QRS characteristics fail to reliably identify ventricular tachycardias that require epicardial ablation in ischemic heart disease

Criteria for Epicardial Origin in Ischemic VT. Objectives: We tested proposed algorithms for idiopathic and nonischemic tachycardias for their ability to identify epicardial LV‐VT origins. Backgroud: Several ECG features have been reported to identify epicardial origins for left ventricular tachycardias (LV‐VTs) in the absence of myocardial infarction. Only limited data exist in postinfarction patients. Methods: The QRS features of 24 VTs that were ablated from the epicardium and 39 left ventricular VTs ablated from the endocardium were retrospectively analyzed for various 12‐lead ECG features previously reported. Results: No ECG feature consistently predicted an epicardial LV‐VT origin in infarct‐related tachycardias, with epicardial VTs showing slightly longer QRS durations (189 ± 32 ms in epicardial vs 179 ± 37 ms in endocardial, P = 0.28). Pseudo‐delta duration was 38 ± 27 versus 47 ± 27 ms (P = 0.2), intrinsicoid deflection time 93 ± 35 versus 86 ± 32 ms (P = 0.4), shortest RS 97 ± 38 versus 99 ± 32 ms (P = 0.77), and median deflection index 0.82 ± 0.25 versus 0.87 ± 0.22 (P = 0.43). The finding of a Q wave in lead I and the absence of a Q wave in the inferior leads failed to predict an epicardial origin in superior LV‐VT sites. Q waves in any inferior lead and aVR/aVL‐ratio<1 were not specific for an epicardial origin in inferior sites (all P = ns). Furthermore, all inferior LV‐VTs showed a Q wave in the inferior leads which correlated with pre‐existing Q‐waves in sinus rhythm (P = 0.045). Conclusion : Proposed 12‐lead ECG features for differentiation of epicardial versus endocardial sites for nonischemic LV‐VTs do not reliably identify VTs that require ablation from the epicardium. Endocardial mapping should be the first approach to catheter ablation for VTs in patients with ischemic heart disease. (J Cardiovasc Electrophysiol, Vol. 23, pp. 188‐193, February 2012)     

Electrocardiographic characteristics of repetitive monomorphic right ventricular tachycardia originating near the His-bundle

INTRODUCTION: Most idiopathic nonreentrant ventricular tachycardia (VT) and ventricular premature contractions (VPCs) arise from the right or left ventricular outflow tract (OT). However, some right ventricular (RV) VT/VPCs originate near the His-bundle region. The aim of this study was to investigate ECG characteristics of VT/VPCs originating near the His-bundle in comparison with right ventricular outflow tract (RVOT)-VT/VPCs. METHODS AND RESULTS: Ninety RV-VT/VPC patients underwent catheter mapping and radiofrequency ablation. ECG variables were compared between VT/VPCs originating from the RVOT and near the His-bundle. Ten patients had foci near the His-bundle (HIS group), with the His-bundle local ventricular electrogram preceding the QRS onset by 15-35 msec (mean: 22 msec) and His-bundle pacing produced a nearly identical ECG to clinical VT/VPCs. The HIS group R wave amplitude in the inferior leads (lead III: 1.0 +/- 0.6 mV) was significantly lower than that of the RVOT group (1.7 +/- 0.4 mV, P < 0.05). An R wave in aVL was present in 6 of 10 HIS group patients, while almost all RVOT group patients had a QS pattern in aVL. Lead I in HIS group exhibited significantly taller R wave amplitudes than RVOT group. HIS group QRS duration in the inferior leads was shorter than that of the RVOT group. Eight of 10 HIS group patients exhibited a QS pattern in lead V1 compared to 14 of 81 RVOT group patients. HIS group had larger R wave amplitudes in leads V5 and V6 than RVOT group. CONCLUSION: VT/VPCs originating near the His-bundle have distinctive ECG characteristics. Knowledge of the characteristic QRS morphology may facilitate catheter mapping and successful ablation.     

