Tilt test in paced patients: Is it worth the effort?

Syncope is an important symptom that though most commonly benign, deserves extensive evaluation since it can also be caused at times by life threatening causes that are potentially treatable. An important cause of syncope is symptomatic bradycardia either due to sick sinus syndrome or atrioventricular block that is treated easily by pacemaker therapy. However, the most common cause of syncope in patients with normal heart is vasovagal or neurocardiogenic syncope where pacemaker therapy has a very limited role. When syncope recurs in a patient who received the pacing therapy for the same symptom, it not only becomes very difficult to explain to the patient but also poses significant diagnostic challenges. Head-up tilt test (HUTT) has been in use for evaluation of patients with suspected recurrent vasovagal syncope for many decades. However, data regarding its use in patients with pacing devices is scanty. Hence, the study by Haarmark et al. in this issue of the journal [1], reporting the results of HUTT in patients with pacemakers and recurrent syncope is a welcome addition to the literature. Though, the authors suggest that a positive HUTT even in a patient with pacemaker indicates a diagnosis of vasovagal syncope implying a benign condition, syncope in paced patients and role of HUTT in its evaluation has to be interpreted in the right perspective. The following discussion points may help in this regard.