The purposes of this study were to describe: clinical symptoms in a sample of consecutive
patients with supraventricular tachycardia (SVT); incidence of sudden death, syncope,
and other disabling symptoms; whether these symptoms differ by tachycardia mechanism;
and to identify predictor variables of syncope in patients with SVT. Data were collected
from chart reviews of 167 consecutive patients with SVT admitted for radiofrequency
ablation. Three patients (2%) had nonlethal cardiac arrest, and a total of 16% (26
of 183) received at least 1 external direct-current shock for arrhythmia management.
Twenty percent of subjects (33 of 167) reported at least 1 episode of syncope which
was preceded by palpitations. The most frequent symptoms were: palpitations (96%),
dizziness (75%), and shortness of breath (47%). We found atrioventricular nodal reentrant
tachycardia (AVNRT) in 64 patients, atrioventricular-reciprocating tachycardia (AVRT)
in 59, atrial tachycardia in 22, and atrial flutter in 22. The symptom profiles of
patients with AVNRT, AVRT, and atrial tachycardia were very similar, but differed
significantly (p <0.05) from those reported in the atrial flutter group. Multivariate
analysis showed that heart rate > or = 170 beats/min was the only independent risk
factor for syncope. Chi-square analysis demonstrated that SVT patients with heart
rate > or = 170 beats/min had significantly more dizziness and syncope. Thus, despite
a low incidence of associated heart disease, and good left ventricular function, there
was a high frequency of disabling, potentially life-threatening symptoms associated
with episodes of SVT in this sample. SVT can have potentially lethal consequences,
and is more disruptive than previously thought.