Electrocardiographic predictors of failure and recurrence in patients with idiopathic right ventricular outflow tract tachycardia and ectopy who underwent radiofrequency catheter ablation

This study reports new electrocardiographic (ECG) predictors of radiofrequency catheter ablation failure and recurrence in idiopathic right ventricular outflow tract (RVOT) ventricular tachycardia (VT) or ectopy based on 91 consecutive patients. Procedural success and failure rates were 85% (77/91) and 15% (14/91), respectively. Twenty three percent (18/77) had recurrence during the follow-up period of 1 to 120 months (mean 56 +/- 31 months). Baseline RVOT VT/ectopy on 12-lead ECG taken prior to ablation from 91 patients were retrospectively analyzed. Ablation performed with RVOT ectopy (isolated ectopies, bigeminy, trigeminy, or couplets) as template arrhythmia was more likely to fail (30% vs. 8%, P =.02) as opposed to RVOT VT (sustained or nonsustained). VT/ectopy-QRS morphology variation was more observed in failed ablations (36% vs. 7%, P =.001). Significantly wider mean VT/ectopy QRS in leads I, II, AVR, V2, V3, V5, and V6 were noted in failed ablation group. Mean R wave amplitude reached statistical significance only in lead II (22.0 +/- 5.1 mV for failed vs. 17.8 +/- 5.2 mV for successful outcomes; P =.009). QRS morphologic variation (47% vs. 16%; P =.009) was the only statistically significant ECG to be more common in patients with arrhythmia recurrence. In conclusion, ablation with ectopy over VT as template arrhythmia, presence of QRS morphologic variation, wider mean QRS width, and taller mean R-wave amplitude in lead II were identified ECG predictors of failed RVOT VT/Ectopy ablation. The only ECG predictor of recurrence was the presence of RVOT VT or ectopy QRS morphologic variation.     

Electrocardiographic features of failed and recurrent right ventricular outflow tract catheter ablation of idiopathic ventricular arrhythmias

1 Introduction

Various ECG algorithms have been proposed to identify the origin of idiopathic outflow tract (OT)‐ventricular arrhythmia (VA). However, electrocardiographic features of failed and recurrent right ventricular outflow tract (RVOT) ablation of idiopathic OT‐VAs have not been clearly elucidated.

2 Methods and results

A total of 264 consecutive patients (mean age: 44.0 ± 13.0 years, 96 male) undergoing RVOT ablation for OT‐VAs with a transition ≥V₃, including 241 patients (91.6%) with initially successful procedures and 23 patients (8.4%) with failed ablation. Detailed clinical characteristics and ECG features were analyzed and compared between the two groups. VAs with failed RVOT ablation had larger peak deflection index (PDI), longer V₂ R wave duration (V₂Rd), smaller V₂ S wave amplitude, higher R/S ratio in V₂, higher V₃ R wave amplitude, and larger V₂ transition ratio than those with successful ablation. Multivariate analysis demonstrated that PDI, V₂Rd, V₂ transition ratio, and pacemapping score acquired during mapping independently predicted failed ablation (P  =  0.01, P  =  0.01, P  =  0.01, and P < 0.001, respectively). In 31 recurrent cases (12.8%) after initially successful ablation, multivariate Cox regression analysis showed that only the earliest activation time acquired during mapping predicted the recurrences after successful ablation (P  =  0.001). The recurrent cases displayed different ECG features comparing with those with failed ablation.

3 Conclusion

The electrocardiographic features of failed RVOT ablation of idiopathic OT‐VAs with a transition ≥V₃ were characterized by PDI, V₂Rd, V₂ transition ratio, and pacemapping score acquired during mapping, unlike the recurrent RVOT ablation.     

The morphology changes in limb leads after ablation of verapamil-sensitive idiopathic left ventricular tachycardia and their correlation with recurrence

Objectives: This study was designed to explore the morphology changes in limb leads of ECGs after successful ablation of verapamil sensitive idiopathic left ventricular tachycardia (ILVT) and their correlation with tachycardia recurrence.
Methods: Between January 2001 and December 2006, 116 patients who underwent successful ablation of ILVT were included in the study. Twelve-lead surface ECG recordings during sinus rhythm were obtained in all patients before and after ablation to compare morphology changes in limb leads.
Results: The ECG morphology changes after ablation were divided into two categories: one with new or deepening Q wave in inferior leads and/or disappearance of Q wave in leads I and aVL, and the other without change. The changes in any Lead II, III, or aVF after ablation occurred significantly more in patients without recurrence of ventricular tachycardia (VT) (P < 0.0001, 0.002, and 0.0001, respectively). The patients with recurrence of VT tended to have no ECG changes, compared with those without recurrence of VT (P = 0.009). The sensitivity of leads II, III, and aVF changes in predicting nonrecurrence VT were 66.7%, 78.7%, and 79.6%, specificity were 100%, 75%, and 87.5%, and nonrecurrence predictive value of 100%, 97.7%, and 98.9%, respectively. When inferior leads changes were combined, they could predict all nonrecurrence patients with 100% specificity.
Conclusions: Successful radiofrequency ablation of ILVT could result in morphology changes in limb leads of ECG, especially in inferior leads. The combined changes in inferior leads can be used as an effective endpoint in ablation of this ILVT.     

