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Biomedical subjects

L Jordaens

Publications and source records attributed to L Jordaens.

At least 37 records · Page 2Linked to original sources
PubMed1999

Report of a study group on ablate and pace therapy for paroxysmal atrial fibrillation. Barcelona Discussion Group. Working Group on Arrhythmias of the European Society of Cardiology.

Atrioventricular junctional (AVJ) catheter ablation followed by pacemaker implantation is now widely accepted for patients affected by paroxysmal atrial fibrillation (PAF) not controlled by antiarrhythmic drugs. However, few data exist on its indications, optimal methodology and complications. Therefore a study group examined current practice in Europe and North America, using a questionnaire, followed by a Study Group Meeting to discuss the results. Based upon this, class I, class II and class III indications were proposed. Class I indications (for which general agreement existed) include drug-refractory PAF, correlating with important symptoms, the bradycardia tachycardia syndrome already treated with a pacemaker, and continued PAF. Large differences exist in the current methodology, but consensus was reached on the technical approaches of right and left-sided AVJ ablation, and on the timing of pacemaker implant in relation to ablation. No complete agreement was reached on technical features such as catheter choice and heparin use. The recommended pacing mode was DDDR with mode switching.

Atrial Fibrillation↗
PubMed1999

Quality of life in patients with complete heart block and paroxysmal atrial tachyarrhythmias: a comparison of permanent DDIR versus DDDR pacing with mode switch to DDIR.

A prospective double-blind randomized crossover study was done in 15 patients with complete heart block and intermittent ATs. The pacemaker was randomly programmed to dual chamber inhibited rate responsive pacing (DDIR) and to DDDR with mode switch, for 1 month each. An event recorder was given to the patients and after each period, a QOL questionnaire was obtained. Based on telemetric data, all but two patients had AT during follow-up. The duration and frequency of these episodes were not related to mode settings. AV synchrony was better preserved in DDDR (P < 0.05). Most symptom-related event recordings during DDIR showed loss of AV synchrony; DDDR with mode switch caused symptoms due to tracking of ST. Overall the QOL score was not different between the modes. Fewer somatic complaints were noted during DDDR pacing than during baseline. DDIR stimulation showed no difference. Twelve patients preferred the period of DDDR pacing; one experienced severe symptoms during DDIR. In conclusion, patients with paroxysmal AT, DDDR with mode switch, and DDIR had no influence on the occurrence, nor on the duration of AT episodes. AV synchrony was better preserved in DDDR, which was also associated with fewer somatic complaints compared to the baseline. In DDDR, symptoms were observed when ST was tracked. QOL was comparable, although more patients preferred DDDR.

Adult↗
PubMed1999

QT dispersion is not related to infarct size or inducibility in patients with coronary artery disease and life threatening ventricular arrhythmias.

OBJECTIVE: To relate QT parameters to infarct size and inducibility during electrophysiological studies. DESIGN: Analysis of a prospective register. SETTING: University hospital. PATIENTS: 64 patients with coronary artery disease and documented life threatening ventricular arrhythmias. INTERVENTIONS: Measurements of QT-max, QTc-max, and QT dispersion (QT-d) on a simultaneous 12 lead ECG (50 mm/s). Estimation of myocardial infarct size with radionuclide left ventricular ejection fraction (LVEF), echocardiography (left ventricular end diastolic diameter, LVEDD), and a defect score based on a quantitative stress redistribution 201-thallium perfusion study. Electrophysiological study to assess inducibility. RESULTS: Mean (SD) QT parameters were: QT-max 440 (50) ms, QTc-max 475 (46) ms, and QT-d 47 (20) ms. Mean (SD) estimates of infarct size were: LVEF 34 (13)%, LVEDD 61 (9) mm, and defect score 18 (11). There was no significant correlation between any index of infarct size and QT parameters. QT parameters were not significantly different between patients with inducible (n = 57) and non-inducible arrhythmias (n = 7) (QT-max: 416 (30) v 443 (51) ms, p = 0.18; QTc-max 485 (34) v 473 (47) ms, p = 0.34; QT-d 47 (12) v 47 (21) ms, p = 0.73). Non-inducible patients had a significant lower defect score: 8 (9) v 19 (11), p = 0.02, but comparable LVEF: 38 (12)% v 34 (12)%, p = 0.58, and LVEDD: 54 (10) v 61 (8) mm, p = 0.13. CONCLUSIONS: QT parameters are not influenced by infarct size and do not predict inducibility during electrophysiological study in patients with coronary artery disease and malignant ventricular arrhythmias. In contrast, the amount of scar tissue determined by perfusion imaging is strongly correlated with inducibility.

