Sick sinus syndrome: Clinical manifestations, diagnosis, and evaluation
- Munther K Homoud, MD
Munther K Homoud, MD
- Associate Professor of Medicine
- Tufts University School of Medicine
Sick sinus syndrome (SSS) is characterized by dysfunction of the sinoatrial (SA) node that is often secondary to senescence of the SA node and surrounding atrial myocardium. Patients with SSS are typically symptomatic with fatigue, lightheadedness, palpitations, presyncope, and/or syncope, although the occasional patient may be identified during electrocardiography (ECG) or ambulatory ECG monitoring performed for another indication.
The clinical manifestations, evaluation, and approach to diagnosis of SSS will be reviewed here. The causes, natural history, and management of SSS, along with the appropriate timing of referral to a specialist, are discussed in detail separately. (See "Sick sinus syndrome: Epidemiology, etiology, and natural history" and "Sick sinus syndrome: Treatment" and "Arrhythmia management for the primary care clinician", section on 'Referral to a specialist'.)
Sick sinus syndrome is a clinical syndrome characterized by chronic sinoatrial (SA) node dysfunction, a sluggish or absent SA nodal pacemaker after electrical cardioversion, and/or depressed escape pacemakers in the presence or absence of atrioventricular (AV) nodal conduction disturbances [1-3]. SSS may also manifest as chronotropic incompetence with inappropriate heart rate responses to physiological demands during activity. SSS can also be accompanied by AV nodal conduction disturbances and by atrial tachyarrhythmias as part of the tachycardia-bradycardia syndrome. (See "Sick sinus syndrome: Epidemiology, etiology, and natural history", section on 'Definition of SSS'.)
Sick sinus syndrome (SSS) is defined by electrocardiogram (ECG) abnormalities (eg, bradycardia, sinus pauses, sinus arrest) that occur in association with clinical signs and symptoms. Most patients with SSS present with one or more of the following nonspecific symptoms: fatigue, lightheadedness, palpitations, presyncope, syncope, dyspnea on exertion, or chest discomfort. Symptoms are frequently intermittent with gradual progression in frequency and severity, although some patients may present with profound, persistent symptoms at the initial visit. Rarely, SSS may be asymptomatic and identified on routine ECG or ambulatory ECG monitoring.
Symptoms — Patients with symptomatic SSS are primarily older and frequently have comorbid diseases. Patients with SSS often seek medical attention with symptoms of lightheadedness, presyncope, syncope, and, in patients with alternating periods of bradycardia and tachycardia, palpitations and/or other symptoms associated with a rapid heart rate. Patients with coexisting cardiac pathology may notice increasing dyspnea on exertion or worsening chest discomfort related to lower heart rate and the resulting reduction in cardiac output. Because symptoms may be variable in nature, nonspecific, and frequently transient, it may be challenging at times to establish this symptom-rhythm relationship.
- Ferrer MI. The sick sinus syndrome in atrial disease. JAMA 1968; 206:645.
- Lown B. Electrical reversion of cardiac arrhythmias. Br Heart J 1967; 29:469.
- Ferrer MI. The Sick Sinus Syndrome, Futura Press, New York 1974.
- SHORT DS. The syndrome of alternating bradycardia and tachycardia. Br Heart J 1954; 16:208.
- BIRCHFIELD RI, MENEFEE EE, BRYANT GD. Disease of the sinoatrial node associated with bradycardia, asystole, syncope, and paroxysmal atrial fibrillation. Circulation 1957; 16:20.
- Rubenstein JJ, Schulman CL, Yurchak PM, DeSanctis RW. Clinical spectrum of the sick sinus syndrome. Circulation 1972; 46:5.
- Kaplan BM, Langendorf R, Lev M, Pick A. Tachycardia-bradycardia syndrome (so-called "sick sinus syndrome"). Pathology, mechanisms and treatment. Am J Cardiol 1973; 31:497.
- Gomes JA, Kang PS, Matheson M, et al. Coexistence of sick sinus rhythm and atrial flutter-fibrillation. Circulation 1981; 63:80.
- Lamas GA, Lee KL, Sweeney MO, et al. Ventricular pacing or dual-chamber pacing for sinus-node dysfunction. N Engl J Med 2002; 346:1854.
- Ferrer MI. The etiology and natural history of sinus node disorders. Arch Intern Med 1982; 142:371.
