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Rik Willems

Publications and source records attributed to Rik Willems.

16 recordsLinked to original sources
PubMed2006

Endurance sports is a risk factor for atrial fibrillation after ablation for atrial flutter.

INTRODUCTION: Sports activity has been associated with the development of atrial arrhythmias. Atrial fibrillation (AF) is frequently observed after successful ablation for atrial flutter. Sports activity as a risk factor for AF development after flutter ablation has not been studied. METHODS: We analyzed outcome in 137 patients (83% men) after ablation for isthmus-dependent atrial flutter (excluding patients with concomitant ablation for atrial tachycardia or fibrillation). Sports activity before and after ablation was evaluated by detailed questionnaires. Endurance sports was defined as (semi-)competitive participation in cycling, running or swimming for > or =3 h/week (and for > or =3 years pre-ablation). Median follow-up was 2.5 years. Survival free of AF was evaluated with Kaplan-Meier curves and log-rank statistics. Multivariate analysis was based on Cox proportional hazard evaluation. RESULTS: Acute ablation success was 99% and flutter recurrence 4.4%. Thirty-one patients (23%) had been regularly engaged in endurance sports before ablation and 19 (14%) continued regular sports activity afterwards. Those performing sports were slightly younger. A history of endurance sports was a significant risk factor for post-ablation AF (univariate HR 1.96 (1.19-3.22), p<0.01, and multivariate HR 1.81 (1.10-2.98), p=0.02). Also continuation of endurance sports activity after ablation showed a trend for increased risk to develop AF despite a relatively small sample size (n=19; multivariate HR 1.68 (0.92-3.06), p=0.08). Cox proportional hazard calculations revealed a 10% and 11% increased risk for AF development per weekly hour sport performed before and after ablation respectively (p<0.01 for both). CONCLUSION: A history of endurance sports activity is associated with the development of AF after ablation of atrial flutter.

Atrial Fibrillation↗
PubMed2006

Long-term symptomatic benefit after radiofrequency catheter ablation for atrial flutter despite a high incidence of post-procedural atrial fibrillation.

OBJECTIVE: A high proportion of patients develops atrial fibrillation (AF) after ablation for atrial flutter (AFL). Radiofrequency ablation for AFL therefore would only be useful if it leads to a better quality of life despite this high incidence of AF post-ablation. METHODS: All patients who underwent AFL ablation in our centre before March 2002 (n=203) were contacted by letter a median of 2.3 years after their ablation. Sixty-eight percent answered the questionnaire polling the perceived benefits of the procedure. The results were stratified according to the presenting arrhythmia before the ablation: only AFL, predominantly AFL, predominantly AF or class Ic-III AFL. RESULTS: Despite a 60% incidence of AF, 84% considered the procedure to be beneficial during the 1st year and 77% during the 2nd year post-ablation. Patients with predominantly AF before the procedure showed significantly less overall improvement than the 3 other groups (50% and 33% after I year and 2 years, p< 0.01) and a smaller reduction in palpitations (50% and 29% after I year and 2 years, p < 0.01). The benefit of an ablation was also significantly less in patients who developed AF post-ablation than in patients who were completely arrhythmia free (75% versus 98% 1st year, 58% versus 91% 2nd year; p 0.01); nevertheless 75% of these patients reported fewer palpitations and 56% tolerated symptoms better than before. CONCLUSIONS: Despite a high incidence of AF after AFL ablation, the majority of patients considered the intervention beneficial. Only in patients with predominantly AF before ablation the procedure does not seem beneficial.

Analysis of Variance↗
PubMed2006

Epicardial pacing: a single-centre study on 321 leads in 138 patients.

