Idiopathic Outflow Tract Ventricular Arrhythmias Research Articles

Centrifugal Wave Front Propagation Speed for Localizing the Origin of Ventricular Arrhythmias: Investigation Using a New Ultra-High-Resolution MappingSystem.

The aim of this study was to assess the use of wave front propagation speed on a right ventricular map for determining the earliest activation site as the origin of outflow tract ventricular arrhythmias (VAs). VAs with centrifugal right ventricular outflow tract (RVOT) activation can be from an RVOT focus or a focus outside the RVOT. This prospective observational study included 23 patients with idiopathic outflow tract VAs. Mapping of theRVOT was performed using a new ultra-high-resolution electroanatomic mapping system. The wave front propagation speed was estimated from the area surrounded by a propagated wave front at 5, 10, 15, and 20 ms after the earliest activation. VAs disappeared following ablations in the RVOT in 15 patients (RVOT origin). The remaining 8 patients hadVAs of non-RVOT origin determined by ablation success at another site or ablation failure. The areas surrounded by apropagated wave front were significantly smaller in VAs of RVOT origin than non-RVOT VAs at 5 ms (1.0 [0.7 to 1.1]cm2vs. 2.2 [1.6 to 4.4] cm2), 10 ms (1.9 [1.4 to 2.2] cm2 vs. 4.5 [3.2 to 5.8] cm2), 15 ms (3.2 [2.3 to 4.4] cm2 vs. 7.1[6.3to 9.8] cm2), and 20 ms (5.0 [3.0 to 6.6] cm2 vs. 9.8 [9.3 to 14.8] cm2). A propagated area of<5.0 cm2 at 15 ms predicted RVOT VAs with 87% sensitivity, 100% specificity, and 91% predictive accuracy. VAs with slow wave front propagation speed on the right ventricular map indicate an RVOT origin.

Automatic activation mapping and origin identification of idiopathic outflow tract ventricular arrhythmias

PurposeActivation mapping is used to guide ablation of idiopathic outflow tract ventricular arrhythmias (OTVAs). Isochronal activation maps help to predict the site of origin (SOO): left vs right outflow tract (OT). We evaluate an algorithm for automatic activation mapping based on the onset of the bipolar electrogram (EGM) signal for predicting the SOO and the effective ablation site in OTVAs. MethodsEighteen patients undergoing ablation due to idiopathic OTVAs were studied (12 with left ventricle OT origin). Right ventricle activation maps were obtained offline with an automatic algorithm and compared with manual annotation maps obtained during the intervention. Local activation time (LAT) accuracy was assessed, as well as the performance of the 10ms earliest activation site (EAS) isochronal area in predicting the SOO. ResultsHigh correlation was observed between manual and automatic LATs (Spearman's: 0.86 and Lin's: 0.85, both p<0.01). The EAS isochronal area were closely located in both map modalities (5.55 ± 3.56mm) and at a similar distance from the effective ablation site (0.15±2.08mm difference, p=0.859). The 10ms isochronal area longitudinal/perpendicular diameter ratio measured from automatic maps showed slightly superior SOO identification (67% sensitivity, 100% specificity) compared with manual maps (67% sensitivity, 83% specificity). ConclusionsAutomatic activation mapping based on the bipolar EGM onset allows fast, accurate and observer-independent identification of the SOO and characterization of the spreading of the activation wavefront in OTVAs.

Electrocardiographic algorithms to guide the management strategy of idiopathic outflow tract ventricular arrhythmias.