致心律失常性右室心肌病患者的心电图aVR导联特征

目的探讨致心律失常性右室心肌病(ARVC)患者的心电图aVR导联特征。方法分析60例ARVC患者的体表心电图aVR导联的波形特征,并与71例正常人心电图作对照。结果 ARVC患者aVR导联呈QR型、rSr型及rSR型的比例明显高于对照组(分别为23.3%vs 5.6%,26.7%vs 8.5%,6.7%vs 0,P<0.01);而呈Qr型者所占的比例明显低于对照组(13.3%vs 46.5%,P<0.01),与对照组相比ARVC患者aVR导联呈碎裂QRS波明显增多(33.3%vs 8.5%,P<0.01);ARVC患者aVR导联Q波或S波振幅减小(0.42±0.26 mV vs 0.62±0.25 mV,P<0.01);且R/S比值明显增大(0.52±0.67 vs 0.21±0.23,P<0.01)。结论 ARVC患者的体表心电图aVR导联特征性改变可作为ARVC的诊断线索。     

Identification of unusual reentry circuit sites of nonischemic ventricular outflow tract tachycardia

Identification of Ventricular Outflow Tract Tachycardia. Background: Reentrant ventricular outflow tract (OT) tachycardia is rare in patients with nonischemic heart disease. The mechanism of ventricular tachycardia (VT) arising from the region of the aortic sinus of Valsalva (ASOV) is usually focal, rather than reentrant. Consequently, less is known about reentrant circuits in the OT and the aortic sinuses. The purpose of this study was to evaluate existence of reentry circuits in these areas using entrainment mapping techniques. Methods: We performed electrophysiological study in 51 consecutive patients with idiopathic or nonischemic symptomatic VT arising from the OT. Six of these patients were found to have VT of reentrant mechanism with 8 VT morphologies. Entrainment mapping, electroanatomical mapping (in 2 patients), and radiofrequency catheter ablation were performed. Results: Pacing entrained the VT at 93 sites, 52 of which were determined to be in the reentry circuit based on matching of the postpacing interval and VT cycle length. Of the reentry circuit sites, 6 were in the aortic sinus, 43 were below the aortic valve, and 3 were in the right OT below the pulmonary valve. Classification of reentry circuit sites identified 7 as exit, 1 as central‐proximal, 19 as inner loop, and 25 as outer loop sites. Catheter ablation terminated VT at 4 of the 6 aortic sinus sites and 4 of the 46 OT sites (P = 0.0006). Conclusions: We definitively demonstrated involvement of the ASOV in OT reentrant tachycardia using entrainment mapping. It may be useful for successful VT ablation to identify reentry circuit localization. (J Cardiovasc Electrophysiol, Vol. 23, pp. 179‐187, February 2012)     

Electrocardiographic patterns of superior right ventricular outflow tract tachycardias: distinguishing septal and free-wall sites of origin

INTRODUCTION: The superior right ventricular outflow tract (RVOT) septum and free wall are common locations of origin for outflow tract ventricular tachycardias (VT). We hypothesized that (1) unique ECG morphologies of pace maps from septal and free-wall sites in the superior RVOT could be identified using magnetic electroanatomic mapping for accurate anatomical localization; and (2) this ECG information could help facilitate pace mapping and accurate VT localization. METHODS AND RESULTS: In 14 patients with structurally normal hearts who were undergoing ablation for outflow tract VT, a detailed magnetic electroanatomic map of RVOT was constructed in sinus rhythm, then pace mapping was performed from anterior, mid, and posterior sites along the septum and free wall of the superior RVOT. Pace maps were analyzed for ECG morphologies in limb leads and transition patterns in precordial leads. Monophasic R waves in inferior leads for septal sites were taller (1.7 +/- 0.4 mV vs 1.1 +/- 0.3 mV; P < 0.01) and narrower (158 +/- 21 msec vs 168 +/- 15 msec; P < 0.01) compared with free-wall sites; lacked "notching" (28.6% vs 95.2%; P < 0.05); and showed early precordial transition (by lead V4; 78.6% vs 4.8%; P < 0.05). A positive R wave in lead I also distinguished posterior from anterior septal and free-wall sites. Based on QRS morphology in limb leads and precordial transition pattern (early vs late), in a retrospective analysis, a blinded reviewer was able to accurately localize the site of origin of clinical arrhythmia (the successful ablation site on the magnetic electroanatomic map) in 25 of 28 patients (90%) with superior RVOT VT. CONCLUSION: Pace maps in the superior RVOT region manifest site-dependent ECG morphologies that can help in differentiating free-wall from septal locations and posterior from anterior locations. Despite overlap in QRS amplitude and duration, in the majority of patients a combination of ECG features can serve as a useful template in predicting accurately the site of origin of clinical arrhythmias arising from this region.     

