Paweł Derejko

Ventricular fibrillation risk factors in over one thousand patients with accessory pathways

BACKGROUND Published data concerning risk factors of VF in WPW patients are inconsistent or contradictory. METHODS AND RESULTS We included 1007 patient (pts) (mean age 35 years; 45% female) with an accessory pathway (AP) referred for non pharmacological treatment. Group 1 consisted of 56 pts (42M, aged 34 ± 15 yrs) with an AP and documented VF and Group 2-951 pts (513M, aged 35 ± 15 yrs) with an AP and without VF. Univariate predictors of VF were: overt pre-excitation, male gender, multiple AP, large AP. Multivariate predictors were: overt pre-excitation, male gender and MAP. The mean shortest pre-excited RR interval during AF was significantly shorter in Group 1: 205 ± 27 vs. 243 ± 64, P=0.019. VF as an end point of the first arrhythmia episode (AVRT or AF) was observed in 20 pts (15M, 5F). Primary VF (no documented arrhythmia prior to aborted SCD) occurred in 16 pts (13M, 3F). The mean age of primary VF pts was significantly lower than of pts with history of AVRT or AVRT and/or AF (24.5 vs. 36.5 vs. 38 yrs., P<0.005 and P=0.002, respectively). Age at VF occurrence shows a bi-modal distribution with peak occurrences in the 2-nd/3-rd and 5-th decades. CONCLUSION In patients with an accessory pathway, overt pre-excitation, male gender and multiple AP constitute independent risk factors of VF episodes. Young patients in the 2-nd/3-rd and older patients in the 5-th decade might be at higher risk of VF occurrence.

Safety of nerve conduction studies in patients with implantable cardioverter–defibrillators

OBJECTIVE A patient with an implantable cardioverter-defibrillator (ICD) may suffer from neuromuscular disorders and may need to undergo a nerve conduction study (NCS). However, a NCS may be a source of electromagnetic interference (EMI). The aim of the present study was to investigate whether the interference from NCS used in a standardised test protocol affects ICD function. METHODS Twenty patients (19 males; mean age of 59.8±9.9 years) with implantable ICDs (eight with integrated and 12 with true bipolar leads), treated with amiodarone and with symptoms suggesting neuropathy were included. NCS were conducted using repetitive stimulation with frequency of 2 Hz and single, rectangular pulses of intensity up to 100 mA. Stimulation was performed in standard sites including proximal sites in the arm. RESULTS The impulses generated NCS were not detected by the ICD, irrespective of the site, rate or stimulus intensity. CONCLUSIONS Standardised test protocol for an NCS is safe in patients with an ICD regardless of the leads type. SIGNIFICANCE Current guidelines which limitate the NCS in patients with ICD may be the subject of revision.

Radiofrequency catheter ablation of accessory pathways in patients with Ebstein’s anomaly: At 8 years of follow-up

BACKGROUND Data regarding long-term follow-up of radiofrequency catheter ablation (RFCA) of accessory pathways (APs) in patients with Ebsteins anomaly (EA) are limited. The procedures are challenging due to multiple or wide APs. METHODS Analysis was performed on clinical and periprocedural data of patients with EA referred to the centre in order to perform catheter ablation of AP. The group consisted of 22 patients (female 40.9%, mean age 33.6 ± 19.1 years). The follow-up utilized electrocardiogram and Holter monitoring. RESULTS Twenty-two patients had 33 accessory pathways (8 patients had multiple APs, 11 patients broad AP). Twenty-nine different arrhythmias were ablated: 20 orthodromic atrioventricular reciprocating tachycardia (O-AVRT), 5 antidromic atrioventricular reciprocating tachycardia (A-AVRT), 3 slow/ fast atrioventricular nodal reentry tachycardia (s/f AVNRT) and 1 cavotricuspid-isthmus-dependent atrial flutter (CTI-AFL). In 3 (13.6%) patients multiple ablation targets for RFCA ablation were observed. The acute procedural success rate after the first RFCA performed was: 100% for AVNRT, 77.3% for APs and 50.0% for CTI-AFL ablation. Follow-up (mean 95.7 ± 49.8 months) was completed in 86.4% of patients. One patient had paroxysmal atrial fibrillation not targeted during ablation. One patient died due to heart failure 12 years after RFCA. Three patients who underwent RFCA of accessory pathways in the mid-1990s were lost in follow-up. CONCLUSIONS Radiofrequency ablation in patients with EA is challenging but safe and have a high short-term as well as long-term success rate.

