patient data. Circulation 2006; 114:11. 15. 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. 16. Connolly SJ, Kerr CR, Gent M, et al. Effects of physiologic pacing versus ventricular pacing on the risk of stroke and death due to cardiovascular causes. Canadian Trial of Physiologic Pacing Investigators. N Engl J Med 2000; 342:1385. 17. Kerr CR, Connolly SJ, Abdollah H, et al. Canadian Trial of Physiological Pacing: Effects of physiological pacing during long-term follow-up. Circulation 2004; 109:357. 18. Andersen HR, Thuesen L, Bagger JP, et al. Prospective randomised trial of atrial versus ventricular pacing in sick-sinus syndrome. Lancet 1994; 344:1523. 19. Rosenqvist M, Obel IW. Atrial pacing and the risk for AV block: is there a time for change in attitude? Pacing Clin Electrophysiol 1989; 12:97. 20. Andersen HR, Nielsen JC, Thomsen PE, et al. Atrioventricular conduction during long-term follow-up of patients with sick sinus syndrome. Circulation 1998; 98:1315. 21. Kristensen L, Nielsen JC, Pedersen AK, et al. AV block and changes in pacing mode during long-term follow-up of 399 consecutive patients with sick sinus syndrome treated with an AAI/AAIR pacemaker. Pacing Clin Electrophysiol 2001; 24:358. https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 12/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate 22. Brandt J, Anderson H, F hraeus T, Sch ller H. Natural history of sinus node disease treated with atrial pacing in 213 patients: implications for selection of stimulation mode. J Am Coll Cardiol 1992; 20:633. 23. Nielsen JC, Thomsen PE, H jberg S, et al. A comparison of single-lead atrial pacing with dual-chamber pacing in sick sinus syndrome. Eur Heart J 2011; 32:686. 24. Alboni P, Menozzi C, Brignole M, et al. Effects of permanent pacemaker and oral theophylline in sick sinus syndrome the THEOPACE study: a randomized controlled trial. Circulation 1997; 96:260. 25. Gillis AM, Morck M. Atrial fibrillation after DDDR pacemaker implantation. J Cardiovasc Electrophysiol 2002; 13:542. 26. Andersen HR, Nielsen JC, Thomsen PE, et al. Long-term follow-up of patients from a randomised trial of atrial versus ventricular pacing for sick-sinus syndrome. Lancet 1997; 350:1210. 27. Rubenstein JJ, Schulman CL, Yurchak PM, DeSanctis RW. Clinical spectrum of the sick sinus syndrome. Circulation 1972; 46:5. 28. Hocini M, Sanders P, Deisenhofer I, et al. Reverse remodeling of sinus node function after catheter ablation of atrial fibrillation in patients with prolonged sinus pauses. Circulation 2003; 108:1172. 29. January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2014; 64:e1. 30. Corea F, Tambasco N. Cardiac pacing: atrial fibrillation may go unrecognised. Lancet Neurol 2005; 4:265. 31. Healey JS, Connolly SJ, Gold MR, et al. Subclinical atrial fibrillation and the risk of stroke. N Engl J Med 2012; 366:120. 32. Hindricks G, Potpara T, Dagres N, et al. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS): The Task Force for the diagnosis and management of atrial fibrillation of the European Society of Cardiology (ESC) Developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC. Eur Heart J 2021; 42:373. 33. Calkins H, Hindricks G, Cappato R, et al. 2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation. Heart Rhythm 2017; 14:e275. https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 13/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate 34. Qin M, Zhang Y, Liu X, et al. Atrial Ganglionated Plexus Modification: A Novel Approach to Treat Symptomatic Sinus Bradycardia. JACC Clin Electrophysiol 2017; 3:950. Topic 1072 Version 35.0 https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 14/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate GRAPHICS Algorithm for treatment of patients with sick sinus syndrome ECG: electrocardiogram; BP: blood pressure; IV: intravenous; PPM: permanent pacemaker; SSS: sick sinus syndrome. The initial dose of atropine is 0.5 mg IV push. This dose may be repeated every three to five minutes to a total dose of 3 mg. https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 15/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate While transcutaneous pacing may be initially successful in stabilizing the patient, it may not be consistently reliable and is frequently uncomfortable for the patient. Prepare for urgent transvenous pacing (if required) and obtain central venous access (preferably right internal jugular vein access). Dopamine IV infusion typically begins at a dose of 2 mcg/kg/minute and can be titrated up to 20 mcg/kg/minute if needed for heart rate and blood pressure augmentation. Epinephrine IV infusion typically begins at a dose of 2 mcg/minute and can be titrated up to 20 mcg/minute if needed for heart rate and blood pressure augmentation. Isoproterenol IV infusion typically begins at a dose of 2 mcg/minute and can be titrated up to 10 mcg/minute if needed for heart rate and blood pressure augmentation. Reversible causes of SSS may include drugs (eg, beta blockers, calcium channel blockers, digoxin), ischemia, and autonomic imbalance. Graphic 113726 Version 1.0 https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 16/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate Adult bradycardia algorithm 2020 update Reprinted with permission. ACLS Provider Manual. Copyright 2020 American Heart Association, Inc. Graphic 130748 Version 10.0 https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 17/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate Selection of pacemaker systems for patients with sinus node dysfunction Decisions are illustrated by diamonds. Shaded boxes indicate type of pacemaker. AV: atrioventricular. Reproduced with permission from: Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2008; 51(21):e1-e62. Illustration used with permission of Elsevier Inc. All rights reserved. Copyright 2008 Elsevier Inc. Graphic 77929 Version 