Cardiac arrhythmia is characterized by abnormal heart rate or rhythm. It typically refers to a condition, where in the electrical activity that regulates heartbeat is irregular, slow or fast.
Presentation
In many instances, cardiac arrhythmia may not produce any signs or symptoms. An abnormal heart rhythm gets diagnosed during a routine checkup, much before signs and symptoms appear. However, when symptoms are experienced, they include pain in chest, dyspnea, onset of tachycardia or bradycardia, flutter in chest, lightheadedness accompanied by dizziness and fainting.
Condition such as ventricular tachycardia can be life threatening causing cardiac arrest, or sudden death and increasing risks for embolisation and stroke [6].
Workup
A preliminary physical examination, along with a careful review of medical history would be done. This will be followed by various tests, which include:
- Electrocardiogram: With the help of electrocardiogram, the time and duration of each and every electrical activity in the heart can be measured.
- Holter monitor: This portable device is meant for recording the heart beats and is worn for a 24 hour period, which would help in determining the heart beat as one carries out daily routine tasks.
- Event monitor: This is useful for individuals experiencing sporadic episodes of arrhythmia. The device is kept handy, and used for recording the heart beats when one is experiencing the symptoms.
- Echocardiogram: This is a non-invasive procedure, wherein a transcuder is placed in the chest for determining the size of the heart, its motion and structure.
In cases, when arrhythmia cannot be diagnosed with the above mentioned tests, then additional methods may be required. These include stress test, tilt table test and electrophysiological testing [7].
Treatment
Often, arrhythmia would not require any treatment, unless the condition is causing severe symptoms which can eventually lead to serious complications. Treatment would depend on the type of arrhythmia that has set in. The following methods are employed:
Treatment for bradycardia: This is treated with pacemaker, if an underlying condition cannot be found. There are no medications for improving the heart beats and therefore pacemaker is the best option [8].
Treatment for tachycardia: Vagal maneuvers such as coughing, holding breath and straining, can help in normalizing the fast heartbeat. If this does not work, medications may be administered for lowering the heartbeat. Anti-arrhythmic medications are given to prevent onset of complications. In case of atrial fibrillation, cardioversion can be employed [9].
In addition to these methods, catheter ablation can also be conducted. In this, with the help of radiofrequency energy, a small part in heart tissue is ablated in order to destroy the point of arrhythmia origination [10].
Prognosis
Prognosis of the condition significantly depends on the type of arrhythmia that has set in. In addition, if prompt treatment is not initiated then cardiac arrhythmia can give rise to life threatening conditions. Individuals who have developed arrhythmia due to underlying condition such as, congestive heart failure or valvular disease have a poor prognosis if the condition is not effectively managed. When there is no structural deformity present, the prognosis is excellent [5].
Etiology
Cardiac arrhythmia can be caused by several factors, which include hypothyroidism, hyperthyroidism, myocardial infarction, congenital heart disease, scarring of the myocardium due to myocardial infarction, cardiomyopathy and electrolyte imbalance [2].
In addition to these factors, some other conditions can favor cardiac arrhythmia. These include stimulant drugs, overuse of products containing caffeine, alcohol consumption, medications taken for management of hypertension and other heart problems, smoking and drugs used for treatment of psychiatric disorders. Medications used for treating a type of arrhythmia can also pave way for development of another type of arrhythmia.
Epidemiology
Cardiac arrhythmia is a common phenomenon and strikes the majority of the population across the globe. According to the statistics provided by the Center for Disease Control and Prevention, it was found that more than 600,000 sudden cardiac deaths are recorded each year. It has also been estimated that, about 50% of patients experienced sudden death as a preliminary manifestation of heart disease.
Pathophysiology
Irrespective of the type of arrhythmia that has set in, the pathophysiology follows any one of the 3 mechanisms; which include triggered activity, enhanced or suppressed automaticity and re-entry. Under normal conditions, the rhythm of heart is controlled by the sinus node, situated in the right atrium. The electrical impulses produced by the sinus node initiate each heart beat. Factors that interfere with the production of electrical impulses, favor the development of arrhythmia [3].
