The Novel Electrophysiology of Complex Fractionated Atrial Electrograms: Insight from Noncontact Unipolar Electrograms

Unipolar Characteristics of CFAEs. Background: The noncontact mapping (NCM) system possesses the merit of global endocardial recording for unipolar and activation mapping. Objective: We aimed to evaluate the unipolar electrogram characteristics and activation pattern over the bipolar complex fractionated atrial electrogram (CFAE) sites during atrial fibrillation (AF). Methods: Twenty patients (age 55 ± 11 years old, 15 males) who underwent NCM and ablation of AF (paroxysmal/persistent = 13/7) were included. Both contact bipolar (32–300 Hz) and NCM virtual unipolar electrograms (0.5–300 Hz) were simultaneously recorded along with the activation pattern (total 223 sites, 11 ± 4 sites/patient). A CFAE was defined as a mean bipolar cycle length of ≤ 120 ms with an intervening isoelectric interval of more than 50 ms (Group 1A, n = 63, rapid repetitive CFAEs) or continuous fractionated activity (Group 1B, n = 59, continuous fractionated CFAEs), measured over a 7.2‐second duration. Group 2 consisted of those with a bipolar cycle length of more than 120 ms (n = 101). Results: The Group 1A CFAE sites exhibited a shorter unipolar electrogram cycle length (129 ± 11 vs 164 ± 20 ms, P < 0.001), and higher percentage of an S‐wave predominant pattern (QS or rS wave, 63 ± 13% vs 35 ± 13%, P < 0.001) than the Group 2 non‐CFAE sites. There was a linear correlation between the bipolar and unipolar cycle lengths (P < 0.001, R = 0.87). Most of the Group 1A CFAEs were located over arrhythmogenic pulmonary vein ostia or nonpulmonary vein ectopy with repetitive activations from those ectopies (62%) or the pivot points of the turning wavefronts (21%), whereas the Group 1B CFAEs exhibited a passive activation (44%) or slow conduction (31%). Conclusions: The bipolar repetitive and continuous fractionated CFAEs represented different activation patterns. The former was associated with an S wave predominant unipolar morphology which may represent an important focus for maintaining AF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 640‐648, June 2010)     

MRI和增强CT诊断重症急性胰腺炎的比较研究

背景：CT尤其是增强CT（CECT）是判断急性胰腺炎严重程度和预后的重要方法,然而近年MRI有取代CT的趋势。目的：比较MRI与CECT诊断重症急性胰腺炎（SAP）的准确性。方法：2006年1月-2008年9月于泰州市人民医院确诊为SAP的住院患者纳入研究。回顾性分析人选患者的临床以及MRI和CECT表现,以Bahhazar分级系统评估MRI严重指数（MRSI）和CT严重指数（CTSI）。结果：共36例患者临床评估为SAP,入院2d内和第7d的MRSI与C偈I无明显差异。MRI诊断SAP的准确率高于CECT（94．4％对83.3％）,但差异无统计学意义（P〉0．05）。结论：MRI用于SAP的诊断,效果与CECT相似且禁忌证相对较少,是判断急性胰腺炎严重程度的可靠方法。     

MGMT、hMLH1和hMSH2基因启动子甲基化状态对脑胶质瘤预后的影响

目的探讨脑胶质瘤DNA修复基因O6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）和错配修复基因（MMR）（hMLH1、hMSH2）启动子甲基化状态及其对患者预后和烷化剂化疗敏感性的影响。方法采用甲基化特异性PCR（MSP）方法检测39例脑胶质瘤和6例正常脑组织MGMT、hMLH1和hMSH2基因启动子区的甲基化状态,免疫组化方法测定其蛋白表达。绘制Kaplan-merier生存曲线。结果脑胶质瘤组织MGMT、hMLH1和hMSH2基因启动子区甲基化发生率分别为46.2%、10.3%和20.5%,而正常脑组织相应基因启动子区未发生甲基化;三种基因启动子未甲基化模式与其对应蛋白表达模式相似。MGMT基因甲基化的脑胶质瘤患者存活率显著高于未甲基化者（P〈0.05）;MMR基因甲基化患者中MGMT基因甲基化与未甲基化者的生存期无统计学差异（P〉0.05）。结论hMLH1、hMSH2及MGMT甲基化是脑胶质瘤发生过程中常见的分子事件;联合检测MGMT、hMLH1和hM-SH2基因启动子甲基化状态可判断脑胶质瘤患者的预后及其对烷化剂化疗的敏感性。     

The Impact of Left Atrial Size on Long-Term Outcome of Catheter Ablation of Chronic Atrial Fibrillation