Aged↗
PubMed1999

The combination of risk factors for sudden death in a resuscitated elderly patient with an exceptional cause of left ventricular hypertrophy.

The work-up of a previously asymptomatic 72-year-old man presenting with sudden cardiac death revealed a coarctation of the aorta as the cause of arterial hypertension, severe left ventricular hypertrophy, in combination with coronary artery disease with an apical myocardial infarction, severe autonomic dysfunction, and AV-nodal reentrant tachycardia. All these elements and their complex, probably synergistic interactions might have been involved in the development of sudden cardiac death.

Aged↗
PubMed1998

Atrioverter: an implantable device for the treatment of atrial fibrillation.

BACKGROUND: During atrial fibrillation, electrophysiological changes occur in atrial tissue that favor the maintenance of the arrhythmia and facilitate recurrence after conversion to sinus rhythm. An implantable defibrillator connected to right atrial and coronary sinus defibrillation leads allows prompt restoration of sinus rhythm by a low-energy shock. The safety and efficacy of this system, called the Atrioverter, were evaluated in a prospective, multicenter study. METHODS AND RESULTS: The study included 51 patients with recurrent atrial fibrillation who had not responded to antiarrhythmic drugs, were in New York Heart Association Heart failure class I or II, and were at low risk for ventricular arrhythmias. The atrial defibrillation threshold had to be </=240 V during preimplant testing. Atrial fibrillation detection, R-wave shock synchronization, and defibrillation threshold were tested at implantation and during follow-up. Shock termination of spontaneous episodes of atrial fibrillation was performed under physician observation. Results are given after a minimum of 3 months of follow-up. During a follow-up of 72 to 613 days (mean, 259+/-138 days), 96% of 227 spontaneous episodes of atrial fibrillation in 41 patients were successfully converted to sinus rhythm by the Atrioverter. In 27% of episodes, several shocks were required because of early recurrence of atrial fibrillation. Shocks did not induce ventricular arrhythmias. Most patients received antiarrhythmic medication during follow-up. In 4 patients, the Atrioverter was removed: in 1 because of infection, in 1 because of cardiac tamponade, and in 1 because of frequent episodes of atrial fibrillation requiring His bundle ablation. CONCLUSIONS: With the Atrioverter, prompt and safe restoration of sinus rhythm is possible in patients with recurrent atrial fibrillation.

Adult↗
PubMed1998

Variations of autonomic tone preceding onset of atrial fibrillation after coronary artery bypass grafting.

Assessment of autonomic tone preceding the onset of atrial fibrillation (AF) after coronary artery bypass grafting (CABG) with heart rate variability was examined in 64 patients scheduled for elective CABG (days 2 to 5). Ninety-six-hour Holter tapes were analyzed in each patient and all events labeled by an experienced technician. The hour preceding AF was divided into 4 quarters (heart rate variability calculated per quarter) and compared with similar time episodes from the group without AF. Twenty-six of 64 patients (40%) had a total of 35 episodes. Only increased age (68+/-5 vs 62+/-9 years) and lower ejection fraction (66+/-16% vs 73+/-8%) were associated with an increased risk for AF. Before onset, a greater number of atrial premature complexes was observed. The standard deviation of all RR intervals (SDNN) showed an increase in the group with AF in the last 15 minutes (significant vs controls and within the AF group). The low-frequency/high-frequency ratio was significantly lower in patients in the first 30 minutes, followed by an increase mainly because the high-frequency spectrum became less important. Thus, initiation of postoperative AF is influenced by autonomic tone variations. A shift in the autonomic balance with a loss of vagal tone and a moderate increase in sympathetic tone are observed before the onset of AF compared with those in controls.

Aged↗
PubMed1998

Intracardiac overdrive pacing as a treatment of atrial flutter in a horse.

A five-year-old warmblood mare with atrial fibrillation was treated with quinidine sulphate. The atrial rhythm changed to atrial flutter and, because there were toxic effects, the treatment was discontinued. Seven months after the occurrence of the atrial flutter, treatment with a rapid atrial pacing technique restored a normal sinus rhythm. One year after the pacing therapy the horse was still in sinus rhythm and had been brought back into training.

Animals↗
PubMed1998

Influence of anaesthesia on defibrillation threshold.

Internal cardioverter-defibrillator implantation can be performed under local or general anaesthesia. Whether the technique of general anaesthesia influences the defibrillation threshold remains a matter of debate. We therefore compared, in a prospective, randomised clinical study, the effect of intravenous anaesthesia using propofol with inhalational anaesthesia using isoflurane on the defibrillation threshold in 68 patients scheduled for transvenous single-lead internal cardioverter-defibrillator implantation. Defibrillation threshold was measured at implantation and at device testing 1 week and 1 month after implantation. Patients acted as their own controls. Neither the anaesthetic technique nor the duration of anaesthesia was associated with significant changes in the defibrillation threshold. We conclude that in this group of high-risk patients, both types of anaesthesia are acceptable techniques for internal cardioverter-defibrillator implantation and testing.