OBJECTIVE: This study presents the long-term outcome of 321 epicardial leads in 138 patients. METHODS AND RESULTS: All leads were Medtronic CapsureEpi model 4965 steroid eluting leads. The 1-, 3-, and 5-year patient survival was 91%, 83% and 77%, respectively.Twenty-seven patients died. In 25/27 deaths a pacing-related death could be excluded. Strangulation of the heart by an abandoned epicardial lead was the cause of death in one child. One other patient died suddenly at the age of 3 years. Failures occurred in 57 of 321 epicardial leads (18%). For all 321 leads, the 1-, 3- and 5-year freedom from failure was 91%, 85% and 71%, respectively. The cumulative proportion of patients without any lead defect was 85% after I year, 76% after 3 years and 62% after 5 years. The percentage of patients without serious adverse events at 1, 3, and 5 years was 97%, 91%, 85%, respectively. Lead fracture was the cause of failure in 15 leads of 9 patients. An important increase in pacing threshold occurred in 35 leads of 30 patients. Other failures were: diaphragmatic stimulation, infection, excessive traction and strangulation. Eighteen failures were repaired by 11 surgical interventions in 9 patients.Thirty-nine defects were corrected non-invasively in 31 patients. CONCLUSIONS: The use of steroid-eluting epicardial leads has proven to be an adequate option. In paediatric cardiology, the epicardial approach remains an indispensable tool for achieving a life-long pacing.

Adolescent↗
PubMed2005

Repeated tilt testing in patients with tilt-positive neurally mediated syncope.

In this study we have included 222 patients with apparent neurally mediated syncope and with a positive diagnostic tilt test. The mean age was 33.4+/-21.2 years (median 25.3): there were 107 men (median age 25.3) and 115 women (median age 22.6). The age difference between males and females was statistically significant (P = 0.002). The response to the diagnostic tilt test was: type 1 (mixed) in 74 patients; type 2A (cardioinhibitory and bradycardia) in 6; type 2B (cardioinhibitory and asystole) in 61; type 3 (vasodepressor) in 81. In all 222 patients the diagnostic tilt test was positive after 19+/-11 min (mean+/-SD), median time: 18 min. For the four types of syncope, the duration in minutes of the diagnostic tilt test was: type 1 (mixed) 19.5+/-11.4; type 2A (cardioinhibitory) 24.8+/-13.6; type 2B (cardioinhibitory and asystole) 14.7+/-10.2; type 3 (vasodepressor) 21.6+/-11.1. A significant difference was found between type 2B and type 3 responses (P = 0.002). Between males and females no significant differences in the duration of the diagnostic tilt test were found, neither for all responses, nor for the four subtypes. A type 2B (cardioinhibitory and asystole) response occurred in 61 patients. The duration of asystole was 12.8+/-10.6s (mean+/-SD; median 9, minimum 3, maximum 60). The head-up tilt test was repeated day after day: one session per day. The response became negative at the second session in 119 patients (54%); at session 3 in 47 (21%); at session 4 in 30 (13%); at session 5 in 15 (7%); at session 6 in 6 (3%); at session 7 in 2 (1%); at session 8 in 3 (1%). For all 222 patients the mean number of sessions in order to obtain a negative tilt test was 2.9 (SD 1.3; median 2). Only 25% of patients remained tilt-positive for three or more sessions. A negative tilt test was ultimately obtained in every patient. Follow-up data are available for 202/222 patients. The time span between the first and last tilt test was 11.1+/-10 months (median 8.8). Of these 202 patients, 163 remained free of any event (80.7%).