Background: The left atrial (LA) size is an important predictor of atrial fibrillation (AF) procedural termination and the long-term outcome. We sought to evaluate the long-term outcome in regard to the LA size and procedural termination.
Methods: Eighty-seven consecutive chronic AF patients (72 males, 53 ± 10 years) underwent 3D mapping (NavX) and ablation. A stepwise approach including circumferential pulmonary vein (PV) isolation, linear ablation, and continuous complex-fractionated electrogram (CFE) ablation (targeting fractionation intervals of < 50 ms). Electrical cardioversion was applied to those without any procedural termination. The freedom from AF was defined as the maintenance of sinus rhythm without the use of any class I or III antiarrhythmic drugs after the blanking period.
Results: Among the 87 patients, all received a circumferential PV isolation, 93% a linear ablation, and 59% a continuous CFE ablation. Those with AF procedural termination (n = 30) had a better long-term outcome when compared with those without termination during a follow-up of 21 ± 12 months. Moreover, a Kaplan-Meier analysis showed that in those with an LA diameter of less than 45 mm (n = 49), the freedom from AF rate was higher when procedural termination was achieved (P = 0.004). On the contrary, the outcome was comparable in those with an LA diameter of ≥ 45 mm (n = 38), whether AF procedural termination occurred or not (P = 0.658).
Conclusions: AF procedural termination was related to the long-term success during chronic AF ablation, especially in those with an LA diameter of less than 45 mm. The favorable effect of termination decreased when the LA diameter was ≥ 45 mm.     

Induced Atrial Tachycardia After Circumferential Pulmonary Vein Isolation of Paroxysmal Atrial Fibrillation: Electrophysiological Characteristics and Impact of Catheter Ablation on the Follow-Up Results

Introduction: Atrial tachycardia (AT), including focal and reentrant AT, can occur after circumferential pulmonary vein isolation (CPVI). The aim of this study was to investigate the electrophysiological characteristics of induced AT and its clinical outcome.
Methods and Results: In our series of 160 patients with paroxysmal atrial fibrillation (AF), 45 ATs were induced by high-current burst pacing after CPVI in 26 patients. All induced ATs were mapped using a three-dimensional ( 3D) mapping system. Noninducibility was the endpoint of the ablation of the AT. Gap-related AT was considered if the AT was related to the CPVI lesions. A 16-slice multidetector computed tomography scan was performed in all patients to correlate the anatomical structure with electroanatomical mapping. Thirty-five (78%) reentrant ATs and 10 (22%) focal ATs were identified. Of those, 34 were gap-related ATs (24 reentrant and 10 focal ATs). Reentrant AT had more gaps in the left atrial appendage ridge than did focal AT (39.6% vs 0%, P = 0.02). Focal AT had a higher incidence of gap in the PV carina compared with reentrant AT (80% vs 10%, P < 0.001). Reentrant ATs were mostly terminated during the ablation creating the mitral and roof lines with crossing of the gaps. During a mean follow-up of 21 ± 8 months, only one patient (0.6%) with induced mitral reentry had a recurrent AT.
Conclusion: The location of the AT gap may be related with the complex anatomy of the LA. The induced ATs after CPVI can be eliminated by catheter ablation.     

Electrophysiologic Characteristics and Radiofrequency Catheter Ablation in Patients with Clockwise Atrial Flutter

