory efficiency, were improved after VA but not PA. Furthermore, heart rate variability increased after VA, but decreased after PA. The 'general health' score and 'body pain' score of the quality-of-life questionnaire SF-36 tended to be improved after VA.Acupuncture may become an additional therapeutic strategy to improve the exercise tolerance of patients with CHF, potentially by improving skeletal muscle function.

Background: The prognostic role of asymptomatic nonsustained ventricular tachycardia (NSVT) and programmed ventricular stimulation (PVS) in patients with idiopathic dilated cardiomyopathy (IDC) remains controversial. Methods: The prognostic significance of ventricular arrhythmias, ejection fraction, NYHA class, atrial fibrillation and age for overall and sudden death mortality was prospectively studied in 157 patients with IDC (group 1) free of documented sustained ventricular arrhythmia and syncope. In 99 patients with asymptomatic NSVT (group 2), PVS with 2 – 3 extrastimuli was performed. Non-inducible patients were discharged without specific antiarrhythmic therapy, whereas those with inducible monomorphic ventricular tachycardia were implanted with an ICD. Results: In group 1, 48% of patients had NSVT. Overall and sudden death mortality were significantly higher in patients with NSVT (34.2 vs. 9.8%, p = 0.0001 and 15.8 vs. 3.7%, p = 0.0037; follow-up 22 ± 14 months). Multivariate analysis revealed that NSVT independently predicts both overall and sudden death mortality (p = 0.0021 and .0221, respectively; adjusted for EF, NYHA class and age). In group 2, inducibility of sustained ventricular tachyarrhythmia was 7%, but sustained monomorphic VT occurred in 3% only. Two of 7 inducible patients experienced arrhythmic events during a follow-up of 25 ± 21 months (positive predictive value 29%). Overall and sudden death mortality were 29% and 0% in the inducible group vs. 17 and 4% in the non-inducible group. Both overall and sudden death mortality were signi.cantly lower in non-inducible patients from group 2 as compared to patients from group 1 with NSVT (p = 0.0043 and 0.0048), most likely due to a more common use of betablockers and a higher EF in the former group (p < 0.001, respectively). Conclusions: In patients with IDC, NSVT independently predicts both overall and sudden death mortality. Due to a low inducibility rate and a poor positive predictive value, PVS seems inappropriate for further arrhythmia risk assessment. However, in spite of documented NSVT, the incidence of SCD in patients on optimized medical treatment including betablockers seems to be very low, questioning the need for specific arrhythmia risk stratification.

It was hypothesized that a wall motion score (WMS) ofor=16% determined by chordal analysis (WMS=% of chords analyzed with normal or hyperkinetic motion) from a right anterior oblique (RAO) left ventriculogram would be a predictor for perioperative (30-day or in-hospital) or long-term mortality in patients from the CABG-Patch Trial.One hundred and eighty-nine patients from the trial with a LVEF ofor=36% were retrospectively studied. Patients were divided into two groups according to a WMS ofor=16% (n=81) or16% (n=108), respectively, calculated from a preoperative RAO ventriculogram. There was no difference in EF between the two groups (26.5+/-5.5 vs. 27.8+/-5.3%, respectively). Eight (9.9%) versus three (2.8%) patients died perioperatively in the low versus the high WMS group, respectively. The relative risk for perioperative death in the low WMS group was 3.6 (P0.04). Kaplan-Meier estimates of cumulative survival did not reveal any statistical difference between the two groups over 4 years (P=0.11). Subgroup analysis revealed that patients with a WMS ofor=16% had a better survival when treated with an ICD at the time of surgery compared to those not treated with an ICD (P=0.046).These data indicate that poor LV function, as assessed by a WMS ofor=16%, can identify a subgroup of low EF patients who are at increased risk for perioperative mortality after bypass surgery. Conversely, long-term estimates of survival in patients with WMSor=16 and16% were not significantly different, although subgroup analysis revealed that patients with a WMSor=16% may benefit from implantation of an ICD at the time of surgery.

