Evaluation and Management of Syncope

Syncope

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

Transient inadequate cerebral perfusion.

Syncope - Epidemiology

 1% of hospital admissions  3% of ER visits  6% annual incidence in the elderly  Upto 50% of young adults have history of isolated LOC  Annual cost $2 B (2005)

Clin Electrophysiol 22:1386,1999 Sun BC, Am J Cardiol 95:668, 2005

Syncope - Prognosis

 Highest mortality in patients with cardiac cause  Neurally mediated syncope/ medication induced syncope did not increase mortality

Soteriades ES, et al: N Eng J Med 347:878, 2002

Causes of Syncope



Vascular

( 58 – 62 % ) : Reflex mediated, orthostatic, anatomic 

Cardiac

( 10 – 23 % ): Arrhythmias, anatomic  Neurologic/cerebrovascular* ( 0.5 – 5 % )  Metabolic/drugs ( 0 – 2 % )  Psychogenic* ( 0.2 – 1.5 % )  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) Hypoglycemia Seizure Psychogenic

Syncope - Clinical Features Suggestive of Specific Causes

Symptom or Finding Diagnostic Consideration After sudden unexpected pain, unpleasant sight, sound or smell During/immediately after micturition, cough, swallow or defecation On standing Vasovagal syncope Situational syncope 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 ) Syncope during exertion Atrial myxoma, thrombus 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) Associated with vertigo, dysarthria, diplopia, and other motor and sensory symptoms of brain stem ischemia With arm exercise Cartoid sinus syncope Transient ischemic attack, subclavian steal, basilar artery migraine Subclavian steal Confusion after episode Seizure

Seizure vs Syncope

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

Syncope – Diagnostic Tests

        History and physical examination: cardiac disease, family h/o SCD, medications, witness Orthostatic BP check ECG: Q waves, QTc, delta wave, epsilon wave Holter monitor: V pause > 3 sec while awake, Mobitz type 2 or CHB, VT.

Arrhythmia event monitor Echocardiogram Tilt table test Electophysiologic testing

Diagnostic Tests for Syncope

Test

Holter Monitor Continuous-Loop Recorder Implantable Loop Recorder Signal-Averaged ECG

Indication

Frequent symptoms of palpitations or dizziness

Disadvantage

Low yield if symptoms are intermittent Intermittent or very transient symptoms; patient has little warning before symptoms occur Infrequent episodes of syncope; diagnosis cannot be made noninvasively Syncope and structural heart disease Inconvenient to use for long periods of time Requires invasive procedure Low positive predictive value

Diagnostic Tests for Syncope (cont’d)

Test

Upright Tilt Testing Electrophysiologic Study

Indication

Suspected vasovagal syncope; syncope without structural heart disease Syncope when diagnosis cannot be made non invasively; syncope with structural heart disease

Disadvantage

Inadequate reproducibility Invasive; low yield when no structural heart disease

Syncope – Indications For Hospitalization

 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 Syncope with severe injury  Syncope during exercise  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  Unexplained syncope at the end of work-up, orthostatic trigger present  Suspected delayed orthostatic hypotension

Neurally Mediated Syncope

   Also known as vasovagal syncope.

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.



Most vasovagal episodes involve both cardioinhibition (drop in heart rate) and vasodepressor response (drop in BP).

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?

Answer:

Tilt table test .

Q: What is the mechanism for the visual symptoms?

Answer:

Collapse of peripheral vessels of the retina.

Syncope:

The Role of Electrophysiologic Testing

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

Guidelines for EP Testing in Syncope

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

   

Electrophysiologic Testing in Syncope

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

Neurally Mediated Syncope

      Precipitating factors: prolonged standing, dehydration, alcohol, diuretics, vasodilators.

Sit/lie down at onset of symptoms, cross the legs and tense them together if sitting.

Salt supplementation and fluids.

Isometric arm, leg counterpressure.

Moderate aerobic and isometric exercise.

Tilt training.

Therapy of Neurocardiogenic Syncope

Treatment

Volume expansion (increase salt and fluid intake, fludrocortisone) Beta-Blockers

Mechanism

Maintain ventricular volume Anticholinergic agents (scopolamine, disopyramide) Serotonin reuptake inhibitors Methylxanthines Midodrine Cardiac pacing Block response to adrenergic stimulation; reduce ventricular contractility; prevent activation of ventricular mechanoreceptors Block vagal response; reduce ventricular contractility (disopyramide) Prevent vasodilation and bradycardia possibly by downregulation of response to serotonin Adenosine receptor antagonist; Phophodiesterase and Ca ++ (maintain vascular tone) transport inhibitor Adrenergic agonist 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.

A small study has reported the efficacy of midodrine.

Metoprolol, propranolol and nadolol are no more effective than placebo.

Orthostatic Intolerance Syndrome

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

Syncope - Prognosis

 Highest mortality in patients with cardiac cause  Neurally mediated syncope/ medication induced syncope did not increase mortality

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  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?

 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.

How would you proceed?

Answer: Implant single chamber rate responsive pacemaker

Diagnostic Evaluation of Syncope

Syncope Hx, physical exam, supine and upright BP, EKG Unexplained syncope NO Is there structural heart disease?

Tilt table test YES Electrophysiologic Study