Catheter ablation of complex left atrial arrhythmias in patients after percutaneous or surgical mitral valve procedures.

BACKGROUND Mitral valve defects are frequently associated with atrial arrhythmias. Percutaneous or surgical mitral valveprocedures may reverse adverse haemodynamic consequences of the valvular defect but have little effect on the arrhythmiaitself. With safety concerns and few outcome data, the role of catheter ablation in these patients has not been established yet. AIM To assess safety and efficacy of catheter ablation of complex left atrial arrhythmias in patients after percutaneous orsurgical mitral valve procedures. METHODS We studied 14 patients (mean age 55 ± 11 years; 9 females) with a history of percutaneous mitral commissurotomy (PMC; n = 5), surgical valvuloplasty (n = 3), or mitral valve replacement (n = 6) due to mitral stenosis (MS; n = 8) or mitral regurgitation (MR; n = 6). In surgically treated patients, concomitant pulmonary vein isolation was performed in 6 patients and tricuspid valvuloplasty in 4 patients. Atrial fibrillation (AF) was the only arrhythmia in 7 patients, including all 5 patients after PMC (paroxysmal AF in 2 patients, persistent AF in 4 patients, long-persistent AF in 1 patient). Left atrial tachycardia (AT) was the prevailing arrhythmia in 7 of 9 patients after surgical procedures (median of 2 morphologies per patient), lasting uninterrupted for 1 to 48 months before the ablation procedure. The ablation scheme was adjusted to the clinical and electrophysiological status and included pulmonary vein isolation, linear lesions and ablation of fragmented potentials. Atrial tachycardias were mapped and ablated using activation and entrainment mapping. RESULTS Efficacy of ablation after a single procedure was 36%. A total of 25 ablations were ultimately performed in the study group. During 23 ± 13 months of follow-up, stable sinus rhythm (SR) was present in 10 (71.4%) patients, including 4 on antiarrhythmic drugs. No differences in the efficacy of ablation were seen between patients with MS and MR, with SR obtained in5 of 8 patients and 5 of 6 patients, respectively (p = 0.57). Similarly, no differences in regard to SR maintenance were noted between patients previously treated by a percutaneous or surgical procedure (percutaneous treatment: SR in 3 of 5 patients; surgical treatment: SR in 7 of 9 patients, p = 0.58). SR was obtained in 5 of 7 patients in whom the original arrhythmia was AF and in 5 of 7 patients who had AT (p = 1.00). Patients in whom stable SR was obtained showed a significantly better functional status as assessed by the New York Heart Association classification, accompanied by a reduction of the left atrial dimension and an increase in the left ventricular ejection fraction. CONCLUSIONS Catheter ablation of complex left atrial arrhythmias in patients after percutaneous or surgical mitral valve proceduresis an effective and safe therapeutic option. Recurrences after the first ablation are frequent and patients may require repeat ablations. Achieving stable SR significantly reduces complaints related to the arrhythmia and improves patient clinical status.

Effect of the restitution properties of cardiac tissue on the repeatability of entrainment mapping response.

