Ventricular Fibrillation

Signs & symptoms

An abnormal heart rhythm is a change in either the speed or the pattern of the heartbeat — the heart may beat too slowly, too rapidly or irregularly. When the heart beats too slowly, too little blood is pumped out to the rest of the body. When the heart beats too quickly, it cannot fill completely so the body doesn't receive the blood volume it needs to function properly. Slow heart rates are called bradycardias. Fast heart rates are called tachycardias.

The heart is made up of four chambers. 上面的腔室，称为心房，接收和收集血液. 下腔称为心室，将血液输送到全身. Working together, the chambers of the heart move life-sustaining blood throughout the body.

心律异常有几种类型, 有些发生在其中一个心房，称为心房, 另一些发生在心室，被称为心室.

心脏跳动过快或过慢都会导致:

• Lightheadedness or dizziness
• 心悸(跳、振或捶胸)
• Fatigue
• Chest pressure or pain
• Shortness of breath
• Fainting spells

Sometimes there are no symptoms at all. 如果不及时治疗，某些异常的心律可能会导致死亡. On the other hand, 有些心律失常是常见的，没有任何不利的十大赌博靠谱网络平台, so-called benign arrhythmias. One of the goals of evaluation is to sort out the serious from the benign forms of heart beat disturbances.

Diagnosis

如果你的十大赌博平台排行榜怀疑你可能有心律失常, he or she will order one or more of the following diagnostic tests to determine the source of your symptoms.

• Electrocardiogram. 心电图(ECG或EKG)记录心脏的电活动. 被称为电极的小贴片被放置在你的胸部, arms and legs, and are connected by wires to the ECG machine. Your heart's electrical impulses are translated into a wavy line on a strip of moving paper, 使十大赌博平台排行榜能够确定心脏中电流流动的模式，并诊断心律失常和心脏损伤.
• Holter monitor. 动态心电图监测仪是一种小型的便携式仪器，可以24小时佩戴. 它可以在您进行日常活动时连续记录您的心电图. 你将被要求记录你的活动和症状. This monitor may detect arrhythmias that might not show up on a resting EKG that only records for a few seconds.
• Exercise stress test. 运动压力(跑步机)测试使十大赌博平台排行榜能够记录您在休息时可能不会发生的心脏电活动.
• Event recorder. An event recorder (loop recorder) is a small portable transtelephonic monitor that may be worn for several weeks. 这种类型的录音机适合那些不经常出现症状的病人. The monitor "loops" a two-minute recording into its memory that is continually overwritten. When you experience symptoms, you press a "record" button on the monitor which stores a correlating strip of EKG material. The recordings are telephoned to a 24-hour monitoring station and faxed directly to the requesting physician.
• Magnetic source imaging. Magnetic source imaging (MSI) is used as an overlay to magnetic resonance imaging (MRI). 该装置可以感知由心肌组织产生的弱磁场，并在无创的情况下定位心律失常，从而节省有创研究的时间.
• Tilt table test. 倾斜试验是用来诊断晕厥或昏迷(血管迷走神经性晕厥)，试图重现昏迷发作. 您将在一张特殊的桌子上直立倾斜约60度一段时间，并连续记录您的心电图和血压.
• The electrophysiology (EP) study. 脑电图研究可以让十大赌博平台排行榜获得更准确的信息, detailed information and, in many cases, provide treatment (i.e. catheter ablation) during the same session.

Treatments

这取决于你心律失常的类型和严重程度, 以及各种测试的结果，包括电生理研究, there are several treatment options. 你和你的十大赌博平台排行榜会决定哪一个是适合你的.

Medications

某些抗心律失常药物可以改变心脏中的电信号，帮助防止异常部位引发不规则或快速的心律.

Follow-up electrophysiology study

确保在住院两天或更长时间后药物能正常工作, 你可能会被带回实验室进行后续研究. 我们的目标是找到对你最有效的药物.

Implantable device (pacemaker)

All implantable devices or pacemakers work on "demand" and are used to treat slow heart rhythms. They are small devices that are implanted beneath the skin below the collarbone and connected to a pace wire(s) positioned inside the heart via a vein; this delivers a small electrical impulse to stimulate the heart to beat when it is going too slow.

Catheter ablation

A technique pioneered at UCSF, radiofrequency catheter ablation destroys or disrupts parts of the electrical pathways causing the arrhythmias, 为可能对药物反应不佳的患者提供缓解, 或者不愿意或不能服药的人.

