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Biomedical subjects

F Anselme

Publications and source records attributed to F Anselme.

At least 37 records · Page 2Linked to original sources
PubMed1998

Twiddler's syndrome variants in ICD patients.

Three cases of twiddler's syndrome in patients with an abdominally implanted cardioverter defibrillator (ICD) and an endocardial lead system are reported. The condition was detected when an increase in pacing threshold or lead impedance was noted at routine follow-up. Successful revision was possible in all patients; however, a recurrence in one patient necessitated removal of the device. Elderly female patients with some degree of obesity appear most susceptible. Minimizing pocket size and suturing of the device to the fascia should decrease the chance of developing this problem.

Aged↗
PubMed1998

Incessant fascicular tachycardia: a cause of arrhythmia induced cardiomyopathy.

An incessant ventricular tachycardia arising from the posterior fascicle is reported in a 29-year-old woman. This fascicular tachycardia was due to triggered activity and was clinically induced by an underlying paroxysmal atrial fibrillation. The initial echocardiographic evaluation revealed biventricular dysfunction with an ejection fraction of 30%. On propranolol, the patient has remained asymptomatic and the ventricular function has become normal after 3 months free of arrhythmia.

Adult↗
PubMed1998

[Gaps: practical implications].

The French translations of the word "gap" include "hole, breach, opening". In the Anglo-saxon literature, the conduction gap or the gap phenomenon is defined as the period of the cardiac cycle during which a premature beat is blocked whereas more delayed or more premature beats are conducted. This rare phenomenon, observed mainly during extrasystolic stimulation, was previously called supernormal conduction. The underlying mechanism is distal block in the conduction system occurring when more premature beats lead to delay in the proximal conduction which gives the distal site time to become excitable again. The excitability gap is one of the main characteristics of reentrant arrhythmias. Its presence in a reentrant circuit ensures the regularity and stability of the arrhythmia. It also allows penetration of the circuit by external stimuli. This different extrasystolic stimulation technique (resetting) or rapid fixed rate pacing (entrainment) may be used diagnostically and therapeutically. It enables the identification of the arrhythmia circuit and a critical zone (protected isthmus, zone of slow conduction) which may constitute a target for ablation. It also offers a possibility for terminating the arrhythmia by external stimulation. Finally, the duration of the excitable gap may guide the choice of antiarrhythmic agent during pharmacological cardioversion of a reentrant tachycardia.

Arrhythmias, Cardiac↗
PubMed1997

Coronary sinus pacing prevents induction of atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is due to reentry, and its incidence has been shown to decrease after dual-site atrial or biatrial pacing. We investigated whether a simpler pacing approach via the distal coronary sinus (CSd) could eliminate AF inducibility by high right atrial (HRA) extrastimuli (APDs). We based our hypothesis on our previous observation that AF inducibility by HRA APDs was associated with conduction delays to the posterior triangle of Koch, whereas AF was never induced with CSd APDs, which were associated with minimal intra-atrial conduction delays. METHODS AND RESULTS: Programmed electrical stimulation was performed from the high right atrium and CSd, and bipolar recordings were obtained from the high right atrium, His bundle, posterior triangle of Koch, and coronary sinus. In 13 patients (age, 44+/-18 years), AF was reproducibly induced with a critically timed HRA APD (220+/-22 ms) delivered during HRA pacing. AF was not induced in any of the patients when HRA APDs were delivered during CSd pacing at the same critical coupling intervals. Coronary sinus APDs delivered during HRA pacing also were not associated with AF induction. The APD coupling interval measured at the posterior triangle of Koch during CSd pacing was significantly prolonged compared with the one measured during HRA pacing and AF induction (381+/-58 versus 263+/-37 ms; P<.0001). CONCLUSIONS: We propose that CSd pacing suppresses the propensity of HRA APDs to induce AF by limiting their prematurity at the posterior triangle of Koch and not allowing local conduction delay and local reentry to occur.

Adolescent↗
PubMed1997

Origin of junctional rhythm during radiofrequency ablation of atrioventricular nodal reentrant tachycardia in patients without structural heart disease.

