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Near-Syncope After Exercise GRAND ROUNDS CLINICIAN’S CORNER AT THE JOHNS HOPKINS BAYVIEW MEDICAL CENTER Near-Syncope After Exercise Roy C. Ziegelstein, MD Syncope and near-syncope are great diagnostic challenges in medicine. On CASE PRESENTATION the one hand, the symptom may result from a benign condition and pose A 72-year-old man complained of near- little or no threat to health other than that related to falling. On the other syncope after exercise that had been oc- hand, syncope or near-syncope can be the manifestation of a serious un- curring for several months. Every morn- derlying condition that poses an imminent threat to life. Patients with a car- ing, he walked at 3.5 mph for about half diac cause of syncope are at far greater risk of dying in the first year after an an hour on his treadmill in the well- ventilated basement of his home. After episode of syncope or near-syncope than individuals with a noncardiac cause. exercising, he would step off the tread- A cardiac cause of syncope should be considered in every patient with syn- mill, check his pulse, and become light- cope or near-syncope, but it is particularly common in older patients or in headed immediately afterward. This feel- patients with known structural heart disease, arrhythmia, or certain electro- ing lasted a few minutes and he would cardiographic abnormalities. Although many diagnostic tests may be help- then go upstairs to eat breakfast and take ful in the evaluation of syncope and near-syncope, the history, physical ex- his medications. amination, and electrocardiogram pinpoint the cause in many circumstances. The patient was referred to me shortly after a very severe episode that almost re- Syncope after exercise may be due to left ventricular outflow tract obstruc- sulted in loss of consciousness. During tion from aortic stenosis or hypertrophic obstructive cardiomyopathy but can that episode, he stepped off the tread- also suggest the diagnosis of postexercise hypotension in which an abnor- mill and tried to feel his pulse as usual. mality in autonomic regulation of vascular tone or heart rate results in va- He then felt that he was losing his pe- sodilation or bradycardia after moderate-intensity aerobic activity. The pa- ripheral vision and thought he would fall. tient discussed in this case highlights the importance of the clinical history He stopped feeling his pulse and eased in the evaluation of this condition, since the diagnosis was revealed as the himself down to the floor without los- patient’s story was described and eventually acted out. ing awareness of his surroundings. Af- ter a few minutes, he felt better and JAMA. 2004;292:1221-1226 www.jama.com walked around the room to “cool down.” amination results were entirely unre- ties during the recording and exercised During the initial evaluation, the pa- markable. Notably, his blood pressure normally on his treadmill in the morn- tient said that he was otherwise well. He and pulse were normal and there was no ing. He reported that he thought every- denied headache, difficulty with speech, significant change in either when he as- thing was the same that day as always, weakness, chest discomfort, shortness of sumed the upright posture. Electrocar- although he did deviate from his rou- breath, palpitations, or lightheaded- diogram results were also normal. tine slightly and did not take his pulse ness either during exercise or at other The patient was sent home with a 24- after exercise because he knew his heart times except immediately after exer- hour ambulatory electrocardiogram rate was already being monitored elec- cise. His medical history was remark- (Holter monitor), and plans were made tronically. He also noted that he did not able only for hypertension. Four years for an exercise treadmill test in the very experience lightheadedness after exer- earlier, a stress test and echocardio- near future. The patient was asked to per- cise on that occasion. gram, performed as part of a routine car- form all his usual activities while wear- diovascular evaluation, were both nor- ing the Holter monitor. Specifically, he Author Affiliation: Department of Medicine, Divi- mal. He was regularly taking vitamin E sion of Cardiology, Johns Hopkins Bayview Medical was asked to exercise on the treadmill in and a combination of hydrochlorothia- Center, Johns Hopkins University School of Medi- his basement as usual. The Holter moni- cine, Baltimore, Md. zide and triamterene. His physical ex- Corresponding Author: Roy C. Ziegelstein, MD, De- tor recording was completely normal and partment of Medicine, Division of Cardiology, Johns demonstrated the expected increase in Hopkins Bayview Medical Center, 4940 Eastern Ave, CME available online at heart rate with exertion. The patient said Baltimore, MD 