Reflex Cardiac Asystole

In this report we present the case of a patient with recurrent syucopal episodes. During one of the attacks the patient was monitoring by telemetry and the ECC lead showed asvstole for more than 7 seconds. As in cases of the carhlinhibitory type of hypersenstive carolid sinus svndrome [HCSS]. asvstole may represent suppression of the sinus node or suppression of both sinus and atioventricular [AV] node. Unfortunately, in contrast to HCSS, there is no maneuver that can reproducibly induce episodes of asystole. Consequentlty, very little is known about the occurrence of AV block in the presence of sinus arrest. In the patient described in this report. We were able to demonstrate that suppression of sinus and AV nodes occured simultaneously. This is interesting to note that in this type of syneope data from noninvasive and invasive techniques in assessing sinus nodal and AV nodal conduction may note be conclusive. In the group of patients with this type of syncope, permanent artial demand pacing is constraindicated.     

心电图引导下非漂浮电极床旁心内起搏与起搏复律的临床应用

目的　探讨心电图引导下非漂浮电极床旁心内起搏与起搏复律的效果。方法　用改良的Seldinger方法穿刺左、右锁骨下静脉或右股静脉 ,置入 5F远端塑成直径为 10cmC型非漂浮起搏电极 ,进行床旁起搏和起搏复律。结果　床旁心脏起搏及起搏复律共 10 9例。进行床旁紧急心内起搏或保护性起搏 86例。其中 31例后来在植入埋藏式起搏器时 ,经X光透视证实临床起搏电极在心尖部 30例 ,在流出道 1例。 1例因心脏停搏 ,从右股静脉置入起搏电极进行起搏成功。进行床旁心内起搏复律 2 3例 ,其中室上性心动过速 17例 ,室性心动过速 6例。所有病例起搏及起搏复律成功。结论　心电图引导下非漂浮电极床旁心内起搏与起搏复律具有快速、简便、安全、有效和起搏稳定的优点 ,值得临床推广应用。     

房间隔缺损患者右室局部容积与功能的实时三维超声评价

目的应用实时三维超声心动图(RT3DE)技术评价房间隔缺损(ASD)患者右室局部容积与功能。方法对36例ASD患者行三维容积成像,应用4D RVQ测量以下诸参数,右室局部容积各指标包括右室流入道部、流出道部、心尖肌小梁部舒张/收缩末期容积(iRVEDV、oRVEDV、aRVEDV/iRVESV、oRVESV、aRVESV),整体舒张/收缩末期容积(gRV-EDV/gRVESV)及相应的局部/整体射血分数(iRVEF、oRVEF、aRVEF/gRVEF),并比较各局部容积和局部射血分数;将LA8-plane法与4D RVQ测量的整体右室容积及射血分数行相关分析。结果4DRVQ法与LA8-plane法测量的gRV-EDV、gRVESV及gRVEF相关良好,r值分别为0.94、0.92及0.80。ASD患者局部收缩、舒张末期容积测值以右室流出道部为低,心尖部射血分数明显低于右室流出道部、流入道部及整体射血分数测值,差异有统计学意义(P<0.05)。结论RT3DE可准确评价ASD患者右室整体及局部容积与功能,且各右室局部收缩功能之间存在差异,整体收缩功能尚未出现变化时,心尖肌小梁部出现早期收缩功能损害。     

经胸超声心动图在室间隔缺损并膜部瘤封堵术中的应用

目的探讨经胸超声心动图在室间隔缺损(VSD)伴室间隔膜部瘤封堵术中的应用价值.方法 35例VSD伴膜部瘤患者,术前明确VSD大小,数目,膜部瘤基底部直径、瘤体长度,以及VSD上缘和膜部瘤基底部上缘距主动脉瓣(AV)距离,术中经胸超声心动图(TTE)监护引导,术后追踪随访.封堵器采用Amplatzer膜部室缺封堵器、国产自膨胀性膜部封堵器及PDA蘑菇伞封堵器.结果左室造影与经胸超声心动图测量VSD大小,数目,膜部瘤直径等大致相符(P＞0.05),VSD上缘及膜部瘤基底部上缘距主动脉瓣距离2种方法检测有差异(P≤0.05).35例患者中33例即刻封堵成功,其余2例未封堵成功者与经胸超声心动图检查应用无直接关系.结论经胸超声心动图在VSD并膜部瘤封堵术前病例筛选、术中监护引导、术后随访有着其他检查不可替代的临床应用价值.     