Anesthesia, General↗
PubMed1998

Factors influencing long term persistence of sinus rhythm after a first electrical cardioversion for atrial fibrillation.

It is conventionally thought that electrical cardioversion in patients with atrial fibrillation (AF) of longstanding duration or with a large left atrial diameter, only seldom results in long term success. Recurrence is common, although antiarrhythmic drugs often effectively decrease the number and duration of recurrent AF episodes. We analysed clinical, functional and pharmacological variables which could possibly influence the long term outcome after a first electrical cardioversion for AF in a retrospective study on 85 patients. Univariate and multivariate analysis was used to identify factors predicting maintenance of sinus rhythm at 100 days, and absence of recurrence during the entire follow-up. In univariate analysis, the only significant predictor for maintenance of sinus rhythm at 100 days was the duration of the preceding AF episode. Multivariate analysis with persistence of sinus rhythm at 100 days as endpoint confirmed this as a prognostic factor (p < 0.03), but sotalol treatment also contributed to maintenance of sinus rhythm (p < 0.05). When considering the entire observation period, class III antiarrhythmic drugs, i.e. sotalol and amiodarone, were useful in preventing recurrence (p < 0.01 and < 0.02). High age (above 75 years) was a predictor of recurrence. In conclusion, class III antiarrhythmic drugs, the duration of atrial fibrillation and high age were the most important determinants of long term outcome, while echocardiographic parameters and the presence of heart disease played no role.

Amiodarone↗
PubMed1998

Electrocardiographic and morphometric features in patients with ventricular tachycardia of right ventricular origin.

OBJECTIVE: To study differences between repetitive monomorphic ventricular tachycardia (RMVT) of right ventricular origin, and ventricular tachycardia in arrhythmogenic right ventricular dysplasia (ARVD). PATIENTS: Consecutive groups with RMVT (n = 15) or ARVD (n = 12), comparable for age and function. METHODS: Analysis of baseline, tachycardia, and signal averaged ECGs, clinical data, and right endomyocardial biopsies. Pathological findings were related to regional depolarisation (QRS width) and repolarisation (QT interval, QT dispersion). RESULTS: There was no difference in age, ejection fraction, QRS width in leads I, V1, and V6, and QT indices. During ventricular tachycardia, more patients with ARVD had a QS wave in V1 (p < 0.05). There were significant differences for unfiltered QRS, filtered QRS, low amplitude signal duration, and the root mean square voltage content. In the absence of bundle branch block, differences became non-significant for unfiltered and filtered QRS duration. Mean (SD) percentage of biopsy surface differed between RMVT and ARVD: normal myocytes (74(3.4)% v 64.5(9.3)%; p < 0.05); fibrosis (3(1.7)% v 8.9(5.2)%; p < 0.05). When all patients were included, there were significant correlations between fibrosis and age (r = 0.6761), and fibrosis and QRS width (r = 0.5524 for lead I; r = 0.5254 for lead V1; and r = 0.6017 for lead V6). CONCLUSIONS: The ECG during tachycardia and signal averaging are helpful in discriminating between ARVD and RMVT patients. There are differences in the proportions of normal myocytes and fibrosis. The QRS duration is correlated with the amount of fibrous tissue in patients with ventricular tachycardia of right ventricular origin.

Adult↗
PubMed1998

Analysis of the P wave with signal averaging to assess the risk of atrial fibrillation after coronary artery bypass surgery.

P wave signal averaging was performed in 91 consecutive patients undergoing coronary artery bypass grafting to detect patients at risk of postoperative atrial fibrillation (AF). Sixteen patients (17.5%) developed AF after surgery. The P wave duration on the signal-averaged electrocardiogram (ECG) and on surface ECG was prolonged in AF patients compared to others (respectively 141 +/- 12 vs. 132 +/- 12 ms and 124 +/- 9 vs. 113 +/- 9 ms). The root mean square voltages (RMS) of the total P wave were not different between the two groups; the RMS of the late portion of the P wave (late RMS) was significantly higher (0.25 +/- 0.15 vs. 0.17 +/- 0.10 microV) and the RMS of the first 110 ms of the P wave (early RMS) significantly lower (0.88 +/- 0.28 vs. 1.09 +/- 0.33 microV) in AF. The late/ early RMS ratio was different (0.29 +/- 0.16 vs. 0.17 +/- 0.11). In a multivariate analysis only age and the late/early RMS ratio were predictive for AF.

