特发性右室流出道室性早搏触发多形性室性心动过速或心室颤动四例的临床特点

目的报道4例特发性右室流出道(RVOT)室性早搏(PVC)触发多形性室性心动过速/心室颤动(PVT/VF)的临床特点。方法 76例起源于RVOT的VT患者,其中4例为PVC触发PVT/VF,总结4例的临床资料并与另72例有关资料相比较。结果所有4例触发PVT/VF时的PVC与孤立PVC的形态一致,但2种PVC的联律间期发生了明显改变,其改变幅度均≥70 ms,其中2例缩短,2例延长。1例孤立PVC时的联律间期亦不恒定。72例PVC触发的单形VT患者每天PVC次数为15 427±1 109,QT间期为404±15 ms,孤立PVC联律间期为419±22ms。4例PVC触发PVT/VF患者中3例1天的PVC次数与72例PVC触发的单形VT患者平均PVC次数相当。4例患者的QT间期及孤立PVC联律间期与另72例患者相当。而4例PVT/VF的周长均小于280 ms,明显短于72例VT的平均周长(324±59 ms)。72例单形VT患者发生晕厥比率4.1%;4例PVT/VF患者中发生晕厥者2例。采用激动标测和起搏标测证实4例患者PVC均起源于RVOT间隔侧,经射频导管消融PVC取得成功。结论起源于RVOT的PVC触发PVT/VF具有PVC联律间期不恒定及PVT/VF的周长短的临床特征,射频导管消融治疗有效。     

A case of short-coupled variant of torsade de pointes characterized by spatial heterogeneity of action potential duration and its restitution kinetics

A 21-year-old male experienced frequent episodes of polymorphic ventricular tachycardia (PVT) initiated by a closely coupled premature ventricular complex (PVC) in the absence of QT prolongation and structural heart disease. Programmed stimulation at right ventricular apex (RVA), but not at the outflow tract (RVOT), provoked PVT degenerating into ventricular fibrillation (VF). Monophasic action potential duration (MAPD) was significantly shorter at RVA than RVOT. The maximum slope of MAPD restitution was much steeper at RVA than RVOT (1.91 versus 0.50). Such spatial heterogeneities of MAPD and its restitution may facilitate wavebreak and functional reentry predisposing to PVT and VF.     

Electrocardiographic determinants of the polymorphic QRS morphology in idiopathic right ventricular outflow tract tachycardia

Coupling Intervals and Polymorphic QRS Morphologies . Introduction: Premature ventricular contractions (PVCs) arising from the right ventricular outflow tract (RVOT) can trigger polymorphic ventricular tachycardia (PVT) or ventricular fibrillation (VF) in patients with no structural heart disease. We aimed to clarify the ECG determinants of the polymorphic QRS morphology in idiopathic RVOT PVT/VF. Methods and Results: The ECG parameters were compared between 18 patients with idiopathic PVT/VF (PVT‐group) and 21 with monomorphic VT arising from the RVOT (MVT‐group). The coupling interval (CI) of the first VT beat was comparable between the 2 groups. However, the prematurity index (PI) of the first VT beat was smaller in the PVT‐group than in the MVT‐group (P < 0.001). Furthermore, the QT index, defined as the ratio of the CI to the QT interval of the preceding sinus complex, was also smaller for the PVT/VF in the PVT‐group than that for the VT in the MVT‐group (P < 0.01). In the PVT‐group, the CI of the first VT beat was comparable between that of VT and isolated PVCs, but the PI of the first VT beat was shorter for VT than isolated PVCs (P < 0.05). The PI was the only independent determinant of the polymorphic QRS morphology (odd ratio = 2.198; 95% confidence interval = 1.321–3.659; P = 0.002). Conclusion: The smaller PIs of the first VT beat may result in a polymorphic QRS morphology. (Cardiovasc Electrophysiol, Vol. 23, pp. 521‐526, May 2012)     

Spatial dispersion of action potential duration restitution kinetics is associated with induction of ventricular tachycardia/fibrillation in humans

