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cardiac arrhythmia

Irregularity or loss of rhythm of the heartbeat. Etiology: 1) heart disease a) dilated cardiomyopathy b) valvular regurgitation - mitral regurgitation, aortic regurgitation, ricuspid regurgitation - scar from myocardial infarction - stenotic lesions - coronary artery disease - aortic stenosis - mitral stenosis c) hypertrophic cardiomyopathy 2) unmodifiable factors - genetics, older age 3) modifiable risk factors - sedentary lifestyle, physical inactivity - smoking - obesity - diabetes mellitus - hypertension - obstructive sleep apnea 4) pharmaceutical agents: - adriamycin - antiarrhythmic drugs - atropine - anticholinesterases - emetine - lithium - phenothiazines - sympathomimetics - thyroid hormones - tricyclic antidepressants History: 1) onset, regularity, duration & pattern of discontinuance* 2) dyspnea 3) chest pain 4) syncope, near-syncope or lightheadedness 5) preciptitating or exacerbating factors 6) familial or congenital arrhythmias 7) comorbidities a) heart disease 1] coronary artery disease 2] valvular heart disease 3] cardiomyopathy 4) conduction system disease b) inflammatory disease c) endocrinopathy d) infection 1] Chaga's disease 2] Lyme disease * patterns 1) arrhythmias that start & terminate abruptly are generally due to re-entry a) paroxysmal supraventricular tachycardia (PSVT) b) ventricular tachycardia 2) an arrhythmia that starts & stops more gradually generally results from increased automaticity Physical examination: 1) pulse rate & regularity 2) orthostatic blood pressure 3) presence of murmurs 4) presence of S3 gallop 5) paradoxical or fixed splitting of S2 6) during the arrhythmia a) indicators of AV synchrony 1] intermittent cannon A waves in jugular venous pulsation 2] variable intensity of S1 3] variable peak systolic blood pressure b) effect of vagal maneuvers 1] carotid sinus massage 2] Valsalva maneuver Clinical manifestations: - symptoms may include: 1) palpitations 2) lightheadedness 3) shortness of breath or dyspnea on exertion 4) syncope or presyncope 5) angina pectoris 6) sudden cardiac death Laboratory: 1) serum electrolytes a) serum K+ b) serum Ca+2 c) serum Mg+2 2) antiarrhythmic drug levels 3) thyroid function tests Special laboratory: 1) electrocardiogram (EKG) a) 12-lead b) rhythm strip c) continuous 24 hour monitor (in hospital) d) Lewis bipolar exploring lead e) transesophageal electrogram f) direct atrial electrogram g) most arrhythmias are intermittent & not recorded on a resting ECG [3] 2) HOLTER if arrhythmia intermittent but occurs at least daily 3) event recorder if arrhythmia is symptomatic but infrequent, i.e. syncope 4) programmed electrical stimulation (electrophysiologic study) is useful for catheter ablation of arrhythmogenic foci Management: 1) treatment & prognosis depend on whether structural heart disease is present 2) inpatient initiation of antiarrhythmic therapy a) all patients who present with a hemodynamically unstable arrhythmia b) antiarrhythmic agents other than amiodarone in patients with structural heart disease, especially with LV ejection fraction < 40% 3) outpatient initiation of antiarrhythmic therapy a) normal cardiac function & absence of hemodynamically compromising arrhythmia b) amiodarone

Related

arrhythmia during pregnancy automaticity cardiac arrhythmia supression trial (CAST)

Specific

atrioventricular (AV) dissociation atrioventricular reciprocating tachycardia (AVRT) bigeminy bradyarrhythmia (bradycardia) cardiac conduction re-entry chronic cardiac arrhythmia heart block premature electrocardiography complex pulseless electrical activity; electromechanical dissociation (PEA) supraventricular arrhythmia tachyarrhythmia (tachycardia) trigeminy ventricular arrhythmia

General

cardiac conduction disorder sign/symptom

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, 16, 17. American College of Physicians, Philadelphia 1998, 2012, 2015
  4. Zimetbaum P, Goldman A. Ambulatory arrhythmia monitoring: choosing the right device. Circulation. 2010 Oct 19;122(16):1629-36 PMID: 20956237
  5. Epstein AE, DiMarco JP, Ellenbogen KA et al 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. Circulation. 2013 Jan 22;127(3):e283-352. PMID: 23255456
  6. AHA SCIENTIFIC STATEMENT. Tisdale JE et al Drug-Induced ArrhythmiasA Scientific Statement From the American Heart Association. Circulation. 2020, 142:00-00. September 19. https://www.ahajournals.org/doi/pdf/10.1161/CIR.0000000000000905
  7. National Heart, Lung, and Blood Institute (NHLBI) Arrhythmia: https://www.nhlbi.nih.gov/health-topics/arrhythmia