INTRODUCTION The current guidelines of the European Society of Cardiology outlined electrocardiographic (ECG) differentiation of the site of origin (SoO) in patients with idiopathic ventricular arrhythmias (IVAs). OBJECTIVES The aim of this study was to compare 3 ECG algorithms for differentiating the SoO and to determine their diagnostic value for the management of outflow tract IVA. PATIENTS AND METHODS We analyzed 202 patients (mean age [SD]: 45 [16.7] years; 133 women [66%]) with IVAs with the inferior axis (130 premature ventricular contractions or ventricular tachycardias from the right ventricular outflow tract [RVOT]; 72, from the left ventricular outflow tract [LVOT]), who underwent successful radiofrequency catheter ablation (RFCA) using the 3‑dimensional electroanatomical system. The ECGs before ablation were analyzed using custom‑developed software. Automated measurements were performed for the 3 algorithms: 1) novel transitional zone (TZ) index, 2) V2S/V3R, and 3) V2 transition ratio. The results were compared with the SoO of acutely successful RFCA. RESULTS The V2S/V3R algorithm predicted the left‑sided SoO with a sensitivity and specificity close to 90%. The TZ index showed higher sensitivity (93%) with lower specificity (85%). In the subgroup with the transition zone in lead V3 (n = 44, 15 from the LVOT) the sensitivity and specificity of the V2-transition‑ratio algorithm were 100% and 45%, respectively. The combined TZ index+V2S/V3R algorithm (LVOT was considered only when both algorithms suggested the LVOT SoO) can increase the specificity of the LVOT SoO prediction to 98% with a sensitivity of 88%. CONCLUSIONS The combined TZ‑index and V2S/V3R algorithm allowed an accurate and simple identification of the SoO of IVA. A prospective study is needed to determine the strategy for skipping the RVOT mapping in patients with LVOT arrhythmias indicated by the 2 combined algorithms.

P803Right-sided transitional zone of ECG in idiopathic outflow tract ventricular arrhythmia associates reduced left ventricular function

P803Right-sided transitional zone of ECG in idiopathic outflow tract ventricular arrhythmia associates reduced left ventricular function

Outcomes of Catheter Ablation of Idiopathic Outflow Tract Ventricular Arrhythmias With an R Wave Pattern Break in Lead V2: A Distinct Clinical Entity.

In outflow tract ventricular arrhythmias (OT-VAs), an abrupt loss of the R wave in lead V2 compared to V1 and V3 (pattern break in V2-PBV2) suggests an origin close to the anterior interventricular sulcus (anatomically opposite to lead V2) and adjacent to proximal coronaries. We studied the outcome of catheter ablation of OT-VAs with a PBV2. Of 130 consecutive patients with idiopathic left bundle block morphology OT-VAs and transition ≤V4, 12 (9%) had PBV2. Outcomes in this group were compared to the remaining 118 patients. Patients with PBV2 were more likely to be younger (41 ± 18 vs. 50 ± 14 years, P = 0.0384) and women (11 [92%] vs. 70 [59%], P = 0.0302). The earliest activation was at the RVOT in seven, left coronary cusp (LCC) in one, anterior interventricular vein (AIV) in two and the epicardium in two. In five (42%) cases (earliest activation in the AIV in two, epicardium in two, and RVOT below the valve level in one), ablation was aborted due to proximity to the left anterior descending (LAD) coronary artery. After 36 ± 17 months and 1.3 ± 0.5 procedures, VAs elimination was achieved in 58% of patients with PBV2 compared to 89% of the reference population (P = 0.0125) with effective site in five of seven at the most anterior and leftward RVOT adjacent to the pulmonic valve (PV). OT-VAs with PBV2 demonstrate a unique ECG pattern and challenging catheter ablation. Proximity to LAD precludes ablation in about half. Long-term VA suppression could be achieved in only 58% of cases most commonly when the earliest site is at the anterior and leftward RVOT just under the PV.

The "Dead-End Tract" and Its Role in Arrhythmogenesis.

Idiopathic outflow tract ventricular arrhythmias (VAs) represent a significant proportion of all VAs. The mechanism is thought to be catecholamine-mediated delayed after depolarizations and triggered activity, although other etiologies should be considered. In the adult cardiac conduction system it has been demonstrated that sometimes an embryonic branch, the so-called “dead-end tract”, persists beyond the bifurcation of the right and left bundle branch (LBB). Several findings suggest an involvement of this tract in idiopathic VAs (IVAs). The aim of this review is to summarize our current knowledge and the possible clinical significance of this tract.