Adult↗
PubMed1998

ECG changes and plasma concentrations of propafenone and its metabolites in a case of severe poisoning.

CASE REPORT: Propafenone is a class IC antiarrhythmic agent metabolized into two major metabolites, 5-hydroxypropafenone and N-depropylpropafenone. The potency of 5-hydroxypropafenone to block fast sodium channels is comparable to that of its parent. We report the positive correlation between plasma concentrations and electrocardiographic changes in a patient with severe oral self-poisoning. Serial ECG changes were measured and plasma concentrations were determined by high-performance liquid chromatography. The initial plasma concentrations of propafenone were in the toxic range and correlated with the widening of the QRS-complex. The slow decline in concentration during this first phase might relate to saturation of the isoenzyme CYP2D6. The half-life of propafenone, calculated from the second phase, was approximately 3 hours, defining the patient as a fast metabolizer. The initial concentrations of the metabolite N-depropylpropafenone were surprisingly higher than those of 5-hydroxypropafenone which may also be due to saturation of CYP2D6.

Anti-Arrhythmia Agents↗
PubMed1998

Signal-averaged P wave: predictor of atrial fibrillation.

Abnormalities of the P wave seen during sinus rhythm are associated with atrial fibrillation and other supraventricular arrhythmias. Intra-atrial conduction delays can be seen on the surface ECG as P wave prolongation, which is more visible with averaging techniques used in advanced recording devices. Averaging followed by amplification after proper filtering of the electrical signal should allow more precise measurements of duration and amplitude of the P wave. Data on reproducibility, filter settings, required number of beats, and precise definitions of onset and offset are dependent largely on the system used, which can be QRS or, preferably, P wave triggered. This explains conflicting data in the literature. It is clear that P wave duration is one of the best predictors of perioperative atrial fibrillation. For paroxysmal forms, the data are less convincing. Root mean square voltages of the P wave can be useful. Combining the P wave duration with other data often improves the diagnostic value of signal averaging. Standardization of the techniques appears to be necessary.

Atrial Fibrillation↗
PubMed1997

Low-energy intracardiac shocks during atrial fibrillation: effects on cardiac rhythm.

The effect on ventricular rate of intracardiac shocks for atrial fibrillation was studied in 13 patients receiving 95 shocks. Shocks were synchronized to the R wave and were delivered after R-R intervals > 500 msec, with increasing strength (20 to 400 V). In 10 patients, conversion to sinus rhythm was achieved in this way. Noneffective shocks increased the mean first postshock R-R interval (compared with 20 V as baseline), for shocks > or = 140 V. The R-R prolongation correlated with the shock level (r = 0.936, p < 0.01). Subsequent R-R intervals were comparable to baseline. A similar trend toward longer first postshock intervals was observed for effective shocks. However, the maximal first R-R interval after noneffective shocks had no relation to the voltage. The number of pauses > 1500 msec tended to increase with voltage (noneffective shocks). Pauses > 2500 msec were exceptional (4 of 85 noneffective shocks). No symptomatic bradycardia occurred. In subsequent intervals (cycles 2 through 10) no pauses > 2500 msec were noted. It is concluded that atrial defibrillation attempts between the right atrium and coronary sinus prolong R-R intervals, in relation to administered energy, but without the need for backup pacing.

Adult↗
PubMed1997

Conversion of atrial fibrillation to sinus rhythm and rate control by digoxin in comparison to placebo.

AIMS: A randomized, double-blind study with a high dose of digoxin administered intravenously for conversion of atrial fibrillation (not due to haemodynamic alternations) to sinus rhythm, and for rate control in converters and non-converters was set up. Outcome measures were conversion within 12 h; time to conversion; early rate control; and stable slowing within 12 h. METHODS: We studied 40 patients with recent onset (< 1 week) atrial fibrillation; controls received saline intravenously, the other patients digoxin 1.25 mg. RESULTS: One patient converted before digoxin administration. Conversion occurred in 9/19 patients on digoxin and in 8/20 on placebo (ns). The mean time to conversion tended to be shorter only for digoxin. Two late conversions on placebo were observed within 24 h. Heart rate during atrial fibrillation decreased after 30 min for converters and non-converters (P < 0.05). For all patients on digoxin, heart rate after 30 min was lower compared to baseline (P < 0.002) and to placebo (P < 0.02). Persistent, stable slowing occurred only in 3/10 non-converters on digoxin (P < 0.05), and two patients developed bradyarrhythmias. QTc was shortened immediately after conversion in all patients. Converters had baseline characteristics similar to those of non-converters. CONCLUSIONS: Intravenous digoxin offers no substantial advantages over placebo in recent onset atrial fibrillation with respect to conversion, and provides weak rate control.

Aged↗