35例窦缓者食道调搏电生理测定报告

本文报告35例不明原因窦缓者的食道调搏电生理检查结果,着重对反映窦房结功能的心脏固有心率。窦房结恢复时间、校正窦房结恢复时间、窦房传导时间进行分析,并揭示了其相关性。     

Anomalous "VVI" Pacing of a Dual Chamber Pacemaker When Programmed in DDI(R) Mode

We describe the case of a dual chamber rate responsive pacemaker (Relay, model 294-03, Intermedics, Angleton, TX, USA) implanted in a 68-year-old male for sick sinus syndrome, which was not working properly when programmed in the DDIR mode, thus determining occasionally a sort of "VVI" pacing. However, the pacemaker performed well when programmed in the DDDR mode. We discovered that this was not a malfunction of a single device but rather a general behavior of this family of Intermedics dual chamber pacemakers (also not rate responsive), caused by a software problem.     

Activation sequence modification during cardiac resynchronization by manipulation of left ventricular epicardial pacing stimulus strength

BACKGROUND: Success of cardiac resynchronization therapy (CRT) depends on altering electrical ventricular activation (VA) to achieve mechanical benefit. That increases in stimulus strength (SS) can affect VA has been demonstrated previously in cardiomyopathy patients undergoing ablation. OBJECTIVE: To determine whether increasing SS can alter VA during CRT. METHODS: In 71 patients with CRT devices, left ventricle (LV) pacing was performed at escalating SS. Timing from pacing stimulus to right ventricular (RV) electrogram, ECG morphology, and maximal QRS duration on 12 lead ECG were recorded. RESULTS: Demographics: Baseline QRS duration 153 +/- 25 ms, ischemic cardiomyopathy 48%, ejection fraction 24%+/- 7%. With increased SS, conduction time from LV to right ventricle (RV) decreased from 125 +/- 56 ms to 111 +/- 59 ms (P = 0.006). QRS duration decreased from 212 +/- 46 ms to 194 +/- 42 ms (P = 0.0002). A marked change in QRS morphology occurred in 11/71 patients (15%). The RV ring was the anode in 6, while the RV coil was the anode in 5. Sites with change in QRS morphology showed decrease in conduction time from LV to RV from 110 +/- 60 ms to 64 +/- 68 ms (P = 0.04). Twelve patients (16%) had diaphragmatic stimulation with increased SS. CONCLUSIONS: Increasing LV SS reduces QRS duration and conduction time from LV to RV. Recognition of significant QRS morphology change is likely clinically important during LV threshold programming to avoid unintended VA change.     

Evaluation of the early hemodynamic changes in carotid arteries during ventricular and dual chamber pacing

In spite of a wide choice of pacemakers, there are some problems in making more rational clinical decisions for individual patients since mode selection and programming is usually performed on the basis of a clinical hunch. The aim of this study was to measure the differences in carotid flow in patients with a pacemaker programmed in the dual chamber and in the single chamber pacing modes. Sixty patients with implanted bipolar DDD pacemakers were enrolled in this study. Blood peak systolic velocity (PSV) and end-diastolic velocity (EDV), cross-sectional area, resistive index (RI), and pulsatility index (PI) were measured in the common (CCA), internal (ICA), and external (ECA) carotid arteries before pacemaker implantation and after dual chamber and ventricular pacing at 60 beats/min. PSVs in the left CCA (79.3 +/- 24.9 cm/s) and right CCA (84.1 +/- 18.7) were shown to significantly decrease after VVI pacing (60.1 +/- 16.6 and 62.1 +/- 20.0, respectively). There was also a similar significant decrease in PSV in the left and right ICAs and ECAs. Besides PSV, RI, and PI in the left and right CCAs, ICAs, and ECAs significantly decreased after VVI pacing. There was no similar decrease after DDD pacing. Cross-sectional area and flow volume in the CCA, ICA, and ECA were similar after DDD and VVI pacing and before pacemaker implantation suggesting that cardiac output was similar when the measurements were recorded. Carotid artery PSVs, pulsatility, and RIs were found to be significantly decreased during VVI pacing compared to baseline and DDD pacing. The greater incidence of adverse cerebral outcomes in patients with VVI rather than DDD pacing may be partly due to decreased carotid PSVs.     

