Evaluation and Management of Syncope

Syncope Definition: Definition: Sudden transient loss of consciousness and postural tone with subsequent spontaneous recovery. ( Greek synkope, “cessation, pause”). Sudden transient loss of consciousness and postural tone with subsequent spontaneous recovery. ( Greek synkope, “cessation, pause”). Transient inadequate cerebral perfusion. Transient inadequate cerebral perfusion.

Syncope - Epidemiology 1% of hospital admissions 1% of hospital admissions 3% of ER visits 3% of ER visits 6% annual incidence in the elderly 6% annual incidence in the elderly Upto 50% of young adults have history of isolated LOC Upto 50% of young adults have history of isolated LOC Annual cost $2 B (2005) Annual cost $2 B (2005) Clin Electrophysiol 22:1386,1999 Clin Electrophysiol 22:1386,1999 Sun BC, Am J Cardiol 95:668, 2005

Syncope - Prognosis Highest mortality in patients with cardiac cause Highest mortality in patients with cardiac cause Neurally mediated syncope/ medication induced syncope did not increase mortality Neurally mediated syncope/ medication induced syncope did not increase mortality Soteriades ES, et al: N Eng J Med 347:878, 2002 Soteriades ES, et al: N Eng J Med 347:878, 2002

Causes of Syncope Vascular ( 58 – 62 % ) : Reflex mediated, orthostatic, anatomic Vascular ( 58 – 62 % ) : Reflex mediated, orthostatic, anatomic Cardiac ( 10 – 23 % ): Arrhythmias, anatomic Cardiac ( 10 – 23 % ): Arrhythmias, anatomic Neurologic/cerebrovascular* ( 0.5 – 5 % ) Neurologic/cerebrovascular* ( 0.5 – 5 % ) Metabolic/drugs ( 0 – 2 % ) Metabolic/drugs ( 0 – 2 % ) Psychogenic* ( 0.2 – 1.5 % ) Psychogenic* ( 0.2 – 1.5 % ) Syncope of unknown origin ( 14 – 18 % ) Syncope of unknown origin ( 14 – 18 % ) Sarasin FP, Am J Med 111: 177, 2001 Alboni P, JACC 37, 1921, 2001

Differential Diagnosis of Syncope Obstruction to Flow Aortic Stenosis Hypertrophic Cardiomyopathy Atrial Myxoma Mitral Stenosis Pulmonic Stenosis Pulmonary Hypertension Pulmonary Embolism Cardiac Tamponade Aortic Dissection Bradyarrhythmias Sinus Node Dysfunction AV Block Pacemaker Malfunction Tachyarhythmias Ventricular Tachycardia Torsade de Pointes Supraventricular Tachycardia Other Causes of Syncope Vasovagal Syncope Carotid Sinus Hypersensitivity Drug-Induced Orthostatic Hypotension Cerbrovascular Disease Situational (e.g. cough/micturition syncope) HypoglycemiaSeizurePsychogenic

Syncope - Clinical Features Suggestive of Specific Causes Symptom or Finding Diagnostic Consideration After sudden unexpected pain, unpleasant sight, sound or smell Vasovagal syncope During/immediately after micturition, cough, swallow or defecation Situational syncope On standing Orthostatic hypotension Prolonged standing Vasovagal syncope

Syncope – Clinical Features Suggestive of Specific Causes (cont’d ) Symptom or Finding Diagnostic Consideration Well-trained athlete after exertion Neurally mediated Change in position ( from sitting to lying, bending, turning over in bed ) Atrial myxoma, thrombus Syncope during exertion Aortic stenosis, pulmonary hypertension, pulmonary embolus, mitral stenosis, IHSS, CAD, neurally mediated syncope

Syncope – Clinical Features Suggestive of Specific Causes ( cont’d ) Symptom or Finding Diagnostic Consideration With head rotation, pressure on cartoid sinus (as in tumors, shaving, tight collars) Cartoid sinus syncope Associated with vertigo, dysarthria, diplopia, and other motor and sensory symptoms of brain stem ischemia Transient ischemic attack, subclavian steal, basilar artery migraine With arm exercise Subclavian steal Confusion after episode Seizure

Seizure vs Syncope Seizure: Seizure: Aura, frothing at the mouth Aura, frothing at the mouth Horizontal eye deviation, tongue biting Horizontal eye deviation, tongue biting Elevated BP, sinus tach Elevated BP, sinus tach Sustained tonic clonic movements, incontinence Sustained tonic clonic movements, incontinence Disorientation, slow recovery Disorientation, slow recovery

Syncope – Diagnostic Tests History and physical examination: cardiac disease, family h/o SCD, medications, witness History and physical examination: cardiac disease, family h/o SCD, medications, witness Orthostatic BP check Orthostatic BP check ECG: Q waves, QTc, delta wave, epsilon wave ECG: Q waves, QTc, delta wave, epsilon wave Holter monitor: V pause > 3 sec while awake, Mobitz type 2 or CHB, VT. Holter monitor: V pause > 3 sec while awake, Mobitz type 2 or CHB, VT. Arrhythmia event monitor Arrhythmia event monitor Echocardiogram Echocardiogram Tilt table test Tilt table test Electophysiologic testing Electophysiologic testing