Prognostic Significance of T‐Wave Amplitude in Lead aVR in Heart Failure Patients with Narrow QRS Complexes

Background: Prolonged duration of the QRS complex is a prognostic marker in patients with heart failure (HF), whereas electrocadiographic markers in HF with narrow QRS complex remain unclear. We evaluated the prognostic value of the T‐wave amplitude in lead aVR in HF patients with narrow QRS complexes. Methods: We examined 331 patients who were admitted to our hospital for worsening HF (68 ± 15 years, mean ± standard deviation) from January 2000 to October 2004 who had sinus rhythm and QRS complex <120 ms. The patients were categorized into three groups according to the peak T‐wave amplitude from baseline in lead aVR: negative (<–0.1 mV; n = 209, 63%), flat (–0.1–0.1 mV; n = 64, 19%), and positive (>0.1 mV; n = 58, 18%). Results: During a mean follow‐up of 33 months, 113 (34%) patients had all‐cause death, the primary end point. After adjusting for clinical covariates, flat T wave (hazard ratio [HR] 1.86, 95% confidence interval [CI] 1.42–2.46), and positive T wave (HR 6.76, 95% CI 3.92–11.8) were independent predictors of mortality, when negative T wave was considered a reference. Conclusions: As the peak T‐wave amplitude in lead aVR becomes less negative, there was a progressive increase in mortality. The T wave in lead aVR provides prognostic information for risk stratification in HF patients with narrow QRS complexes. Ann Noninvasive Electrocardiol 2011;16(3):250–257     

Evaluation and management of ventricular outflow tract tachycardias

Ventricular tachycardia (VT) arising from the right or left ventricular outflow tract (OT) is a recognized arrhythmia in individuals with structurally normal hearts. Treatment options for OTVT include medications, ablation and, rarely, an implantable cardioverter defibrillator (ICD). In the past few years ablation techniques have developed to the point where most OTVTs can be successfully ablated. However, a percentage of cases have remained where ablation is unsuccessful. Some of these cases may represent an epicardial focus of the VT. Several approaches to epicardial VT ablation have been described. We recently described a LVOT-VT variant, which may be epicardial in nature, in a group of patients in whom prior ablation attempts had failed. A trans-aortic ablation approach to outflow tract VT was successful in these patients.     

Relation between Beat‐to‐Beat QT Interval Variability and T‐Wave Amplitude in Healthy Subjects

Objectives: Elevated beat‐to‐beat QT interval variability (QTV) has been associated with increased cardiovascular morbidity and mortality.The aim of this study was to investigate interlead differences in beat‐to‐beat QTV of 12‐lead ECG and its relationship with the T wave amplitude. Methods: Short‐term 12‐lead ECGs of 72 healthy subjects (17 f, 38 ± 14 years; 55 m, 39 ± 13 years) were studied. Beat‐to‐beat QT intervals were extracted separately for each lead using a template matching algorithm. We calculated the standard deviation of beat‐to‐beat QT intervals as a marker of QTV as well as interlead correlation coefficients. In addition, we measured the median T‐wave amplitude in each lead. Results: There was a significant difference in the standard deviation of beat‐to‐beat QT intervals between leads (minimum: lead V₃ (2.58 ± 1.36 ms), maximum: lead III (7.2 ± 6.4 ms), ANOVA: P < 0.0001). Single measure intraclass correlation coefficients of beat‐to‐beat QT intervals were 0.27 ± 0.18. Interlead correlation coefficients varied between 0.08 ± 0.33 for lead III and lead V₁ and 0.88 ± 0.09 for lead II and lead aVR. QTV was negatively correlated with the T‐wave amplitude (r =–0.62, P < 0.0001). There was no significant affect of mean heart rate, age or gender on QT variability (ANOVA: P > 0.05). Conclusions: QTV varies considerably between leads in magnitude as well as temporal patterns. QTV is increased when the T wave is small.     