Adult↗
PubMed2005

Matrix metalloproteinases and atrial remodeling in patients with mitral valve disease and atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is associated with extracellular matrix remodeling involving atrial fibrosis and atrial dilatation. Angiotensin II mediated pathways and matrix metalloproteinases (MMPs) have been implicated in these processes. Our aim was to study atrial structural remodeling and the expression of the angiotensin receptor subtypes and MMPs and their inhibitors (TIMPs) in patients with mitral valve disease with and without AF. METHODS AND RESULTS: Biopsies from right and left atrial appendages (RA and LA) were taken from patients undergoing CABG (n=9, all in sinus rhythm (SR)) or mitral valve surgery (MVS; n=19; 9 with permanent AF and 10 in SR). Patients with MVS and AF had significantly larger atria (versus MVS and SR: p=0.02; versus CABG: p<0.01). The MVS patients had significantly more fibrosis than the control CABG group. Fibrosis was increased in both the AF and SR MVS groups in the LA, but only in the MVS-AF group in the RA. These AF patients had significantly more tricuspid regurgitation than SR patients. MMP-1 was down-regulated in LA of MVS patients (p=0.02) independent of the underlying rhythm (SR or AF; p=0.95). In RA biopsies, MMP-1 was down-regulated only in the MVS and AF group. MMP-9 was down-regulated in the MVS patients compared to CABG both in the RA and LA, and without a difference between the SR and AF groups. Protein expression of AT-1, AT-2, MMP-2, TIMP-1, -2 and -4, TNF-alpha, and TNF-alpha-converting enzyme did not differ significantly between the 3 groups. CONCLUSIONS: Concordant changes between MMP-expression and fibrosis during mitral valve disease, both in LA and RA, suggest involvement of MMPs in structural atrial remodeling. AF itself did not contribute to altered fibrosis or MMP-expression in the LA. The association between AF and RA changes may be precipitated by greater hemodynamic load due to tricuspid regurgitation in these patients.

Aged↗
PubMed2005

Controversies in pacing: indications and programming.

This article reviews controversies in cardiac pacing in four areas: methods to prevent unnecessary right ventricular pacing and optimal ventricular pacing sites in the bradycardia population, pacing for prevention of atrial fibrillation (AF), a novel pacing technique for the treatment of heart failure, and pacing for the treatment of sleep apnea. Frequent right ventricular pacing has been reported to increase the incidence of AF and congestive heart failure. However, many patients with pacemakers for bradycardia have intrinsic atrioventricular conduction most of the time. Optimal programming of pacemakers and new algorithms designed to reduce unnecessary ventricular pacing are discussed. Pacing algorithms for prevention of AF have generally been shown to be ineffective. Atrial antitachycardia pacing has been shown to reduce the burden of atrial tachyarrhythmias in selected patients. Cardiac contractility modulation has recently been reported to be a promising new approach to the treatment of heart failure. Some pacing techniques may be effective in the treatment of sleep apnea but larger, long-term clinical trials are required to demonstrate a significant clinical benefit.

Atrial Fibrillation↗
PubMed2004

Ventricular high-rate episodes in pacemaker diagnostics identify a high-risk subgroup of patients with tachy-brady syndrome.

OBJECTIVES: The purpose of this study was to evaluate the frequency and clinical significance of ventricular high-rate (VHR) episodes (ventricular rate >162 bpm) in patients with symptomatic bradycardia and paroxysmal atrial fibrillation (AF). BACKGROUND: Newer pacemakers have enhanced diagnostic features that permit detection and storage of detailed information about the frequency, duration, and time of onset of multiple episodes of AF, atrial tachycardia (AT), and ventricular tachycardia (VT). However, the prevalence and prognostic value of AF associated with rapid ventricular rates in the pacemaker population are unknown. METHODS: We prospectively followed 125 patients who received a Medtronic AT 500/501 pacemaker for symptomatic bradycardia and paroxysmal AF. RESULTS: AF recurred in 112 patients (90%) during 22 +/- 8 months of follow-up. A total of 1,324 VHR episodes occurred in 38 patients (30%). Episodes with available electrograms (n = 560) were reviewed and classified as AF (n = 279; 50%), AT (n = 266; 47%) or VT (n = 15; 3%). AF burden was higher in patients with VHR episodes (median 1.9 vs 0.2 hours/day; P < .001). After controlling for AT/AF burden and heart disease, VHR episodes were a significant independent predictor of hospitalization for cardiovascular symptoms (odds ratio 2.92, 95% confidence interval 1.33-6.38; P = .007). Heart rate control improved over time in the cohort, and the frequency of VHR episodes decreased during follow-up (P < .001). CONCLUSIONS: VHR episodes documented in the pacemaker diagnostics identify a high-risk subgroup of patients with AF. Monitoring VHR episodes may be useful for identifying pacemaker patients with AF who require more vigilant monitoring, additional investigations, and/or additional interventions.