导管消融包括将一根微小的金属头导线导管穿过腿部的静脉或动脉进入心脏. Fluoroscopy, 它可以让心脏病专家在监视器上看到导管在血管中的移动, provides a road map. Other catheters, usually inserted through the neck, 包含电子传感器，以帮助找到导致短路的区域. 然后将金属头的导管移动到每个问题部位，射频波——与用于广播和电视传输的能量相同——轻轻地烧掉每条不需要的组织链. When catheter ablation was first tried, direct current shocks were used, but researchers later developed the use of radiofrequency waves — a more precise form of energy. With radiofrequency catheter ablation, 病人通常在一天内出院, compared to open heart surgery, 需要一个星期的住院治疗和几个月的康复.

比如沃尔夫-帕金森-怀特综合症, 一根发丝般细的组织在上下心室之间创造了一条额外的电通路, radiofrequency ablation offers a cure. 它已经成为对药物治疗反应不佳或有心率加快倾向的患者的首选治疗方法.

即使是可以用药物控制的心律失常, the procedure has been shown to be cost effective because it eliminates medication failures that require hospitalization. 对于容易遭受药物治疗副作用的老年患者和由于潜在的胎儿健康风险而不能服用药物的育龄妇女来说，这也是一个有吸引力的选择.

While studies have shown that catheter ablation is more cost effective than drug therapy or surgery, patients who undergo the procedure also experience remarkable improvement in quality of life. 最近的一项研究对近400名心率异常快的消融患者进行了研究，其中近三分之一的患者被认为是心脏直视手术的候选者。研究发现，手术一个月后，98%的患者不需要药物治疗，95%的患者报告说他们的整体健康状况有了明显改善. 加州大学旧金山分校的研究还发现，患者的工作能力有所改善, exercise and take on physical activities.

Internal cardioversion

1991年，加州大学旧金山分校医学中心开发了将心房颤动和心房扑动转化为正常窦性心律的内部转复术. 内部心律复律是一种低能量的电击(1到10焦耳)，通过插入腹股沟静脉的两根导管和胸部的一个小电极垫在心脏内部传递. 这个过程由我们的电生理学家在电生理学实验室进行.

During the internal cardioversion, short-acting sedatives are given to make the patient sleepy. Currently, atrial flutter is successfully "cured" by radiofrequency catheter ablation; but treatment to restore atrial fibrillation to sinus rhythm has been the traditional use of medications and external cardioversion. 体外心脏复律是通过连接在胸部的两个除颤器垫输送50到300焦耳的高能量冲击. In some cases, 体外心脏复律失败是因为电流在到达心脏之前必须先通过胸部肌肉和骨骼结构. 当药物和体外心律转复不能使患者的心律恢复到正常的窦性心律时，就进行内心律转复.

加州大学旧金山分校将患者从心房颤动转化为正常窦性心律并进行内部心律转复的成功率为95%. 患者心房颤动的时间越短, 就越容易恢复到正常的心律, 但即使是长期慢性心房颤动的患者也可以通过内部心律转复成功地转化为正常的心律. With internal cardioversion, 我们的电生理小组成功地转化了一个患有慢性心房颤动八年的病人.

Implantable cardioverter defibrillator

An implantable cardioverter defibrillator is a device for people who are prone to life-threatening rapid heart rhythms. It is slightly larger than a pacemaker and usually is implanted beneath the skin below the collarbone. It is connected to a defibrillation/pace wire(s) positioned inside the heart via a vein. It has the capability of delivering an electric shock to the heart when it determines the heart rate is too fast. 当心脏跳动过慢时，它也能调节或刺激心脏.

Biventricular pace maker

The U.S. 美国食品和药物管理局(FDA)最近批准了第一种新型心脏起搏器，这种起搏器可以调节心脏的两个心室的速度，以协调它们的收缩，提高它们的泵送能力. According to the test results presented to the FDA, cardiac resynchronization therapy (CRT):

• Increases the amount of daily activities patient can perform without the symptoms of heart failure
• Extends the exercise capacity of heart failure patients as measured by the distance they can walk in 6 minutes
• 根据标准测量，提高整体生活质量
• 促进心脏解剖结构的改变，改善心脏功能
• Reduces the number of days patients spend in the hospital and the total number of hospitalizations

CRT装置通过同时对左、右心室起搏来工作, which results in resynchronizing the muscle contractions and improving the efficiency of the weakened heart. In the normal heart, 电传导系统以高度有序的收缩方式向左心室传递电脉冲，从而非常有效地将血液泵出心室. 心脏增大引起的收缩期心力衰竭(扩张型心肌病), this electrical coordination is lost. Uncoordinated heart muscle function leads to inefficient ejection of blood from the ventricles.