Ultra High‐Density Multipolar Mapping With Double Ventricular Access: A Novel Technique for Ablation of Ventricular Tachycardia

Ultra High‐Density Multipolar Mapping With Double Ventricular Access . Background: Analogous to the use of circular loop catheters to guide ablation around the pulmonary veins, it may be advantageous to use a multipolar catheter in the ventricle for rapid mapping and to guide ablation. We describe a technique using double access into the left ventricle for multipolar electroanatomic mapping and ablation of scar‐mediated ventricular tachycardia (VT). Methods: Double access into the left ventricle was obtained via transseptal technique. Endocardial mapping was performed via the first transseptal sheath using a steerable duodecapolar catheter. Higher density mapping was performed in areas of dense scar (<0.5 mV) and border zone (0.5–1.5 mV). All late potentials (LPs) observed on the 20 poles were tagged and pacemapping was performed at these sites for comparison with the clinical or induced VT 12‐lead template. If VT was hemodynamically tolerated, entrainment mapping was attempted at sites demonstrating diastolic activity. Ablation was performed through the second transseptal sheath with an open‐irrigated catheter at target sites identified by LPs, pacemapping, and/or entrainment on the duodecapolar catheter. Results: Seventeen patients (88% ischemic cardiomyopathy) underwent electroanatomic mapping and ablation with double transseptal access. The mean number of endocardial mapping points was 819 ± 357 with an average mapping time of 31 ± 7 minutes. The mean number of VTs induced was 2.8 ± 1.6, mean cycle length 418 ms ± 101. LPs were seen in all patients during endocardial mapping with the duodecapolar catheter. Good (56%) and perfect (44%) pacemaps were seen in all patients when performed. Concealed entrainment, guided by the earliest diastolic activity seen on the duodecapolar catheter, was demonstrated in 4 patients (24%). Acute success was achieved in 94% of patients with complete success in 47% and partial success in 47%. The intermediate success rate (free of VT recurrence) was 69%, with an average follow‐up of 8 ± 3 months. Conclusion: Mapping and ablation of scar‐mediated VT using a multipolar catheter results in ultra high‐density delineation of the left ventricular substrate. A novel double ventricular access strategy has the potential to facilitate identification of LPs, pacemapping, and entrainment mapping. (J Cardiovasc Electrophysiol, Vol. 22, pp. 49‐56, January 2011)     

起源于左主动脉窦的室性心律失常的心电生理特点和消融治疗

目的报道21例起源于左主动脉窦的室性心律失常的心电生理特征和射频消融疗效。方法分析术前体表心电图(ECG)和Holter心电图室性早搏(VPB)或室性心动过速(VT)的形态特点,测量V1导联r波振幅和时限,计算r与QRS波的振幅和时限比值。术中在自发VPB或VT时标测主动脉窦,以局部室波最早部位放电消融,并进行冠状动脉造影,测量消融靶点距左冠状动脉口的距离。结果21例均有频发VPB,8例有反复短阵VT。VPB或VT在Ⅱ、Ⅲ、aVF导联为高大R波,V1导联r波振幅为QRS波的1/3或以上,r波时限87.5±9.5 m s,为QRS波时限的1/2以上。V3导联多为R s形,V5、V6导联无S波。有效消融靶点局部电图室波明显超前ECG的QRS波(36.2±12.2 m s),距左冠状动脉口部1 cm左右。有效靶点放电2~8 s VPB消失或VT终止。结论起源于左主动脉窦的VPB或VT其Ⅱ、Ⅲ、aVF导联为高大R波,V1导联r波振幅高(≥1/3QRS波),时限宽(≥1/2QRS波);主动脉窦激动顺序标测可安全有效地指导消融治疗。     

Electrocardiographic diagnosis of atrial infarction in patients with acute inferior ST‐segment elevation myocardial infarction

Background

Patients with atrial myocardial infarction (ATMI) have frequent cardiac and noncardiac complications. However, ATMI is uncommonly diagnosed because of its nonspecific ECG changes. Our objective was to analyze the ECG characteristics of ATMI in patients with inferior STEMI.