Idiopathic outflow tract ventricular arrhythmias

Idiopathic outflow tract ventricular arrhythmias

GW26-e1472 More accurate way for localization of idiopathic outflow tract ventricular arrhythmia

GW26-e1472 More accurate way for localization of idiopathic outflow tract ventricular arrhythmia

Discrete potentials guided ablation for idiopathic outflow tract ventricular arrhythmias

Discrete potentials (DPs) have been recorded and targeted as the site of ablation of the outflow tract arrhythmias. The aim of the present study was to investigate the significance of DPs with respect to mapping and ablation for idiopathic outflow tract premature ventricular contractions (PVCs) or ventricular tachycardias (VTs). Seventeen out of 24 consecutive patients with idiopathic right or left ventricular outflow tract PVCs/VTs who underwent radiofrequency catheter ablation between September 2012 and December 2013 in our department were included. Intracardiac electrograms during the mapping and ablation were analyzed. During sinus rhythm, sharp high-frequency DPs that displayed double or multiple components were recorded following or buried in the local ventricular electrograms in all of the 17 patients, peak amplitude was (0.51 ± 0.21) mV. The same potential was recorded prior to the local ventricular potential of the PVCs/VTs. Spontaneous reversal of the relationship of the DPs to the local ventricular electrogram was noted during the arrhythmias. The DPs were related to a region of low voltage showed by intracardiac high-density contact mapping. At the sites with DPs, unipolar and bipolar ventricular voltage of sinus beats were lower compared with the adjacent regions without DPs (unipolar: (6.1 ± 1.8) mV vs. (8.3 ± 2.3) mV, P < 0.05; bipolar: (0.62 ± 0.45) mV vs. (1.03 ± 0.60) mV, P < 0.05). The targeted DPs were still present in 12 patients after successful elimination of the ectopies. Discrete potentials were not present in seven controls. Discrete potentials and related low-voltage regions were common in idiopathic outflow tract ventricular arrhythmias. Discrete potential- and substrate-guided ablation strategy could help to reduce the recurrence of idiopathic outflow tract arrhythmias.

The QRS morphology pattern in V5R is a novel and simple parameter for differentiating the origin of idiopathic outflow tract ventricular arrhythmias

There are many reports on the ECG characteristics of idiopathic outflow tract ventricular arrhythmias (OT-VAs) to predict their origin. However, differentiating near regions using 12-lead ECGs is still complicated. The synthesized 18-lead ECG derived from the 12-lead ECG can provide virtual waveforms of the right-sided chest leads (V3R, V4R, and V5R) and back leads (V7, V8, and V9). The aim of this study was to develop a simple and useful parameter for differentiating OT-VA origins using the 18-lead ECG. We studied 28 and 73 patients with idiopathic VAs in a pacemapping study and validation cohort, respectively. In the pacemapping study, several sites out of five different sites were paced in each patient: the anterior and posterior right ventricular OT (RVOT-ant and RVOT-post), right and left coronary cusps (RCC and LCC), and junction of both cusps (RLJ). The 18-lead ECGs during pacemapping among the five sites were compared for establishing a simple parameter to predict VA origins. A novel parameter using 18-lead ECGs was tested prospectively in 73 patients. In the pacemapping study, the dominant QRS morphology pattern in the synthesized V5R significantly differed among those sites (RVOT-ant:Rs, RVOT-post:rS, RCC:QS, RLJ:qR, and LCC:R). The patients in the validation cohort were divided into five groups depending on those QRS morphology patterns during VAs in the synthesized V5R. Each V5R QRS morphology pattern could predict a precise origin of the OT-VAs with an overall accuracy of 75%. The QRS morphology pattern in V5R was a simple and useful parameter for differentiating detailed OT-VA origins.

Discrete potentials guided radiofrequency ablation for idiopathic outflow tract ventricular arrhythmias.