Diagnostic Tests for Syncope TestIndicationDisadvantage Holter Monitor Frequent symptoms of palpitations or dizziness Low yield if symptoms are intermittent Continuous-Loop Recorder Intermittent or very transient symptoms; patient has little warning before symptoms occur Inconvenient to use for long periods of time Implantable Loop Recorder Infrequent episodes of syncope; diagnosis cannot be made noninvasively Requires invasive procedure Signal-Averaged ECG Syncope and structural heart disease Low positive predictive value

Diagnostic Tests for Syncope (cont’d) TestIndicationDisadvantage Upright Tilt Testing Suspected vasovagal syncope; syncope without structural heart disease Inadequate reproducibility Electrophysiologic Study Syncope when diagnosis cannot be made non- invasively; syncope with structural heart disease Invasive; low yield when no structural heart disease

Syncope – Indications For Hospitalization Presence of heart disease, dyspnea, CHF, VT, acute coronary syndrome Presence of heart disease, dyspnea, CHF, VT, acute coronary syndrome ECG suggestive of arrhythmic syncope in: WPW, long QTc, Sick Sinus Syndrome, AV block, VT, Brugada syndrome, RV dysplasia ECG suggestive of arrhythmic syncope in: WPW, long QTc, Sick Sinus Syndrome, AV block, VT, Brugada syndrome, RV dysplasia Syncope with severe injury Syncope with severe injury Syncope during exercise Syncope during exercise Family h/o sudden cardiac death Family h/o sudden cardiac death

Sinus Arrest on Holter Monitor ACCSAP 2005

Syncope – Loop Event Recorder ACCSAP 6, 2005

Implantable Loop Recorder

Implanted Loop Event Recorder

Head Up Tilt Table Testing

Tilt Table Testing: When to do it? For diagnosis: Suspected reflex, atypical presentation Suspected reflex, atypical presentation Unexplained syncope at the end of work-up, orthostatic trigger present Unexplained syncope at the end of work-up, orthostatic trigger present Suspected delayed orthostatic hypotension Suspected delayed orthostatic hypotension

Neurally Mediated Syncope Also known as vasovagal syncope. Also known as vasovagal syncope. Recurrent syncope in the absence of structural heart disease is most likely neurally mediated. Recurrent syncope in the absence of structural heart disease is most likely neurally mediated. Head-upright tilt test maximizes venous pooling, sympathetic activation and circulating catecholamines. Head-upright tilt test maximizes venous pooling, sympathetic activation and circulating catecholamines. Most vasovagal episodes involve both cardioinhibition (drop in heart rate) and vasodepressor response (drop in BP). Most vasovagal episodes involve both cardioinhibition (drop in heart rate) and vasodepressor response (drop in BP).

Case # 1 Case # 1 A 20 year old female presents with recurrent near syncope and syncope preceded by nausea, sweating and gradual “tunnel vision”usually after prolonged standing. The ECG and 2-D echocardiogram are normal. What would be the next step? A 20 year old female presents with recurrent near syncope and syncope preceded by nausea, sweating and gradual “tunnel vision”usually after prolonged standing. The ECG and 2-D echocardiogram are normal. What would be the next step? Answer: Tilt table test. Answer: Tilt table test. Q: What is the mechanism for the visual symptoms? Q: What is the mechanism for the visual symptoms? Answer: Collapse of peripheral vessels of the retina. Answer: Collapse of peripheral vessels of the retina.

Syncope: The Role of Electrophysiologic Testing Most important diagnostic tool is the history Most important diagnostic tool is the history High risk historical elements High risk historical elements Syncope resulting in injury Syncope resulting in injury Syncope resulting in motor vehicle accident Syncope resulting in motor vehicle accident Syncope in the setting of structural heart disease Syncope in the setting of structural heart disease Syncope preceded by palpitations Syncope preceded by palpitations Syncope while supine Syncope while supine Abnormal ECG Abnormal ECG Lack of “low risk” elements Lack of “low risk” elements

Guidelines for EP Testing in Syncope Class I: General agreement Class I: General agreement Patients with structural heart disease and unexplained syncope Patients with structural heart disease and unexplained syncope Class II: Less certain, but accepted Class II: Less certain, but accepted Patients with recurrent unexplained syncope without structural heart disease and a negative tilt test Patients with recurrent unexplained syncope without structural heart disease and a negative tilt test Class III: Not indicated Class III: Not indicated Patients with known cause of syncope in whom treatment will not be guided by EP testing Patients with known cause of syncope in whom treatment will not be guided by EP testing

Electrophysiologic Testing in Syncope Electrophysiologic Testing in Syncope Sinus node function: prolonged sinus node recovery time Sinus node function: prolonged sinus node recovery time Abnormal AV conduction: ↑HV interval, infra His block Abnormal AV conduction: ↑HV interval, infra His block Inducibility of sustained VT Inducibility of sustained VT Inducibility of rapid SVT with symptoms, hypotension Inducibility of rapid SVT with symptoms, hypotension