Aged↗
PubMed2004

Do population studies confirm the benefit of oral anticoagulation in atrial fibrillation demonstrated in clinical trials?

Atrial fibrillation (AF) is associated with a significant morbidity and mortality, mainly due to an increased risk of thromboembolic stroke. Several large randomized trials have demonstrated the efficacy of oral anticoagulation to reduce this risk of ischemic events in patients with non-valvular AF. Despite the translation of these results into clear practice guidelines, oral anticoagulation remains underused. This reflects doubts about the real effectiveness of oral anticoagulation in daily practice. This paper gives an overview of the available evidence of the effectiveness of oral anticoagulation in population studies and tries to identify some remaining barriers in the prescription of oral anticoagulation in real life.

Administration, Oral↗
PubMed2004

Ablation of focally induced atrial fibrillation: selective or extensive?

INTRODUCTION: Focally induced atrial fibrillation (AF) often is due to ectopic activity in the pulmonary veins (PV). Although initial approaches were aimed at ablating only the ectopic foci, more extensive ablation approaches have evolved that isolate all PVs empirically and/or create circumferential ablation lines in the left atrium (LA). These techniques last longer and may be associated with more risks. We retrospectively evaluated the outcome and risks of ablation for focally induced AF in a single-center patient population. METHODS AND RESULTS: We report on 47 patients (32 men and 15 women; age 47 +/- 10 years) in whom 52 ablations were performed. In 19 patients (22 sessions), ablation was directed at the site(s) of overt ectopic activity ("selective" group), whereas in 28 patients (30 sessions) without sufficient ectopy to determine the culprit PV a mean of 3.5 PVs were empirically targeted for bidirectional disconnection from the LA ("extensive" group). On a preprocedural Holter recording, the "selective" group had significantly more isolated atrial ectopy (3,276 +/- 2,933 vs 620 +/- 937 beats/24 hours) and runs of atrial tachycardia (330 +/- 202 vs 53 +/- 87 runs/24 hours) than the "extensive" group (P < 0.01 for both). Only 11% had persistent AF before ablation. Acute procedural success was 81% (elimination of all ectopy) and 83%, respectively (bidirectional and fully circumferential isolation of all targeted PVs). Procedure and fluoroscopy times were significantly shorter in the "selective" group. There were no major complications, but 7 minor complications and 2 acute PV stenoses > 50% in the 30 "extensive" procedures were observed. Mean follow-up was 8.4 +/- 8.5 months (median 6.9). Kaplan-Meier analysis, excluding recurrences during only the first month ("delayed cure"), showed AF recurrence in 45% after 6 months and in 55% after 1 year. Outcome was not dependent on ablation approach ("selective" or "extensive") nor was time to first AF (22 +/- 64 days and 30 +/- 69 days). AF recurrence tended to be higher in patients with larger LA (P = 0.08), underlying heart disease or hypertension (P = 0.08), and those "extensive" patients in whom not all 4 PVs were targeted (P = 0.07). CONCLUSION: Trigger-directed ablation for focally induced AF is associated with a relatively high recurrence rate during follow-up. Apart from recurrence of the ectopic trigger, this may point to underlying structural changes in the atrial substrate not addressed by the ablation. Prospective evaluation of the risk-to-benefit profile of any technique (selective, extensive, including linear lines) is required.

Adult↗
PubMed2003

New indications for pacing.

This article reviews developments in four areas: single- versus dual-chamber pacing, pacing for prevention of atrial fibrillation (AF), pacing for the treatment of neuromediated syncope, and pacing in patients with congestive heart failure. Large, randomized clinical trials comparing physiologic and ventricular pacing in different pacemaker populations have demonstrated that physiologic pacing does prevent AF but does not reduce cardiac mortality or stroke. The benefit for prevention of AF appears to be in patients with sinus node disease as the primary indication for pacing. Selective atrial pacing algorithms designed for the prevention of AF have not been shown to substantially reduce the overall burden of AF. Cardiac pacing has been shown to have a moderate benefit in the treatment of neuromediated syncope. Cardiac resynchronization therapy is emerging as a promising new treatment for heart failure. Long-term studies report that it improves quality of life and functional capacity, and reduces hospitalizations for heart failure. The impact of this therapy on mortality awaits the results of ongoing studies.