Background—The difference between the postpacing interval (PPI) and the tachycardia cycle length (TCL; PPI−TCL) is a useful tool in mapping macro-reentrant tachycardias. However, entrainment pacing causes some perturbation of the conduction velocity within the tachycardia circuit, which may affect the repeatability and consequently the accuracy of the measurement of PPI−TCL. The aim of this study was to assess PPI−TCL repeatability both in vivo and in silico. Methods and Results—In the experimental part, entrainment pacing was performed twice at each of the 124 tested sites for 30 patients undergoing radiofrequency ablation of atrial and ventricular re-entrant arrhythmias. A similar protocol was used in a simplified computer model of the cardiac tachycardia circuit in a 2-dimensional tissue strip using a Fenton–Karma model of cardiac tissue. In vivo, in the case of fast tachycardias (<350 ms), PPI−TCL variability observed was doubled compared with slow tachycardias (>350 ms; 95% Limits of Agreement ranged from −21.4 to 21.6 ms for TCL<350 ms and from −10.8 to 11.5 ms for TCL>350 ms). Simulations show that this increase of variability may be because of the oscillations of the conduction velocity inside the tachycardia circuits. The effect of the restitution properties of cardiac tissue on the outcome of entrainment pacing is discussed. Conclusions—PPI−TCL is characterized by a high repeatability with the differences between the results for individual stimulations of ⩽20 ms. The variability of this parameter is significantly lower in the case of slow tachycardias.

Ablation of atrial tachyarrhythmias late after surgical correction of tetralogy of Fallot: long-term follow-up

BACKGROUND After the surgical correction of tetralogy of Fallot, surgical scars and natural obstacles form pathways capable of supporting an atrial tachyarrhythmia (AT). Radiofrequency (RF) ablation is effective, although the few studies published on this topic had relatively short follow-up periods. AIM The aims of the study were to evaluate the acute and long-term effects of RF ablation of AT and examine the charac-teristics of arrhythmia recurrence. METHODS Tetralogy of Fallot patients (n = 16, age 44.7 ± 10.7 years) referred for ablation of ATs, appearing 25.7 ± 9.6 years after repair, were studied. RESULTS Twenty-five ATs were ablated, including 16 cavo-tricuspid isthmus atrial flutters (CTI-AFLs) and nine intraatrial reentrant tachycardia (IART). In one patient with paroxysmal atrial fibrillation (PAF), pulmonary vein isolation was also performed. Ten patients had permanent, and six had paroxysmal arrhythmia prior to the first ablation. Four patients had PAF. Regardless of the type of first ablated arrhythmia, all 16 patients required CTI-AFL ablation. The effectiveness of the first RF ablation reached 88%. The acute efficacy of RF ablation was 100% for CTI-AFL and 78% for IART. Long-term follow-up was possible in 15 out of 16 patients (mean follow-up 68.8 ± 36.6 months). Four patients were free of sustained arrhythmia, nine (60%) had AF. After the last RF ablation, an episode suggestive of CTI-AFL/IART was documented only in one patient. CONCLUSIONS Ablation of CTI-AFL/IART in tetralogy of Fallot patients is safe and effective. AF was observed in most patients during the long-term follow-up. Regardless of the type of the first ablated arrhythmia, all patients required CTI-AFL ablation.

High-density automated mapping and entrainment pacing for successful atypical flutter ablation with one RF application.

Atypical left atrial flutter may occur as a complication after atrial fibrillation ablation, especially when linear and substrate ablation were initially deployed. In such cases, the most effective therapy is radiofrequency ablation, but the procedure can be long lasting and challenging. Use of multielectrode catheters and high-density mapping algorithms together with a conventional electrophysiological approach may shorten and simplify treatment. Case report A 43-year-old woman, after previous ablations for atrial fibrillation and typical atrial flutter, was scheduled for another ablation, due to symptomatic atypical atrial flutter. Echocardiography showed left atrial (LA) diameter within the normal range (40 mm) and normal ejection fraction (65%). Previously the patient underwent circumferential pulmonary vein isolation and linear ablation with lines in the cavo-tricuspid isthmus (CTI), left atrial roof and mitral isthmus groove. During the last ablation, bi-directional block was confirmed in all locations and no arrhythmia was induced with aggressive stimulation during isoproterenol infusion. The ECG recorded on admission suggested left atrial flutter with 2:1 conduction, with positive F waves in leads II, III, aVF, and V1 and negative in leads aVR and AVL (Fig. 1). Intracardiac signals (IC) showed atrial flutter with CL 295-300 ms, with proximal and distal bipoles at the catheter placed in the coronary sinus (CS) activated simultaneously. Due to the electrographic pattern of arrhythmia and previous catheter ablations the operator (JK) decided to perform high-density mapping of left atrial endocardial activation using a multielectrode mapping (MEM) catheter (PentaRay, 20 poles, spacing 2-6-2, 1 mm width electrodes) and dedicated automatic algorithm[1] (Confidense, Carto 3 Biosense Webster).