Junctional rhythm is commonly observed during radiofrequency catheter ablation of the fast or slow pathways of atrioventricular nodal reentrant tachycardia (AVNRT). However, the origin of these beats remains unclear. We analyzed the retrograde atrial activation sequence of 16 patients (mean +/- SD: 41.2 +/- 18.9 years old) undergoing catheter ablation for typical AVNRT with detailed catheter mapping of the triangle of Koch. The earliest atrial activations were concordant during tachycardia and junctional rhythm in only 5 of 16 patients. The findings suggest that junctional rhythm is unlikely to represent direct stimulation of the atrioventricular (AV) node via a discrete slow pathway but rather results from enhanced automaticity from > or =1 sites in the AV nodal transitional zone. The ensuing atrial activation pattern results from anisotropic spread from these sites. In addition, these data imply that the original concept of the AV node comprising 2 anatomically defined pathways may not be valid, and that a functionally defined pathway model may be a more accurate representation.

Adolescent↗
PubMed1997

Electrophysiology of atrial fibrillation and its prevention by coronary sinus pacing.

Atrial fibrillation (AF) is a re-entrant rhythm, and patients with AF have intra-atrial conduction abnormalities as evidenced by prolonged P-wave duration, abnormal SAECG of P wave, fragmented atrial electrograms and greater intra-atrial conduction delays in response to APDs. Our previous work has proposed that intra-atrial conduction delays and dispersion of refractoriness during extrastimulus testing are site dependent; high right atrial (HRA) stimulation results in marked prolongation of intra-atrial conduction times and AF, whereas distal coronary sinus (CS) stimulation is associated with minimal conduction delays and absence of AF inducibility. Patients with AF induction during HRA stimulation also manifest non-uniform anisotropic conduction in the region of the posterior triangle of Koch. We postulated that if the posterior triangle of Koch is a critical area for re-entry that initiates AF, then prevention of early activation of the posterior triangle may prohibit AF induction by HRA APDs. Distal CS pacing pre-excites the posterior triangle in relation to HRA activation, therefore a subsequent HRA APD will activate the posterior triangle with a longer coupling interval. AF induction by HRA APDs following HRA pacing is prevented when same HRA APDs follow distal CS pacing. We propose that distal CS pacing eliminates the propensity of HRA extrasystoles to induce AF. This observation may have further clinical applicability in AF prevention.

Atrial Fibrillation↗
PubMed1996

Radiofrequency catheter ablation of atrial flutter. Further insights into the various types of isthmus block: application to ablation during sinus rhythm.

BACKGROUND: Radiofrequency ablation of type 1 atrial flutter (AF1) has recently evolved toward an anatomically guided procedure directed to isthmuses at the lower part of the right atrium (RA). However, different types of block at these isthmuses may be observed and potentially correlated with different late outcomes. In addition, because the ablation is anatomically guided, ablation should be possible during sinus rhythm. METHODS AND RESULTS: Forty-four patients underwent ablation of type 1 AF1 performed during ongoing tachycardia (33 patients) or sinus rhythm (11 patients). Evidence of inferior vena cava-tricuspid annulus isthmus block was assessed by changes in RA impulse propagation while pacing from both sides of the ablation site. Apparent complete isthmus block was achieved in 43 of 44 patients with 9 +/- 7 pulses. However, incomplete block mimicking complete block because of intra-atrial conduction delay but leading to a different low RA activation pattern was individualized. At the end of the procedure, isthmus block was complete in 35 patients and incomplete in 8, but since AF1 reinduction was no longer possible, patients were discharged. During a follow-up period of 12.1 +/- 5.5 months, 4 patients experienced AF1 recurrence; all had shown incomplete or no block. CONCLUSIONS: Detailed multiple-point low RA mapping is necessary to differentiate incomplete from complete isthmus block. Complete block is the best marker for long-term success of AF1 ablation, although incomplete block may be sufficient to prevent recurrence in a significant number of cases. Isthmus block is achievable during sinus rhythm, and AF1 induction is not mandatory.

Atrial Flutter↗
PubMed1996

Heterogeneity of retrograde fast-pathway conduction pattern in patients with atrioventricular nodal reentry tachycardia: observations by simultaneous multisite catheter mapping of Koch's triangle.

