Elimination Of Atrial Fibrillation Research Articles

Electrophysiologically guided ablation of the pulmonary veins for the curative treatment of atrial fibrillation

Catheter ablation of triggers that induce paroxysms of atrial fibrillation (AF) is an emerging curative therapy for this most common of supraventricular arrhythmias. In a series of 225 consecutive patients with multidrug resistant AF, 96% of triggering foci originated from one or several pulmonary veins (PV) independent of ambient ectopy or structural heart disease. This article describes an ablation procedure that is guided by activation mapping tailored to each individual PV, including criteria to define an arrhythmogenic PV, the use of provocative manoeuvres, the role of circumferential mapping catheters to provide information on the extent, distribution and activation of PV muscle as well as the monitoring of distal PV potentials (PVP) during ablation. Radiofrequency ablation to eliminate distal PVPs is performed by targeting the proximal PVP during sinus rhythm (right PV) or left atrial pacing (left PV). This end-point predicts a successful outcome more often than acute ectopy suppression. Complete elimination of AF is presently achieved in 70% of the patients, resulting in the elimination of antiarrhythmic treatment and suspension of anticoagulant treatment. It is anticipated that continued technological development will improve and facilitate this technique of curative treatment of AF.

Long-term follow-up after right atrial radiofrequency catheter treatment of paroxysmal atrial fibrillation.

Catheter ablation of paroxysmal atrial fibrillation using long linear lesions in the right atrium is still under investigation, and its long-term follow-up is unknown. Thirty-six men and nine women (aged 51 +/- 12 years) with symptomatic daily episodes of AF for 6 +/- 5 years despite the use of 4.7 +/- 1.5 antiarrhythmic drugs were studied between July 1994 and January 1996. Progressively longer ablation lines were performed in 3 groups of 15 consecutive patients each, using a 14-electrode catheter or a single-electrode dragging technique. Success was defined as atrial fibrillation elimination or recurrence for no longer than 6 hours over 3 months of observation. Patients who had fewer than 6 hours of atrial fibrillation per month were considered "improved." Medium- (11 +/- 4 months) and long-term (26 +/- 5 months) results were assessed clinically from a patient's diary and from Holter recordings. After a follow-up of 11 months, 24 patients had a favorable result of the ablation procedure with or without additional antiarrhythmic drug therapy, representing 53% of the original cohort. After 26 +/- 5 months of follow-up, these successful results were reduced to 17 patients (37%). After linear atrial ablation, a significant long-term attrition of arrhythmia-free patients was observed. This may be due to a combination of disease progression, incomplete linear block, and ineffective ablation of arrhythmogenic triggers.

Electrophysiological properties in patients undergoing atrial compartment operation for chronic atrial fibrillation with mitral valve disease.

Surgical treatment for atrial fibrillation is now feasible in selective cases. The aim of this study was to assess the electrophysiological properties of patients undergoing atrial compartment operation for chronic atrial fibrillation. Electrophysiological studies were performed in 20 mitral valve patients with atrial fibrillation who had been maintained in sinus rhythm for more than 1 year after atrial compartment operation. Intra-cardiac recording and programmed electrical stimulation were performed in various atrial compartments. The parameters studied included sinus node function, atrial conduction and refractoriness, atrioventricular conduction function and inducible arrhythmias if any. Intra-cardiac recordings showed that the rhythm was of sinus origin in all cases, with the earliest atrial activity located in the high right atrium. The mean sinus cycle length was 750 +/- 110 ms, AH time 106 +/- 29 ms, and HV time 53 +/- 7 ms. The sinus node function was normal in 18 patients (90%), and only two patients had prolonged sinus node recovery and sino-atrial conduction. The right atrial appendage compartment was driven by the sinus node in all patients. However, the conduction time from the high right atrium to the right atrial appendage compartment was markedly prolonged in 12 of 15 patients (80%) undergoing the three-compartment operation in which an incision was placed between the high right atrium and right atrial appendage compartments. On the other hand, the electrical activities in the left atrial compartment were much more varied. In 13 of 20 patients (65%), the left atrial compartment was driven by the sinus node; 11 of the 13 patients had a normal or mildly prolonged conduction time (ranged 75 to 146 ms), whereas two patients had a marked delay in conduction (200 ms and 266 ms, respectively). In the remaining seven patients, the left atrial compartments were dissociated from the rest of the heart; five of them had a quiescent left atrium, one a fluttering left atrial rhythm, and one a slow left atrial rhythm. The effective refractory period was longer in the left atrial compartment (242 +/- 47 ms) as compared to that of the high right atrium (224 +/- 26 ms, P < 0.01) and right atrial appendage compartments (219 +/- 25 ms, P < 0.01). Programmed electrical stimulation could not induce atrial fibrillation in any patient, whereas two patients had inducible atrial flutter and three repetitive atrial responses. (1) Atrial compartment operation does not impair sinus node function in most cases. (2) Elimination of atrial fibrillation while maintaining the electrical connection between different atrial compartments is feasible.

Cerebral embolization is reduced with use of the stab technique for aortic cannulation compared with the side-clamp technique

heart rate response can be similar to that of the transplanted heart, 2 the attenuated heart rate response to exercise early after the maze procedure may be caused by denervation of the sinoatrial node as a result of multiple incisions in the atrial wall. If the attenuated heart rate response to exercise early after the maze procedure was caused by denervation of the sinoatrial node, recovery of the heart rate response late after operation can be explained by the time course of reinnervation of the sinoatrial node. 3 ANPs have been extracted from atrial myocytes of mammals, including human beings, and play an important role in natriuresis and vasodilation. Because ANP was excreted markedly after exercise, the determination of plasma ANP level after exercise allows evaluation of the atrial function as the excretion ability. Percent increase of ANP after exercise was higher in the late phase than that in the control and early phases, which suggests that atrial function of ANP excretion was restored over time. Transient atrial dysfunction occurred in patients with atrial fibrillation who underwent electrical cardioversion, and mechanical atrial function is reduced when conversion is achieved after atrial fibrillation has been sustained for more than a week. 4 The mechanism of atrial dysfunction after elimination of atrial fibrillation is unknown. Shapiro and colleagues 4 postulated that postischemic stunned atrial myocardium, as in the occurrence of ischemia during ventricular fibrillation, may explain this phenomenon. The delayed recovery of atrial function may influence the improved exercise capacity in the late phase after combined treatment consisting of surgical repair for organic heart disease and atrial fibrillation. We conclude that transient attenuation of atrial function, seen as sinoatrial node response, excretion of ANP, and mechanical contractility, occurred in patients after combined treatment with surgical repair for heart disease and the maze procedure for atrial fibrillation. The late recovery of atrial function may improve exercise capacity over time.

The functional state of the myocardium and pulmonary hemodynamics after the elimination of atrial fibrillation

The structure of ventricular systole and pulmonary rheogram in atrial fibrillation and after restoration of sinus rhythm were studied in 49 patients. Atrial fibrillation is accompanied by a decrease in myocardial contractile function and pulmonary hypertension. After the reversion of the sinus rhythm, the phase shifts of the systole structure and the symptoms of pulmonary hypertension significantly decreased, some of the indicators returned to normal. The best results were achieved with the use of electro-impulse therapy, which makes it possible to consider this method more beneficial in comparison with quinidine therapy.