INTRODUCTION: Action potential duration restitution (APDR) plays a role in initiation and maintenance of ventricular tachycardia (VT)/ventricular fibrillation (VF). We hypothesized that the steeply sloped APDR and its spatial heterogeneity contribute to VT/VF inducibility in patients with ventricular arrhythmia. METHOD AND RESULTS: After programmed ventricular stimulation (PVS) for evaluation of clinically documented VT, patients (n = 20, 15 male, age 52.5 +/- 9.5 years) were divided into two groups: inducible sustained VT/VF (IVT, n = 10) and noninducible VT/VF (NVT, n = 10). Data were compared with the corresponding results obtained from normal controls (C, n = 10). Right ventricular (RV) monophasic action potential duration at 90% repolarization (APD90) and ventricular effective refractory period (VERP) in the right ventricular apex (RVA) and right ventricular outflow tract (RVOT) were determined. APDR was acquired by scanning diastole with premature ventricular beats during a pacing cycle length of 600 msec (S1-S2) in all patients and by rapid pacing at the cycle lengths that induced APD alternans in three patients. Maximal slopes (Smax) of the APDR curves and DeltaAPD90 (APD90 at S2 400 ms - APD90 at the shortest S2) were measured. VERP and APD90 at each RV site did not differ among the three groups. Smax obtained by S1-S2 (1.6 +/- 0.6) did not differ from Smax obtained by rapid pacing (1.2 +/- 0.7), with a significant correlation noted between these values (r = 0.92, P < 0.01). The IVT group had a higher spatial dispersion of Smax (Smax at RVOT - Smax at RVA) compared to the C group (P < 0.05), with no difference between the NVT group and the IVT or C groups. The IVT group had a higher spatial dispersion of DeltaAPD90 compared to the NVT and C groups (P < 0.01, respectively). Smax at the RVOT (2.7 +/- 1.9) was steeper than that at the RVA (1.9 +/- 1.2, P < 0.05). Inducibility of sustained VT/VF was greater at the RVOT (83.3%) than at the RVA (50.0%, P < 0.05). CONCLUSION: In patients with ventricular arrhythmia, VT/VF is highly inducible under conditions of greater spatial dispersion of ventricular refractoriness and APDR.     

Frequent Premature Ventricular Complexes Originating from the Right Ventricular Outflow Tract Are Associated with Left Ventricular Dysfunction

Background : Recent case series have shown reversal of left ventricular (LV) dysfunction after catheter ablation of frequent premature ventricular complexes (PVCs) originating from the right ventricular outflow tract (RVOT). We conducted a retrospective study to evaluate the prevalence of patients with frequent RVOT PVCs (≥10 per hour) and LV dysfunction. Methods : RVOT PVC was defined as PVC with left bundle branch block morphology and inferior axis on a 12‐lead ECG. We included patients with frequent RVOT PVCs on 24‐hours Holter monitor who had a recent evaluation of LV function. Patients with structural heart disease, including obstructive coronary artery disease, were excluded. Patients were divided into three groups based on the number of PVCs (<1000/24 hour, 1000–10,000/24 hour, ≥10,000/24 hour), and the prevalence of LV dysfunction was evaluated in each group. Results : Our analysis included 108 patients: 24 patients had <1000PVCs/24 hour, 55 patients had 1000–10,000PVCs/24 hour, and 29 patients had ≥10,000PVCs/24 hour. The prevalence of LV dysfunction was 4%, 12%, and 34%, respectively (P = 0.02). With logistic regression analysis, non‐sustained ventricular tachycardia was an independent predictor of LV dysfunction with odds ratio of 3.6 (1.3–10.1). Conclusion : We demonstrated a significant association between frequent RVOT PVCs and LV dysfunction in patients without structural heart disease.     