BACKGROUND: Selective ablation of either the fast of the slow pathway resulting in cure of AV nodal reentry tachycardia (AVNRT) has led to the concept that these pathways are discrete, anatomically defined structures. We hypothesized that if a discrete retrograde fast pathway exists, it should be possible to record a single focus of early atrial activation near the apex of Koch's triangle, with sequential spread of depolarization to the rest of the atria. METHODS AND RESULTS: We evaluated 46 patients (33 women, 13 men; mean age, 45 +/- 17 years) undergoing electrophysiology study and catheter ablation for typical AVNRT. Retrograde atrial activation during AVNRT (337 +/- 43 ms) and ventricular pacing at a similar cycle length (352 +/- 51 ms) was recorded in the region of Koch's triangle with a decapolar catheter in the His bundle position, a multipolar catheter in the coronary sinus, and a deflectable quadripolar catheter along the tricuspid annulus anterior to the coronary sinus ostium. Earliest atrial activation was recorded at the apex of the triangle of Koch in 38 patients during ventricular pacing and in 43 patients during AVNRT. A broad wave front of atrial activation was recorded in 17 patients during ventricular pacing and in 26 patients during AVNRT. During AVNRT, only 2 patients had a single early site with focal and sequential activation along the tendon of Todaro. There was concordance in the pattern of atrial activation between ventricular pacing and AVNRT in only 21 of 46 patients. CONCLUSIONS: Retrograde atrial activation over the fast pathway is heterogeneous within Koch's triangle and the coronary sinus, both for the entire population and for individual patients during different modes of activation. These data do not support the concept of an anatomically discrete retrograde fast pathway.

Adult↗
PubMed1996

Electrocardiographic patterns and results of radiofrequency catheter ablation of clockwise type I atrial flutter.

INTRODUCTION: Counterclockwise right atrial propagation is usually observed in common atrial flutter, but little is known regarding flutter with clockwise right atrial rotation. The aim of this study is to describe the ECG characteristics and results of catheter ablation of atrial flutter with clockwise right atrial rotation. METHODS AND RESULTS: Among the 38 patients with type I atrial flutter in this study population, right atrial impulse propagation was counterclockwise in 20 and clockwise in 8. In the remaining 10 patients, both clockwise and counterclockwise patterns were seen. Clinical and ECG parameters associated with clockwise flutter were compared to those of 28 cases of counterclockwise atrial flutter. Ablation was performed in 11 of 18 cases using a technique identical to that used for counterclockwise flutter. A classical "sawtooth" pattern of the flutter wave was observed in 28 of 28 counterclockwise and 14 of 18 clockwise flutter. A shorter plateau phase, a widening of the negative component of the F wave in the inferior leads, and a negative F wave in V1 were the most consistent findings in clockwise flutter. Coronary sinus recording always showed septal to lateral left atrial impulse propagation. Ablation was successful in 11 of 11 cases of clockwise flutter in whom this procedure was performed, with 9.5 +/- 11.6 radiofrequency pulses delivered between the tricuspid valve and the coronary sinus ostium (n = 5) or the inferior vena cava (n = 5), and in the proximal coronary sinus (n = 1). After a follow-up of 46.6 weeks, two recurrences of clockwise flutter were encountered, which were successfully treated with a second session. CONCLUSION: Contrary to commonly accepted concepts, clockwise rotation of atrial flutter is not an infrequent phenomenon and can mimic counterclockwise rotation. It can also be successfully ablated by radiofrequency pulses.

Atrial Flutter↗
PubMed1996

Nonuniform anisotropy is responsible for age-related slowing of atrioventricular nodal reentrant tachycardia.

