Introduction: Currently, definition of success following atrial fibrillation (AF) ablation is commonly based on the lack of symptoms. The purpose of this study was to evaluate the correlation between symptoms and the underlying rhythm after AF ablation.Methods and Results: Eighty consecutive patients (pts) were treated for paroxysmal episodes of AF by segmental ostial ablation of all pulmonary veins and right atrial isthmus ablation. For 6 months pts transmitted transtelephonic (T-) ECG recordings in combination with comments daily or in the event of symptoms. Eligible comments were classified as: (1) asymptomatic, (2) symptomatic. Analysis was performed at 1-month intervals, defining an acute (first month) and chronic period (second to sixth month) after ablation. Overall 6,835 T-ECGs were analyzed. Of these 5,437 (79.5%) showed sinus rhythm (SR) and 1,398 (20.5%) showed AF. Pts in SR reported symptoms for 593 (10.9%) episodes, whereas 4,844 (89.1%) episodes were asymptomatic. During AF, 646 (46.2%) episodes were associated with symptoms, and 752 (53.8%) episodes remained asymptomatic. Exclusively asymptomatic were 7 (8.8%) pts. In 30 (52.6%) of 57 pts with AF, arrhythmic events were confined to the acute phase. Of the remaining 27 pts 14 (52%) reported an improvement, 12 (44%) the same, and 1 (4%) worsened symptoms after 3 months. A significant change (P < 0.01) toward more asymptomatic episodes from the acute (43.5%) to the chronic (57.5 +/- 4.5%) period was evident.Conclusion: Assessment of success after AF ablation cannot be based on the absence of symptoms due to a high prevalence of asymptomatic episodes.

Background— Neutrophils and monocytes are centrally linked to vascular inflammatory disease, and leukocyte-derived myeloperoxidase (MPO) has emerged as an important mechanistic participant in impaired vasomotor function. MPO binds to and transcytoses endothelial cells in a glycosaminoglycan-dependent manner, and MPO binding to the vessel wall is a prerequisite for MPO-dependent oxidation of endothelium-derived nitric oxide (NO) and impairment of endothelial function in animal models. In the present study, we investigated whether heparin mobilizes MPO from vascular compartments in humans and defined whether this translates into increased vascular NO bioavailability and function. Methods and Results— Plasma MPO levels before and after heparin administration were assessed by ELISA in 109 patients undergoing coronary angiography. Whereas baseline plasma MPO levels did not differ between patients with or without angiographically detectable coronary artery disease (CAD), the increase in MPO plasma content on bolus heparin administration was higher in patients with CAD ( P =0.01). Heparin treatment also improved endothelial NO bioavailability, as evidenced by flow-mediated dilation ( P <0.01) and by acetylcholine-induced changes in forearm blood flow ( P <0.01). The extent of heparin-induced MPO release was correlated with improvement in endothelial function ( r =0.69, P <0.01). Moreover, and consistent with this tenet, ex vivo heparin treatment of extracellular matrix proteins, cultured endothelial cells, and saphenous vein graft specimens from CAD patients decreased MPO burden. Conclusions— Mobilization of vessel-associated MPO may represent an important mechanism by which heparins exert antiinflammatory effects and increase vascular NO bioavailability. These data add to the growing body of evidence for a causal role of MPO in compromised vascular NO signaling in humans.