WERETKA, S., et al.: Far-Field R Wave Oversensing in a Dual Chamber Arrhythmia Management Device: Predisposing Factors and Practical Implications. Initial experience with the Medtronic Jewel 7250, the ICD designed to detect and treat ventricular and supraventricular tachyarrhythmias, is very promising. Its effectiveness, however, depends on sensing performance, which has not yet been systematically examined. The aim of the study was to determine the incidence of, predisposing factors for, and practical implications of far-field R wave oversensing (FFRWOS) in this dual chamber ICD. During a total follow-up of 797 months in 48 patients who had the Jewel 7250, follow-up strip charts, 12-channel Holter recordings and, in particular cases, Holter recordings with intracardiac markers were analyzed for the presence of FFRWOS. FFRWOS was documented in ten (21.3%) patients. Compared to other lead locations, the right atrial appendage lead position was most frequently associated with FFRWOS (7/27 vs 3/21, P < 0.05). Patients with FFRWOS had significantly more treated and nontreated atrial episodes, many of which were judged to have been detected inappropriately. In one case, inappropriate atrial antitachycardia pacing due to R wave oversensing triggered sustained ventricular tachycardia, terminated eventually with a high energy shock. In dual chamber ICDs, FFRWOS may represent a frequent phenomenon possibly leading to serious consequences. For atrial leads, a lateral atrial wall position seems to be preferable. In most cases, FFRWOS can be eliminated by optimization of atrial sensing parameters. Given the possibility of ventricular proarrhythmia with atrial pacing therapy, the capability of ventricular backup defibrillation in respective devices is at least reassuring.

In recent years abundant information has been obtained about the relationship of heart disease and cardiac late potentials. Non-invasive recordings of ventricular late potentials are useful in risk stratification of various clinical conditions, in particular, in patients following myocardial infarction. Here a close correlation has been established between cardiac late potentials and spontaneous or induced sustained ventricular tachycardias using programmed electrical stimulation. Cardiac late potentials also appear to be associated with arrhythmic events in patients with cardiomyopathies, and following unsuccessful antitachycardia surgery. Furthermore, recording of abnormal late potentials are associated both with acute rejection after cardiac transplantation and unsuccessful thrombolytic therapy after myocardial infarction. Interestingly, antiarrhythmic drugs have no clear effect on cardiac late potentials.

To evaluate the antiarrhythmic efficacy of l-sotalol and bisoprolol on inducible ventricular arrhythmias, conscious dogs with 4- to 8-day-old myocardial infarction were studied by programmed electrical stimulation. Direct recordings from infarcted and adjacent normal subepicardium were made using a specially designed composite electrode. From 18 dogs developing sustained ventricular tachycardia (sVT) during control stimulation, l-sotalol (1.5 mg/kg i.v.) prevented reinducibility of sVT in 10 animals, while in seven other animals it significantly reduced the rate of tachycardia. Bisoprolol (0.2 mg/kg i.v.), tested in a separate group of 10 dogs susceptible to sVT, was mostly ineffective in preventing or slowing the tachycardia. Both agents significantly prolonged conduction time and refractoriness within the atrioventricular conduction system, and decreased heart rate. However, while l-sotalol lengthened ventricular refractoriness and QT interval, bisoprolol exerted only a minor effect on these parameters. Neither of the drugs affected conduction in normal and infarcted myocardium, as indicated by almost unchanged QRS complex width and duration of ventricular late potentials, respectively. The results indicate that acute beta-blockade is ineffective against sVT induced during the subacute stage of myocardial infarction. The antiarrhythmic efficacy of l-sotalol may predominantly be related to its prolonging effect on ventricular refractoriness, supporting the concept of pure class III action.

Non-thoracotomy implantation of implantable cardioverter defibrillators (ICDs) has simplified the process of device inserfion, promising to decrease associated procedural coniplications while providing sudden death protection at least equal to epicardial systems. This study presents the acute and chronic results of 110 patients who underwent attempted non-thoracotomy ICD impiuntation wiih the Medtronic Transvene lead system and PCD model 7217 or 7219. Of the 110 patients attempted, 100 (91%) had the system successfully implanted without the need for an epicar-dial patch. One patient died 1 week postoperatively of septic shock related to the implantation (0.9% perioperative mortality). During folloiv-up of 16 ± 11 months, 45% of the patients had an event detected as ventricular tachycardia; 26% of these detections were felt clinically to be due to supraventricular rhythms. Of the remainder, 87% were successfully treated with the first VT therapy, and 98% were terminated by the final therapy; 66% of the patients had at least one episode of ventricular fibrillation, of which 5% were felt to be inappropriate detections; 65% of the appropriate episodes were successfully treated with the first VF therapy, and all were converted by the final therapy. Total mortality at 6, 12, and 24 months was 3%, 11%, and 19% respectively. Only one patient had sudden cardiac death, occurring at 13 months postimplant. Overall, the non-thoracotomy lead system for this ICD displayed infrequent implant complications and proved to be reliable ai terminating arrhythmias and maintaining a low rate of sudden cardiac death in this high risk popuiation.