Clarifying the arrhythmogenic substrate for Brugada syndrome

The right ventricular outflow tract (RVOT) is considered the arrhythmogenic region that gives rise to Brugada syndrome. To obtain a better understanding of this substrate, we performed electroanatomic mapping of the right ventricle (RV) in patients with Brugada syndrome. The RV was mapped electroanatomically with the CARTO system in 11 patients with asymptomatic Brugada syndrome but in whom ventricular fibrillation was induced by programmed ventricular stimulation, and in 5 control patients. The low voltage zone area (< 1.5 mV) was larger (16.1% versus 7.8%, P < 0.01) and the bipolar electrogram duration was greater (81.6 ± 7.8 ms versus 53.4 ± 5.6 ms, P < 0.01) in the patients with Brugada syndrome versus the control patients; the bipolar electrogram duration was greater in the septal portion and free wall of the RVOT. Our data suggest that regional endocardial conduction slowing based on structural abnormalities exists at the RVOT in Brugada syndrome.     

Long‐Term Mechanical Consequences of Permanent Right Ventricular Pacing: Effect of Pacing Site

Optimal Right Ventricular Pacing Introduction: Long‐term right ventricular apical (RVA) pacing has been associated with adverse effects on left ventricular systolic function; however, the comparative effects of right ventricular outflow tract (RVOT) pacing are unknown. Our aim was therefore to examine the long‐term effects of septal RVOT versus RVA pacing on left ventricular and atrial structure and function. Methods: Fifty‐eight patients who were prospectively randomized to long‐term pacing either from the right ventricular apex or RVOT septum were studied echocardiographically. Left ventricular (LV) and atrial (LA) volumes were measured. LV 2D strain and tissue velocity images were analyzed to measure 18‐segment time‐to‐peak longitudinal systolic strain and 12‐segment time‐to‐peak systolic tissue velocity. Intra‐LV synchrony was assessed by their respective standard deviations. Interventricular mechanical delay was measured as the difference in time‐to‐onset of systolic flow in the RVOT and LV outflow tract. Septal A’ was measured using tissue velocity images. Results: Following 29 ± 10 months pacing, there was a significant difference in LV ejection fraction (P < 0.001), LV end‐systolic volume (P = 0.007), and LA volume (P = 0.02) favoring the RVOT‐paced group over the RVA‐paced patients. RVA‐pacing was associated with greater interventricular mechanical dyssynchrony and intra‐LV dyssynchrony than RVOT‐pacing. Septal A’ was adversely affected by intra‐LV dyssynchrony (P < 0.05). Conclusions: Long‐term RVOT‐pacing was associated with superior indices of LV structure and function compared with RVA‐pacing, and was associated with less adverse LA remodeling. If pacing cannot be avoided, the RVOT septum may be the preferred site for right ventricular pacing. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1120‐1126)     

右室心尖部起搏与右室流出道起搏对Ⅲ度房室传导阻滞患者疗效的对比研究

目的:比较右室心尖部起搏与右室流出道起搏对Ⅲ度房室传导阻滞患者心室间运动同步性及左室内运动同步性,以及对患者心功能的影响。方法:选取因Ⅲ度及高度房室传导阻滞患者置入双腔起搏器患者共38例。其中心室电极置入右室流出道者20例(RVOT组),置入右室心尖部18例(RVA组),超声心动图术前测量左室舒张末内径(LVEDD),左室收缩末内径(LVESD)、左室射血分数(LVEF)、E/A值、心室间激动延迟时间(IVMD)、室间隔与左心室后壁间收缩延迟时间(SPWMD)。术后1个月、12个月随访。结果:术后1个月,与RVOT组比较,RVA组IVMD、SPWMD明显延长[IVMD(39.83±6.01)∶(31.95±7.86)ms,P=0.02],[SP-WMD(97.83±20.81)∶(84.6±10.89)ms,P=0.023]。术后12个月,与ROVT组比较,RVA组LVEDD明显增大[(49.11±2.39)∶(47.4±1.96)mm,P=0.02],LVESD明显增大[(34.28±3.41)∶(32.5±1.5)mm,P=0.04];LVEF明显降低[(59.56±3.38)∶(62.8±2.14)%,...     

