Biomedical subjects

Pierre Jaïs

Publications and source records attributed to Pierre Jaïs.

81 records · Page 5Linked to original sources

PubMed2002

Role of Purkinje conducting system in triggering of idiopathic ventricular fibrillation.

Ventricular fibrillation is the main mechanism of sudden cardiac death, but the source of its spontaneous initiation has not been mapped. 16 patients were investigated by electrography and radiofrequency ablation after resuscitation from recurrent idiopathic ventricular fibrillation. Triggers of ventricular fibrillation originated from various locations within the Purkinje system in 12 patients and from the ordinary myocardial muscle in four. The accuracy of mapping was confirmed by acute elimination of triggers by radiofrequency delivery, and there was no recurrence of ventricular fibrillation in 14 patients. Long-term follow-up is necessary to establish that ablation is curative and avoids use of a defibrillator.

Adolescent↗

PubMed2002

Benefit of atrial pacing in sleep apnea syndrome.

BACKGROUND: Many patients with sleep apnea syndrome have nocturnal bradycardia, paroxysmal tachyarrhythmias, or both, which can be prevented by permanent atrial pacing. We evaluated the effect of using cardiac pacing to increase the heart rate during sleep in patients with sleep apnea syndrome. METHODS: We studied 15 patients (11 men and 4 women; mean [+/-SD] age, 69+/-9 years) with central or obstructive sleep apnea who had received permanent atrial-synchronous ventricular pacemakers for symptomatic sinus bradycardia. All patients underwent three polysomnographic evaluations on consecutive nights, the first night for base-line evaluation and then, in random order, one night in spontaneous rhythm and one in dual-chamber pacing mode with atrial overdrive (basic rate, 15 beats per minute faster than the mean nocturnal sinus rate). The total duration and number of episodes of central or obstructive sleep apnea or hypopnea were analyzed and compared. RESULTS: The mean 24-hour sinus rate during spontaneous rhythm was 57 +/- 5 beats per minute at base line, as compared with 72 +/- 3 beats per minute with atrial overdrive pacing (P<0.001). The total duration of sleep was 321 +/- 49 minutes in spontaneous rhythm, as compared with 331 +/- 46 minutes with atrial overdrive pacing (P=0.48). The hypopnea index (the total number of episodes of hypopnea divided by the number of hours of sleep) was reduced from 9 +/- 4 in spontaneous rhythm to 3 +/-3 with atrial overdrive pacing (P<0.001). For both apnea and hypopnea, the value for the index was 28 +/- 22 in spontaneous rhythm, as compared with 11 +/- 14 with atrial overdrive pacing (P<0.001). CONCLUSIONS: In patients with sleep apnea syndrome, atrial overdrive pacing significantly reduces the number of episodes of central or obstructive sleep apnea without reducing the total sleep time.

Aged↗

PubMed2002

Ablation therapy for atrial fibrillation (AF): past, present and future.

Atrial fibrillation, the most common arrhythmia, is frequently disabling and drug resistant. Non-pharmacological approaches including surgery and catheter-based ablation have been developed for the most symptomatic patients. These new treatment strategies have dramatically increased our knowledge of the pathophysiology of this arrhythmia but most importantly demonstrated that atrial fibrillation is curable. These approaches are far from being perfect but good enough to be offered in routine practice to selected patients in experienced centers. The importance of pulmonary veins in the initiation of AF has clearly been demonstrated and their role in maintaining AF is likely. Most of the curative approaches are therefore based on their isolation. Future technical improvements based on presently applied concepts are likely to widen the indications for ablation therapy of AF.

Atrial Fibrillation↗

PubMed2002

Dilatation as a marker of pulmonary veins initiating atrial fibrillation.

BACKGROUND: The pulmonary veins (PVs) have been shown to trigger paroxysmal atrial fibrillation. The relationship of anatomical dimensions versus arrhythmogenicity has not been assessed. METHODS: The diameters of four PVs were measured by selective PV angiography before ablation in 39 consecutive patients (23 male, mean age 46 years) with only one (25 patients) or two (14 patients) arrhythmogenic PVs (ArPVs). After ablation of ArPVs, no patient had recurrence of atrial fibrillation from the remaining PVs. Comparisons were performed variously between ArPV and non-ArPV, and within and across both groups. RESULTS: ArPVs were distributed as follows; left superior PV: 40%, left inferior PV: 28%, right superior PV: 26%, and right inferior PV: 6%. Statistical comparisons showed that (1) Triggers of atrial fibrillation were located in the largest PV in 72% of patients, (2) For each PV, the mean diameter of ArPV was significantly larger than that of non-ArPV (p < 0.05), (3) No significant difference was observed in the diameter of the four different ArPVs (range 16.2 +/- 1.3 to 17.2 +/- 4.4). CONCLUSIONS: In patients with atrial fibrillation initiated from one or two ArPVs, the diameters of ArPVs were significantly larger than those of non-ArPVs irrespective of the specific PV concerned, which might imply a possible role of PV dilatation in the arrhythmogenesis.