5.0 https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 18/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate Comparison of the CHADS and CHA DS -VASc risk stratification scores for 2 patients with nonvalvular AF 2 2 Definition and scores for CHADS and Stroke risk stratification with the 2 CHA DS -VASc CHADS and CHA DS -VASc scores 2 2 2 2 2 Unadjusted [1] CHADS acronym Score CHADS acronym ischemic stroke rate (% per year) 2 2 Congestive HF 1 0 0.6 Hypertension 1 1 3.0 Age 75 years 1 2 4.2 Diabetes mellitus 1 3 7.1 Stroke/TIA/TE 2 4 11.1 Maximum score 6 5 12.5 6 13.0 Unadjusted ischemic stroke rate CHA DS -VASc acronym 2 2 [2] CHA DS -VASc acronym Score 2 2 (% per year) Congestive HF 1 0 0.2 Hypertension 1 1 0.6 Age 75 years 2 2 2.2 Diabetes mellitus 1 3 3.2 Stroke/TIA/TE 2 4 4.8 Vascular disease (prior MI, PAD, or aortic plaque) 1 5 7.2 Age 65 to 74 years 1 6 9.7 Sex category (ie, female sex) 1 7 11.2 Maximum score 9 8 10.8 9 12.2 AF: atrial fibrillation; CHADS : Congestive heart failure, Hypertension, Age 75 years, Diabetes mellitus, prior Stroke or TIA or thromboembolism (doubled); CHA DS -VASc: Congestive heart failure, Hypertension, Age 75 years (doubled), Diabetes mellitus, prior Stroke or TIA or thromboembolism (doubled), Vascular disease, Age 65 to 74 years, Sex category; HF: heart failure; TIA: transient ischemic attack; TE: thromboembolism; MI: myocardial infarction; PAD: peripheral artery disease. 2 2 2 https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 19/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate [3] These unadjusted (not adjusted for possible use of aspirin) stroke rates were published in 2012 Actual rates of stroke in contemporary cohorts might vary from these estimates. . References: 1. Gage BF, Waterman AD, Shannon W, et al. Validation of clinical classi cation schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 2001; 285:2864. 2. Lip GYH, Nieuwlaat R, Pisters R, et al. Re ning clinical risk strati cation for predicting stroke and thromboembolism in atrial brillation using a novel risk factor-based approach: the euro heart survey on atrial brillation. Chest 2010; 137:263. 3. Friberg L, Rosenqvist M, Lip GY. Evaluation of risk strati cation schemes for ischaemic stroke and bleeding in 182 678 patients with atrial brillation: the Swedish Atrial Fibrillation cohort study. Eur Heart J 2012; 33:1500. Original table and unadjusted ischemic stroke rates, as noted above, have been modi ed for this publication. January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2014; 64:e1. Table used with the permission of Elsevier Inc. All rights reserved. Graphic 94752 Version 14.0 https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 20/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate Clinical characteristics comprising the HAS-BLED bleeding risk score Letter Clinical characteristic* Points H Hypertension (ie, uncontrolled blood pressure) 1 A Abnormal renal and liver function (1 point each) 1 or 2 S Stroke 1 B Bleeding tendency or predisposition 1 L Labile INRs (for patients taking warfarin) 1 E Elderly (age greater than 65 years) 1 D Drugs (concomitant aspirin or NSAIDs) or excess alcohol use (1 point each) 1 or 2 Maximum 9 points HAS-BLED Bleeds per 100 patient-years score (total points) 0 1.13 1 1.02 2 1.88 3 3.74 4 8.70 5 to 9 Insufficient data The HAS-BLED bleeding risk score has only been validated in patients with atrial fibrillation receiving warfarin. Refer to UpToDate topics on anticoagulation in patients with atrial fibrillation and on specific anticoagulants for further information and other bleeding risk scores and their performance relative to clinical judgment. INR: international normalized ratio; NSAIDs: nonsteroidal antiinflammatory drugs. Hypertension is defined as systolic blood pressure >160 mmHg. Abnormal renal function is defined as the presence of chronic dialysis, renal transplantation, or serum creatinine 200 micromol/L. Abnormal liver function is defined as chronic hepatic disease (eg, cirrhosis) or biochemical evidence of significant hepatic derangement (eg, bilirubin more than 2 times the upper limit of normal, plus 1 or more of aspartate transaminase, alanine transaminase, and/or alkaline phosphatase more than 3 times the upper limit of normal). Bleeding predisposition includes chronic bleeding disorder or https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 21/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate previous bleeding requiring hospitalization or transfusion. Labile INRs for a patient on warfarin include unstable INRs, excessively high INRs, or <60% time in therapeutic range. Based on initial validation cohort from Pisters R. A novel-user-friendly score (HAS-BLED) to assess 1- year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest 2010; 138:1093. Actual rates of bleeding in contemporary cohorts may vary from these estimates. Original gure modi ed for this publication. Lip GY. Implications of the CHA2DS2-VASc and HAS-BLED Scores for thromboprophylaxis in atrial brillation. Am J Med 2011; 124:111. Table used with the permission of Elsevier Inc. All rights reserved. Graphic 75259 Version 16.0 https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 22/23 7/6/23, 11:22 AM Sinus node dysfunction: Treatment - UpToDate Contributor Disclosures Munther K Homoud, MD Speaker's Bureau: Abbott [Live heart dissection]. All of the relevant financial relationships listed have been mitigated. N A Mark Estes, III, MD Consultant/Advisory Boards: Boston Scientific [Arrhythmias]; Medtronic [Arrhythmias]. All of the relevant financial relationships listed have been mitigated. Susan B Yeon, MD, JD, FACC No relevant financial relationship(s) with ineligible companies to disclose. Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence. Conflict of interest policy https://www.uptodate.com/contents/sinus-node-dysfunction-treatment/print 23/23