射频消融治疗室性早搏触发特发性室性心动过速／心室颤动的病例分析

目的探讨射频消融治疗在室性早搏（室早）触发特发性室性心动过速／心室颤动（室速／室颤）中的作用。方法总结3例由室早触发室速／室颤的治疗经验,1例对室早进行射频消融（RF—CA）并植入心律转复除颤器（ICD）,另1例经射频消融未完全消除室早而选择植入ICD,第3例经射频消融成功消除室早,未再发室颤。结果随访2年,3例患者均存活,ICD未再记录到室速／室颤。结论在室早触发室速／室颤病例中,应分析室早与室速／室颤的相关性,给予个体化治疗,射频消融室早可以消除／减少晕厥和室颤的发作。     

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.     

右室流出道室性期前收缩的心电图特征及射频消融治疗

目的:探讨右室流出道室性期前收缩(室性早搏,室早)的心电图特征和评价单导管法消融单形性右室流出道室性早搏的有效性、安全性和实用性。方法:对52例心脏结构正常的右室流出道单形性室早的心电图特征进行分析并行单导管射频消融。采用起搏标测法,以起搏时与自发室性早搏形态波形态完全相同点为消融靶点。结果:右室流出道的室性早搏体表12导联心电图特征,呈完全性左束支阻滞形态,Ⅰ导联呈rs、m、QS及R型,aVR、aVL均呈QS型,Ⅱ、Ⅲ、aVF、V5~6导联均呈单向R波型,胸前导联R波移行区常在V3、V4导联之后。成功消融结果显示26例室早起源右室流出道间隔部:其中前间隔7例、中间隔5例、后间隔14例,游离壁21例:其中前游离壁6例、后游离壁15例,希氏束附近1例,肺动脉瓣下1例。消融即刻成功率94%(49/52),未成功的3例。手术操作时间30~150 min,X线曝光时间5~29 min。术后随访2~48个月无复发。结论:起源于右室流出道的室性早搏有其独特的心电图表现,单导管射频消融可有效、安全地消融心脏结构正常的右室流出道单形性室性早搏。     

Electrophysiologic characteristics and implications of induced ventricular fibrillation in symptomatic patients with Brugada syndrome

OBJECTIVES: The study examined the electrocardiographic and electrophysiologic characteristics in relation to programmed ventricular stimulation (PVS)-induced ventricular fibrillation (VF), as well as the implications of PVS-induced VF on the recurrence of cardiac events in symptomatic Brugada syndrome. BACKGROUND: Brugada syndrome is characterized by ST-segment elevation in the right precordial leads (V(1)-V(3)) and an episode of VF. METHODS: Thirty-four symptomatic patients with Brugada syndrome (33 men and 1 woman; 44 +/- 12 years old) were classified into two groups according to the inducibility of VF with PVS: 22 patients with induced VF requiring direct cardioversion for termination (Induced VF group) and 12 patients without induced VF (Noninduced VF group). RESULTS: The induced VF group showed a longer QRS duration, a higher incidence of right bundle branch block and late potentials detected on the signal-averaged electrocardiogram, longer His-ventricular intervals and a longer conduction time from the RVOT to the left ventricle at extrastimulation than those in the non-induced VF group. However, there was no significant difference in the recurrence of cardiac events (VF documented by an implantable cardioverter-defibrillator and sudden cardiac death) between the two groups (8 [36%] of 22 patients vs. 7 [58%] of 12 patients) during long-term follow-up (range 1 to 149 months; mean 38). CONCLUSIONS: Our data suggest that induction of VF by PVS depends on the severity of depolarization abnormalities but does not predict the recurrence of cardiac events in symptomatic Brugada syndrome, indicating that both depolarization and repolarization abnormalities are important in the development of VF.     