RF Catheter Ablation of Clockwise Atrial Flutter. introduction: Although the mechanism and radiofrequency catheter ablation of counterclockwise (typical) atrial flutter have been studied extensively, information about the electrocardiographic and electropbysiologic characteristics and effects of radiofrequency ablation in patients with clockwise atrial flutter is limited. Methods and Results: Thirty consecutive patients with clinically documented paroxysmal clockwise atrial flutter were studied. Endocardial recordings and entrainment study using a “halo” catheter with 10 electrode pairs in the right atrium were performed. Radiofrequency energy was applied to the inferior vena cava-tricuspid annulus (IVC-TA) and/or coronary sinus ostium-tricuspid annulus (CSO-TA) isthmus to evaluate the effects of linear catheter ablation. Eighteen patients had both counterclockwise and clockwise atrial flutters, and 12 patients had only clockwise atrial flutter. Both forms of atrial flutter had similar flutter cycle lengths (232 ± 30 vs 226 ± 25 msec, P = 0.526) but reverse activation sequences. Right atrial pacing at a cycle length 20 msec shorter than the flutter cycle length from the CSO-TA isthmus, IVC-TA isthmus, and the area between the two isthmuses revealed concealed entrainment with stimulus-to-P wave intervals of 32 ± 19, 95 ± 14, and 50 ± 17 msec (P = 0.022) in the counterclockwise form, and 110 ± 12, 40 ± 20, and 60 ± 15 msec (P = 0.018) in the clockwise form. In clockwise atrial flutter, 20 patients with biphasic P waves in the inferior leads had the presumed exit site of slow conduction area located at the low posterolateral right atrium; 10 patients with positive P waves in the inferior leads had the presumed exit site located at the mid-high posterolateral right atrium. Among the 18 patients with both forms of atrial flutter, linear ablation lesions directed at the IVC-TA isthmus eliminated both forms of atrial flutter in 14 patients; in the remaining 4 patients. CSO-TA linear lesions eliminated the counterclockwise form and IVC-TA lesions eliminated the clockwise form. Among the 12 patients with the clockwise form only, CSO-TA linear lesions eliminated flutter in 2 and IVC-TA linear lesions eliminated flutter in 10 patients. Successful ablation was confirmed by creation of bidirectional conduction block in the IVC-TA and/or CSO-TA isthmus during pacing from the proximal coronary sinus and right posterolateral atrium sandwiching the linear lesions. During the follow-up period of 17 ± 8 months, 2 patients had recurrence of clockwise atrial flutter, 1 patient had new onset of atypical atrial flutter, and 2 patients had new onset of atrial fibrillation. Conclusions: Counterclockwise and clockwise atrial flutters may have overlapping slow conduction areas with different exit sites. Radiofrequency catheter ablation using the linear method directed at the IVC-TA and CSO-TA isthmuses was feasible and effective in treating both forms of atrial flutter.     

Electrophysiologic Characteristics and Radiofrequency Catheter Ablation in Atrioventricular Node Reentrant Tachycardia with Second-Degree Atrioventricular Block

Second-Degree AV Block During AVNRT. Introduction : Detailed electrophysiologic study of AV nodal reentrant tachycardia (AVNRT) with 2:1 AV block has been limited.
Methods and Results : Six hundred nine consecutive patients with AVNRT underwent electrophysiologic study and radiofrequency catheter ablation of the slow pathway. Twenty-six patients with 2:1 AV block during AVNRT were designated as group I, und those without this particular finding were designated as group II. The major findings of the present study were: (1) group I patients had better anterograde and retrograde AV nodal function, shorter tachycardia cycle length (during tachycardia with 1:1 conduction) (307 ± 30 vs 360 ± 58 msec, P < 0.001), and higher incidence of transient bundle branch block during tachycardia (18/26 vs 43/609, P < 0.001) than group II patients: (2) 21 (80.8%) group I patients had alternans of AA intervals during AVNRT with 2:1 AV block. Longer AH intervals (264 ± 26 vs 253 ± 27 msec, P = 0.031) were associated with the blocked beats. However, similar HA intervals (51 ± 12 vs 50 ± 12 msec, P = 0.363) and similar HV intervals (53 ± 11 vs 52 ± 12, P = 0.834) were found in the blocked and conducted beats; (3) ventricular extrastimulation before or during the His-bundle refractory period bundle could convert 2:1 AV block to 1:1 AV conduction.
Conclusions : Fast reentrant circuit, rather than underlying impaired conduction of the distal AV node or infranodal area, might account for second-degree AV block during AVNRT. Slow pathway ablation is safe and effective in patients who have AVNRT with 2:1 AV block.     