Atrial Fibrillation↗
PubMed2003

High prevalence of right ventricular involvement in endurance athletes with ventricular arrhythmias. Role of an electrophysiologic study in risk stratification.

BACKGROUND: Electrocardiographic abnormalities and premature ventricular contractions are common in athletes and are generally benign. However, the specific outcome of high-level endurance athletes with frequent and complex ventricular arrhythmias is unclear. Also, information on the predictive accuracy of different investigations in this subgroup is unknown. RESULTS: We report on 46 high-level endurance athletes with ventricular arrhythmias (45 male; median age 31 years) followed-up for a median of 4.7 years. Eighty percent were cyclists. Hypertrophic cardiomyopathy or coronary abnormalities were present in < or =5%. Eighty percent of the arrhythmias had a left bundle branch morphology. Right ventricular (RV) arrhythmogenic involvement (based on a combination of multiple criteria) was manifest in 59% of the athletes, and suggestive in another 30%. Eighteen athletes developed a major arrhythmic event (sudden death in nine, all cyclists). They were significantly younger than those without event (median 23 years vs 38 years; P=0.01). Outcome could not be predicted by presenting symptoms, non-invasive arrhythmia evaluation or morphological findings at baseline. Only the induction of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) during invasive electrophysiological testing was significantly related to outcome (RR 3.4; P=0.02). Focal arrhythmias were associated with a better prognosis than those due to reentry (P=0.02) but the mechanism could be determined in only 22 (48%). CONCLUSIONS: Complex ventricular arrhythmias do not necessarily represent a benign finding in endurance athletes. An electrophysiological study is indicated for risk evaluation, both by defining inducibility and identifying the arrhythmogenic mechanism. Endurance athletes with arrhythmias have a high prevalence of right ventricular structural and/or arrhythmic involvement. Endurance sports seems to be related to the development and/or progression of the underlying arrhythmogenic substrate.

Adolescent↗
PubMed2003

Total atrioventricular nodal ablation increases atrial fibrillation burden in patients with paroxysmal atrial fibrillation despite continuation of antiarrhythmic drug therapy.

INTRODUCTION: Total atrioventricular nodal (TAVN) ablation and pacing is an accepted and safe treatment for patients with drug-refractory paroxysmal atrial fibrillation (AF). Many patients develop permanent AF within the first 6 months after TAVN ablation. This usually is ascribed to the cessation of antiarrhythmic drug therapy. We hypothesized that TAVN ablation itself creates an atrial substrate prone to AF. METHODS AND RESULTS: Patients participating in the Atrial Pacing Periablation for Paroxysmal Atrial Fibrillation (PA3) study who remained on stable antiarrhythmic drug therapy throughout follow-up were included in this analysis. AF burden and the development of persistent AF in the preablation period were compared to two consecutive postablation periods. Echocardiographic changes also were evaluated. Twenty-two patients remained on stable drug therapy (9 men and 13 women, age 59 +/- 3 years). One patient developed persistent AF preablation compared to 10 postablation (P < 0.05). AF burden preablation was 3.0 +/- 1.2 hours/day and increased to 10.4 +/- 2.2 hours/day and 11.8 +/- 2.3 hours/day in the two postablation follow-up periods (P < 0.05). In patients with fractional shortening (FS) >30% prior to ablation, FS decreased significantly from 39.4% +/- 1.3% to 36.4%+/- 1.7% (P < 0.05). In contrast, in patients with a FS < or =30% prior to ablation, FS increased from 27% +/- 0.8% to 33.6 +/- 1.7% (P < 0.05). CONCLUSION: TAVN ablation increases AF burden and facilitates the development of persistent AF in patients with paroxysmal AF despite the continuation of antiarrhythmic drugs. Loss of AV and/or interventricular synchrony may lead to altered cardiac hemodynamics resulting in atrial stretch and increasing AF burden.

