1. Syncope Wm. W. Barrington MD FACC Wm. W. Barrington MD FACC Associate Professor of Medicine University of Pittsburgh Medical Center PaACC Fellows in Training Program May 2008

2. What is syncope? Sudden, temporary loss of consciousness associated with the inability to maintain postural tone, followed by spontaneous recovery. Also referred to as: “Fainting”“Fainting” “Passing out”“Passing out”

3. Syncope Affects 1 million Americans each year. (1)Affects 1 million Americans each year. (1) Accounts for 3% of ED visits and 6% of hospital admissions. (1)Accounts for 3% of ED visits and 6% of hospital admissions. (1) Prevalence of syncope in general population is between 15% and 40%. (2)Prevalence of syncope in general population is between 15% and 40%. (2) 39% of medical students have “passed out” at least once. (2)39% of medical students have “passed out” at least once. (2) 1. Shukla GJ and Zimetbaum PJ Circulation (2006) 113; 715-17 2. Sheldon RS, Sheldon AG, Connolly SJ et al J Cardiovasculatr Electrophysiology (2006) 17 ;49-54. Significant Medical Problem

4. EtiologySyncope CardiacNonCardiacUnknown

5. Etiology Cardiac BradycardiaBradycardia TachycardiaTachycardia Aortic StenosisAortic Stenosis Aortic dissectionAortic dissection Hypertrophic cardiomyopathyHypertrophic cardiomyopathy Long QT SyndromeLong QT Syndrome Unknown ? Unknown We will focus today on the noncardiac causes of syncope.

6. Etiology (3) NonCardiac Reflex Syncope POTS Autonomic Failure 3. Grubb B Circulation (2005) 111;2997-3006 X

7. Reflex syncope is a sudden failure of the autonomic nervous system (ANS) to maintain adequate vascular tone during orthostatic stress

8. Reflex syncope NeurocardiogenicSituational Carotid Hypersensitivity

9. Neurocardiogenic Syncope Typically occurs in younger patients and has 3 distinct phases: Typically occurs in younger patients and has 3 distinct phases: Prodrome of lightheadedness, diaphoresis, nausea Prodrome of lightheadedness, diaphoresis, nausea Sudden loss of consciousness (LOC) Sudden loss of consciousness (LOC) Rapid recovery Rapid recovery In older patients, prodromal symptoms less common, but LOC still sudden In older patients, prodromal symptoms less common, but LOC still sudden

10. Neurocardiogenic Syncope A comprehensive history and physical is the most important aspect of the evaluation Supine, sitting and upright blood pressures may be helpful Head up Tilt Table (HUTT) testing is often employed to confirm or establish the diagnosis Evaluation of Neurocardiogenic Syncope

11. Neurocardiogenic Syncope 60° to 70° HUTT removes the effect of the lower extremity “muscle pump” 60° to 70° HUTT removes the effect of the lower extremity “muscle pump” Consciousness is thus maintained by appropriate interaction of the sympathetic and parasympathetic limbs of the ANS Consciousness is thus maintained by appropriate interaction of the sympathetic and parasympathetic limbs of the ANS Head up Tilt Table (HUTT) testing is a method of examining the effect of the autonomic nervous system on heart rate and BP

12. Neurocardiogenic Syncope Specificity 90% (without provocation) Specificity 90% (without provocation) Short term reproducibility is 80% to 90% Short term reproducibility is 80% to 90% Individuals with NCS demonstrate a “sudden” drop in BP that is frequently followed by a drop in heart rate Individuals with NCS demonstrate a “sudden” drop in BP that is frequently followed by a drop in heart rate Commonly, we see one of 3 abnormal responses Commonly, we see one of 3 abnormal responses Head up Tilt Table (HUTT) testing

13. Vasodepressor Response

14. 12.4 seconds Continuous recording Syncope After 15 minutes of HUTT testing 60 bpm 30 bpm 18 bpm

15. Mixed Vasodepressor/Cardioinhibitory Response

16. 10 seconds Continuous recording Seizure like activity 7 minutes of HUTT testing 20 bpm Asystole

