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Biomedical subjects

R Tavernier

Publications and source records attributed to R Tavernier.

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

Incessant automatic atrial tachycardia: a reversible cause of tachycardiomyopathy.

We describe the case of a 23-year-old man with incessant atrial tachycardia complicated with tachycardiomyopathy. Transseptal ablation of the arrhythmia focus, located between the ostia of the left and right inferior vena pulmonalis, resulted in a restoration of normal sinus rhythm and a complete regression of the signs of tachycardiomyopathy.

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

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

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

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↗
PubMed1997

Changes in the QT interval and its adaptation to rate, assessed with continuous electrocardiographic recordings in patients with ventricular fibrillation, as compared to normal individuals without arrhythmias.

Various QT interval variables and heart rate variability parameters were studied in six patients with ventricular fibrillation but without heart disease and compared with findings in 21 normal persons. QT and QT dispersion (QTd) were measured from conventional 12 lead ECGs: for dynamic QT analysis, QT intervals were automatically measured to the end of the T wave (QTe) on a 24 h ECG recording. The adaptation of the QT interval to changes in heart rate was expressed as the slope of the linear regression lines relating QTc to the RR interval (Sc). The complete 24 h ECG recording and four 6 h segments were studied (morning, day, evening, and night). Ventricular fibrillation patients had slightly prolonged QTmax intervals on the 12 lead ECG, QT dispersion was longer in ventricular fibrillation patients than in normal persons (88 +/- 29 ms vs 59 +/- 26 ms. P < 0.05), and on the 24 h ECG recording, normal persons and ventricular fibrillation patients had a comparable RR. In addition, parameters for long-term (SD, standard deviation of normal RR intervals) and short-term (RMSSD, the root-mean-square successive differences of normal RR intervals heart rate variability were not different. Automatic measurement of the QT interval and the QTc/RR slopes was possible over 24 h and in the 6 h intervals in a large majority of patients (25/27 and 88/108 readings). The mean 24 h QT and the mean 6 h QT interval were comparable in normal subjects and ventricular fibrillation patients except for the day segment. The 24 h Se was significantly lower in ventricular fibrillation patients, compared to normal individuals. Furthermore, Se in the morning and night segment was also significantly lower in ventricular fibrillation patients (both P < 0.05). In conclusion, patients with ventricular fibrillation but without underlying structural heart disease have normal heart rate variability parameters. However, abnormal repolarization behaviour, characterized by an increased QTd and a depressed adaptation of QT to variations in RR (especially during the night and the morning), is present. These findings may help to understand and treat arrhythmias in this patient group.

Adult↗
PubMed1997

Ventricular arrhythmias in apparently healthy subjects.

While it is assumed that the normal heart does not predispose to serious arrhythmias, several conditions are now being recognized as being associated with short-lasting ventricular arrhythmias. It also becomes clear that idiopathic VT (or repetitive monomorphic VT) sometimes exists on the background of a compromised heart. Whether this dysfunction is due to the arrhythmia or vice versa is not evident. Finally, VF occurs in patients who, at a first glance, have no apparent heart disease, and it is then called idiopathic VF. These complex electrical abnormalities probably reflect disorders, which often are genetically determined. Recognition of these syndromes, often characterized by abnormal repolarization or a disturbed autonomic function is possible if appropriate techniques are used.

Arrhythmogenic Right Ventricular Dysplasia↗
PubMed1997

The actual therapy and in-hospital mortality of acute myocardial infarction in Flanders. Mirracle's Investigators.

We studied influences on treatment and mortality in 787 patients with myocardial infarction in the setting of a prospective registry. Fifty % of patients received thrombolytics, 81% aspirin, and 46% beta-blockers. Decisions to give thrombolytics were influenced by gender and function. During hospital stay angioplasty was performed in 21%, and grafting in 11%. In hospital-mortality (11%) was related to age and function. In multivariate analysis, only age influenced the use of angioplasty and revascularization. In conclusion, in-hospital mortality remains high, while 50% of patients receive thrombolytic therapy. Some therapeutic options are highly influenced by age, gender, and cardiac function.

Adrenergic beta-Antagonists↗
PubMed1990

Combination of flecainide and mexiletine for the treatment of ventricular tachyarrhythmias.

A combination of oral flecainide and mexiletine was given to 11 patients in whom monotherapy with one of these drugs was ineffective for the suppression of inducible ventricular tachycardia or fibrillation. In eight of 11 studies, combination therapy prevented inducibility of a sustained ventricular tachycardia or resulted in induction of only nonsustained tachycardia (P = 0.0003, when compared to monotherapy). In one patient, a slow ventricular tachycardia was induced. During exercise testing ventricular tachycardia occurred in two of these nine patients, and ventricular fibrillation in another patient. Seven patients received combination on the long term, for a mean of 18 months. One patient had recurrences of ventricular tachycardia which was well tolerated. Another patient had a recurrent episode of ventricular fibrillation, but was successfully resuscitated. Severe congestive heart failure occurred in two patients. ACE inhibitors were given to them and to another four patients. No other important unwanted effects occurred. The combination of mexiletine and flecainide is very effective in suppressing inducible sustained ventricular tachycardia. The efficacy of this combination to prevent recurrences of ventricular tachyarrhythmias is acceptable. Exercise testing is of importance to unmask proarrhythmic effects before discharge from hospital.

Aged↗
PubMed1979

Isolation of human C1q as a by-product of routine fractionation.

Clq can be isolated as a by-product of large scale fractionation. The euglobulins of fraction III are submitted to chromatography on CM-cellulose in a batch-procedure. The active fraction being frequently contaminated by lysozyme the protein can be further purified by gel-filtration in the presence of carbohydrates. The purified Clq is suitable for the detection of immune complexes.

Chemical Fractionation↗