- Simonsen E, Nielsen JS, Nielsen BL. Sinus node dysfunction in 128 patients. A retrospective study with follow-up. Acta Med Scand 1980; 208:343.
- Thery C, Gosselin B, Lekieffre J, Warembourg H. Pathology of sinoatrial node. Correlations with electrocardiographic findings in 111 patients. Am Heart J 1977; 93:735.
- Eraut D, Shaw DB. Sinus bradycardia. Br Heart J 1971; 33:742.
- Kay GN. Quantitation of chronotropic response: comparison of methods for rate-modulating permanent pacemakers. J Am Coll Cardiol 1992; 20:1533.
- Epstein AE, Dimarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 Guidelines for device-based therapy of cardiac rhythm abnormalities. Heart Rhythm 2008; 5:e1.
- Josephson, ME. Sinus Node Function. In: Clinical Cardiac Electrophysiology: Techniques and Interpretations, 4th, Lippincott, Williams, & Wilkins, Philadelphia 2008. p.69-92.
- Furukawa T, Maggi R, Bertolone C, et al. Additional diagnostic value of very prolonged observation by implantable loop recorder in patients with unexplained syncope. J Cardiovasc Electrophysiol 2012; 23:67.
- Lipski J, Cohen L, Espinoza J, et al. Value of Holter monitoring in assessing cardiac arrhythmias in symptomatic patients. Am J Cardiol 1976; 37:102.
- Reiffel JA, Bigger JT Jr, Cramer M, Reid DS. Ability of Holter electrocardiographic recording and atrial stimulation to detect sinus nodal dysfunction in symptomatic and asymptomatic patients with sinus bradycardia. Am J Cardiol 1977; 40:189.
- Gibson TC, Heitzman MR. Diagnostic efficacy of 24-hour electrocardiographic monitoring for syncope. Am J Cardiol 1984; 53:1013.
- Kerr CR, Strauss HC. The measurement of sinus node refractoriness in man. Circulation 1983; 68:1231.
- Kinlay S, Leitch JW, Neil A, et al. Cardiac event recorders yield more diagnoses and are more cost-effective than 48-hour Holter monitoring in patients with palpitations. A controlled clinical trial. Ann Intern Med 1996; 124:16.
- Zimetbaum PJ, Josephson ME. The evolving role of ambulatory arrhythmia monitoring in general clinical practice. Ann Intern Med 1999; 130:848.
- Vavetsi S, Nikolaou N, Tsarouhas K, et al. Consecutive administration of atropine and isoproterenol for the evaluation of asymptomatic sinus bradycardia. Europace 2008; 10:1176.
- Dhingra RC, Amat-Y-Leon F, Wyndham C, et al. Electrophysiologic effects of atropine on sinus node and atrium in patients with sinus nodal dysfunction. Am J Cardiol 1976; 38:848.
- Talano JV, Euler D, Randall WC, et al. Sinus node dysfunction. An overview with emphasis on autonomic and pharmacologic consideration. Am J Med 1978; 64:773.
- Burnett D, Abi-Samra F, Vacek JL. Use of intravenous adenosine as a noninvasive diagnostic test for sick sinus syndrome. Am Heart J 1999; 137:435.
- Fragakis N, Iliadis I, Sidopoulos E, et al. The value of adenosine test in the diagnosis of sick sinus syndrome: susceptibility of sinus and atrioventricular node to adenosine in patients with sick sinus syndrome and unexplained syncope. Europace 2007; 9:559.
- Viskin S, Justo D, Halkin A. Should the 'adenosine-challenge test' be part of the routine work-up for syncope? Europace 2007; 9:557.
- Opthof T. The normal range and determinants of the intrinsic heart rate in man. Cardiovasc Res 2000; 45:177.
- Thormann J, Schwarz F, Ensslen R, Sesto M. Vagal tone, significance of electrophysiologic findings and clinical course in symptomatic sinus node dysfunction. Am Heart J 1978; 95:725.
- CLINICAL PRESENTATION
- ECG findings
- APPROACH TO THE DIAGNOSIS
- DIAGNOSTIC TESTING
- Ambulatory ECG monitoring and event recording
- Pharmacologic challenge
- Calculating the intrinsic heart rate
- Electrophysiologic testing
- DIFFERENTIAL DIAGNOSIS
- SOCIETY GUIDELINE LINKS
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS