From Dr Andrew To, Cardiologist, WDHB

Arrhythmia  心律不整

Arrhythmia is a problem with the rate or rhythm of our heartbeat.  The heart can beat too fast, too slow, or with an irregular rhythm.
心律不整是我們心跳速率或節律的問題。心臟可能跳動過快，過慢或者是有不規則的節奏。

Tachycardia is the term that refers a heart beat that is too fast. Bradycardia describes a heart beat that is too slow.
心動過速是指心臟跳動太快。心動過緩是指心臟太慢。

Arrhythmia encompasses a diverse range of conditions, some harmless, but some serious or even life threatening.
心律不整包括多種多樣的病症，有一些是無害，但有一些卻是嚴重的，甚至危及生命。

Arrhythmias are more common in people with heart diseases. This includes heart attacks (myocardial infarction), heart failure, abnormal thickening of heart tissue, heart valve problems, congenital heart disease (heart defects present at birth).  Other conditions can also cause arrhythmia, including high blood pressure, diabetes, and abnormal thyroid function.
心律不整在比較常見於有心臟疾病的人；包括心臟病發作（心肌梗死），心衰竭，心臟組織異常增厚，心臟瓣膜疾病，先天性心臟病。其他引起心律失常的病症還包括高血壓，糖尿病，甲狀腺功能異常。

Normal Conduction System  正常心臟傳導系統

Normal heart function relies four components
正常的心臟功能依靠四個部分：

• heart muscle contraction
  – 心臟肌肉的收縮
• normal valve function
  – 正常的心臟瓣膜功能
• coronary arteries providing blood supply and nutrients
  – 冠狀動脈提供的血液供應和營養
• conduction system coordinating the pumping of blood through the atria and the ventricles
  – 傳導系統協調血液在心房和心室的泵送

Conduction system is our heart’s internal electrical system, controlling the rate and rhythm of our heartbeat.  With each heartbeat, an electrical signal spreads from the top of the heart to the bottom.  The electrical signal stimulates the heart contraction. The normal heartbeat with its subsequent electrical propagation is often referred to as the normal sinus rhythm.
心臟傳導系統是我們心臟內部的電流系統，控制我們的心跳速度和節奏。隨著每次心跳，電流信號從心的頂部傳播到底部。電流信號刺激心臟的收縮。這正常的心跳，及隨後的電流傳播， 通常被稱為正常竇性心律。

The intrinsic pacemaker sits in a group of cells called the sinoatrial (SA) node, where each electrical signal originates. At rest, our SA nodes send an electrical signal 60-100 times a minutes, making our normal pulse rate at 60-100 a minute.
我們心臟本身的起搏器位於竇房結的一組細胞，是心臟電流信號的起源。人休息時，竇房結每分鐘發送 60-100 次信號，使我們的正常脈搏率大約在每分鐘 60-100。

The electrical signal from the SA node travels through the atria (the upper collecting chambers of the heart), causing it to pump blood into the heart’s ventricles (the lower pumping chambers).
從竇房結的電流信號通過心房（心臟收集血液的地方），心房的收縮將血液泵送到心臟的心室（心臟泵送血液的地方）。

The signal reaches a group of cells at the atrioventricular (AV) node, located between the atria and the ventricles. There is a slowing of the signal at this point to allow for the ventricles to fill after atrial contraction.
電流信號然後到達的一組細胞，是位於心房和心室之間的 。房室結將信號放緩，讓心室在心房收縮後有足夠的時間注滿。

Finally, the electrical signal leaves the AV node and rapidly travels the bundle of His and the Purkinje fibres to activate the rest of the ventricles. The end result is the ventricular contraction and pumping of blood to the lungs and the rest of the body. This process is rapid, so that the entire ventricle is coordinated in contracting at the same time to maximize the pumping efficiency.
最後，電流信號離開房室結，經希氏束及蒲金氏維束，迅速的行進到心室的其餘部分，最終的結果是整個心室有協調和效率地收縮，泵送血液到肺和身體其他部位。

