Cardiac Arrhythmia

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Contents 1 More Specific Terms 2 Introduction 3 Etiology 4 History 5 Physical-examination 6 Clinical-manifestations 7 Laboratory 8 Diagnostic-procedures 9 Management 10 More General Terms 11 Additional Terms 12 References

More Specific Terms

• atrioventricular (AV) dissociation
• bigeminy
• bradyarrhythmia (bradycardia)
• heart block
• premature electrocardiography complex
• pulseless electrical activity (PEA, electromechanical dissociation)
• re-entry
• supraventricular arrhythmia
• tachyarrhythmia (tachycardia)
• trigeminy
• ventricular arrhythmia

Introduction

• Irregularity or loss of rhythm of the heartbeat.

Etiology

• pharmaceutical agents:
• adriamycin
• antiarrhythmic drugs
• atropine
• anticholinesterases
• emetine
• lithium
• phenothiazines
• sympathomimetics
• thyroid hormones
• tricyclic antidepressants

History

• onset, regularity, duration & pattern of discontinuance*
• dyspnea
• chest pain
• syncope, near-syncope or lightheadedness
• preciptitating or exacerbating factors
• familial or congenital arrhythmias
• comorbidities

• heart disease

• coronary artery disease
• valvular heart disease
• cardiomyopathy

• conduction system disease

• inflammatory disease
• endocrinopathy
• infection

• Chaga's disease
• Lyme disease

• * patterns

• arrhythmias that start & terminate abruptly are generally due to re-entry

• paroxysmal supraventricular tachycardia ( PSVT)
• ventricular tachycardia

• an arrhythmia that starts & stops more gradually generally results from increased automaticity

Physical-examination

• pulse rate & regularity
• orthostatic blood pressure
• presence of murmurs
• presence of S3 gallop
• paradoxical or fixed splitting of S2
• during the arrhythmia

• indicators of AV synchrony

• intermittent cannon A waves in jugular venous pulsation
• variable intensity of S1
• variable peak systolic blood pressure

• effect of vagal maneuvers

• carotid sinus massage
• Valsalva maneuver

Clinical-manifestations

• symptoms may include:
• palpitations
• lightheadedness
• shortness of breath or dyspnea on exertion
• syncope or presyncope
• angina pectoris
• sudden cardiac death

Laboratory

• serum electrolytes

• serum K+
• serum Ca+2
• serum Mg+2

• antiarrhythmic drug levels
• thyroid function tests

Diagnostic-procedures

• electrocardiogram ( EKG)

• 12- lead
• rhythm strip
• continous 24 hour monitor (in hospital)
• Lewis bipolar exploring lead
• transesophageal electrogram
• direct atrial electrogram

• HOLTER if arrhythmia intermittant but occurs at least daily
• event recorder if arrhythmia is symptomatic but infrequent, i.e. syncope
• programmed electrical stimulation ( electrophysiologic study) is useful for catheter ablation of arrhythmogenic foci

Management

• treatment & prognosis depend on whether structural heart disease is present
• inpatient initiation of antiarrhythmic therapy

• all patients who present with a hemodynamically unstable arrhythmia
• antiarrhythmic agents other than amiodarone in patients with structural heart disease, especially with LV ejection fraction < 40%

• outpatient initiation of antiarrhythmic therapy

• normal cardiac function & absence of hemodynamically compromising arrhythmia
• amiodarone

More General Terms

• cardiac conduction disorder
• sign/symptom

Additional Terms

• arrhythmia during pregnancy
• automaticity
• cardiac arrhythmia supression trial (CAST)

References

1. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 829-39
2. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 138
3. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
4. Arrhythmia: NIH Institute and Center Resources [1]
5. National Guideline Clearinghouse Arrhythmia ngc-guideline: [2] ngc-guideline: [3]

cardiac arrhythmia