Hypothesis

Electrocardiographic P wave parameters can help in diagnosis of ATMI.

Methods

We evaluated 932 patients who underwent coronary angiography and recruited 39 patients with ATMI and 33 patients without ATMI with inferior STEMI for a retrospective study. Twelve‐lead ECGs were obtained to measure P‐wave parameters in diagnosis of ATMI. P‐wave parameters and PR‐segment displacement were compared in patients with and without ATMI.

Results

In inferior leads, PWD and PWDisp were significantly longer in the ATMI group than in the non‐ATMI group (limb lead II, 109.79 ±15.51 ms and 86.65 ±5.02 ms, respectively; P < 0.001; limb lead III, 108.31 ±12.51 ms and 85.27 ±7.47 ms, P < 0.001; aVF, 106.49 ±13.68 ms and 83.01 ±7.89 ms, P < 0.001; PWDisp, 41.67 ±10.72 ms and 25.18 ±5.17 ms, P < 0.001). By contrast, PWA was significantly lower in the ATMI group than in the non‐ATMI group (limb lead II, 0.96 ±0.18 mV and 1.39 ±0.22 mV, respectively; P < 0.001; limb lead III, 0.90 ±0.11 and 1.21 ±0.23, P < 0.001; aVF, 0.88 ±0.17 and 1.26 ±0.28, P < 0.001). PR‐segment displacement was found in 8 (20.5%) patients with ATMI. A PWD ≥95.5 ms in lead DII diagnosed ATMI with a higher sensitivity and specificity (90%, 94%) than did PWA or PWDisp.

Conclusions

This study suggests P‐wave parameters might be considered ECG findings in diagnosis of ATMI in patients with inferior STEMI.     

Postextrasystolic Repolarization Abnormalities in ST‐U Segment in Patients with Ventricular Arrhythmias

Background: Changes in U‐wave amplitude after premature ventricular contractions (PVC) are known as prognostic markers in the long QT syndrome dependent on bradycardia. The purpose of the study was to find correlation between postextrasystolic ST‐U segment changes and a history of sustained ventricular tachycardia or ventricular fibrillation (VT/VF). Methods: The ST‐U segment configurations were taken from the 24‐hour ambulatory ECG. The comparison of the morphology of these segments was performed between sinus beats preceding PVC's and first postextrasystolic beats. Population: Two groups of patients were evaluated: 1) 32 patients with VT/VF history (VT/VF group), and 2) 36 patients with potentially malignant arrhythmia (structural heart disease with frequent PVCs and/or nonsustained VT‐nsVT) tnon‐VT/VF group). Results: We found T‐wave changes in 8 patients (25%) from the VT/VF group and in 12 patients (33.3%) from the nonVT/VF group (P = NS) and U‐wave changes in 13 patients (40.6%) and 3 patients (8.3%), respectively (P < 0.05). Other ECG indexes related to PVC's were also considered: RR interval, coupling interval (Cl), prematurity index (Pl), and postextrasystolic pause (PP). The analysis of these ECG indices revealed, when compared with patients without T‐U‐wave changes, that the occurrence of U‐wave changes was significantly related to longer RR interval of the sinus rhythm preceding PVC: 1025 ± 211 vs 918 ± 200 ms (P < 0.05). The prematurity index was lowest in patients with U‐wave changes: 0.54 ± 0.12 vs 0.65 ± 0.16 (P < 0.01) while postextrasystolic pauses leading to the postextrasystolic U‐wave changes were significantly longer: 1383 ± 223 vs 1130 ± 247 ms (P < 0.001). Cl did not differentiate patients: 556 ± 108 vs 584 ± 117 ms (P = NS). Conclusions: Postextrasystolic changes in ST‐U segment configuration are dependent on bradycardia, low prematurity index of the PVC, and the lengthening of the postextrasystolic pause. U‐wave changes more frequently appeared in patients with malignant arrhythmias. Follow‐up study is needed to assess if they might be predictive for the occurrence or reoccurrence of arrhythmic episodes. A.N.E. 2002;7(1):17–21     

Electrocardiographic and electrophysiologic characteristics of ventricular tachycardia originating within the pulmonary artery