Clinical and echocardiographic parameters as risk factors for atrial fibrillation in patients with hypertrophic cardiomyopathy

Atrial fibrillation (AF) is a common complication in patients with hypertrophic cardiomyopathy (HCM) and may contribute to high cardiovascular morbidity and mortality. Therefore, it is important to assess parameters associated with AF in HCM patients.

Risk factors of atrial fibrillation recurrence despite successful radiofrequency ablation of accessory pathway: At 11 years of follow-up

BACKGROUND Previous reports on patients with radiofrequency catheter ablation (RFCA) of accessory pathway (AP) and atrial fibrillation (AF) include only short follow-up periods. The aim of this study was to analyze predictors of recurrence of AF in patients after successful RFCA of APs over long term follow-up periods. METHODS Of the 1,007 patients who underwent non-pharmacological treatment of APs (between the years 1993-2008), data of 100 consecutive patients were retrospectively analyzed (75 men, mean age 43.6 ± 14.7), with the longest period of follow-up (mean 11.3 ± 3.5 years) after successful RFCA of AP. In Group 1, there were 72 patients (54 men, mean age 40.66 ± 13.85 years) without documented episodes of AF after RFCA of AP. Group 2 consisted of 28 patients (21 men, mean age 50.79 ± 14.49 years) with AF episodes despite successful elimination of AP. RESULTS In univariate analysis, patients from Group 1 were significantly younger at the time of abla-tion than patients from Group 2 (40.66 ± 13.85 vs. 50.79 ± 14.49 years; p = 0.002), had shorter his¬tory of AF episodes (4.11 ± 4.07 vs. 8.25 ± 7.50 years; p = 0.024) and had less frequently documented atrial tachycardia (AT) prior to ablation (3.39 vs. 20.00% years; p = 0.022). In multivariate analysis, the history of AF in years (p = 0.043), was an independent risk factor for AF recurrences. CONCLUSIONS Older patient age, longer history of AF and AT prior to RFCA of APs identified a sub-group of patients who required additional treatment. In the multivariate analysis, the history of AF in years (p = 0.043) was a risk factor for AF recurrence.

Characteristic features of patients with multiple accessory pathways

Abstract Objective Only limited clinical and electrophysiological data concerning patients (pts) with multiple accessory pathways (MAP) in comparison to large control groups are available. The aim of our study was to analyse these data from the largest cohort of patients with multiple accessory pathways and a large control group. Method and results We analysed data from pts with MAP (group 1) and pts with a single accessory pathway (AP) (group 2) referred for radiofrequency catheter ablation (RFCA) at our tertiary centre. Group 1 consisted of 124 pts (M 62.10%, mean age 33.00 ± 5.26) with MAP and RFCA. Group 2 consisted of 376 pts (M 51.20%, mean age 35.87 ± 16.15) with a single accessory pathway and RF ablation. Group 1 exhibited a higher incidence of overt APs (P < 0.0001), Ebstein anomaly (P = 0.001), ventricular fibrillation (P = 0.012), antidromic atrioventricular re-entrant tachycardia (A AVRT) (P = 0.025) and male gender (P = 0.038). The mean age at the first documented atrioventricular re-entrant tachycardia (AVRT) episode was lower in pts with MAP than in pts with single APs: 16.79 ± 13.41 vs 20.84 ± 14.29, respectively (P = 0.001). Concealed accessory pathways (P < 0.0001) occurred more frequently in the control group. Group 1 had more right-lateral (P = 0.0001), mid-septal (P = 0.0001), left-posterior (P = 0.01), left-anterior (P = 0.013) and left-lateral localizations of AP (P < 0.037). Conclusions The MAP group included statistically significantly more men, Ebstein anomaly and overt APs. The mean age of the first episode of atrioventricular re-entrant tachycardia was lower in pts with MAP. Certain distribution patterns are apparent for single and MAP. Pts with MAP are at higher risk of VF and antidromic atrioventricular re-entrant tachycardia.