Neurally Mediated Syncope Precipitating factors: prolonged standing, dehydration, alcohol, diuretics, vasodilators. Precipitating factors: prolonged standing, dehydration, alcohol, diuretics, vasodilators. Sit/lie down at onset of symptoms, cross the legs and tense them together if sitting. Sit/lie down at onset of symptoms, cross the legs and tense them together if sitting. Salt supplementation and fluids. Salt supplementation and fluids. Isometric arm, leg counterpressure. Isometric arm, leg counterpressure. Moderate aerobic and isometric exercise. Moderate aerobic and isometric exercise. Tilt training. Tilt training.

Therapy of Neurocardiogenic Syncope TreatmentMechanism Volume expansion (increase salt and fluid intake, fludrocortisone) Maintain ventricular volume Beta-Blockers Block response to adrenergic stimulation; reduce ventricular contractility; prevent activation of ventricular mechanoreceptors Anticholinergic agents (scopolamine, disopyramide) Block vagal response; reduce ventricular contractility (disopyramide) Serotonin reuptake inhibitors Prevent vasodilation and bradycardia possibly by downregulation of response to serotonin Methylxanthines Adenosine receptor antagonist; Phophodiesterase and Ca ++ transport inhibitor (maintain vascular tone) Midodrine Adrenergic agonist Cardiac pacing Maintain heart rate, AV synchrony

Pharmacologic Therapy of Neurally Mediated Syncope Despite the widespread use of drug therapy, none of these pharmacologic agents have been demonstrated to be effective in large prospective randomized clinical trials. Despite the widespread use of drug therapy, none of these pharmacologic agents have been demonstrated to be effective in large prospective randomized clinical trials. A small study has reported the efficacy of midodrine. A small study has reported the efficacy of midodrine. Metoprolol, propranolol and nadolol are no more effective than placebo. Metoprolol, propranolol and nadolol are no more effective than placebo.

Orthostatic Intolerance Syndrome Vasovagal Syncope Delayed Orthostatic Intolerance Counterpressure Maneuvers Elastic Stockings JACC :1652JACC 2006: 48:1425

Syncope - Prognosis Highest mortality in patients with cardiac cause Highest mortality in patients with cardiac cause Neurally mediated syncope/ medication induced syncope did not increase mortality Neurally mediated syncope/ medication induced syncope did not increase mortality Soteriades ES, et al: N Eng J Med 347:878, 2002 Soteriades ES, et al: N Eng J Med 347:878, 2002

Suggested Strategies for Syncope Management

Syncope: May be a harbinger of sudden cardiac death Evaluation – purpose is to determine if pt is at increased risk for death Evaluation – purpose is to determine if pt is at increased risk for death Identify pts with underlying heart disease (ischemic CM, non-ischemic CM, HCM), myocardial ischemia, WPW, genetic diseases (long-QT syndrome, Brugada Syndrome), catecholaminergic polymorphic VT Identify pts with underlying heart disease (ischemic CM, non-ischemic CM, HCM), myocardial ischemia, WPW, genetic diseases (long-QT syndrome, Brugada Syndrome), catecholaminergic polymorphic VT

Case # 2 65 year old male with h/o inferior wall myocardial infarction 1 year ago presents with rapid palpitation and syncope. An ECG shows SR and old inferior wall myocardial infarction. A 2D echo shows LVEF 40% with inferoapical dyskinesis. Coronary angiography reveals totally occluded right coronary artery with collaterals. What is the next step? 65 year old male with h/o inferior wall myocardial infarction 1 year ago presents with rapid palpitation and syncope. An ECG shows SR and old inferior wall myocardial infarction. A 2D echo shows LVEF 40% with inferoapical dyskinesis. Coronary angiography reveals totally occluded right coronary artery with collaterals. What is the next step? Answer: Electrophysiologic study (to look for inducible sustained VT) Answer: Electrophysiologic study (to look for inducible sustained VT)

Case #3 72 year old male with chronic atrial fibrillation of greater than 10 years’ duration is admitted following a syncopal episode. A 2D echo shows markedly dilated left atrium and LVEF 60%. Telemetry reveals atrial fibrillation with slow ventricular response and pauses of 5 to 7 seconds associated with near syncope. 72 year old male with chronic atrial fibrillation of greater than 10 years’ duration is admitted following a syncopal episode. A 2D echo shows markedly dilated left atrium and LVEF 60%. Telemetry reveals atrial fibrillation with slow ventricular response and pauses of 5 to 7 seconds associated with near syncope. How would you proceed? How would you proceed? Answer: Implant single chamber rate responsive pacemaker Answer: Implant single chamber rate responsive pacemaker

Diagnostic Evaluation of Syncope Syncope Hx, physical exam, supine and upright BP, EKG Unexplained syncope Is there structural heart disease? NOYES Electrophysiologic Study Tilt table test