Journal of Cardiovascular Electrophysiology

Introduction: A patent foramen ovale (PFO) is located at the anterior and superior part of the anatomical interatrial septum, the area that is targeted during transseptal puncture. This study sought to investigate the impact of accessing the left atrium via a PFO on paroxysmal AF ablation.

Methods: From March 2004, 203 patients (55 ± 11 years) underwent catheter ablation for paroxysmal AF (80 ± 71 months), with the endpoint being electrical isolation of all pulmonary veins (PV) and AF noninducibility. The presence of a PFO was determined by both transesophageal echocardiography and catheter probing. Procedural difficulty was evaluated by radiofrequency (RF), procedural, and fluoroscopic durations. Clinical follow‐up was also investigated.

Results: A PFO was detected in 27 patients (13%) by transesophageal echocardiography and in 22 additional patients (total 49 patients, 24%), by catheter probing (P < 0.001). A PFO was associated with longer total RF applications (57 ± 19 vs 51 ± 18 min, P = 0.04) and RF applications to isolate the PVs (42 ± 16 vs 35 ± 12 min, P = 0.001). Procedural and fluoroscopic times were unaffected. Seventy‐three patients (36%) required a second procedure; there was no difference in the number of PV reconnections (1.3 vs 1.8 veins, P = NS). After a mean follow‐up of 19 ± 9 months, 194/203 patients (96%) were free of AF, with no difference in patients in whom a PFO had been used.

Conclusion: Although isolation of PVs is longer, overall procedural duration and success is not affected when using a PFO compared with a transseptal puncture. The presence of a PFO is underestimated by transesophageal echocardiography with brachial injection when compared with catheter probing.

Impact of PFO on LA Linear Ablation. Introduction: We investigated the impact of the mode of left atrial (LA) access via patent foramen ovale (PFO) versus transseptal (TS) puncture on LA linear lesions during atrial fibrillation (AF) ablation.

Methods and Results: We investigated 139 (PFO: 25) consecutive patients who underwent mitral isthmus (MI) and/or LA roof linear ablation. Technical endpoint was completeness of linear lesions and duration of radiofrequency (RF) application. During the initial procedure, complete MI and LA roof blocks were created in 13 of 19 (68%) and 14 of 17 (82%) patients in the PFO group, and in 57 of 94 (61%) and 54 of 70 (74%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (11.1 ± 8.9 and 15.1 ± 7.6 minutes, P = 0.11), and LA roof (10.1 ± 3.5 and 8.3 ± 5.0 minutes, P = 0.21) between the 2 groups. Among 28 patients who underwent repeat linear ablation, complete MI and LA roof blocks were created in 3 of 4 (75%) and 0 of 1 (0%) patients in the PFO group, and in 16 of 21 (76%) and 7 of 10 (70%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (15.3 ± 8.3 and 19.5 ± 18.3 minutes, P = 0.71), and LA roof (19.0 and 10.3 ± 5.4 minutes, P = 0.19) between the 2 groups. Clinical outcomes at 12 months were also similar.

Conclusion: There were no significant differences in the procedural success rates, durations of RF application, 12‐month clinical outcomes, and complication rates of LA linear ablation between the PFO and TS groups. Accessing the LA via a PFO is not an unfavorable approach toward LA linear ablation. (J Cardiovasc Electrophysiol, Vol. 22, pp. 846‐850, August 2011)

The recent completion of five trials comparing the strategy of rhythm control versus the strategy of rate control in the management of recurrent atrial fibrillation has advanced considerably our understanding of the treatment of this common clinical problem. The background to this research question is outlined, followed by an overview of the five trials and their results. Data on important clinical events from four of the trials are pooled and presented. The aggregate results of the trials do not demonstrate any clear advantage of the rhythm control approach. The findings elevate rate control to the position of an acceptable primary therapy in the types of patients studied and underline the concept that the primary goal of antiarrhythmic therapy for atrial fibrillation at this time is control of symptoms. Under these circumstances, a “safety first” approach is prudent and monitoring for adverse drug effects is mandatory. The results underscore the importance of continuous anticoagulation in patients with stroke risk factors. Finally, the results from these trials help to set the agenda for future research on rhythm management in atrial fibrillation. (J Cardiovasc Electrophysiol, Vol. 14, pp. S35‐S39, September 2003, Suppl.)

This report describes a fatal case of left atrial‐esophageal fistula occurring in a 72‐year‐old man after a radiofrequency catheter ablation of paroxysmal atrial fibrillation. Catheter ablation was performed around the pulmonary vein using an 8‐mm‐tip electrode (60 W or 55°C) guided by a 25‐mm circular catheter. On day 22 of follow‐up, the patient presented with seizures followed by hematemesis due to left atrial–esophageal fistula. His clinical condition deteriorated, and he died of speticemia. Thus, left atrial–esophageal fistula is a sever complication of radiofrequency catheter ablation of the left atrial posterior wall. (J Cardiovasc Electrophysiol, Vol. 15, pp. 960‐962, August 2004)

Introduction: Catheter ablation has recently been used for curative treatment of atrial fibrillation.

