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  • Gregg M. Yamada, MD FACC

Syncope (Fainting): How Cardiologists Evaluate This Condition.

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Fainting, or syncope, is a very dramatic and frightening situation. Become familiar with the term ‘syncope’-- it is a common medical term and condition. Syncope refers to a transient loss of consciousness. This article will provide you with a general overview of how cardiologists evaluate fainting (syncope), near fainting (near syncope), and dizziness.

  • Depending upon the circumstances you may be asked to limit activities such as driving, climbing, operating heavy equipment, and swimming. The latter is especially important in Hawaii where many people are involved in water sports.

Cardiac Vs. Noncardiac Syncope

  • Cardiologists separate syncope (fainting) into cardiac causes (arrhythmia, structural heart disease) vs. noncardiac causes (neurologic, orthostatic, vasovagal, etc.).

  • Cardiac causes are then subdivided into electrical causes and mechanical causes.

Evaluation of Cardiac Related Syncope

  • A careful intake history is important. Most often, the cardiologist can determine the cause of fainting by asking a few obvious questions.

  • Many syncopal episodes are due to vagal causes or orthostasis and have nothing to do with serious heart conditions.

  • Others are due to medication side effects, low blood sugar. Your PCP will exclude neurologic causes with the use of CT scans, MRI and MRA.

  • Cardiac syncope may be associated with >30% death rate at one year. Some experts have quoted a 40% mortality at one year. This is why so much time, effort and money are spent looking for a cardiac cause.

  • The cardiac causes of syncope will, of course, differ depending upon the age of the individual and their underlying medical condition. We have different concerns for a young high school or collegiate athlete (SCD: HCM, long QT, ARVD) vs. an elderly patient with diabetes, hypertension and Parkinson’s disease (CVD, CM, AS, PE, bradyarrhythmia, SCD, medication related side effects), for example.

A Typical Cardiac Evaluation will include:

1. History

2. EKG

3. CXR

4. Stress testing or equivalent

5. Echocardiogram or equivalent

6. Event monitor

7. Other studies such as implantable loop records (ILR) tilt table testing, EP studies are less common.

  • The purpose of the above it to determine if you do or do not have underlying structural heart disease. See my post on ‘stress test and echo’. If you have severe coronary artery or carotid/vertebral artery blockages (CAD), a weak or damaged heart (cardiomyopathy, ARVD), a damaged heart valve (aortic stenosis), elevated heart/lung blood pressure (pulmonary hypertension), a slow heart beat (bradyarrhythmia), or congenital heart disease (long QT, ARVD, anomalous coronary arteries)—syncope could be a warning of pending sudden cardiac death.

  • It is imperative that we document the rhythm associated with syncope, near syncope or dizziness. This is key. An event monitor will usually be placed and, if syncope is recurrent and no obvious cause, an implantable loop recorder may be required. This is also where devices like an Apple Watch or Fitbit may be helpful. (See my post on the evaluation of arrhythmia).

What You Can Do

Prior to your cardiology appointment and even afterwards, there are several steps you can take to help your cardiologist find out why you fainted or experienced dizziness and help prevent a recurrence.

1. Hydrate

It is important that you be sure to hydrate yourself. Most people should be drinking at least 8 glasses of liquid; much more if you exercise and perspire a lot. Many people, especially older folks do not want to get stuck looking for a bathroom and intentionally avoid drinking. Younger people who cannot leave their job/post to use the bathroom also do the same.

2. Document

  • Take careful notes of the circumstances surrounding any complaints of dizziness, near fainting or fainting.

  • Did you experience any warning symptoms? Chest pain, racing heartbeats. Nausea. Shortness of breath. Diffuse perspiration.

  • How long were you dizzy or unconscious? Who was with you? Did someone call 911? What hospital ER were your evaluated in?

  • Many people make the mistake of not going to the ER after a fainting episode. The best time to be evaluated for syncope is when it occurs.

  • Examples of questions you will asked by your cardiologist: Do you typically feel dizzy or lightheaded with standing rapidly? What was your blood pressure and heart rate at that time of the syncopal episode? What time of day did it occur? Before or after meals? Before of after medications? If diabetic, what was your blood sugar, when did you last eat? What was the environment like? Was the room hot? Did you come out of a hot bath or shower? Are symptoms associated with a change in position, coughing, laughing or using the bathroom? Have you lost weight? Were there any neurologic complaints: visual or hearing changes, incoordination, paralysis? Have you been sick with a cold or flu? Are you taking any supplements or over the counter medications that doctors are not aware of? Are you using any ilicit substances? Are you on an intermittent fasting diet? Have you started any new medications or changed dosages? Do you drink enough liquid? Do you feel there is any pattern to your episodes?

3. Monitor Your Blood pressure

Take your blood pressure morning, night and at any time you have dizziness or lightheadedness. Write down your medications and when you take them.

4. Use Your Apple Watch

If you have a heart monitoring device. Make use of it.

5. Stop Caffeine and Alcohol

Avoid caffeine: Caffeine is a diuretic. For example if you drink 8 glasses of fluid per day and two of them are coffee, you need to ‘minus two cups of liquid’ from what you report. Avoid all caffeine during your evaluation as it may also result in arrhythmia which will further result in more tests and procedures.

6. Dieting:

Stop any diets: People often become dizzy or faint after losing a lot of weight on a diet. Don't use intermittent fastng, keto diet while being evaluated for syncope or dizziness.

7. Activity Restrictions:

Curtail activities: Speak to your cardiologist about what activities you can and should not continue. This include driving, swimming, climbing, etc. If you become dizziness or fainting only related to a change in position activities may not have to be restricted once you correct the cause of your orthostasis (positional drop in blood pressure). If, however, you suffer a drop attack: lose consciousness without warning, you must restrict activities.


  • Your cardiologist will determine if your syncope is due to a safe preventable/avoidable condition vs. a life-threatening arrhythmia.

  • Fortunately, very few patients have life-threatening causes of fainting, but when present may result in sudden cardiac death. For this reason, a comprehensive and often inconvenient evaluation is required in an attempt to identify the rare patient whose life can be saved by proper diagnosis.

Note: Understanding your heart condition is not difficult. Patients become frustrated and confused when doctors don’t explain things clearly. If you don’t understand what your doctor is talking about, then you won’t be able to ask meaningful questions. I hope that my posts provide you with a framework that you can build upon to become an active participant in your healthcare.

Stay Healthy!

Gregg M. Yamada MD FACC


Disclaimer: I hope you find my posts to be educational, pertinent, interesting, and thought provoking. The information provided is educational and should not be taken as medical advice. I am a doctor, but I am not your doctor. I am a cardiologist, but I am not your cardiologist. Schedule an appointment with your doctor/cardiologist to discuss these issues and to determine what is right for you.

© 2020. Gregg M. Yamada, MD FACC. All rights reserved



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