In 12 anesthetized mongrel dogs (30 mg/kg pentobarbital), a thoracotomy was performed, and the left anterior descending coronary artery was ligated proximally. Eight to 12 days later, monophasic action potentials were recorded endocardially from the apex of the noninfarcted right ventricle and infarcted areas of the left ventricle, and the effects of 1.5 mg/kg intravenous sotalol were evaluated. Monophasic action potentials from the infarcted zone of the left ventricle were obtained from areas where fractionated bipolar electrograms could be recorded; this was histologically confirmed. After sotalol, in sinus rhythm, the monophasic action potential duration at 90% repolarization of the infarcted zone increased from 186 +/- 31 to 226 +/- 45 ms (+ 22%, p less than 0.05), and monophasic action potential duration of the noninfarcted zone increased from 184 +/- 31 to 225 +/- 47 ms (+ 22%, p less than 0.05). Programmed ventricular stimulation was performed with single extrastimuli at a basic drive cycle length of 300 ms. With long coupling intervals (290 ms), monophasic action potential duration of the infarcted zone increased from 165 +/- 23 to 183 +/- 25 ms (+ 11%, p less than 0.05) after sotalol; and monophasic action potential duration of the noninfarcted zone increased from 159 +/- 20 to 180 +/- 25 ms (+ 13%, p less than 0.05). With short coupling intervals (200 ms), the monophasic action potential duration of the noninfarcted zone increased from 157 +/- 19 to 173 +/- 18 ms (+ 10%, p less than 0.05), and monophasic action potential duration of the noninfarcted zone increased from 150 +/- 18 to 157 +/- 18 ms (+ 5%, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Die INSIDE-Studie vergleicht prospektiv randomisiert den Stellenwert der VDD-Stimulation im Vergleich zur DDD-Stimulation. VDD-Schrittmacher detektierten niedrigere P-Wellenamplituden als Zweikammerschrittmacher; die atriale Sensitivitat war dementsprechend auf empfindlichere Werte programmiert worden. Die Sinusknotenfrequenz stieg in der Fahrradergometrie in beiden Gruppen gleichermasen an. Atriales Undersensing war sowohl im Langzeit-EKG als auch wahrend der Belastungsuntersuchung selten in der DDD-Gruppe nachweisbar und in der VDD-Gruppe nicht signifikant erhoht. In beiden Behandlungsgruppen fanden sich keine Beschwerden infolge atrialen Undersensings.

Study objective — The aim was to characterise monophasic action potentials recorded from subacutely infarcted myocardial regions, where fractionated bipolar electrograms could be obtained. Design — Dogs underwent ligation of the left anterior descending coronary artery. Before and 8-12 d after ligation, monophasic action potentials and local electrograms were recorded endocardially from the apex of the left ventricle. Experimental material — 15 anaesthetised mongrel dogs (30 mg pentobarbitone·kg−1) were used. Measurements and main results — Multiphasic fractionated bipolar electrograms could be recorded from infarcted sites of the left ventricle with a mean duration of 69(SD 10) ms and a mean amplitude of 3.7(1.6) mV, compared to control values of 42(7) ms (p

QT interval dispersion measured as interlead variability of QT, is a marker of dispersion of ventricular repolarization and, hence, of cardiac electrical instability. The influence of the new class III agent d-sotalol on QT dispersion (QT disp) was investigated in 20 patients (pts) with recurrent sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF). All pts had inducibile VT/VF at baseline and were electrophysiologically studied under oral d-sotalol (460 ± 94 mg/day). In 10 pts d-sQTalol suppressed the induction of VT/VF, whereas 10 pts did not respond. QTand RR intervals of 3 consecutive beats were measured in 6 simultaneously recorded precordial leads (VI-V6) by two independent blinded investigators. Under oral d-sotalol, the QT disp was reduced in 9/10 responders but only in 4/10 non-responders, despite comparable doses of the drug in both groups. The relative changes between control and under d-sotalol therapy in responders and non-responders of corrected maximal QT (QTc max.), QT disp., dispersion of the QTc (QTc disp.) and adjusted QTc (adj. QTc disp) are presented as means ± SD. responder non-responder p Δ QTc max. 32.9 ± 69.2 27.5 ± 41.4 NS Δ QT disp. - 30.3 ± 16.8 20.3 ± 38.2 0.001 Δ QTc disp. - 34 ± 31 18.5 ± 37.8 0.003 Δ adj. QTc disp - 13.3 ± 12.9 7.5 ± 15.6 0.004 Dosage 480 ± 103 440 ± 84 NS The new class III agent d-sotalol produced a significant reduction of QTc dispersion in responders in contrasts to non-responders. Conclusion QT dispersion may be potentially useful in the assessment of the efficacy of class III antiarrhythmic drugs. This effect may be due to homogenization of repolarization in both normal and diseased myocardium representing the arrhythmogenic substrate.