Tachycardias that originate in the atria include supraventricular tachycardia, atrial fibrillation, Wolff-Parkinson-White syndrome and atrial flutter. The ones which originate in the ventricles include long QT syndrome, ventricular tachycardia and ventricular fibrillation [4].
Prevention
Adopting a healthy lifestyle can help in preventing occurrence of cardiac arrhythmia. Individuals can improve their heart health by following an active lifestyle, along with consuming a healthy diet and maintaining healthy weight. Avoiding smoking, alcohol and limiting consumption of caffeine can also reduce the risk of developing cardiac arrhythmias.
Summary
In cardiac arrhythmia the heart may beat either too fast, too slow or it might beat irregularly. When the heart beat is more than 100 beats per minute, the condition is termed as tachycardia; when the rate is slower than 60 beats per minutes, the condition is termed as bradycardia. In majority of instances, arrhythmias are not life threatening; however, if it causes impairment of cardiac function it can lead to cardiac arrest [1].
Patient Information
Definition: Cardiac arrhythmia is defined as onset of abnormal heart rhythm or rate that occurs when there is some problem with the electrical impulses of the heart. In such a type of condition, the heart can either beat too fast, too slow or can be irregular.
Cause: Several factors that favor the development of arrhythmia include conditions of hyperthyroidism, hypothyroidism, diabetes, and heart attack, damage to heart tissue due to heart attack, alcohol abuse, stress, medications and hypertension.
Symptoms: Symptoms include pain in chest, followed by shortness of breath along with dizziness and lightheadedness.
Diagnosis: Cardiac arrhythmia is usually diagnosed with help of electrocardiogram. In addition, devices such as holter monitor and event monitor can also help detect abnormal heart beats for a 24 hour period or when symptoms are occurring. Echocardiogram is indicated to determine the size, motion and structure of heart.
Treatment: Bradycardia is treated with pacemaker, as no medications are available to treat slow heartbeat. Tachycardia is treated with help of vagal maneuvers, medications and cardioversion techniques. In many cases, catheter ablation can also be carried out.
References
- Seferović PM, Ristić AD, Maksimović R, et al. Cardiac arrhythmias and conduction disturbances in autoimmune rheumatic diseases. Rheumatology (Oxford) 2006; 45 Suppl 4:iv39.
- Francis GS. Development of arrhythmias in the patient with congestive heart failure: pathophysiology, prevalence and prognosis. Am J Cardiol 1986; 57:3B.
- Podrid PJ, Fogel RI, Fuchs TT. Ventricular arrhythmia in congestive heart failure. Am J Cardiol 1992; 69:82G.
- Newman BJ, Donoso E, Friedberg CK. Arrhythmias in the Wolff-Parkinson-White syndrome. Prog Cardiovasc Dis 1966; 9:147.
- Holmes J, Kubo SH, Cody RJ, Kligfield P. Arrhythmias in ischemic and nonischemic dilated cardiomyopathy: prediction of mortality by ambulatory electrocardiography. Am J Cardiol 1985; 55:146.
- Teerlink JR, Jalaluddin M, Anderson S, et al. Ambulatory ventricular arrhythmias in patients with heart failure do not specifically predict an increased risk of sudden death. PROMISE (Prospective Randomized Milrinone Survival Evaluation) Investigators. Circulation 2000; 101:40.
- Milner PG, Dimarco JP, Lerman BB. Electrophysiological evaluation of sustained ventricular tachyarrhythmias in idiopathic dilated cardiomyopathy. Pacing Clin Electrophysiol 1988; 11:562.
- McMullan J, Valento M, Attari M, Venkat A. Care of the pacemaker/implantable cardioverter defibrillator patient in the ED. Am J Emerg Med. Sep 2007;25(7):812-22.
- Mason JW. A comparison of seven antiarrhythmic drugs in patients with ventricular tachyarrhythmias. Electrophysiologic Study versus Electrocardiographic Monitoring Investigators. N Engl J Med 1993; 329:452
- Morady F. Radio-frequency ablation as treatment for cardiac arrhythmias. N Engl J Med 1999; 340:534.