运动试验诱发心肌缺血和心绞痛的性别特点研究

目的：观察运动试验诱发男女心肌缺血和心绞痛的特点和差异。方法：将运动试验阳性中出现终止指征没完成次极量的94例患者分为男、女两组，分析其心电图、运动能力、临床症状等，并和部分患者的冠状动脉造影结果对照。结果：男性代谢当量、运动时间明显大于女性（P〈0．05），男性终止症状多见于Bruce2级，女性多见于Bruce1级结束时。ST段下移程度男性高于女性（P〈0．05），下移形态女性水平型多（P〈0．05）、男性近似水平型多（P〈0．05），男性T波倒置多（P〈0．05）。冠状动脉造影结果男性异常率高（78％），女性低（50％）。结论：运动试验对男性心肌缺血和心绞痛的诊断价值较女性大。男性运动试验诱发心肌缺血和心绞痛多发生于Bruce2级。     

Predictors of exercise induced myocardial ischemia in patients with isolated coronary artery ectasia

The aim of this study was to investigate the angiographic predictors of exercise induced ischemia in patients with isolated coronary ectasia. We have prospectively analysed coronary angiograms of 1521 consecutive patients undergoing cardiac catheterisation. The overall incidence of coronary ectasia was 6.7% (102 patients). Forty-six patients (3%) with non-obstructive, diffuse or segmental coronary ectasia (i.e. isolated coronary ectasia) constituted the main study group. Coronary angiograms were reviewed for stigmata of an impaired coronary blood flow such as 'slow flow', 'segmental backflow phenomenon' and stasis. 'Slow flow' was quantified with frame counting. An ectasia-jeopardy score was also described in order to assess the effect of the extent of coronary ectasia on exercise induced ischemia. Exercise induced ischemia was observed in 24 patients (52%). Exercise test was abnormal in 70% of the patients with diffuse ectasia and 26% of patients with segmental ectasia (p = 0.003). The frame count of the arteries of the study group was higher than the control group but the correlation between the frame count of the ectatic vessels and exercise induced ischemia was not significant. Stasis of the dye also did not correlate with ischemia. There was a significant correlation between exercise induced ischemia and backflow phenomenon in left anterior descending artery (LAD) (r = 0.56, p = 0.0001). Exercise induced ischemia was best correlated with the ectasia-jeopardy score (r = 0.77, p = 0.0001) and a score of > or =4 identified the patients at risk with 90% sensitivity and 80% specificity. In conclusion, the extent of the ectasia within the coronary tree, diffuse ectasia and backflow-phenomenon in LAD were identified as the most important predictors of exercise induced ischemia.     

Permanent Left Atrial Pacing with a Specifically Designed Coronary Sinus Lead

This article reports the original use of a specifically designed coronary sinus (CS) lead for permanent left atrial (LA) pacing. The device is characterized by its distal end shape featuring a double 45° angulation. which ensures very close contact with the CS upper wall. The device was successfully implanted in 39 out of 40 patients (97.5%). The tip electrode was eventually positioned in the distal CS in 9 patients, in the middle CS in 21 patients, and close to the ostium in the proximal CS in 9 patients. The mean acute pacing threshold voltage was 0.9 ± 0.5 V with a mean impedance of 578 ± 144 Ω as measured in unipolar distal configuration at 0.5 ms pulse width (PW). The mean A wave amplitude was 3.5 ± 2.1 mV. Early lead dislodgment occurred only once (3%) when the tip electrode was placed in the distal or middle CS, but more often (4/9 cases) when it was placed in the proximal CS. After a mean follow-up duration of 14 ± 8.5 months, 35 of the 39 successfully implanted leads (89.7%) were still functional in terms of LA pacing and sensing. The mean chronic pacing threshold voltage was 1.5 ± 0.8 V and the mean A wave amplitude was 2.7 ± 1.6 mV. There were no lead related complications. In conclusion, the device proved to be safe and highly effective for permanent LA pacing, provided the distal tip could be positioned in the distal or middle part of the CS.     

Pacing lead adhesions after long-term ventricular pacing via the coronary sinus

Left ventricular pacing via the coronary sinus is being increasingly used. There is little data to guide possible lead extractions that might be required in the future. Significant adhesions to the coronary veins were found 12 years after placing a pacing lead in the posterolateral coronary vein in a man with double inlet left ventricle and severe subpulmonary stenosis who had undergone a Fontan operation. The appearances suggest that percutaneous extraction from the proximal coronary sinus may be feasible but that difficulty may be encountered if the lead tip is placed into the distal coronary veins.     