A problem with any part of this process can cause an arrhythmia.
在這個過程中的任何部分出現問題，都可能會導致心律不整 。

Diagnosing arrhythmia  診斷心律不整

Arrhythmia covers a wide range of conditions. Most arrhythmias are harmless, but some are not.  The outlook depends on the type and severity of the arrhythmia. Establishing the right diagnosis is most important.
心律不整涵蓋了各種各樣的病症。大多數的心律不整是無害，但有些情況卻不是。嚴重程度取決於心律不整的類型和原因，所以正確的診斷是最為重要。

Many arrhythmias cause no symptom. This is part of the reason for heart attack patients to be admitted to the coronary care unit, where arrhythmias are actively looked for and treated.
很多時候，心律不整不會引起任何症狀；這也是心臟病發後患者要入住冠心病監護病房的原因，為著要監測和及早治療心肌梗死引發的嚴重心律不整。

In others, arrhythmias can present as
在其他情況下，心律不整引起的症狀包括：

• palpitations (heart flutters)
  – 心悸
• a fast heart beat
  – 心搏過快
• a slow heart beat
  – 心搏過慢
• an irregular heart beat
  – 心搏不規則的跳動
• pauses between heart beats
  – 心搏短暫的停頓

Other more serious symptoms include
其他更嚴重的症狀包括：

• dizziness, lightheadedness
  – 頭暈
• fainting, near-fainting, collapse
  – 近昏厥，昏厥，暈眩，休克
• fatigue, weakness
  – 疲勞，乏力
• anxiety
  – 焦慮
• sweating
  – 冒汗
• chest pain
  – 胸痛
• shortness of breath
  – 氣短

ECG (electrocardiogram) is the cornerstone of diagnosing arrhythmias.  Using leads on the chest, arms and legs, the ECG records the heart’s electrical activity and diagnoses abnormal heart rate and rhythm. Its limitation, however, is the fact that a standard ECG only records the heartbeat for a few seconds.  In arrhythmias that come and go, other tests may have to be done.
心電圖是診斷心律不整的最基本的測試。利用放在胸，胳膊和腿的電極，心電圖記錄心臟的電流活動的情形， 診斷心臟異常的速度和節奏。心電圖檢查的局限性，在於一個標準的心電圖只記錄幾秒鐘的心跳；如果心律不整的症狀是斷斷續續，就可能要用其他的測試。

A Holter monitor records the heart’s electrical signals for a full 24 or 48 hours. Every heartbeat is counted and analyzed, when we do our normal daily activities. When symptoms occur, we can correlate back to the ECG and see what caused the event.
攜帶式心電圖記錄檢查監視 24 或 48 小時的心臟電流活動，完整的分析每一次心跳，讓症狀發生時可以看看心電圖的診斷是甚麼。

An event monitor is similar to the Holter monitor, but can be worn for longer, e.g. a week or two. However, it requires the patient to push a button to start recording when symptoms are felt.  Again, the ECG gives information about what the symptoms were caused by.
事件記錄器跟攜帶式心電圖差不多，但可以延長記錄時間至一兩個星期。但病人是需要在感到不舒服的時候按下按鈕，開始記錄心電圖的診斷。

In rare cases, implantable loop recorder can be surgically placed under the skin in the chest area, in order to figure out what arrhythmia is causing the patients’ symptoms.  These recorders are left for as long as 1-2 years and are used in more serious cases of suspected arrhythmia.
在少數情況下，為了弄清楚患者的嚴重症狀是從那一種心律不整的病症引起，患者可能需要利用手術在胸前皮膚下放置植入式循環記錄器，記錄長達 1-2 年的心臟電流活動。

Echocardiography is often used in the workup of arrhythmia, despite the fact that it does not record the heart’s electrical activities.  This ultrasound examination gives information about the function of the heart muscles and heart valves. If abnormal, the chance of sinister arrhythmia is much higher.
超聲心動圖經常用於評估心律不整，儘管它不記錄心臟的電流活動。超聲檢查探討心臟肌肉和心臟瓣膜的功能；如有異常，嚴重及有危險性的心律不整的機率就高得多。