Discrete potentials (DPs) have been recorded and targeted as the site of ablation of the outflow tract arrhythmias. The aim of the present study was to investigate the significance of DPs with respect to mapping and ablation for idiopathic outflow tract premature ventricular contractions (PVCs) or ventricular tachycardias (VTs). Seventeen consecutive patients with idiopathic right or left ventricular outflow tract PVCs/VTs who underwent radiofrequency catheter ablation were included. Intracardiac electrograms during the mapping and ablation were analysed. During sinus rhythm, sharp high-frequency DPs that displayed double or multiple components were recorded following or buried in the local ventricular electrograms in all of the 17 patients, peak amplitude 0.51 ± 0.21 mV. The same potential was recorded prior to the local ventricular potential of the PVCs/VTs. Spontaneous reversal of the relationship of the DPs to the local ventricular electrogram during the arrhythmias was noted. The DPs were related to a region of low voltage showed by intracardiac high-density contact mapping. At the sites with DPs, lower unipolar and bipolar ventricular voltage of sinus beats were noted compared with the adjacent regions without DPs (unipolar: 6.1 ± 1.8 vs. 8.3 ± 2.3 mV, P < 0.05; bipolar: 0.62 ± 0.45 vs. 1.03 ± 0.60 mV, P < 0.05). The targeted DPs were still present in 12 patients after successful elimination of the ectopies. Discrete potentials were not present in seven controls. Discrete potentials and related low-voltage regions were common in idiopathic outflow tract ventricular arrhythmias. Discrete potential- and substrate-guided ablation strategy will help to reduce the recurrence of idiopathic outflow tract arrhythmias.

Estrogen replacement therapy for idiopathic outflow tract ventricular arrhythmias: A potential therapeutic approach

Idiopathic outflow tract ventricular arrhythmias (IOTVA), including left and right ventricular outflow tract, are dued to cyclic adenosine monophosphate (cAMP)-mediated calcium-dependent delayed after depolarizations. A growing body of evidence suggests that the changes of sex hormone levels and gender differences may affect ventricular repolarization and be associated with the occurrence of ventricular arrhythmias. Recent studies showed that the level of estradiol in the IOTVA male patients decreased significantly and the count of ventricular arrhythmias was significantly negatively correlated with the level of estradiol in male patients with IOTVA. Meanwhile, estrogen replacement therapy could inhibit significantly the count of ventricular arrhythmias in the postmenopausal patients with IOTVA. In conclusion, estrogen replacement therapy may be a potential therapeutic approach for IOTVA besides postmenopausal patients.

Effect of oestrogen replacement therapy on idiopathic outflow tract ventricular arrhythmias in postmenopausal women

Sex hormones and gender differences are associated with the occurrence of ventricular arrhythmias. To investigate the relationship between sex hormones and idiopathic outflow tract ventricular arrhythmias (IOTVA), and the effect of oestrogen replacement therapy on IOTVA, in postmenopausal female patients. Plasma sex hormone concentrations and ventricular arrhythmia counts were estimated in postmenopausal patients with IOTVA and control postmenopausal women. The effect of oestrogen replacement therapy on IOTVA was observed in postmenopausal patients with IOTVA. The concentration of oestradiol in postmenopausal patients with IOTVA was significantly lower than that in control postmenopausal women (8.4 ± 3.4 vs 36.9 ± 12.8pg/mL, respectively; P<0.001). The ventricular arrhythmia count in postmenopausal patients with IOTVA was significantly higher than that in controls (10,171 ± 6091 vs 209 ± 468 counts/24 hours, respectively; P<0.001). After 3 months of oestrogen replacement therapy, the ventricular arrhythmia count was significantly lower than that before therapy (3958 ± 1972 vs 10171 ± 6091 counts/24 hours, respectively; P<0.001). This study showed that the concentration of oestradiol was lower in postmenopausal patients with IOTVA than in control postmenopausal women, and that oestrogen replacement therapy can inhibit effectively the genesis of IOTVA.