Adult↗

PubMed2002

Atypical left atrial flutters.

Left atrial flutters are not as common as peri-tricuspidian circuits. Their systematic study is much more recent and had greatly benefited from the use of 3 D mapping systems. Reentry has been demonstrated as being the mechanism but the circuits are not stereotypical like in the right atrium. Multiple macroreentrant circuits with one or more loops have been described as well as small re-entrant circuits. The complexity and variability of these circuits is related to the presence of zone of block, slow conduction and electrically silent areas. They create the conditions for the arrhythmia maintenance as they stabilize the circuit and prevent short circuiting. Most of the patients with left atrial flutter have an underlying structural heart disease, but their arrhythmia is amenable to curative catheter ablation.

Atrial Flutter↗

PubMed2002

Electrophysiological evaluation and ablation of atypical right atrial flutter.

Right atrial reentry which does not critically depend upon activation through the cavotricuspid isthmus is considered to be a subtype of atypical flutter. Diagnosis is dependent upon demonstrating the nonparticipation of the cavotricuspid isthmus. Right atrial free wall atriotomy incisions, the superior vena cava, the inferior vena cava, electrically silent or mute areas, incomplete variants of the posterior intercaval crista terminalis line of block and other functional/anisotropic lines of block form the central barriers around which macroreentry occurs. The length, location and orientation of fixed lines of block such as atriotomy incisions are important determinants of their arrhythmogenicity. Successful catheter ablation depends upon delineating the circuit in order to choose the optimal isthmus for ablation and producing complete block across it.

Adult↗

PubMed2002

Accessory pathway automaticity after radiofrequency ablation.

Mapping in a patient undergoing radiofrequency ablation for a left-sided concealed accessory pathway showed that the site with the shortest VA conduction time was in the great cardiac vein. Epicardial radiofrequency delivery at that site was successful. After ablation, a potential dissociated from both atrial and ventricular activity during sinus rhythm and atrial pacing was noted on the distal bipole of the ablation catheter. During incremental ventricular pacing, intermittent ventricular to potential conduction was observed. This indicates complete block at the atrial-accessory pathway interface and impaired conduction at the ventricular interface. This dissociated activity originating neither from the ventricle nor from the atria provides evidence of automatic accessory pathway activity.

Adolescent↗

PubMed2002

High-resolution mapping of tachycardia originating from the superior vena cava: evidence of electrical heterogeneity, slow conduction, and possible circus movement reentry.

Superior Vena Cava Reentry. High-resolution mapping of a tachycardia originating from the superior vena cava (SVC) in a patient with atrial fibrillation is described. Unidirectional circuitous repetitive activation encompassing the full tachycardia cycle length was documented around a line of block within the myocardial sleeve of the SVC. Intermittent conduction to the right atrium resulted in an irregular atrial tachycardia. Evidence of electrical heterogeneity and slow conduction persisted in sinus rhythm and was exaggerated by premature stimulation but did not reproduce the activation pattern during tachycardia. All the available evidence is best compatible with circus movement reentry within the SVC, with marked slow and anisotropic conduction responsible for the restricted dimensions of the reentrant circuit. These findings may suggest a similar substrate and arrhythmia mechanism in the myocardium of the pulmonary veins.

Atrial Fibrillation↗

PubMed2002

Irrigated-tip catheter ablation of pulmonary veins for treatment of atrial fibrillation.

INTRODUCTION: Catheter ablation of pulmonary veins (PV) for treatment of atrial fibrillation (AF) is limited by the disparate requirements of sufficient energy delivery to achieve PV isolation while avoiding PV stenosis. The aim of the present study was to evaluate the safety and efficacy of using an irrigated-tip catheter for systematic isolation of PV. METHODS AND RESULTS: The study population consisted of 136 consecutive patients (109 men, mean age 52 +/- 10 years) with symptomatic, drug-refractory paroxysmal (122) or persistent (14) AF. Cavotricuspid isthmus ablation and systematic radiofrequency isolation of all four PVs (guided by a circumferential mapping catheter) was performed in all patients with a protocol using an irrigated-tip catheter. PV diameter was assessed by selective angiography. The electrophysiologic endpoint of PV isolation was achieved in 100% of patients. Bidirectional cavotricuspid isthmus block was achieved in 99% of patients. Moderate PV stenosis (50% narrowing) was observed in one patient (0.7%) without clinical consequence. No other complications were observed. Reablation procedures were required in 67 patients (49%). After a mean follow-up of 8.8 +/- 5.3 months, 81% of patients were free of AF clinical recurrence, including 66% not taking any antiarrhythmic drugs. CONCLUSION: Systematic radiofrequency ablation of PV using an irrigated-tip catheter in patients with atrial fibrillation allows complete isolation of all four PVs with a very low incidence of stenosis.

Adult↗