Adult↗
PubMed2002

Simultaneous creation and evaluation of linear radiofrequency lesions.

BACKGROUND: Catheter based "maze" procedures for atrial fibrillation have been hampered by difficult creation and evaluation of continuous and transmural linear lesions. Our aim was to develop an online evaluation method for effective lesion creation based on conventional techniques and using the multipolar ablation catheter, already in place. METHODS AND RESULTS: We created 15 linear lines in right atria of 13 anesthetized sheep using three multipolar catheter designs (8 x 4 mm 7 Fr, 4 x 6 mm 7 Fr, 8 x 4 mm 3.7 Fr). The lesions were placed on the right posterolateral wall between the orifices of the superior and inferior vena cava. Radiofrequency energy was applied in the temperature-controlled mode to prespecified endpoints (electrogram amplitude decrease to < or = 50%; pacing threshold increase by > or = 100%; split potentials indicating conduction block). Macroscopically transmural and continuous lesions were achieved in only 3 experiments (29 +/- 12 mm x 5 +/- 1 mm), all created by 3.7 Fr octapolar catheters inserted through long sheaths. Preset temperature was reached in 96% of the electrodes (vs. 64% in the non-effective experiments; p < 0.01). Electrogram amplitude decrease (to < or = 50%) and pacing threshold increase (by > or = 100%) did not predict effectiveness. The only criterion that could reliably predict transmural continuous necrosis at histology was the development of split potentials (p < or = 0.05). CONCLUSIONS: Effective creation of linear lesions is difficult. Pliable catheters that conform to the endocardial contour give the best results. The only endpoint that reliably predicted histological transmural continuous necrosis was development of split potentials indicating conduction block.

Animals↗
PubMed2002

Mind the model: effect of instrumentation on inducibility of atrial fibrillation in a sheep model.

INTRODUCTION: Atrial electrical remodeling, shortening of the atrial effective refractory period (AERP) underlying atrial fibrillation (AF) has been described in different animal models. However, there remains some controversy regarding the time course of this electrical remodeling and the need for secondary factors in the development of AF. We investigated the effect of instrumentation on the inducibility of AF. We hypothesized that epicardial instrumentation could be a confounding factor that accelerates the development of AF. METHODS AND RESULTS: Thirty sheep were rapidly atrially paced at 600 beats/min for 15 weeks: 15 were endocardially instrumented and paced (endo), and 15 were both endocardially and epicardially instrumented. Six of these animals were endocardially paced (sham) and 9 were epicardially paced (epi). The underlying rhythm was determined at regular intervals, and electrophysiologic study was performed. AF developed significantly faster in the epi group. After 3 weeks of pacing, the cumulative incidence of sustained AF (>1 hour) already was 70% in this group versus only 14% and 20% in the endo and sham groups, respectively. After 15 weeks of pacing, this difference was no longer evident. Baseline AERP and minimal AERP, reached before the development of AF, were not significantly different in the three groups. Epicardial instrumentation (epi and sham) increased baseline left and right atrial pressures, but only epicardial stimulation (epi) led to early development of AF. CONCLUSION: In this sheep model of AF, the experimental setup is a major determinant of the inducibility of AF. Not epicardial instrumentation per se but epicardial stimulation accelerated the development of AF. Different animal models

Animals↗
PubMedDate not supplied

Nonpharmacologic treatment of atrial fibrillation in elderly persons.

In recent years, new nonpharmacologic possibilities have emerged for the treatment of atrial fibrillation. The roles of surgery, radiofrequency catheter ablation, pacing, and atrial defibrillation in the treatment of atrial fibrillation are discussed. This text focuses on the interaction between different treatment modalities and the pathophysiologic mechanisms of atrial fibrillation and on the available data about the effectiveness in elderly persons.

Aged↗