Idiopathic ventricular arrhythmias arising from the pulmonary artery: Prevalence, characteristics, and topography of the arrhythmia origin

BACKGROUND: The characteristics of idiopathic ventricular tachycardias (VTs) or idiopathic premature ventricular contractions (PVCs) arising from the pulmonary artery (PA) have not been sufficiently clarified. OBJECTIVE: The purpose of this study was to clarify the prevalence, characteristics, and preferential sites of idiopathic VT/PVCs arising from the PA (PA-VT/PVCs). METHODS: Data obtained from 276 patients with idiopathic VT/PVCs who underwent radiofrequency (RF) catheter ablation were analyzed. RESULTS: Twelve VT/PVCs (4%) were PA-VT/PVCs, and their onset (34 +/- 14 years) was the youngest among all subgroups. Because those QRS morphologies were similar to VT/PVCs arising from the right ventricular outflow tract (RVOT-VT/PVC) and the earliest ventricular activation was from the RVOT, an initial ablation was performed in the RVOT in all patients. However, RF catheter ablation at the RVOT resulted in a QRS morphology change in all patients, so thereafter PA mapping and ablation was performed. A characteristic potential during sinus rhythm and/or the arrhythmia was recorded at the successful PA ablation site in all patients. A perfect or good pace map was obtained in 7 (70%) of 10 patients. The successful ablation site was the septal side of the PA close to the posterolateral attachment in 9 patients (75%) and the septal side close to the anterior attachment in the remaining 3 (25%). No PA-VT/PVCs recurred during follow-up of 27 +/- 13 months. CONCLUSION: PA-VT/PVCs should always be considered when the ECG suggests RVOT-VT/PVCs and RF catheter ablation in the RVOT results in both a failed ablation and a change in QRS morphology. PA-VT/PVCs often originate from the septal side of the PA.     

右心室流出道室性早搏的定位与导管消融

目的本文旨在探索判断右心室流出道室性早搏（室早）起源的新流程,以便快速、准确地找到消融靶点。方法采用非接触三维标测系统对右心室流出道室早进行标测与导管消融,并分析右心室流出道室早体表心电图特征。根据三维标测与导管消融结果,并结合先前报道的室早起源判断流程,设计新的判断室早起源流程。结果标测与消融结果显示21例患者室早起源于右心室流出道间隔部,其中5例起源于前间隔,4例起源于中间隔,12例起源于后间隔;17例患者室早起源于右心室流出道游离壁,其中5例起源于前游离壁,2例起源于中游离壁,10例起源于后游离壁;1例患者室早起源于希氏束附近。判断室早起源新流程的总阳性预测值（77．3％）较Ito等报道的73．3％、Joshi等报道的73．3％、Dixit等报道的53．8％显著提高（P〈0．05）。新流程在判断室早具体起源部位较Ito等、Joshi等与Dixit等报道的室早起源部位判断流程有较大的优势,其敏感性、特异性与阳性预测值分别为78．1％,88．9％与84．2％,Joshi等报道的流程分别为32．9％,65．8％与48．1％,Dixit等报道的流程分别为50．7％,63．9％和55．2％（P均〈0．05）。结论非接触三维标测系统指导右心室流出道室早消融成功率高,判断室早起源新流程的敏感性、特异性与阳性预测值较先前报道的高,有良好的临床应用价值。     

Programmed Electrical Stimulation in Brugada Syndrome: How Reproducible Are the Results?

INTRODUCTION: Inducibility of ventricular arrhythmias at programmed electrical stimulation (PES) ranges between 50% and 80% of patients with Brugada syndrome. However, the variety of PES protocols and the lack of data relative to a control group or to ventricular arrhythmia reproducibility contribute to a still undefined interpretation of PES outcome in Brugada syndrome. METHODS AND RESULTS: Twenty-one patients with Brugada syndrome (18 men and 3 women; mean age 34 years; 9/21 symptomatic; 8/21 with SCN5A gene mutation) underwent a PES protocol from two right ventricular sites. The endpoint was PES protocol completion or induction of sustained or reproducible (>6 consecutive inductions) nonsustained (>6 beats) fast ventricular arrhythmia. In 17 of 21 patients with Brugada syndrome, PES was repeated 2 months later to test ventricular arrhythmia reproducibility. Twenty-five healthy patients (17 men; mean age 36 years) formed the control group. In patients with Brugada syndrome, ventricular arrhythmia inducibility rate at PES was high (18/21 patients [85%]) and increased with protocol aggressiveness, independent of clinical presentation. In control subjects, no ventricular arrhythmias were induced. Among patients with Brugada syndrome, 14 (82%) of 17 patients remained inducible at a second PES. CONCLUSION: In our experience, ventricular arrhythmia inducibility in patients with Brugada syndrome, at variance with healthy controls, is high and does not correlate with clinical presentation. PES inducibility is deeply influenced by the protocol used. PES outcome is reproducible at a mid-term follow-up mainly if a categorical endpoint (inducible vs noninducible) is used. The need to assess the predictive value of specific PES protocols in targeted studies is widely emerging and is confirmed by our results.     

