syncope in kids

in recent study looked at factors which might distinguish cardiac syncope from vasovagal syncope in children up to 18 years old (see syncope in kids j peds 2013 in dropbox, orhttp://dx.doi.org/10.1016/j.jpeds.2013.07.023 ). the study was set in a pediatric cardiology clinic including 89 patients who had vasovagal syncope over a one year period, compared with children with known cardiac syncope (given the relative rarity of cardiac syncope, they searched their files and found 17 patients who had significant cardiac disease and syncope).  8 with cardiac syncope had long QT syndrome, 3 had cardiomyopathy (2 HOCM), and one of each had  left coronary artery originating from the right aortic cusp, primary pulmonary hypertension, myocarditis with ventricular tachycardia, catecholaminergic polymorphic ventricular tachycardia, cardiac fibroma, and idiopathic ventricular tachycardia (notably, no Brugada or arrhythmogenic right ventricular dysplasia). results (only statistically significant ones noted), comparing cardiac syncope with vasovagal syncope:

--71% those with cardiac syncope had no previous syncopal event, versus 36% with vasovagal syncope.

--trigger event (noxious stimuli or frightening events) was not found in any patient with cardiac syncope but 24% of those with vasovagal syncope

--presyncopal symptoms not leading to syncope in 12% with cardiac syncope and 69% with vasovagal

--preceding symptoms such as lightheadedness or visual changes in 41% with cardiac etiology vs 84% with vasovagal

--prolonged standing was found in none with cardiac syncope but 82% with vasovagal syncope

--syncope with activity in 65% in cardiac syncope vs 18%; syncope at peak exercise in 53% vs 6%

--PE overall abnormal in 29% vs 0%

--EKG abnormal in 76% vs 0%

--but no difference in chest pain or palpitations before the syncope or history of decreased exercise tolerance preceding the event.  

--overall: if compare the combo of exertional syncope (at peak or post exercise), concerning cardiac family history (syncope; heart probs including arrhythmia, congenital heart dz, cardiomyopathy; sudden death younger than 50 yo), abnl PE or abnormal EKG – mean number of these items found in cardiac syncope was 2.1 vs 0.4 with vasovagal.  And, if use the presence of any one of these 4 as basis for referral to cardiology, would have identified 100% of those with cardiac syncope, and (perhaps most importantly), would have avoided 60% of those with vasovagal being referred to this cardiology clinic.

so, small study, esp in the number of kids with cardiac syncope (though this is really pretty uncommon), but suggests that the rather common vasovagal syncope typically does not require referral if the above 4 items are assessed