应变率显像定量评价经皮冠状动脉介入治疗前后冠心病患者左心室局部功能

目的应用应变率显像技术（SRI）评价经皮冠状动脉介入治疗（PCI）前后冠心病患者的左心室局部功能变化。方法在28例冠心病患者中,分别于PCI前、PCI后1周和1个月行经胸超声心动图检查,应用SRI技术对左室心尖四腔观及两腔观各节段的心内膜下心肌和心外膜下心肌局部心功能进行定量分析。根据冠状动脉造影结果将心肌节段分为：正常组,冠脉狭窄1级组、2级组、3级组和4级组（冠脉狭窄分别为〈50%、50%～75%、76%～99%和100%）。结果①PCI术前：2、3、4级组的心内膜下心肌和心外膜下心肌收缩期（S）、舒张早期（E）和舒张晚期（A）最大应变率（SRS、SRE、SRA）与正常组测值相比均降低（P〈0.05）;4级组心内膜下心肌和心外膜下心肌SRS、SRE和SRA均小于2级组（P〈0.05）。在正常组和1级组心内膜下心肌的SRS、SRE和SRA均大于心外膜下心肌的测值,差别有统计学意义（P〈0.05）;在2、3、4级组心内膜下心肌SRS、SRE和SRA与心外膜下心肌的测值比较差别无统计学意义（P〉0.05）。②PCI术后：3组和4组于PCI术后1周和1个月时心内膜下心肌和心外膜下心肌的SRS、SRE和SRA均较PCI术前增加（P〈0.05）,3级组心内膜下心肌的SRE和SRA大于心外膜下心肌的测值,差别有统计学意义（P〈0.05）;在3组,术后1周和1个月时心内膜下SRS和SRE变化率均明显大于心外膜下心肌（P〈0.05）;在4组,术后1周和1个月时心外膜下心肌SRS、SRE和SRA的变化率均明显大于心内膜下心肌,差别有统计学意义（P〈0.05）。结论应用SRI技术测量心内膜下心肌和心外膜下心肌的应变率可定量评价冠心病患者缺血心肌的局部功能,动态观察PCI前、后局部心肌功能变化,评价PCI的治疗效果。     

Reliability of a New Algorithm for Automatic Mode Switching from DDDR to DDIR Pacing Mode in Sinus Node Disease Patients with Chronotropic Incompetence and Recurrent Paroxysmal Atrial Fibrillation

To evaluate the safety and efficacy of a new algorithm for automatic mode switching (AMS) from DDD-DDDR to DDIR, 26 patients, 16 females and 10 males, mean age 73 ± 6 years of age, affected by sinus node disease, chronotropic incompetence, and recurrent paroxysmal atrial fibrillation (PAF) received the Medtronic Them DR pacemaker. The device continuously calculates, in ms, the running average of the intrinsic atrial rate (MAR) and compares the current atrial interval (CAI) with the stored MAR. When the CAI is greater than the MAR it increases by 8 ms, and when the CAI is less than the MAR, it decreases by 23 ms. When MAR ± 330 ms (182 beats/mm), tachycardia is detected and AMS is activated. All patients had clinical evaluation, 12-lead ECG, Holter monitoring, and exercise testing after implantation and every 3 months for 1 year. The results were compared with the data stored in the pacemaker memory: AMS episodes number; the histogram of the last 14 episodes; and atrial electrogram recording. Twenty-two Holier recordings in 13 patients showed PAF and in all of them AMS occurred simultaneously. AMS lasted between 10 seconds and 20 hours, and MAR ranged from 195–400 beats/mm. No episode of PAF and no AMS were recorded in 39 Holter recordings in 22 patients. Appropriate AMS was confirmed in five patients by stored atrial electrogram and in nine by 12-lead ECG and pacemaker event markers. Mean atrial sensing was 2.13 ± 1.04 mV during PAF and 3,18 ± 1.46 mV during sinus rhythm. No PAF episode and no AMS were recorded during exercise testing. In conclusion, this new algorithm was very reliable, sensitive, and specific.