Novel Transitional Zone Index Allows More Accurate Differentiation between Idiopathic Right Ventricular Outflow Tract and Aortic Sinus Cusp Ventricular Arrhythmias

Background: Although several ECG algorithms have been proposed for differentiating the origins of outflow tract ventricular arrhythmia (OT-VA), their accuracy is still limited in cases with cardiac rotation.Objective: The purpose of this study was to assess whether a novel “cardiac rotation-corrected” transitional zone (TZ) index would be a useful marker for differentiating right ventricular outflow tract (RVOT) origin from aortic sinus cusp (ASC) origin.Methods: Surface ECGs of OT-VAs with left bundle branch block morphology and inferior axis in 112 patients who were successfully ablated in the RVOT (n=87) or the ASC (n=25) were analyzed. According to the site of R-wave transition, TZ score was graded with 0.5-point increments (e.g. V2=2-point, V3–V4=3.5-point, V5=5-point) and TZ index was defined as follows: TZ score of OT-VA minus TZ score of sinus beat.Results: The TZ index was significantly lower in the ASC origin than in the RVOT origin (−1.2±0.9 vs. 0.3±0.7, p<0.0001). A cutoff value of the TZ index <0 predicted the ASC origin with 88% sensitivity and 82% specificity. The previously reported R-wave duration index ≥50% had a high specificity of 85% but a low sensitivity of 44%, and R/S-wave amplitude index ≥30% had 68% sensitivity and 79% specificity. The area under the curve by receiver operating characteristic curve analysis was 0.90 for the TZ index, which was significantly higher than the R-wave duration index and R/S-wave amplitude index of 0.74 and 0.76, respectively.Conclusion: This novel TZ index can be a more useful marker for differentiating RVOT origin from ASC origin.

Relationship between sex hormones and idiopathic outflow tract ventricular arrhythmias in adult male patients

Sex hormones and gender differences have been reported to be associated with the occurrences of ventricular arrhythmias. This study investigated the relationship between sex hormones and idiopathic outflow tract ventricular arrhythmias (IOTVA) in adult male patients. Serum sex hormonal levels, which include testosterone, estradiol, and progestogen, were measured by using commercially prepared immunoassay kits. The average count of premature ventricular contractions (PVCs) (number/24h) was assessed by 72h electrocardiographic monitoring. No differences were found in the levels of testosterone and progestogen between the IOTVA male patients and the control males (both P>0.05). However, the level of estradiol in the IOTVA male patients was significantly lower than that in the control males (P<0.05). A significant negative correlation was observed between the number of PVCs and the level of estradiol in the IOTVA male patients (r=0.702, P<0.05). The current study suggested that IOTVA might be associated with the reduction of estradiol level in adult male patients.

Frequency of Spontaneous and Inducible Atrioventricular Nodal Reentry Tachycardia in Patients with Idiopathic Outflow Tract Ventricular Arrhythmias

We sought to assess the frequency of spontaneous or inducible atrioventricular nodal reentry tachycardia (AVNRT) in patients referred for radiofrequency ablation (RFA) of idiopathic outflow tract ventricular arrhythmias. In patients with no obvious heart disease, AVNRT and outflow tract ventricular tachycardia (VT) are the most frequently encountered supraventricular and ventricular tachycardias, respectively. An increased coexistence of the two arrhythmias has been recently suggested. In 68 consecutive patients referred for RFA of an idiopathic ventricular outflow tract arrhythmia, a stimulation protocol including repeated bursts of rapid atrial pacing, up to triple atrial extrastimuli during sinus rhythm and rapid ventricular pacing was performed before and after isoproterenol infusion following RFA of the ventricular arrhythmia. In patients with inducible AVNRT, RFA of the slow pathway was performed. Of the 68 study patients, 17 (25%) had either spontaneous AVNRT documented prior to RFA of the ventricular arrhythmia (n = 4) or inducible AVNRT at the time of RFA of the ventricular arrhythmia (n = 13). AVNRT was induced by atrial pacing in 15 (88%) of 17 patients: in 3 patients without isoproterenol and in 12 patients during isoproterenol infusion. Uncomplicated RFA of the slow pathway was successfully achieved in all patients with inducible AVNRT. Spontaneous or inducible AVNRT is relatively common in patients with idiopathic outflow tract ventricular arrhythmias. Atrial stimulation, especially when performed after isoproterenol infusion plays a major role in AVNRT inducibility. Although we performed RFA of the slow pathway in patients with inducible AVNRT and no prior tachycardia documentation, the question whether this is mandatory remains unsettled.