右心室心尖部起搏与右心室流出道起搏的临床研究

目的利用超声多普勒优化房室间期后,比较右心室心尖部（RVA）起搏与右心室流出道（RVOT）起搏对左、右心室间收缩同步性的差别。方法（1）共入选45例三度房室阻滞患者,其中男16例,女29例。RVA组31例,RVOT组14例,出院前进行程控。（2）将感知的房室间期（SAV）由70～170ms递增,每次递增20ms,分别行超声心动图检查,测定心肌做功指数（MPI）,将MPI最小时的SAV确定为最适SAV。比较不同起搏部位所测最适SAV的差异。（3）应用组织多普勒同步图（TSI）技术分别测量左、右心室侧壁基底部心肌收缩达峰时问,二者之差用ATs表示,代表室间不同步程度。比较不同起搏部位ATs的差异。结果（1）RVA与RVOT起搏的最适SAV分别为（80．0±9．8）ms对（92±18）ms,差异有统计学意义（P〈0．01）。（2）RVA与RVOT组室间隔与左心室侧壁收缩达峰时间差分别为（89．5±25．7）ms对（27．94-10．5）ms（P〈0．001）,左、右心室侧壁基底部收缩达峰时间之差分别为（88．3±23．4）ms对（29．54-16．7）ms,差异有统计学意义（P〈0．001）。结论与RVA起搏比较,RVOT起搏对心室收缩同步性影响较小,分析其效果与RVOT起搏部位有关。     

右心室流出道间隔部起搏对左心室功能的影响

目的比较右心室流出道间隔部(RVOT)起搏与右心室心尖部(RVA)起搏的血流动力学差异;评估RVOT起搏技术的可行性与安全性。方法选择有永久起搏器置入适应证的患者75例。根据术者建议和患者意愿分为RVOT组(40例)和RVA组(35例)。所有房室传导阻滞及病窦综合征合并一度房室传导阻滞患者采用双腔起搏双腔感知触发抑制型起搏模式,心房颤动伴长间歇患者采用抑制型心室按需起搏模式。比较2组的血流动力学差异。结果 RVOT组的QRS波宽度较RVA组缩窄(23.2±28.7)ms,差异有统计学意义(P<0.01)。与RVA组比较,RVOT组LVEF、左心室短轴缩短率明显升高,左心室舒张末容积明显下降(P<0.05,P<0.01)。与术前比较,RVA组LVEF、左心室短轴缩短率明显下降,左心室舒张末容积明显升高,差异有统计学意义(P<0.01)。结论利用螺旋电极进行RVOT起搏可行且较为安全。RVOT起搏的血流动力学参数优于RVA。     

右室流出道起搏现状

右室心尖部作为传统的永久心脏起搏器植入位点,主要是因为电极容易放置及电极脱位率低。但是心尖部起搏属非生理性起搏,它使心室除极和机械收缩发生异常,从而导致长期的血流动力学紊乱(心室收缩和舒张异常)和组织结构的改变。随着近年主动固定的螺旋电极及螺旋电极操作手柄的问世,使右室流出道起搏成为可能。大量动物实验和临床研究提示右室流出道靠近房室结、希氏束部位,在此部位起搏心室激动和收缩顺序趋于正常,从而能明显的改善血流动力学指标。目前右室流出道起搏尚处于临床实验阶段,且关于右室流出道解剖位点的确定,适宜患者群的筛选标准、监测和评价指标的选择尚无统一的标准。其长期效果及能否改善患者预后等还有待更深入的研究。现就目前国内外关于右室流出道起搏的研究现状综述如下。     