Electrophysiology study (EPS) is used to assess serious arrhythmias.  It is an invasive procedure that involves the passing of thin flexible electrodes through the groin veins and arteries to the heart, in order to record the heart’s electrical signals. The wires can also stimulate and trigger an arrhythmia, in order to make the correct diagnosis.  Catheter radiofrequency ablation may be performed during EPS, if it has been determined that the patient’s specific arrhythmia can be treated by delivering a special energy through the ablation catheter and destroying small areas of heart tissue responsible for the arrhythmia.
電氣生理學檢查是用來評估嚴重的心律不整。它是一種侵入性的手術，將電極導管通股動脈和靜脈，放進心臟內，記錄心臟的電流信號；電極導管也可以刺激和觸發心律失常，從而作出正確的診斷。射頻波導管燒灼術可以在電氣生理學檢查過程中進行，通過特殊的射頻波能量，破壞引發心律不整的心臟組織，從而根治病症。

Important types of arrhythmia  一些心律不整重要的類型

The clinical characteristics, presentation, prognosis and treatment of arrhythmias differ according to its type.
心律不整的臨床特徵，症狀，預後和治療方法，取決於病症的起因和類型。

Bradyarrhythmias  心動過緩

Bradyarrhythmias occur when the heart rate is slower than normal. When the heart rate is too slow, the brain does not receive enough blood, and causes patients to pass out.
心動過緩（心臟傳導障礙）是指心率比正常的要慢。當心率太慢，大腦可能沒有得到足夠的血液，造成患者暈倒了。

Not all patients with a heart rate slower than 60 beats per minute has bradyarrhythmia, as those who are physically fit can often have slow heart rates. In others, bradyarrhythmias can be dangerous and life threatening.
不是所有心臟速度慢於每分鐘 60 次的人，就患上心動過緩，例如有強健體魄的人，往往有慢心率。在某些情況下，心動過緩可以是危險，甚至危及生命的。

Bradyarrhythmias can be caused by a variety of conditions, including
心動過緩可能是由於多種原因引起，包括：

• aging
  – 衰老
• heart attacks
  – 心肌梗死
• electrolyte imbalance (e.g. potassium, calcium…)
  – 電解質失衡（例如鉀，鈣…）
• medications that slow down our heart rate (e.g. beta-blockers, calcium channel blockers…)
  – 減慢我們心率的藥物
• conditions that alter the heart’s electrical activity, including an underactive thyroid gland
  – 改變心臟的電流活動的疾病，包括甲狀腺功能減退

The ECG is most helpful in sorting out the underlying diagnosis, its prognosis and therefore treatment. In many with bradyarrhthmias, a pacemaker is necessary.
心電圖在心動過緩的診斷最為有幫助。心臟起搏器（心律調節器）是很多心動過緩患者治療的唯一方法 。

  Image from Medtronic.com

A pacemaker is a device implanted under the skin of the chest, with sensors that detect the heart’s electrical activity. When there is a block in the electrical signaling, electrical impulses are sent from the pacemaker to prompt the heart to beat at a normal rate.  Most pacemakers only weigh about 20-50 grams and sit under the collarbone.  They are smaller than an average matchbox.
心臟起搏器是植入胸部皮膚下的，以電極及導線檢測心臟的電流活動。如電流活動過慢，節律器便會發送電脈衝，使心臟在正常的速度跳動。起搏器大多數僅重約 20-50 克，坐在鎖骨下，小於一般的火柴盒。

Premature beats  早搏

The most common type of arrhythmia is premature beats and is harmless most of the time.  In most cases, premature beats happen naturally and do not cause symptoms. If they do, people usually feel a chest fluttering or a feeling of skipped heartbeat.  Stress, caffeine or nicotine exacerbates this condition.
早搏是最常見的心律不整，在大部分情況下是自然發生，不引起症狀，及無害的。早搏常見的症狀，包括心搏短暫的停頓。通常早搏會被壓力，咖啡因或尼古丁加劇。