INTRODUCTION: AV nodal reentrant tachycardia cycle length has been shown to be longer in the elderly population. Microfibrosis associated with aging producing nonuniform anisotropic conduction or changes in membrane ionic properties could explain this finding. METHODS AND RESULTS: Forty-five patients (33 women and 12 men) with typical AV nodal reentrant tachycardia were studied to analyze the effects of age on electrophysiologic characteristics of the tachycardia using high-density catheter mapping of the triangle of Koch. We classified patients into group A (age < or = 45 years, mean [+/-SD] 32.7 +/- 8.8, n = 27) and group B (age > 45 years, mean [+/-SD] 61.1 +/- 10.2, n = 18). Retrograde atrial activation was recorded during tachycardia by means of a 2-mm decapolar catheter at the His bundle, a quadripolar catheter at the high right atrium, a multipolar catheter (6 to 10 poles) in the coronary sinus, and a deflectable quadripolar catheter at the posterior triangle of Koch. The AH interval at the AV junction as well as HA intervals at several atrial sites were measured during tachycardia. HA intervals at all atrial recording sites except in the posterior triangle of Koch were significantly longer in group B, as well as the tachycardia cycle length (362 vs 329 msec, P = 0.01). The mean AH interval was prolonged by 24 msec in group B, but this difference did not reach statistical significance. A sequential pattern of retrograde atrial activation during tachycardia was more frequently recorded in group B. CONCLUSIONS: Since the delayed activation to the atrium was heterogeneous, transverse nonuniform anisotropic conduction is a likely explanation of these age-related modifications of AV nodal reentrant tachycardia characteristics.

Adolescent↗
PubMed1995

Aerobic and anaerobic contribution to Wingate test performance in sprint and middle-distance runners.

We investigated the aerobic and anaerobic contributions to performance during the Wingate test in sprint and middle-distance runners and whether they were related to the peak aerobic and anaerobic performances determined by two commonly used tests: the force-velocity test and an incremental aerobic exercise test. A group of 14 male competitive runners participated: 7 sprinters, aged 20.7 (SEM 1.3) years, competing in 50, 100 and 200-m events and 7 middle-distance runners, aged 20.0 (SEM 1.0) years, competing in 800, 1,000 and 1,500 m-events. The oxygen uptake (VO2) was recorded breath-by-breath during the test (30 s) and during the first 20 s of recovery. Blood samples for venous plasma lactate concentrations were drawn at rest before the start of the test and during the 20-min recovery period. During the Wingate test mean power (W) was determined and three values of mechanical efficiency, one individual and two arbitrary, 16% and 25%, were used to calculate the contributions of work by aerobic (Waer,ind,16%,25%) and anaerobic (Wan,ind,16%,25%) processes. Peak anaerobic power (Wan,peak) was estimated by the force-velocity test and maximal aerobic energy expenditure (Waer,peak) was determined during an incremental aerobic exercise test. During the Wingate test, the middle-distance runners had a significantly greater VO2 than the sprinters (P < 0.001), who had significantly greater venous plasma lactate concentrations (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Balloon aortic valvuloplasty in elderly patients at high risk for surgery, or inoperable. Immediate and mid-term results.

Although aortic valve replacement is undoubtedly the treatment of choice for aortic valve stenosis, balloon aortic valvuloplasty may represent the only possible treatment for some frail elderly patients who may have additional medical problems. We evaluated immediate and 1-year results of balloon aortic valvuloplasty in 86 patients > or = 80 years with severe aortic stenosis. Mean age was 84 +/- 3 years. Forty-four % were 85 years or older. Mean gradient decreased from 68 to 26 mm Hg and valve area increased from 0.53 to 0.96 cm2 (P<0.05). There were two per-procedural deaths. No local vascular complication was observed. During the follow-up (13 +/- 9 months), 27 patients died, four had repeat balloon aortic valvuloplasty and eight underwent aortic valve replacement. Persistent clinical improvement was observed in 78% of the surviving patients. One-year actuarial survival rate was 73%. Balloon aortic valvuloplasty appears to be a safe and valuable technique in cases where surgery cannot be performed or carries a very high risk.

Aged↗
PubMed1995

Computerized tomography and pulmonary diffusing capacity in highly trained athletes after performing a triathlon.