Successful Long-Term Ventricular Pacing Via the Coronary Sinus After the Fontan Operation

A man with double inlet left ventricle and severe subpulmonary stenosis underwent a Fontan operation at the age of 29 years. Eight years later he developed atrial flutter with complete heart block. To avoid a further thoracotomy, a unipolar carbon tipped electrode was placed into the posterior cardiac vein via the coronary sinus. More than 8 years after implantation of the original lead, and after two generator changes, telemetric thresholds remain between 1.8–2.1 volts. Percutaneous transvenous ventricular pacing via the coronary sinus can produce an excellent long-term result and should be the initial approach of choice after a Fontan-type operation.     

双心房同步起搏的临床应用

目的 探讨冠状窦起搏电极行双心房起搏的有效性、安全性,并观察双心房同步起搏对伴房内／房间传导阻滞的 性快速房性心律失常的临床应用效果。方法 为７例病态窦房结综合征,阵发性房颤伴房内／房间传导阻滞的患植入冠状窦起搏电极、常规右心耳及右心尖电极,行双心房同步起搏。结果 冠状窦起搏电极均成功植入,术后双房同步起搏可使Ｐ波时限缩短,寻预防房颤发作。本组术后３月脱位１例,予成功复位。结论 应用冠状窦起搏电     

Is DDD Pacing Superior to VVI,R? A Study on Cardiac Sympathetic Nerve Activity and Myocardial Oxygen Consumption at Rest and During Exercise

Rate responsive ventricular pacing (VVI,R) has been demonstrated to equal atrial synchronous ventricular pacing (DDD) with regard to hemodynamics and exercise tolerance. Whether the two modes are also comparable, with regard to cardiac metabolic effects, is not yet dear. We assessed central hemodynamics, cardiac sympathetic nerve activity fcardiac norepinephrine overflow), and myocardial oxygen consumption in 16 patients treated with rate responsive atrial synchronous ventricular pacemakers (DDD,R), due to high degree AV block. The study was performed at rest and during supine exercise at two workloads (30 ± 12 and 68 ± 24 watts, respectively) during VDD and rate matched VVI pacing (VVI_m). Ventricular rates at rest and during both workloads were almost identical. Cardiac output at rest tended to be higher in the VDD mode, due to a slightly higher stroke volume. Central pressures including right atrial pressure and pulmonary capillary wedge pressure were similar in the pacing modes. The coronary sinus blood flow, the coronary sinus arteriovenous oxygen difference, and the myocardial oxygen consumption did not differ between the two pacing modes. Cardiac norepinephrine overflow was similar in the two pacing modes, at rest or during exercise. Thus, we found no significant differences between VDD and VVI_m pacing with regard to central hemodynamics, cardiac sympathetic nerve activity (cardiac norepinephrine overflow), or myocardial oxygen consumption either at rest or during moderate exercise.     

Electrocardiographic Recognition of Variant Angina During Permanent Pacing

We present a patient with a permanent venlricular pacemaker who was investigated for episodes of chest pain associated with syncope. Ambulatory electrocardiographic monitoring showed essentially paced rhythm. ST segment elevation of the paced beats was observed during spontaneous chest pain, but the significance of this finding was initially unclear in the context of the abnormal repolarization associated intrinsically with paced rhythm. At angiography, coronary spasm was demonstrated after ergonovine, and this was associated with ST segment elevation during paced rhythm and with chest pain. We conclude that ST segment elevation may indicate myocardial ischemia even when observed in the face of abnormal repolarization associated with paced rhythm.     

Ventricular Pacing from the Middle Cardiac Vein Mimicking Supraventricular Morphology

A case is described in which ventricular pacing from the middle cardiac vein produced an electrocardiographic pattern which mimicked the morphology of the normally conducted beats. The possible etiologies of this unusual phenomenon and its implications concerning the functional anatomy of the normal conduction system in the human heart are discussed.     

The coronary sinus reducer: clinical evidence and technical aspects

Introduction: Chronic refractory angina is often a disabling condition, predominantly due to severe obstructive coronary artery disease, that is inadequately controlled by optimal medical therapy and not amenable to further percutaneous or surgical revascularization. mortality rates associated with this condition are relatively low in clinically stable patients. however, it is associated with a high hospitalization rate and a reduction in both exercise capacity and quality of life. due to the paucity of available treatment options, there is an unmet need for new therapies for these patients and for a reduction in the associated economic healthcare burden.

Areas covered: This review is focusing on the clinical evidence and technical aspects of this new therapeutic modality in refractory angina patients unsuitable for revascularization.