Premature beats can originate from the atria, premature atrial contractions (PACs), or ventricles, premature ventricular contractions (PVCs).
早搏可源於心房或心室，分別稱為房性早搏和室性早搏。

In rare cases, premature beats are associated with heart diseases. Excluding structural heart disease may be important in patients with suspected premature beats.
在少數情況下，早搏可能與心臟疾病有關聯；所以在疑似早搏的患者，是需要剔除結構性心臟疾病的可能性。

Atrial fibrillation  心房顫動

Atrial fibrillation (AF) is the most common serious arrhythmia, characterized by the fast but irregular activation of the atria.
心房顫動（房顫）是最常見的嚴重心律不整，其特徵在於心房快而不規則的活動。

Electrical signals in the atria spread in a rapid and disorganized manner, resulting in the atrial wall quivering very quickly (fibrillating), instead of beating normally and emptying blood from the atria to the ventricles.
房顫的電流信號，在心房內迅速和雜亂無章的傳播，導致心房壁非常迅速地微微顫動, 心房失去從心房排空血液到心室的正常功能。

In some people, AF occurs for a short duration of time, coming and going on their own; i.e. paroxysmal AF.  In others, AF may be present all the time; i.e. persistent AF.
有時候，房顫發生的時間很短，斷斷續續，即陣發性房顫；有時候，房顫不斷持續，即持續性房顫。

The result of the atrial fibrillation is that these electrical signals travel to the ventricles at rates of >300 per minute. They cause the ventricles to beat irregularly and too fast.  This results in the failure of the ventricles to fill completely with blood, and hence prevent the heart from pumping enough blood to meet the body’s needs. Heart failure ensues, presenting with shortness of breath, poor exercise capacity, ankle swelling, and inability to lie flat at night.
心房顫動的結果, 是電信號從心房以大於每分鐘三百次的頻率到達心室，導致心室的跳動太快而不規則，無法泵送足夠的血液滿足人體的需求；從而引起心臟衰竭，出現氣短，運動能力變差，踝關節腫脹，無法夜間平躺等症狀。

Atrial fibrillation also prevents the emptying of blood from the atria, causing blood clots to form.  When a blood clot breaks off and travels to the brain, it can cause a stroke.
心房顫動也防止血液從心房排空， 導致血液凝塊形成及脫落前往大腦，引發中風。

Management of atrial fibrillation is often complicated and should always be tailored to the individual patient’s condition.  Options include controlling the rapid heart rate with medications, cardioverting patients from atrial fibrillation back to normal sinus rhythm.  Cardioversion can either be performed using medicines (chemical cardioversion) or by electrical cardioversion that involves a brief general anaesthetic and a brief low-energy electrical shock to restore normal rhythm.
房顫的治療往往很複雜，根據個別病人的病情而改變。方法包括用藥物控制快速的心率，或者使用藥品或電擊整律術還原正常竇性心律。心臟電擊整律術運用簡短的全身麻醉，以簡短和低能量的電擊恢復正常竇性心律。

In addition, the stroke risk should be minimized by the use of blood thinning medications, such as Warfarin or Dabigatran. These medications can cause significant bleeding as potential side effects, hence are recommended in those with moderate-high stroke risk.
稀釋血液的藥物可減少房顫引起的中風風險。常見的抗凝血藥包括華法林或新藥達比加群。出血是潛在的副作用，所以抗凝血藥只用於那些中風風險中度以上的病人。

In a minority of AF patients who failed medical therapy, ablation procedure can be performed to restore normal rhythm.
導管燒灼術最近也開始應用於少數房顫藥物治療功效不理想的患者，以恢復正常的節奏。

Atrial flutter is a similar condition to atrial fibrillation, though less common.  The origin of the abnormal electrical signals is different with a fast but regular, instead of irregular, rhythm. However it presents with similar symptoms and has similar complications as atrial fibrillation.
心房撲動是跟心房顫動相似的病症，但較少見。異常的電流信號起源自是一個節奏快，但有規律的。心房撲動的症狀及併發症與房顫類似。