OBJECTIVES: We investigated the electrocardiographic (ECG) and electrophysiologic characteristics of ventricular tachycardia (VT) originating within the pulmonary artery (PA). BACKGROUND: Radiofrequency catheter ablation (RFCA) is routinely applied to the endocardial surface of the right ventricular outflow tract (RVOT) in patients with idiopathic VT of left bundle branch block morphology. It was recently reported that this arrhythmia may originate within the PA. METHODS: Activation mapping and ECG analysis were performed in 24 patients whose VTs or ventricular premature contractions (VPCs) were successfully ablated within the PA (PA group) and in 48 patients whose VTs or VPCs were successfully ablated from the endocardial surface of the RVOT (RV-end-OT group). RESULTS: R-wave amplitudes on inferior ECG leads, aVL/aVR ratio of Q-wave amplitude, and R/S ratio on lead V(2) were significantly larger in the PA group than in the RV-end-OT group. On intracardiac electrograms, atrial potentials were more frequently recorded in the PA group than in the RV-end-OT group (58% vs. 12%; p < 0.01). The amplitude of local ventricular potentials recorded during sinus rhythm within the PA was significantly lower than that recorded from the RV-end-OT (0.62 +/- 0.56 mV vs. 1.55 +/- 0.88 mV; p < 0.01). CONCLUSIONS: Ventricular tachycardia originating within the PA has different electrocardiographic and electrophysiologic characteristics from that originating from the RV-end-OT. When mapping the RVOT area, the catheter may be located within the PA if a low-voltage atrial or local ventricular potential of <1-mV amplitude is recorded. Heightened attention must be paid if RFCA is required within the PA.     

Comparison of Electrocardiographic Repolarization Patterns between Hypogonad Males and Normal Subjects

Background: There is a significant difference in repolarization on the surface ECG between men and women. The effect of testosterone on repolarization of myocardium may provide a basis for the physiological and pathophysiological importance of these distinctions between sexes. The purpose of this study is to compare the repolarization characteristics of surface ECG in patients with secondary hypogonadotropic hypogonadism to those of healthy men and women. Methods: The study consisted of 45 consecutive patients with the diagnosis of secondary hypogonadotropic hypogonadism (study group) and age‐, weight‐ and height‐matched normal healthy men (n = 35) and women (n = 39) (control group). 12‐lead ECG recordings were obtained and electronic calipers were used for measurements of ECG repolarization variables. ECG variables were compared with those of control groups. Results: J point amplitude (0.12 ± 0.07 vs 0.05 ± 0.05 mV, respectively), T max (0.74 ± 0.28 vs 0.60 ± 0.27 mV, respectively), T wave area (81 ± 36 vs 60 ± 29 mVms, respectively) and T wave descending time (93 ± 16 vs 85 ± 15 ms, respectively) were significantly higher in healthy subjects than hypogonadal men. In comparison with those of healthy women, hypogonad males have higher J point (0.05 ± 0.05 vs 0.02 ± 0.02 mV), taller T wave (0.60 ± 0.27 vs 0.34 ± 0.13 mV), consequently less T wave area (60 ± 29 vs 34 ± 16 mVms), ascending (62 ± 18 vs 53 ± 11) and descending angle (67 ± 17 vs 55 ± 12). Corrected QT was not different among groups. Conclusions: Testosterone deprivation in hypogonadotropic hypogonadism attenuates J point, T wave peak, T wave area, and T wave descending time, but does not reach to the level of those in healthy women. Testosterone has no effect on QT interval in this group of age. Hormone replacement therapy of these patients will provide informative contribution.     

Identification of distinct electrocardiographic patterns from the basal left ventricle: distinguishing medial and lateral sites of origin in patients with idiopathic ventricular tachycardia.