AIMS:Paroxysmal atrial fibrillation (PAF) is predominantly triggered by focal ectopies located within the pulmonary veins (PV). The BITMAP Study (Breakthrough and Isolation Trial: Mapping and Ablation of Pulmonary Veins) investigated prospectively the safety and efficacy of a catheter design with circumferential mapping and ablation electrodes. We report the phenomenon of ST-segment-elevation during catheter placement in the left atrium (LA) and superior PVs in this multi-centre study.METHODS AND RESULTS:Forty-three patients (57+/-10 years) with PAF were included in this study. Radiofrequency catheter (RFC) ablation supported by the 4F REVELATION Helix microcatheter (Cardima Inc., Freemont, CA, USA) with eight distal-coiled microelectrodes for bipolar mapping and ablation. RFC was applied at the ostial region of PV (30 W, 45-50 degrees C) with a maximum of four RFC applications per electrode. In four of the 43 patients from three centres, we recorded the occurrence of ST-segment-elevation greater than 0.2 mV and accompanying left thoracic discomfort. The ECG changes and the symptoms started abruptly and lasted for 4.2+/-2.2 min. Pericardial effusion could instantaneously be excluded by echocardiography in all cases. Coronary angiograms were performed in three patients with the longest episodes; no thrombotic material or air emboli were present. The symptoms and the ECG changes resolved completely in all patients.CONCLUSION:The phenomenon of ST-segment-elevation during LA- and PV-mapping in patients with PAF may be a common occurrence. In this prospective multi-centre trial, we demonstrated the reversibility of this phenomenon; no cardiovascular or cerebral damage was reported during both the procedure and the follow-up. Although the mechanism is still unclear, vasospasm may contribute to this phenomenon because of autonomic dysregulation.

Introduction: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common regular supraventricular tachycardia in the general population as well as in elderly patients. The purpose of the study was to investigate the success and complication rate particularly regarding the induction of an atrioventricular (AV) block by radiofrequency (RF) ablation in elderly patients with and without a preexisting AV block. Methods and Results: Between February 1998 and July 2004, all patients with symptomatic AVNRT referred for slow‐pathway ablation in our institution were included and divided into two groups: group 1 patients younger than 75 years (n = 508) and group 2 patients ≥75 years (n = 70).A preexisting prolonged PR interval was present in 17 (3.3%) patients of group 1 and in 26 (37%, P < 0.0001) patients of group 2. Following successful slow‐pathway ablation (follow‐up time group 1: 37 ± 22, group 2: 37 ± 24 months) no induction of an AV block was observed in group 2 but in four patients of group 1 (0.79%) a complete heart block was induced requiring a pacemaker implantation. In group 1, 15 (2.95%) patients with a recurrence of AVNRT were readmitted for a repeat ablation procedure. No recurrences occurred in group 2. Conclusion: Despite a higher incidence of preexisting prolonged PR intervals slow‐pathway ablation in elderly patients is both effective and safe and should be considered as the first line therapy also in this patient population

Multiple strategies for ablation of monomorphic ventricular tachycardia (VT) remote after myocardial infarction have been proposed. Definition of the most relevant isthmus site remains a common therapeutic problem. 7 pts with documented recurrent and inducible or incessant monomorphic VT have been included in the study. Noncontact maps were obtained using the Ensite-Array® system during VT, programmed right ventricular stimulation (PVS) and sinus rhythm (SR). Geometry creation and ablation was performed with a 7F, 4mm irrigated tip catheter (50W, 60°, 17ml/s flow). In all pts multiple, median 4 (3-6), VT morphologies were inducible by PVS or overdrive stimulation. In 6 pts an endocardial origin was associated with the clinical VT. In 4 pts the clinical VT isthmus was identified by late activation during SR and concurrent left ventricular (LV) activation via the isthmus in addition to the septal activation wave during PVS (fig.). This was not the observed for any other than the clinical VT isthmus. Short ablation lines of 8 (5-12) radiofrequency current applications perpendicular to the direction of activation at the isthmus exit site rendered the clinical VT noninducible in all pts with endocardial reentries. Additional linear lesions were employed for the treatment of further inducible, predominantly faster, VTs. Late and simultaneous activation of the LV can readily be identified by noncontact mapping and is indicative for the dominant isthmus. Short ablation lines at this site are effective for the treatment of the dominant VT.