Expert commentary: The Coronary Sinus Reducer (Neovasc Inc. Richmond B.C., Canada) is a new percutaneous device designed to achieve a controlled narrowing of the coronary sinus that may alleviate myocardial ischemia, possibly by redistributing blood from the less ischemic sub-epicardium to the more ischemic sub-endocardium, or by neoangiogenesis. Recently, a randomized, double-blind, multi-center clinical trial demonstrated a benefit in improving symptoms in 104 refractory angina patients, when compared to placebo.     

Long-term Stability of Endocardial Left Ventricular Pacing Leads Placed via the Coronary Sinus

Background: Left ventricular endocardial pacing leads placed via the coronary sinus (CS) are increasingly implanted to achieve cardiac resynchronization therapy (CRT); however, the long-term stability of these leads is unknown. We sought to determine the implant success and long-term stability of CS leads in our single center experience.
Methods: All consecutive patients who underwent CRT via implantation of the CS lead between January 1999 and December 2005 were included. Pacing thresholds at implant and during long-term follow-up were reviewed and the rate of acute (within 24 hours of implant) and chronic (>24 hours) lead failure was determined.
Results: A total of 512 patients (mean age 68 ± 12 years; 409 [80%] male) underwent CRT device implantation and were included. The CS lead implantation was successful on the initial implantation in 487 patients (95%) and subsequently successful in six patients (24%) in whom initial attempts were unsuccessful. Acute lead failure occurred in 25 patients (5.1%) and was most commonly due to persistent extra-cardiac stimulation. The rate of chronic lead failure was 4% in the first year and remained stable during long-term follow-up. The CS lead pacing thresholds remained stable with only minimal increase (1.42 ± 0.85 V/0.42 ± 0.25 ms vs 1.51 ± 1.05 V/0.47 ± 0.29 ms; P = 0.04).
Conclusions: Placement of a left ventricular pacing lead via the CS is feasible and safe in the vast majority of patients. Once placed, the CS leads remain stable with excellent pacing thresholds over the longer term.     

Permanent Pacing from the Coronary Sinus in a Patient with an Implantable Defibrillator

A woman with an ICD underwent permanent pacemaker implantation for bradycordia-tachycardia syndrome. Despite multiple right atrial positions, oversensing secondary to "double counting" was always noted. A coronary sinus pacing catheter was inserted and left atrial pacing was accomplished with acceptable pacing and sensing characteristics. The patient has since done well without further shocks.     

经食管心房调搏负荷超声评价无痛性心肌缺血的严重程度

超声负荷试验可观察左室功能和节段性室壁运动异常（ＲＷＭＡ）。我们应用２４小时动态心电图（ＡＥＣＧ）监测了６２例心肌缺血患者，其中男４６例，女１６例，年龄４０～６６岁，平均年龄５６±８岁。根据有无心绞痛再分为无痛组和疼痛组。所有患者经食管心房调搏负荷试验，再以二维超声心动图（２ＤＥ）评价左室功能障碍情况。结果表明：无痛组ＲＷＭＡ发生率明显低于疼痛组，分别为４６．８％和９０％（Ｐ值＜０．０１）。总的缺血评分，无痛组明显低于疼痛组，分别为１３±１．６和１７±３．３（Ｐ值＜０．０１）。左室收缩功能以射血分数为代表，负荷试验后无痛组大于疼痛组（Ｐ值＜０．０１）。无痛性心肌缺血患者心肌功能障碍明显比疼痛性缺血患者轻。     

Acute Effects of Different Atrial Pacing Sites in Patients with Atrial Fibrillation: Comparison of Single Site and Biatrial Pacing

It has been reported that a trial single site or biatrial pacing can suppress the occurrence of AF. However, its mechanism remains unclear. The study population included 32 patients with AF (n = 20: AF group), or without paroxysmal AF (n = 12: control group). The mechanism and efficacy of atrial pacing were investigated by electrophysiological studies to determine which was more effective for suppressing AF induction; single site pacing of the right atrial appendage (RAA) or distal coronary sinus (CS-d), or biatrial (simultaneous BAA and CS-d) pacing. In the AF group, AF inducibility was significantly higher with BAA extrastimulus during RAA (12/20; P < 0.0001) or biatrial paced drive (7/20; P < 0.01) than during CS-d paced drive (0/20). In the control group, AF was not induced at any site paced. In the AF group, the conduction delay and other parameters of atrial vulnerability significantly improved during CS-d paced drive. The atrial recovery time (ART) at RAA and CS-d was measured during each basic pacing mode. ART was defined as the sum of the activation time and refractory period, and the difference between ARTs at RAA and CS-d was calculated as the ART difference (ARTD). The ARTD was significantly longer during BAA pacing in the AF group than in control group (155.0 +/- 32.8 vs 128.8 +/- 32.9 ms, P < 0.05). In the AFgroup, ARTDs during biatrial (52.0 +/- 24.2 ms) and CS-d pacing (51.7 +/- 26.0 ms) were significantly shorter than ARTD during RAA pacing. The CS-d paced drive was more effective for suppressing AF induction than biatrial or RAA paced drive by alleviating conduction delay. CS-d and biatrial pacing significantly reduced ARTD compared with RAA pacing.     