BACKGROUND: Idiopathic ventricular tachycardias (IVTs) can originate from the basal left ventricle (LV). OBJECTIVE: To determine if using magnetic electroanatomic mapping (MEAM) for accurate localization (1) unique ECG morphologies on pace maps from medial and lateral sites in basal LV could be identified and (2) this ECG information would facilitate VT localization. METHODS: In 12 patients with structurally normal hearts undergoing ablation for IVT, detailed MEAM of LV was constructed in sinus rhythm and pace-mapping was done from the septal-parahisian (S-P) region, aortomitral continuity (AMC), and superior, superolateral, and lateral mitral annular (MA) locations. Pace maps were analyzed for ECG morphologies in limb leads and transition patterns in precordial leads. RESULTS: Medial pacing sites (S-P and AMC) compared with lateral sites (superolateral and lateral MA) demonstrated narrower QRS complexes (134 +/- 24 msec vs. 182 +/- 18 msec; P < .05) with initial negative forces in lead V1 and predominantly positive forces in lead I (amplitude 0.59 +/- 0.27 mV vs. 0.16 +/- 0.34 mV; P < .05). The ratio of QRS complexes in leads II and III was >1 for all (12 of 12) S-P pace maps and 11 of 12 lateral MA pace maps but remained < or =1 for pace maps from 10 of 12 AMC locations, 11 of 12 superior MA locations, and 10 of 11 superolateral MA locations. Using these ECG criteria, a blinded reviewer was able to accurately localize the site of origin (SOO) of clinical arrhythmia (successful ablation site on MEAM) in 10 of 12 cases (83%) of IVT originating from basal LV. CONCLUSION: Pace maps from basal LV endocardium manifest site-dependent ECG morphologies that can help differentiate medial from lateral locations and can predict the SOO of clinical arrhythmias from this region.     

起源于主动脉窦内反复单形室性心动过速和/或频发室性早搏的心电图特征及射频消融治疗

探讨起源于主动脉窦内的反复单形室性心动过速(简称室速)和/或频发室性早搏(简称室早)的心电图特点和射频消融治疗。分析35例该类患者的室速和频发室早的心电图、心内电生理检查和射频消融治疗情况。结果:室性心律失常起源于左冠状动脉窦(简称左冠窦)的30例、无冠状动脉窦3例和主动脉根部左冠窦下2例。左冠窦的心电图特点:Ⅰ和aVL导联为rs、rS或QS波形,Ⅱ、Ⅲ和aVF导联为R波形,胸导联R波移行区在V2或V3导联,V5、V6导联为高振幅R波,无S波;V2导联R高度/S高度比值1.29±0.36。主动脉根部左冠窦下起源的心电图特点:和左冠窦起源室性心律失常的心电图特点基本相同,但V5、V6导联有S波。无冠状动脉窦起源的心电图特点:Ⅰ和aVL导联为Rs或R波形,Ⅱ、Ⅲ和aVF导联为R波形,胸导联R波移行区在V3导联。34例消融成功,手术操作时间65~120min,X光曝露时间12~30min。1例出现冠状动脉前降支急性闭塞。随访2~53个月,无复发病例。结论:起源于主动脉窦内的室速和/或频发室早有其独特的心电图表现,射频消融能安全、有效地根治此类心律失常。     

Catheter ablation of ventricular tachycardias using remote magnetic navigation: a consecutive case-control study

Remote Magnetic Navigation for VT Ablation. Background: This study aimed to compare acute and late outcomes of VT ablation using the magnetic navigation system (MNS) to manual techniques (MAN) in patients with (SHD) and without (NSHD) structural heart disease. Methods: Ablation data of 113 consecutive patients (43 SHD, 70 NSHD) with ventricular tachycardia treated with catheter ablation at our center were analyzed. Success rate, complications, procedure, fluoroscopy, and ablation times, and recurrence rates were systematically recorded for all patients. Results: A total of 72 patients were included in the MNS group and 41 patients were included in the MAN group. Patient age, gender, and right ventricular and left ventricular VT were equally distributed. Acute success was achieved in 59 patients in the MNS group (82%) versus 27 (66%) patients in the MAN group (P = 0.046). Overall procedural time (177 ± 79 vs 232 ± 99 minutes, P < 0.01) and mean patient fluoroscopy time (27 ± 19 vs 56 ± 32 minutes, P < 0.001) were all significantly lower using MNS. In NSHD pts, higher acute success was achieved with MNS (83,7% vs 61.9%, P = 0.049), with shorter procedure times (151 ± 57 vs 210 ± 96, P = 0.011), whereas in SHD‐VT these were not significantly different. No major complications occurred in the MNS group (0%) versus 1 cardiac tamponade and 1 significantly damaged ICD lead in the MAN group (4.9%, NS). After follow‐up (20 ± 11 vs 20 ± 10 months, NS), VT recurred in 14 pts (23.7%) in the MNS group versus 12 pts (44.4%) in the MAN group (P = 0.047). Conclusions: The use of MNS offers advantages for ablation of NSHD‐VT, while it offers similar efficacy for SHD‐VT. ((J Cardiovasc Electrophysiol, Vol. 23, pp. 948‐954, September 2012)