Syncope without prodromes in patients with normal heart and normal electrocardiogram: a distinct entity

Area of Science:

• Cardiology
• Clinical Medicine
• Neuroscience

Background:

• The cause of sudden syncope without warning in patients with normal cardiac function is unclear.
• Understanding this condition is crucial for accurate diagnosis and treatment.

Purpose of the Study:

• To investigate clinical and laboratory findings in patients with unexplained syncope.
• To differentiate this syncope from vasovagal syncope (VVS).
• To explore the potential role of the adenosine pathway.

Main Methods:

• Compared 15 patients with unexplained syncope to 31 patients with VVS.
• Analyzed clinical data, syncope episode history, and adenosine plasmatic levels.
• Utilized tilt table and adenosine/adenosine triphosphate testing.

Main Results:

• Study group patients were older (61±12 vs 46±17 years) with fewer syncope episodes.
• Lower median adenosine plasmatic levels were observed in the study group (0.25 μmol/l vs 0.85 μmol/l).
• Adenosine levels ≤0.36 showed high sensitivity (73%) and specificity (93%) in distinguishing groups.

Conclusions:

• A distinct syncope form is characterized by specific clinical features and low adenosine levels.
• Low adenosine levels help differentiate this condition from VVS.
• Findings suggest a potential causal role for the adenosine pathway.