Introduction: Pulmonary veins (PVs) are the predominant location of triggers for atrial fibrillation (AF), but little is known about the electrophysiologic properties of PVs. In addition, the influence of amiodarone on the electrophysiologic properties of PVs has not been elucidated. Methods and Results: Fifty‐five patients with symptomatic and drug‐resistant AF were divided into two groups: group 1 patients (n = 29) without antiarrhythmic drug therapy at the time of electrophysiologic study (EPS), and group 2 patients (n = 26) undergoing continuous long‐term treatment with amiodarone. EPS including programmed stimulation of both atria and within the PVs was performed in both groups. In group 1, the effective refractory period (ERP) of all PVs (174 ± 62 msec) was significantly shorter than the ERP of the left atrium ([LA] 254 ± 30 msec, P = 0.0001) and right atrium ([RA] 221 ± 29 msec, P = 0.0001). The same pattern was observed in group 2 (PV: 210 ± 58 msec; LA: 259 ± 35 msec, P = 0.0001; RA: 246 ± 37 msec, P = 0.0255). The ERP of all stimulated PVs was significantly lower in group 1 (174 ± 62 msec) than in group 2 (210 ± 58 msec; P = 0.0001). The ERP of the left superior and right superior PVs and RA but not the left inferior PV and LA were significantly increased in patients treated with amiodarone. Decremental conduction properties were observed in all stimulated PVs, and there were no significantly differences between the maximal decrement of both groups. Conclusion: The distinctive electrophysiologic properties of PVs are emphasized by amiodarone therapy. Long‐term amiodarone treatment is responsible for heterogeneous alteration of the PV electrophysiology, which may account for the individual antiarrhythmic responses in a subset of patients with paroxysmal AF.

Background: In the era of cardiac resynchronization therapy interest has focused on cardiac contraction in the diseased heart. Purpose of this study was to delineate the influence of infarcted and ischemic tissue on cardiac excitation-contraction (EC) spread and to demonstrate the feasibility of a novel mapping technique allowing combined analysis of EC-timing in vivo.

This case report describes a patient with a sustained monomorphic VT after surgical repair of a tetralogy of Fallot (TOF). In combination with the three‐dimensional electroanatomic mapping system, CARTO, and conventional mapping techniques the VT was identified as a macro‐reentrant tachycardia circling around the border between pulmonary graft and right ventricular outflow tract (RVOT). A y‐shaped ablation line crossing this zone was created. The VT terminated during RF application and was not inducible again. This case underlines the use of a combined conventional and three‐dimensional electroanatomic mapping technique can be helpful for catheter ablation of ventricular arrhythmias in TOF patients. (PACE 2004; 27[Pt. I]:801–804)

Aim Sub-threshold stimulation (STS) applied during atrioventricular nodal re-entrant tachycardia (AVNRT) of the common (slow-fast) type has been shown to effectively characterise target sites suitable for slow pathway (SP) ablation but has not been investigated in the setting of fast-slow and slow-slow variants.Methods and results Seventeen consecutive patients (52 +/- 16 years, 12 female) with sustained uncommon type AVNRT (fast-slow: n = 13, slow-stow: n = 4) were investigated. Mapping of the SP was started postero-septally close to the coronary sinus ostium and continued toward mid-septal sites, if required. Target sites for STS were selected according to established criteria including the recording of the earliest retrograde atrial activation during AVNRT. Long duration (5 s) constant current STS during AVNRT variants was performed in a stepwise manner (max 5 mA) at each site eligible for SP ablation until termination or capture occurred. Radiofrequency current (RFC) was delivered following successful STS termination of tachycardia (65 degreesC, 60 s) and exclusion of catheter dislodgement. Uncommon AVNRT with a mean cycle length of 405 +/- 70 ms was induced without spontaneous termination in all patients. Interruption of AVNRT variants due to selective STS-induced block of the retrograde (n = 12) or anterograde (n = 2) SP occurred without capture in 14/17 (82%) patients. This was exclusively observed at sites with successful subsequent RFC application. AVNRT was rendered non-inducible in all patients after a median of 1 (1-11) RFC pulses without complications.Conclusions Uncommon AVNRT can be interrupted by STS delivered at subsequently successful target sites for SP ablation in most patients (82%). The high positive and negative concordance between the effects of STS and following RFC application indicates that STS-mapping is also useful in the setting of AVNRT variants. (C) 2004 Published by Elsevier Ltd on behalf of The European Society of Cardiology.

