Mechanisms of Vasovagal Syncope
Vasovagal Syncope, Postural Tachycardia Syndrome
About this trial
This is an interventional diagnostic trial for Vasovagal Syncope focused on measuring Vasovagal Syncope, Postural Tachycardia Syndrome, Orthostatic Intolerance, Nitric Oxide (NO), Orthostatic Stress, L-Ng-monomethyl Arginine (L-NMMA), Phenylephrine, Sodium Nitroprusside
Eligibility Criteria
Inclusion Criteria:
POTS patients referred for day to day orthostatic intolerance with greater than 3 symptoms for greater than 3 months and will have the diagnosis of symptomatic postural tachycardia made during a screening tilt table test :
- dizziness
- nausea and vomiting
- palpitations
- fatigue
- headache
- exercise intolerance
- blurred vision
- abnormal sweating heat.
- Vasovagal Syncope patients will have at least 3 episodes of fainting episodes in the past year.
- Healthy control subjects
Cases will be between the ages of 14 and 29 years old Cases will have normal physical examination, and normal electrocardiographic and echocardiographic evaluations.
Only those free from heart disease, and from systemic illness will be eligible to participate.
This excludes patients with illnesses and disease states known to be associated with endothelial cell dysfunction such as diabetes, renal disease, congestive heart failure, systemic hypertension, acute and chronic inflammatory diseases, neoplasm, immune mediated disease, trauma, morbid obesity and peripheral vascular disease.
At the time of testing all patients and control subjects must refrain from vasoactive drugs for two weeks. Please check with us about any medication that you are taking.
Exclusion Criteria:
- Cardiovascular causes of syncope
- An active medical condition that may explain the diagnosis
- A previous medical condition with undocumented resolution that may explain the diagnosis
- Past or present major psychiatric disorder
- Substance abuse within 2 years before onset of symptoms.
Sites / Locations
- New York Medical College/Bradhurst Building
Arms of the Study
Arm 1
Experimental
Phenylephrine and L-Ng-monomethyl Arginine (L-NMMA)