Background: Patients with unexplained syncope should undergo the tilt table test, it is the only clinical laboratory test indicated to identify susceptibility to vasovagal fainting.
The Aim of the work: To evaluate the effect of sublingual nitrates [Nitroglycerine] on the result of tilt table test in patients with unexplained syncope.
Patients and Methods: This was prospective observational study enrolled 60 patients with history of unexplained syncope. patients with cardiac or neurologic syncope were excluded. All patients were subjected to thorough history taking, physical examination [blood pressure, pulse and complete cardiac examination], standard 12 lead electro-cardiography, transthoracic echocardiography, passive tilt table test for 45 minutes with negative response and provocation tilt table test by sublingual isosorbide dinitrate for 15 minutes.
Results: After provocation by isosorbide dinitrate 5 mg, 38 patients [63.3 %] turned from negative to a positive response. The most common type was Vasodepressor [35 %]. There was a statistically significant increase in heart rate from passive stage to provocation stage in positive patients [P <0.001] and in negative patients [P <0.001], While there was a statistically significant decrease in blood pressure in positive patients [P <0.001] and in negative patients [P <0.001]. There is no statistically significant difference between males and females regarding test results [P = 0.464] or type of response [P = 0.727]. There was no statistically significant difference between positive and negative patients regarding comorbidities, smoking [P =0.552], diabetes mellitus [P = 0.879], hypertension [P = 0.338], or medications, angiotensin converting enzyme inhibitors [P = 0.419], beta blockers [P = 0.636], calcium channel blockers [P = 0.616].
Conclusion: The sublingual nitroglycerine has positive impact on the result of tilt table test in individuals with unexplained syncope. Gender, comorbidities and medications didn't affect the result of tilt table test.