Methods and Results: Three of 239 patients who underwent ablation close to the pulmonary vein (PV) ostia at our institute developed severe hemoptysis, dyspnea, and pneumonia as early as 1 week and as late as 6 months after the ablation. Because the patients were arrhythmia‐free, the treating physician initially attributed the symptoms to new‐onset pulmonary disease (e.g., bronchopulmonary neoplasm). After absent PV flow was confirmed by transesophageal echocardiography, transseptal contrast injection depicted a totally occluded PV in all three patients. Successful recanalization, even in chronically occluded Pvs, was performed in all patients. During follow‐up, Doppler flow measurements by transesophageal echocardiography demonstrated restenosis in all primarily dilated PV, which led to stent implantation.

Conclusion: PV stenosis/occlusion after catheter ablation of atrial fibrillation occurs in a subset of patients. However, because in‐stent restenosis occurred in two patients after 6 to 10 weeks, final interventional strategy for PV stenosis or occlusion remains unclear. To prevent future PV stenosis or occlusion, a decrease in target temperature and energy of radiofrequency current or the use of new energy sources (ultrasound, cryothermia, microwave) seems necessary. (J Cardiovasc Electrophysiol, Vol. 14, pp. 366‐370, April 2003)

PV Stenosis after AF Ablation. Introduction: Elimination of the initiating focus within the pulmonary vein (PV) using radiofrequency (RF) catheter ablation is a new treatment modality for treatment of drug‐refractory atrial fibrillation. However, information on the long‐term safety of RF ablation within the PV is limited.

Methods and Results: In 102 patients with drug‐refractory atrial fibrillation and at least one initiating focus from the PV, series transesophageal echocardiography was performed to monitor the effect of RF ablation on the PV. There were 66 foci in the right upper PV and 65 foci in the left upper PV. Within 3 days of ablation, 26 of the ablated right upper PVs (39%) had increased peak Doppler flow velocity (mean 130 ± 28 cm/sec, range 106 to 220), and 15 of the ablated left upper PVs (23%) had increased peak Doppler flow velocity (mean 140 ± 39 cm/sec, range 105 to 219). Seven patients had increased peak Doppler flow velocity in both upper PVs. No factor (including age, sex, site of ablation, number of RF pulses, pulse duration, and temperature) could predict PV stenosis after RF ablation. Three patients with stenosis of both upper PVs experienced mild dyspnea on exertion, but only one had mild increase of pulmonary pressure. There was no significant change of peak and mean flow velocity and of PV diameter in sequential follow‐up studies up to 16 (209 ± 94 days) months.

Conclusion: Focal PV stenosis is observed frequently after RF catheter ablation applied within the vein, but usually is without clinical significance. However, ablation within multiple PVs might cause pulmonary hypertension and should be considered a limiting factor in this procedure.

Pulmonary Vein Stenosis. Introduction: A recently described focal origin of atrial fibrillation, mainly inside pulmonary veins, is creating new perspectives for radiofrequency catheter ablation. However, pulmonary venous stenosis may occur with uncertain clinical consequences. This report describes a veno‐occlusive syndrome secondary to left pulmonary vein stenosis after radiofrequency catheter ablation.

Methods and Results: A 36‐year‐old man who experienced daily episodes of atrial fibrillation that was refractory to antiarrhythmic medication, including amiodarone, was enrolled in our focal atrial fibrillation radiofrequency catheter ablation protocol. The left superior pulmonary vein was the earliest site mapped, and radiofrequency ablation was performed. Atrial fibrillation was interrupted and sinus rhythm restored after one radiofrequency pulse inside the left superior pulmonary vein. Atrial fibrillation recurred and a new procedure was performed in an attempt to isolate (26 radiofrequency pulses around the ostium) the left superior pulmonary vein. Ten days later, the patient developed chest pain and hemoptysis related to severe left superior and inferior pulmonary veins stenosis. Balloon angioplasty of both veins was followed by complete relief of symptoms after 2 months of recurrent pulmonary symptoms. The patient has been asymptomatic for 12 months, without antiarrhythmic drugs.

Conclusion: Multiple radiofrequency pulses applied inside the pulmonary veins ostia can induce severe pulmonary venous stenosis and veno‐occlusive pulmonary syndrome.

Changing QRS During Ventricular Tachycardia. Introduction: Spontaneous changes in QRS morphology during sustained reentrant ventricular tachycardia, occurring gradually or abruptly, causing the tachycardia to be polymorphic, have been described in clinical cases. The purpose of this study was to determine the mechanism for such changes in a canine infarct model.

Methods and Results: Reentrant circuits were mapped in the epicardial border zone during sustained ventricular tachycardia in the canine heart, 4 days after left anterior descending coronary occlusion. In 10 tachycardias, there was either an abrupt change in QRS morphology or a gradual change that took up to 25 cycles. When the latter occurred, the ECG resembled torsades de pointes. Maps showed that the predominant mechanism for the change in QRS was a shift in the exit route by which the impulse left the reentrant circuit to activate the ventricles (9/10 tachycardias). Such shifts resulted from small changes in conduction velocity in segments of the circuit, either speeding or slowing, which modified the length of the functional lines of block. Movement of the circuit to a different region was responsible for the change in QRS in only one of these experiments, in which the reentrant mechanism also changed from functional to anatomic.

Conclusion: Subtle changes in conduction in reentrant circuits can alter QRS morphology. Changes in the exit route from a stable reentrant circuit can cause the ECG characteristics to resemble torsades de pointes.