Sinister causes of syncope

Useful features from history

  • Have you ever fainted, passed out, or had an unexplained seizure suddenly and without warning, especially during exercise or in response to sudden loud noises, such as doorbells, alarm clocks, and ringing telephones?

  • Have you ever experienced breathlessness or chest pain while exercise?

  • Has anyone in your immediate family or more distant relatives (aunts, uncles, cousins) passed away suddenly or unexpectedly before the age of 50 due to cardiac issues? This includes unexpected drownings, unexplained auto crashes in which the relative was the driver?

  • Is there anyone in your family under the age of 50 who has a pacemaker or implantable defibrillator, or to anyone with hypertrophic obstructive cardiomyopathy, Marfan syndrome, LQTS, arrhythmogenic cardiomyopathy, short QT syndrome, Brugada syndrome, or CPVT?

Causes of cardiac arrest by age group

  • Adolescents and Young adults (age 14-35)

    • Inherited Channelopathies (long QT/Brugada/CPVT),

    • Wolff-Parkinson-White

    • Cardiomyopathies (hypertrophic/dilated/restrictive/ARVC/non-compaction).

    • Myocarditis.

    • Drug

  • Adult (>35)

    • Coronary artery disease

    • Structural abnormalities

Notable points

  • No single tool would perfectly predict sudden cardiac death

  • History alone identifies 20% of at-risk

  • Physical examination identifies 9%

  • ECG/echocardiogram and genetic testing only if indicated (AHA0

  • Routine ECG screening is not recommended (AHA)

AHA 14-element checklist (Maron BJ Circ 2014)

  • Personal history

    • 1. exertional chest pain / discomfort

    • 2. exertional syncope, or near-syncope

    • 3. excessive exertional and unexplained fatigue / fatigue associated with exercise

    • 4. prior recognition of heart murmur

    • 5. elevated systemic blood pressure

    • 6. prior restriction from sports participation

    • 7. prior testing for heart ordered by a physician

  • Family history

    • 8. premature death, sudden and unexpected before age 50 due to heart disease, in one or more relatives

    • 9. disability from heart disease in a close relative <50

    • 10. specific knowledge of certain cardiac conditions in family members: hypertrophic or dilated cardiomyopathy, long QT syndrome, or other ion channelopathies, Marfan syndrome, or clinically important arrhythmias

  • Physical exam

    • 11. heart murmur - exam supine and standing or with valsalva, specifically to identify murmurs of dynamic left ventricular outflow tract obstrruction

    • 12. femoral pulses to exclude aortic stenosis

    • 13. physical stigmata of Marfan syndrome

    • 14. brachial artery BP (sitting, preferably taken in both arms)

Dr James Fu