Paroxysmal supraventricular tachycardia (SVT)
陣發性上心室心搏過速

SVT is a condition characterized by a very fast heartbeat that begins and ends abruptly. The abnormal electrical signal originates in the area between the atria and the ventricles.  Symptoms may include palpitations, with or without dizziness and chest discomfort.
上心室心搏過速的特徵是非常快速的心率，突然開始也突然結束。異常的電信號起源於心房和心室之間的區域。症狀包括心悸，頭暈，胸部不適等。

In this type of arrhythmia, vagal manoeuvers can sometimes control the heart rate.  These include holding our breath and bearing down (Valsalva manoeuver), coughing and immersing our face in ice-cold water. In others, medications such as adenosine may be needed to restore normal rhythm. Other medications (e.g. beta-blockers) may be used to reduce the occurrence of these arrhythmias.  In most cases, if medications are ineffective, radiofrequency ablation is highly effective.
迷走神經刺激有時可以控制這種心搏過速，這包括冰水敷臉法、伐氏操作憋氣法，及咳嗽。其他患者可能需要藥物（如腺苷）恢復正常的節奏； 其他的藥物（如 β-阻斷劑）則減少這種心搏過速發生的機會。在大多數情況下，如藥物無效，射頻導管燒灼術是非常有效的。

Wolff-Parkinson-White syndrome is a special subtype of SVT that involves electrical signals travelling along an extra pathway from the atria to the ventricles. Such extra pathway may cause the abnormal contraction of the ventricles and potentially is life threatening.
沃爾夫．巴金森．懷特氏症候群是一種特殊的上心室心搏過速。電信號從心房途經心房與心室之間的附加傳導路徑到達心室。這種附加傳導路徑能導致異常的心室收縮，並有可能危及生命。

Ventricular arrhythmias  心室性心律不整

Ventricular arrhythmias originate from the hearts’ lower chambers, the ventricles; and are dangerous and life threatening. These include ventricular tachycardia and ventricular fibrillation.  They usually present in the context of a heart attack (myocardial infarction), weakened heart muscle (cardiomyopathy), or rarer rhythm disorders of the heart.
心室性心律不整源於心室，是危險和能致命性的心律不整 。心室性心律不整包括心室性心搏過速和心室纖維顫動。它們通常發生於心臟病發（心肌梗塞），心肌疾病，或較罕見的心臟節律疾病的患者。

Both conditions cause significant compromise of heart function and lead to sudden collapse (cardiac arrest) and death within minutes.  These arrhythmias are responsible in causing sudden cardiac death in those who had heart attacks.
心室性心律不整會導致心臟突然失去功能，在幾分鐘之內，導致嚴重的心臟衰竭，休克，昏迷，猝死。這種心律不整就是導致心肌梗塞患者猝死的主因。

Treatment is with an electric shock to the heart called defibrillation. This is usually delivered by emergency first responders such as ambulance personnel.  Recent use of automated external defibrillator (AED) strategically placed in public spaces has improved the chance of survival from sudden cardiac arrest.
治療心室性心律不整通常是在救護人員到達患者後，以體外去顫器電擊心臟除顫。最近在公共場所策略性地放置的自動體外除顫器大大提高心肌梗塞後心律不整患者存活的機會。

In survivors of sudden cardiac arrest, or in those with a high risk of ventricular arrhythmias, doctors may recommend the use of an implantable cardiac defibrillator (ICD) on top of usual medicines to control the condition.  This device is similar to a pacemaker, though slightly bigger. Its role is in detecting ventricular arrhythmias and delivering an internal electrical shock to revive the heart.  It has been shown to improve these patients’ long-term survival.
在心臟驟停的倖存者，或在那些室性心律不整高風險的病人，醫生可能建議使用植入式心臟除顫器控制病情。此設備類似心臟起搏器，但稍大一點，作用是探測室性心律不整， 提供內部電擊，使心臟復甦。植入式心臟除顫器大大改善這類患者長期生存的機會。