The present study sought to investigate the electrophysiological properties of isolated pulmonary veins following successful radiofrequency (RF) catheter ablation in patients with paroxysmal atrial fibrillation (PAF). Overall, 71 pulmonary veins in 37 consecutive patients (age: 56 +/- 9 years) with recurrent PAF were targeted for RF ablation at the ostial region in order to achieve a complete functional block. Following disconnection, the incidence of dissociated pulmonary vein (PV) activity and its response to orciprenalin were studied. RF ablation abolished conduction in 67 (94%) of 71 potentially arrhythmogenic PVs after a mean of 10.7 +/- 6.4 RF applications for each PV. After ablation, spontaneous dissociated automatic activity (9 to 52 beats/min, median 27) was found in 6 out of 67 isolated PVs (left superior: n = 1, left inferior: n = 1, right superior: n = 2, common left PV: n = 2). Slight acceleration (13 to 68 beats/min, median 29) of dissociated PV activity was observed during infusion of orciprenalin. Following isolation, initiation of sustained or nonsustained local fibrillation was recorded in only two cases of the common left sided PV with preceding automatic activity. In one patient PV fibrillation occurred during orciprenalin infusion following a repetitive response to a dissociated automatic rhythm with increasing duration as well as destabilization. In the other patient, PV fibrillation occurred immediately after the occurrence of PV automaticity. Slow dissociated automatic rhythms are detectable within 9% of disconnected PVs. The unique anatomic substrate of common left PVs seem to favor the occurrence of local fibrillation following isolation. The initiation pattern of fibrillation within the isolated PV has pathophysiological implications and underlines the contribution of multiple factors to the onset and sustenance of PAF.

The present study sought to investigate the electrophysiological properties of isolated pulmonary veins following successful radiofrequency (RF) catheter ablation in patients with paroxysmal atrial fibrillation (PAF). Overall, 71 pulmonary veins in 37 consecutive patients (age: 56 ± 9  years ) with recurrent PAF were targeted for RF ablation at the ostial region in order to achieve a complete functional block. Following disconnection, the incidence of dissociated pulmonary vein (PV) activity and its response to orciprenalin were studied. RF ablation abolished conduction in 67 (94%) of 71 potentially arrhythmogenic PVs after a mean of 10.7 ± 6.4  RF applications for each PV. After ablation, spontaneous dissociated automatic activity (9 to 52 beats/min, median 27) was found in 6 out of 67 isolated PVs (left superior: n = 1 , left inferior: n = 1 , right superior: n = 2 , common left PV: n = 2 ). Slight acceleration (13 to 68 beats/min, median 29) of dissociated PV activity was observed during infusion of orciprenalin. Following isolation, initiation of sustained or nonsustained local fibrillation was recorded in only two cases of the common left sided PV with preceding automatic activity. In one patient PV fibrillation occurred during orciprenalin infusion following a repetitive response to a dissociated automatic rhythm with increasing duration as well as destabilization. In the other patient, PV fibrillation occurred immediately after the occurrence of PV automaticity. Slow dissociated automatic rhythms are detectable within 9% of disconnected PVs. The unique anatomic substrate of common left PVs seem to favor the occurrence of local fibrillation following isolation. The initiation pattern of fibrillation within the isolated PV has pathophysiological implications and underlines the contribution of multiple factors to the onset and sustenance of PAF. (PACE 2003; 26:1363–1370)