Characteristics of Cardiac vs Vasovagal Syncope in Kids CME/CE
CME/CE Released: 10/02/2013; Valid for credit through 10/02/2014
Clinical Context
Syncope is a common event among children and adolescents. The authors of the current study note that 15% of children experience at least 1 episode of syncope. Although these episodes are distressing, only 1.5% to 5% of all cases of syncope are the result of underlying cardiac disease. Aberrant coronary artery anomalies are one of the most feared causes of syncope, as children with these anomalies may present with normal physical examination and electrocardiographic (ECG) findings. Coronary anomalies may account for 17% to 23% of cases of sudden cardiac death among children.
Increased scrutiny for cardiac abnormalities among young athletes has led to increased recognition of syncopal episodes, and many of these patients are then referred to cardiology practices for further evaluation. Are there clinical characteristics that might help differentiate vasovagal from cardiac syncope and thereby reduce the rate of cardiology referrals? The current study by Tretter and Kavey evaluates this issue.
Study Synopsis and Perspective
A new screening rule can help distinguish cardiac syncope from vasovagal syncope in young people, its developers say.
In a review of children and adolescents diagnosed with cardiac syncope, they found that characteristics in the history, physical exam, and ECG will accurately identify those with a cardiac etiology.
In their series, all patients with a cardiac etiology for syncope had at least one of the following: (1) history of syncope associated with exertion; (2) a concerning cardiac family history; (3) an abnormal physical examination; or (4) an ECG interpreted as abnormal by a pediatric cardiologist.
Syncope is a common problem in children and adolescents and is rarely cardiogenic in origin, creating a diagnostic challenge for primary care physicians, say Dr. Justin Tretter and Dr. Rae-Ellen Kavey from Golisano Children's Hospital at the University of Rochester Medical Center in Rochester, New York.
In The Journal of Pediatrics, online August 29, they point out that as many as 15% of children experience a syncopal event, but only 1.5% to 5% of these are caused by underlying cardiac disease.
Increased attention from the media to sudden death in young athletes has led to more visits to physicians for syncope during the past two decades. Yet, research on syncope has largely focused on adults, "with no uniform diagnostic approach to pediatric syncope, leading to high costs with low diagnostic yield."
Drs. Tretter and Kavey compared the characteristics of 89 individuals with confirmed vasovagal syncope and 17 with confirmed cardiac syncope, all age 18 or younger.
Characteristics seen more often with cardiac than vasovagal syncope included syncope surrounding activity (65% vs. 18%, p<0.001); family history of cardiac disease or sudden cardiac death (41% vs. 25%, p=0.2); abnormal findings on the physical examination supporting cardiac diagnosis (29% vs. 0%, p<0.001); and abnormal findings on ECG (76% vs. 0%, p<0.001).
"This analysis points to dramatic differences in presentation between those with cardiac etiology and those with benign vasovagal syncope," write Drs. Tretter and Kavey.
They say screening for cardiac disease using any one of these four characteristics had a sensitivity of 100% and specificity of 60%. "Using this screening rule, we found that 60% of patients with vasovagal syncope would not have been referred to cardiology."
Dr. Samuel Asirvatham, a pediatric cardiologist at Mayo Clinic Children's Center in Rochester, Minnesota, commented that "fainting is a very common problem both in children and adults. With adults, the issue is more that they have other cardiac causes, like slow heart rate, previous heart attack and so on. With children, sometimes the mistake is made in that we think just because it's a young person it's going to be vasovagal. What this study shows is, just like in adults, if the history doesn't fit with vasovagal, just because they are children you shouldn't assume it's vasovagal."
On the other hand, "the more the history favors vasovagal syncope, the less you need a workup for cardiogenic syncope," Dr. Asirvatham, who wasn't involved in the study, told Reuters Health.
Overall, he said, this study is "a good contribution to the literature, but it's a very small study for such a common problem. To really test out an algorithm I would guess we would need something close to 10 times the number of patients."
Drs. Tretter and Kavey acknowledge this limitation and others in their paper, including the study's retrospective design, which depended on the validity of documented patient details. "Historic details may not have been asked or recorded by the physician," they point out.
The authors did not respond to request for comment.
J Pediatr. Published online August 29, 2013.
Study Highlights
- Study data were drawn retrospectively from a single tertiary pediatric cardiology practice in the United States. Children and adolescents up to 18 years old with vasovagal and cardiac syncope were compared for demographic and clinical factors.
- Children with vasovagal syncope were identified during a 1-year period. As cases of cardiac syncope are far less common, these children were identified during a 10-year period by a record review of 14 diagnosis codes commonly associated with syncope.
- 89 children between 4 and 18 years old with vasovagal syncope were compared vs 17 children between 4 months and 17 years old with cardiac syncope. The mean ages of children in the cardiac syncope and vasovagal cohorts were 10.5 and 12.7 years, respectively. The overall study cohort was fairly balanced between male and female patients.
- The most common underlying diagnosis among children with cardiac syncope was long-QT syndrome (8/17 cases).
- Rates of a previous syncopal event were 71% in the cardiac syncope group and 36% in the vasovagal syncope group. Conversely, the respective rates of presyncopal symptoms were 12% and 69%.
- There was no difference between groups in the rates of chest pain or palpitations before syncope or exercise tolerance.
- However, cardiac syncope occurred around exercise in 65% of children vs only 18% of children with vasovagal syncope.
- Rates of a positive family history of heart disease in the cardiac and vasovagal syncope groups were 41% and 25%, respectively.
- 29% of children with cardiac syncope had abnormal physical examination findings vs none of the children with vasovagal syncope.
- 76% of children with cardiac syncope had an abnormal ECG result vs none of the children with vasovagal syncope.
- Researchers concluded that 4 variables were most helpful in discriminating cardiac vs vasovagal syncope: exertional syncope (especially around peak exercise), a family history of cardiac problems, abnormal physical examination findings, and abnormal ECG results. The average number of these characteristics present among children with cardiac syncope and children with vasovagal syncope was 2.1 and 0.4, respectively.
- With use of the presence of any of these 4 variables as a guide, all cardiac syncope patients would receive a specialist evaluation. However, 60% of cardiology referrals for what turned out to be vasovagal syncope could have been avoided.
Clinical Implications
- An estimated 15% of children experience at least 1 episode of syncope, and only 1.5% to 5% of all pediatric cases of syncope are the result of underlying cardiac disease. Children with syncope from aberrant coronary artery anomalies may present with normal physical examination and ECG findings. Coronary anomalies may account for 17% to 23% of cases of sudden cardiac death among children.
- In the current study by Tretter and Kavey, the 4 variables with the greatest power to discriminate between cardiac and vasovagal syncope were exertional syncope (especially around peak exercise), a family history of cardiac problems, abnormal physical examination results, and abnormal ECG findings.
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