17. Cardioinhibitory Response

18. Situational Syncope Syncope that occurs under a specific set of circumstances: Syncope that occurs under a specific set of circumstances: Micturition Micturition Defecation Defecation Cough Cough Patients are typically free of symptoms at other times Patients are typically free of symptoms at other times Sudden activation of mechanoreceptors at an affected “site” may activate the ANS leading to hemodynamic collapse Sudden activation of mechanoreceptors at an affected “site” may activate the ANS leading to hemodynamic collapse

19. Carotid Sinus Hypersensitivity Pressure on the carotid sinus is thought to “mimic” hypertension leading to bradycardia Pressure on the carotid sinus is thought to “mimic” hypertension leading to bradycardia The symptoms are very similar to those seen with NCS The symptoms are very similar to those seen with NCS

20. Postural Orthostatic Tachycardia Syncope (POTS) Hallmark of syndrome is persistent tachycardia while upright Hallmark of syndrome is persistent tachycardia while upright Severe fatigue Severe fatigue Exercise intolerance Exercise intolerance Palpitations Palpitations Syncope and near syncope Syncope and near syncope

21. Postural Orthostatic Tachycardia Syncope (POTS) Pathophysiology appears to be failure of peripheral vascular resistance to increase in the face of orthostatic stress, thus the heart rate and inotropic state increase to compensate. Pathophysiology appears to be failure of peripheral vascular resistance to increase in the face of orthostatic stress, thus the heart rate and inotropic state increase to compensate. Tilt Table Testing Tilt Table Testing >30 bpm increase in heart rate >30 bpm increase in heart rate Heart increases to > 120 bpm (in first 10 minutes) Heart increases to > 120 bpm (in first 10 minutes)

22. POTS Response

23. Therapeutic Approach Avoid precipitating circumstances Avoid precipitating circumstances Dehydration Dehydration Extreme heat Extreme heat Increase Fluid intake (possibly salt) Increase Fluid intake (possibly salt) Lay or sit down when prodromal symptoms begin Lay or sit down when prodromal symptoms begin Encourage moderate aerobic and isometric exercise Encourage moderate aerobic and isometric exercise

24. Therapeutic Approach Tilt table training may be helpful Tilt table training may be helpful Elastic support hose (effective if waist high and provide >30 mm Hg ankle pressure) Elastic support hose (effective if waist high and provide >30 mm Hg ankle pressure) Elevation of head of bed Elevation of head of bed Isometric “counter maneuvers” such as leg or arm tensing may abort episodes that are detected early. Isometric “counter maneuvers” such as leg or arm tensing may abort episodes that are detected early. Many individuals finally need pharmacotherapy Many individuals finally need pharmacotherapy

25. From Grubb B Circulation (2005) 111;2997-3006

26. Beta blockers Disopyramide Fluids/salt Stockings Fludrocortisone Anticholenergics Selective serotonin Re-uptake inhibitors Midodrine

27. Therapeutic Approach Early studies showed single chamber VVI pacing was ineffective. Early studies showed single chamber VVI pacing was ineffective. Original, non-blinded studies showed a benefit with dual chamber pacing Original, non-blinded studies showed a benefit with dual chamber pacing Two recent randomized, blinded studies failed to show a benefit with pacing Two recent randomized, blinded studies failed to show a benefit with pacing Vasovagal Pacemaker Study (VPS) II (4) Vasovagal Pacemaker Study (VPS) II (4) Vasovagal Syncope and Pacing Trial (5) Vasovagal Syncope and Pacing Trial (5) Is there a role for cardiac pacing? 4. Connolly sj et al JAMA (2003) 289;2224-9 5.Raviele A et al European Heart Journal (2004)25;1741-48

28. Therapeutic Approach In patients with recurrent syncope where no other therapy is effective, pacing may have a role in reducing the frequency of syncope or prolonging the time from onset of symptoms to frank syncope, allowing the patient to avoid injury. In patients with recurrent syncope where no other therapy is effective, pacing may have a role in reducing the frequency of syncope or prolonging the time from onset of symptoms to frank syncope, allowing the patient to avoid injury. Cardiac pacing is not routinely first line therapy.

29. Thank you for your attention. I would be happy to take any questions.