A starting point for structure function relationships in the canine pulmonary veins.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
Dipen C Shah
Publications and source records attributed to Dipen C Shah.
Successful ablation of Hisian ectopy identified by a reversed His bundle activation sequence.
Junctional ectopy or tachycardia have been mapped and ablated in the atrioventricular node or its posterior extensions. There is no report of Hisian ectopy convincingly demonstrated and then successfully treated by ablation. A 39-year-old man presented with a 9-year history of recurrent supraventricular ectopy refractory to medical treatment. Intracardiac mapping revealed that the ectopy originated from the His bundle, which was indicated by a reversed His bundle activation sequence during ectopy compared to that during sinus rhythm, while the right bundle branch potential was anterogradely activated. Low power RF energy delivered to the site of earliest activation completely abolished the ectopic activity without modification of Hisian or atrioventricular conduction. After a 12-month followup, the patient remains free of recurrence.
Adult↗
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↗
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↗
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↗
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↗
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↗