We investigated the computerized tomographies (CTs) of the thorax and the pulmonary diffusing capacity for CO (DLCO) in eight male athletes before and after a triathlon. DLCO and alveolar volume (VA) were simultaneously measured during 9 s of breath holding. The transfer coefficient (KCO = DLCO/VA) was then calculated. CT scanning was performed during breath holding with the subjects in the supine position. Scanner analysis was done by 1) counting the linear and polygonal opacities (index of interstitial fluid accumulation) and 2) calculating the physical mean lung density and the mean slice mass. Results showed a significant reduction in DLCO (44.9 +/- 2.3 vs. 42.9 +/- 1.7 ml.min-1.mmHg-1; P < 0.05) and KCO (6.0 +/- 0.3 vs. 5.6 +/- 0.3 ml.min-1.mmHg-1.l of VA-1; P < 0.05) after the triathlon and an increase in mean lung density (0.21 +/- 0.009 vs. 0.25 +/- 0.01 g/cm3; P < 0.0001). The number of polygonal and linear opacities increased after the race (P < 0.001). This study confirmed that DLCO and KCO decrease in elite athletes after a long-distance race and showed a concomitant increase in CT lung density and in the number of opacities.

Adult↗
PubMed1994

Effects of 2-chloropropionate on venous plasma lactate concentration and anaerobic power during periods of incremental intensive exercise in humans.

We investigated the effects of a stimulation of pyruvate dehydrogenase (PDH) activity induced by 2-chloropropionate (2-CP) on venous plasma lactate concentration and peak anaerobic power (W an, peak) during periods (6 s) of incremental intense exercise, i.e. a force-velocity (F-v) test known to induce a marked accumulation of lactate in the blood. The F-v test was performed twice by six subjects according to a double-blind randomized crossover protocol: once with placebo and once with 2-CP (43 mg.kg-1 body mass). Blood samples were taken at ingestion of the drug, at 10, 20, and 40 min into the pretest period, at the end of each period of intense exercise, at the end of each 5-min recovery period, and after completion of the F-v test at 5, 10, 15, and 30 min. During the F-v test, venous plasma lactate concentrations with both placebo and 2-CP increased significantly when measured at the end of each period of intense exercise (F = 33.5, P < 0.001), and each 5-min recovery period (F = 24.6, P < 0.001). Venous plasma lactate concentrations were significantly lower with 2-CP at the end of each recovery period (P < 0.01), especially for high braking forces, i.e. 8 kg (P < 0.05), 9 kg (P < 0.02), and maximal braking force (P < 0.05). After completion of the F-v test, venous plasma lactate concentrations were also significantly lower with 2-CP (P < 0.001). The percentage of lactate decrease between 5- and 30-min recovery was significantly higher with 2-CP than with the placebo [59 (SEM 4)% vs 44.6 (SEM 5.5)%, P < 0.05]. Furthermore, W an, peak was significantly higher with 2-CP than with the placebo [1016 (SEM 60) W vs 957 (SEM 55) W, P < 0.05]. In conclusion, PDH activation by 2-CP attenuated the increase in venous plasma lactate concentration during the F-v test. Ingestion of 2-CP led to an increased W an, peak.

Adult↗
PubMed1994

Atrioatrial conduction after orthotopic heart transplantation.

OBJECTIVES: In two patients with orthotopic heart transplantation, the surface electrocardiogram suggested interaction between the donor right atrium and the recipient right atrium. An electrophysiologic investigation was performed to assess possible atrioatrial conduction. BACKGROUND: After orthotopic heart transplantation, both recipient and donor atrial activities are usually independent, but in humans they may synchronize for short periods during exercise. METHODS: Electrophysiologic recordings were made using standard techniques. The atrial electrode locations (anterior for the donor and posterior for the recipient right atria) were confirmed by fluoroscopy. Incremental and programmed donor and recipient right atrial pacing protocols were performed. RESULTS: Unidirectional conduction between native and graft atria occurred in both patients. This phenomenon was evident at rest, during normal sinus rhythm and at various pacing rates, resulting in frequent atrial bigeminy and trigeminy. CONCLUSIONS: Possible atrioatrial conduction after orthotopic heart transplantation may potentially be arrhythmogenic for the chamber where extrasystoles occur. This should be taken into account in attempting to devise new pacing modes if both atria are rendered electrically common.

Adult↗