Cardiac Arrhythmia

Cardiac arrhythmia is a group of conditions in which the muscle contraction of the heart is irregular or is faster or slower than normal. Cardiac dysrhythmia might be a more correct phrase to describe the condition, as arrhythmia would imply that there is "no rhythm," but this term is not used frequently.

Some arrhythmias are life-threatening medical emergencies that can cause cardiac arrest and sudden death. Others cause aggravating symptoms, such as an awareness of a different heart beat, or palpitation, which can be annoying. Some are quite benign and normal. Sinus arrhythmia is the mild acceleration followed by slowing of the normal rhythm that occurs with breathing. In adults the normal heart rate ranges from 60 beats per minute to 100 beats per minute. The normal heart beat is controlled by a small area in the upper chamber of the heart called the sinoatrial node or sinus node. The sinus node contains specialized cells that have spontaneous electrical activity that starts each normal heart beat.

Cardiac dysrhythmias are often first detected by simple but nonspecific means: auscultation of the heartbeat with a stethoscope, or feeling for peripheral pulses. These cannot usually diagnose specific dysrhythmias, but can give a general indication of the heart rate and whether it is regular or irregular. Not all the electrical impulses of the heart produce audible or palpable beats; in many cardiac arrhythmias, the premature or abnormal beats do not produce an effective pumping action and are experienced as "skipped" beats.

There are many classes of antiarrhythmic medications and many individual drugs within these classes. Dysrhythmias may also be treated electrically. Cardioversion is the application of electrical current across the chest wall to the heart and it is used for treatment of supraventricular or pulsed ventricular tachycardia. Defibrillation differs in that it is used for ventricular fibrillation and pulseless ventricular tachycardia, and more electricity is delivered with defibrillation than with cardioversion. In cardioversion, the recipient is either sedated or lightly anesthetized for the procedure. In defibrillation, the recipient has lost consciousness so there is no need for sedation.

Electrical treatment of dysrhythmia includes cardiac pacing. Temporay pacing may be done for very slow heartbeats, or bradycardia, from drug overdose or myocardial infarction. A pacemaker may be placed in situations where the bradycardia is not expected to recover.

Atrial fibrillation can also be treated through a procedure, e.g. pulmonary vein isolation. This is performed by a cardiologist who specializes in electrophysiology and is done percutaneously with catheters. Alternatively, a maze procedure can be performed through cardiothoracic surgery.

Transvenous catheter ablation is established as a curative treatment for many arrhythmias. Using Image Integration Guided Catheter Ablation it is possible to know the precise location of the catheter in relation to the cardiac anatomy. The CartoMergeTM mapping system from Biosense Webster integrates pre-procedural computed tomography (CT) or magnetic resonance (MR) images with electroanatomic maps has recently been approved for patient care.

...More at Wikipedia

Related Links:

• American Heart Association
• US National Library of Medicine
• Mayo Clinic

Recent Hope Cube Blog Entries For Cardiac Arrhythmia

• New Trigger For PVC Thu, August 09, 2007 - [view]
  I went to play tennis with my wife today. It wasn't intensive at all but I started to get PVCs soon after. Argh! It seems like anything and everything can trigger an arrhythmia episode. What's next? Watching TV?
• Weird BP and heart rate Mon, July 30, 2007 - [view]
  Since I've been getting PVCs recently, I measure my blood pressure and heart rate at least once a day. The readings I get is kind of weird (105-110/50-55). The systolic pressure is perfect but the diastolic is very low. I don't know what this means but I hope it isn't bad. My heart rate is also very slow at times (50-55). This is probably good if I run a lot, but I don't.
• Cardiologist appointment... in 1 month! Wed, July 25, 2007 - [view]
  Made an appointment with a cardiologist today. The earliest time he has available to check out my heart is... hold your breath... in 1 month! The scheduler didn't even ask me what's wrong with my heart. What if I had something serious? I'll probably be dead within a month. Something has to change in the American health care system. I have full coverage Blue Cross PPO and I cannot imagine someone with Medicaid or HMO trying to make an appointment.
• Diet Soda Tue, July 24, 2007 - [view]
  I found an article today about Diet soda linked to heart risks. "People who drank one or more diet sodas each day developed the same risks for heart disease as those who downed sugary regular soda,..." Diet or regular, they're all just sugar water. Nothing beats a glass of refreshing h2o. Study: Diet Soda Linked to Heart Risks
• Fever + Arrhythmia! Fri, July 20, 2007 - [view]
  Came home yesterday and all of the sudden felt sick. I had a fever and the arrhythmia went crazy. I guess fever is a trigger for arrhythmia as well.