老年冠心病患者抑郁程度与心肌缺血的关系

目的观察老年患者心肌缺血与抑郁程度的关系 ,了解老年冠心病患者发生抑郁的一般规律。方法根据流行病研究中心抑郁度量表 (CES D)评分 ,将完成冠状动脉造影确诊为冠心病的老年患者 12 1例分为无抑郁组 (A组 ,64例 ) ,轻中度抑郁组(B组 ,3 4例 )和严重抑郁组 (C组 ,2 3例 ) ,观察不同组别之间在日常生活和活动平板运动试验中心肌缺血发生状况。结果无抑郁组以单支冠状动脉病变为主 ,轻中度抑郁组单支、双支和 3支病变比例相近 ;严重抑郁组以 3支病变为主。日常生活中 ,轻中度抑郁组ST段下降 (4 2± 1 3 )次 ,ST段下降持续时间 (3 5 8± 9 2 )min ,ST段下降指数 (3 2 8± 0 9)min/h ,均高于无抑郁组的 (1 8±0 3 )次、(16 6± 4 2 )min、(1 76± 0 4)min/h和严重抑郁组的 (2 1± 0 7)次、(17 8± 5 8)min、(1 69± 0 5 )min/h(P <0 0 5 ) ;运动试验中 ,轻中度抑郁组心肌缺血阳性率与严重抑郁组相近 ,明显高于无抑郁组 (P <0 0 5 )。日常生活中缺血症状与无抑郁组相似 ,但活动后明显高于无抑郁组 (P <0 0 5 )。结论抑郁程度与冠脉病变程度有关 ,不同抑郁程度的患者心肌缺血的表现不同。     

Sinus Arrest in Diaphragmatic Myocardial Infarction: Treatment of Power Failure with Atrial Pacing

Sinus arrest occurred in a patient with acute diaphragmatic myocardial infarction associated with right ventricular infarction. Cardiac output fell dramatically despite maintenance of a junctional rate of 72. Ventricular pacing at rate 82 and dopamine administration resulted in only slight hemodynamic improvement. Atrial pacing at rate 84 restored normal cardiac output until resumption of sinus node activity. These results suggest that atrial contraction is important for the maintenance of ventricular function in some patients with acute infarction, and may be of particular importance in the presence of right ventricular infarction. Temporary atrial or atrioventricular sequential pacing may be of great hemodynamic benefit in selected patients with conduction defects complicating myocardial infarction.     

Angiogenic gene therapy for refractory angina

ABSTRACT

Introduction: Stimulation of coronary collateral vessel growth by therapeutic angiogenesis (TA) offers an alternative treatment option for patients with refractory angina. Several TA modalities, including delivery to the heart of angiogenic growth factors (proteins or genes) and cells have been tested in clinical trials in the past two decades, but so far none of them resulted in significant therapeutic efficacy in large scale studies. This review attempts to identify the main obstacles hindering clinical success and recommends measures to overcome them in the future.

Areas covered: After stating the medical need and rational for TA, and listing and briefly discussing past and current TA clinical trials, three main areas of obstacles are described: conceptual questions, technical limitations and clinical design uncertainties. Based on scientific and technical advances and lessons learned in past clinical trials, potential solutions to overcome some of these obstacles are proposed.

Expert opinion: Several success criteria are identified, which apply to any TA approach of choice. It is emphasized, that each of these criteria needs to be met in future clinical trials to have a chance of therapeutic success.     

临时起搏在急性下壁心肌梗死中的临床应用

目的:探讨临时起搏在急性下壁心肌梗死接受急诊冠状动脉介入治疗术(PCI)患者中应用的适应证及时机。方法:回顾性分析我院2003年1月至2013年1月成功行急诊PCI的下壁心肌梗死213例的临床资料,其中行临时起搏治疗84例,未行临时起搏治疗129例。结果:临时起搏并不减少急性下壁心肌梗死的住院心血管事件发生率,且长时间使用(48 h)或保护性临时起搏在急性下壁心肌梗死患者中增加室性心律失常、感染、心脏破裂的机会,且延长住院日。结论:临时起搏在急性下壁心肌梗死中的应用应严格把握指征并尽快拔除。