Comparison of the Acute Hemodynamic Effect of Right Ventricular Apex,Outflow Tract,and Dual‐Site Right Ventricular Pacing

Background: We studied the acute effect of pacing at the right ventricular outflow tract (RVOT), right ventricular apex (RVA) and simultaneous RVA and RVOT—dual‐site right ventricular pacing (DuRV) in random order on systolic function using impedance cardiography. Methods: Seventy‐three patients (46 males), aged 52–89 years (mean 71.4 years) subjected to routine dual chamber pacemaker implantation with symptomatic chronic II or atrioventricular block, were included to the study. Results: DuRV pacing resulted in significantly higher cardiac index (CI) in comparison to RVOT and RVA and CI at RVOT was higher than at RVA pacing (2.46 vs 2.35 vs 2.28; P < 0.001). In patients with ejection fraction >50% significantly higher CI was observed during DuRV pacing when compared to RVOT and RVA pacing and there was no difference of CI between RVOT and RVA pacing (2.53 vs 2.41 vs 2.37; P < 0.001). In patients with ejection fraction <50%, DuRV and RVOT pacing resulted in significantly higher CI in comparison to RVA pacing while no difference in CI was observed between RVOT and DuRV pacing (2.28 vs 2.21 vs 2.09; P < 0.001). Conclusion: Dual‐site right ventricular pacing in comparison to RVA pacing improved cardiac systolic function. RVOT appeared to be more advantageous than RVA pacing in patients with impaired, but not in those with preserved left ventricular function. No clear hemodynamic benefit of DuRV in comparison to RVOT pacing in patients with impaired systolic function was observed. Ann Noninvasive Electrocardiol 2010;15(4):353‐359     

右心室流出道与右心室心尖部起搏对心室收缩同步性和心功能的影响

目的研究右心室流出道(right ventricular outflow tract,RVOT)间隔部和右心室心尖部(right ventricularapex,RVA)起搏对心脏收缩同步性、收缩功能的影响,探讨RVOT间隔部起搏的意义。方法 50例病态窦房结综合征患者分为RVOT组(n=25)和RVA组(n=25),起搏器置入1个月后通过调整房室间期使心室节律全部为起搏节律或房室结自身下传节律,观察起搏参数,并行超声心动图检查。结果RVOT组与RVA组电极导线植入时间、X线曝光时间比较,差异无统计学意义(P>0.05)。全部患者未出现植入并发症。两组随访1个月时起搏参数比较,差异无统计学意义(P>0.05)。RVOT组和RVA组起搏后的QRS波时限较前明显增宽,差异有统计学意义[RVOT组:(135±8)ms vs.(88±8)ms,P<0.001;RVA组:(154±8)ms vs.(90±6)ms,P<0.001]。RVA组起搏后QRS波时限较RVOT组增宽更为明显,差异有统计学意义(P<0.001)。两组起搏后室间机械延迟(interventricularmechanical delay,IVMD)和室间隔-左心室后壁收缩运动延迟时间(septal-to-posteriowall motion delay,SPWMD)较起搏前均显著增加,差异有统计学意义(P<0.001)。RVA组起搏后IVMD和SPWMD绝对值较RVOT组显著延长,差异有统计学意义[IVMD:(38±7)ms vs.(24±5)ms,P<0.001;SPWMD:(118±21)ms vs.(60±11)ms,P<0.001]。两组左心室舒张末内径及左心室射血分数比较,差异无统计学意义(P>0.05)。结论右心室起搏会造成心室收缩不同步,RVOT起搏对心室收缩不同步的影响较RVA起搏小,提示RVOT起搏是较为生理的起搏位点。