21224-2780 ([email protected]). www.jama.com Grand Rounds Section Editor: David S. Cooper, MD, that he engaged in all his usual activi- Contributing Editor, JAMA. ©2004 American Medical Association. All rights reserved. (Reprinted) JAMA, September 8, 2004—Vol 292, No. 10 1221 NEAR-SYNCOPE AFTER EXERCISE sciousness. Given the importance of the tality of patients with a cardiac cause of Box 1. Causes of Syncope clinical history in the evaluation of syn- syncope is 2 to 5 times that of patients 2,3 Cardiac or Cardiopulmonary cope and near-syncope and sensing that with noncardiac syncope. In particu- Causes a clue was revealed by the absence of lar, it is important to consider poten- Arrhythmias symptoms during Holter monitoring, I tially lethal or imminently lethal condi- Aortic stenosis asked the patient to describe his epi- tions like ventricular tachycardia, rapid Hypertrophic obstructive sodes in detail again and the diagnosis supraventricular tachycardia, torsades de cardiomyopathy became apparent. pointes in the setting of congenital or ac- Aortic dissection quired long QT syndrome, myocardial Myocardial ischemia DISCUSSION ischemia, or critical aortic stenosis. A car- Pericardial tamponade Syncope is one of the greatest diagnos- diac cause of syncope is particularly com- Pulmonary embolism tic challenges in medicine. While the mon in older patients or in patients with Pulmonary hypertension cause is often benign with no imminent structural heart disease, a history of ar- Noncardiac Causes threat to the patient other than that due rhythmia, or who have certain electro- Neurally mediated reflex syndromes to physical injury as a result of falling, it cardiographic abnormalities (BOX 2).4,5 Vasovagal faint is sometimes a sign of a potentially le- Given this, older patients like the 72- Micturition or defecation syncope thal condition such as critical aortic ste- year-old man or patients with a history Postprandial hypotension nosis, hypertrophic obstructive cardio- of heart disease should be considered to Orthostatic hypotension myopathy, or ventricular tachycardia. have a cardiac cause of syncope until Cerebrovascular steal Syncope is a sudden loss of conscious- proven otherwise. Although the his- Conditions Frequently ness, usually accompanied by falling due tory, physical examination, electrocar- Misdiagnosed as Syncope to loss of postural tone, with subse- diogram, and normal stress test and echo- Hypoglycemia quent spontaneous recovery. It is typi- cardiogram from 4 years earlier made a Epilepsy cally due to a transient global decrease cardiac cause less likely in this patient Cataplexy in blood flow to the brain for more than despite his age, the patient was sent home Vertebrobasilar transient ischemic 8 to 10 seconds. The inadequate blood with a 24-hour ambulatory electrocar- attacks flow to the brain is most often caused by diographic recording device and plans systemic hypotension resulting from in- were made for an exercise treadmill test adequate vasoconstriction, hypovole- in the near future, given the relation- mia, decreased venous return, an abrupt ship of his symptoms to exercise. Exer- Box 2. Electrocardiographic change in heart rate, or an acute de- cise stress testing is a particularly valu- Features Suggesting a Cardiac crease in cardiac contractility. “Near- able part of the evaluation of patients Cause of Syncope syncope” or “presyncope” are terms used with exertional syncope or near- Atrial fibrillation or flutter when the patient feels as if loss of con- syncope. The normal response to tread- Multifocal atrial tachycardia sciousness is about to occur but does not. mill exercise is a progressive increase in Paced rhythm The major causes of syncope are systolic blood pressure and no change or Frequent premature ventricular listed in BOX 1 and may be separated a decrease in diastolic blood pressure; a contractions into conditions that are primary car- drop of the systolic blood pressure dur- Ventricular arrhythmia diac or cardiopulmonary and those that ing exercise below the standing pre- Bundle branch block 1 Left ventricular hypertrophy are noncardiac. Some conditions are exercise value typically defines exercise- 6 Pathologic Q waves indicative of frequently misdiagnosed as syncope induced hypotension. Exercise- prior myocardial infarction (Box 1) since they also produce a tem- induced hypotension during treadmill Mobitz II or higher atrioventricular porary disturbance of consciousness testing often reflects left ventricular dys- block that may result in loss of postural tone. function or myocardial ischemia. When Wolff-Parkinson-White syndrome Although an individual with one of associated with either of these 2 factors, these conditions may resemble a pa- it indicates a significantly increased risk tient
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