介入治疗与常规药物治疗对伴QRS波碎裂不稳定心绞痛患者自主神经及C反应蛋白的影响

目的 探讨介入治疗与常规药物治疗对伴QRS波碎裂(fQRS)不稳定心绞痛(UA)患者自主神经及C反应蛋白(CRP)的影响. 方法 收集伴QRS波群碎裂UA患者60例,年龄(46.2± 10.3)岁,分为药物组和介入组,各30例.测定两组治疗前和治疗后1个月时心率变异性(H RV)、窦性心率震荡(HRT)和CRP变化. 结果 (1)HRV时域指标(SDNN、SDANN、rMSSD、PNN50、HF、LF)治疗前介入组分别为[(88.2±20.6)ms、(76.2±9.3)ms、(18.6±7.9)ms、(5.5±2.8)％、(219.4±131.6) Hz、(459.6±135.2)Hz]、治疗后介入组分别为[(122.5±15.5) ms、(105.3±5.2)ms、(49.3±4.3)ms、(9.1±1.8)％、(292.5±125.5)Hz、(345.1±175.1)Hz],治疗前后比较为(t=9.4、15.69、8.37、4.68、3.26、3.57,P＜0.01或0.05);治疗前药物组分别为[(86.9±23.4 )ms、(74.3±10.4)ms,(19.3±7.4)ms、(5.3±2.1)％、(217.2±133.2) Hz、(445.8±144.3)Hz],治疗后药物组分别为[(106.7±18.8)ms、(89.8±7.6)ms、(29.4±5.2)ms、(7.2±3.2)％、(213.2±120.2)Hz、(396.1±182.3)Hz],治疗前后比较(t=7.3、12.36、6.98、2.94、4.89、5.01,P＜0.01或0.05);治疗后介入组与药物组比较,介入组变化更为显著(t=8.90、13.75、7.52、3.27、4.21、4.01,P＜0.01或0.05).(2)震荡初始(TO)、震荡斜率(TS)、CRP治疗前介入组分别为(0.45±0.44)％、(2.12±0.13)ms/RR、(5.74±2.46)mg/L,治疗后分别为(0.16±0.20)％、(2.98±0.25)ms/RR、(2.61±1.22) mg/L;治疗前药物组分别为(0.49±0.38)％、(2.15±0.19) ms/RR、(5.81±2.35)mg/L,治疗后分别为(0.32±0.26)％、(2.51±0.11)ms/RR、(3.56±1.43)mg/L.TO治疗前后比较药物组为(t=16.78,P=0.001),介入组为(t=15.63,P＜0.01),治疗后介入组与药物组比较(t=15.95,P＜0.001);TS治疗前后比较药物组为(t=19.52,P=0.001),介入组为(t=14.36,P=0.001),与药物组比较介入组变化更为显著(t=18.13,P=0.001);CRP治疗前后比较药物组为(t=9.76,P=0.01),介入组为(t=12.49,P=0.001),治疗后介入组与药物组比较为(t=10.73,P=0.001). 结论 冠脉介入治疗更显著改善伴QRS波碎裂UA患者的心肌供血,从而减轻炎症反应,改善自主神经功能.     

脑囊尾蚴病患者治疗后脑CT影像学特征变化

目的 探讨脑囊尾蚴病患者抗囊尾蚴治疗期间脑CT影像变化。方法 选择2010年5月至2015年5月在山东省医学科学院第三附属医院就诊的380例脑囊尾蚴病住院患者作为研究对象,临床给予3阶段阿苯达唑、吡喹酮抗囊尾蚴化疗,治疗前后均行头颅CT扫描,其中210例行增强扫描,对治疗不同阶段患者脑CT影像学资料进行分析。结果 脑囊尾蚴病患者治疗前CT影像显示有单个或多个小囊状低密度,囊内可见小结节状高密度头节影,伴周围水肿;治疗后脑CT复查显示81.58% （310/380）的脑囊尾蚴病患者低密度灶完全吸收,16.32% （62/380）病灶大部分吸收,2.11%（8/380）CT影像显示为钙化灶。患者一般于服用抗囊尾蚴药物2～3 d后出现杀虫反应;随着治疗时间的延长,抗囊尾蚴药物反应逐渐减轻,在第3阶段治疗后大多数患者病灶吸收或钙化。结论 CT检查可明确脑囊尾蚴病病变部位、范围,并可对脑囊尾蚴病进行分型,还能根据抗囊尾蚴治疗期间影像学变化评价治疗效果。     

Hyperventilation Facilitates Induction of Supraventricular Tachycardia: A Novel Method and the Possible Mechanism

INTRODUCTION: Hyperventilation has been demonstrated to alter autonomic function. Sympathomimetic drugs (isoproterenol) and parasympatholytic drugs (atropine) may be needed to facilitate induction of supraventricular tachycardia (SVT). The aim of this study was to test the clinical utility and mechanisms of hyperventilation to facilitate SVT initiation. METHODS AND RESULTS: Fourteen patients with clinically documented SVT (9 AV nodal reentrant tachycardia and 5 AV reciprocating tachycardia) but noninducible during baseline electrophysiologic study were included. Immediately after hyperventilation test (at least 30 respirations/min) for 2 minutes, systolic blood pressure, sinus cycle length, anterograde and retrograde 1:1 conduction, and induced SVT were measured. Arterial blood gas, pH, and heart rate variability before and after hyperventilation were measured. Seven of nine patients with AV nodal reentrant tachycardia and 3 of 5 patients with AV reciprocating tachycardia could be induced immediately after the hyperventilation test. After hyperventilation, anterograde AV and retrograde VA 1:1 conduction were improved, sinus cycle length was decreased, and heart rate variability were decreased in both groups. CONCLUSION: Hyperventilation can facilitate induction of SVT. Improvement of conduction properties and changes of autonomic function are the possible mechanisms.