Dr. Michele Brignole,
In vasovagal syncope and situational syncope - “reflex” syncope -, tilt table testing (TTT) is not necessary for confirmation of an already certain diagnosis but can still be useful for therapeutic purposes (to demonstrate susceptibility of the patient). In cardiac patients, cardiac evaluation must be done first. In delayed orthostatic hypotension, when standard active standing test is negative, diagnosis can be made only by means of TTT. Read more about TTT and our findings regarding sensitivity of TTT, all in relation to the latest, 2009 ESC guidelines.
Tilt table testing (TTT) was introduced over 20 years ago for the evaluation of patients with unexplained syncope. Its use has spread unevenly in clinical practises, because initial enthusiasm has been hampered by the recognition of several limitations. Tilt table testing is often negative in cases of typical vasovagal syncope (i.e., “low sensitivity”) and positive in patients without syncope (i.e., “low specificity”). Additionally, it has offered minimal or no value in assessing the efficacy of treatment with drugs or pacemakers. Thus, a number of physicians have concluded that management guided by careful clinical history was superior to TTT for identification of patients affected by reflex syncope, in particular. However, the latest ESC guidelines on syncope (2009) have provided new insights into the correct use of TTT, which in fact, should remain an important diagnostic tool in a number of clinical settings - provided that physicians learn its appropriate indications and the correct interpretations of results.
The ESC 2009 Guidelines for the management of syncope:
Prior to the 2009 guidelines, the sensitivity of TTT could not be calculated and was surrogated by the evaluation of a more general “positivity rate”, arousing some concern as to the real diagnostic yield of the test. In this respect the guidelines indicate that the specificity of TTT potentiated with nitroglycerin or clomipramine is approximately 10%. Thus, when TTT, performed for diagnostic purposes in patients affected by uncertain syncope, should in all likelihood provide a positive response. In a study conducted in our centre, we have thus been able to establish “true positive” cases in view of calculating the true sensitivity of TTT (3). We have thus identified a group of patients affected by established reflex syncope based on clinical presentation. These patients - the “true positive group”- constituted a “gold standard” population that allowed us to calculate the sensitivity of TTT applied to our group (n=360). Sensitivity of TTT, when potentiated with nitroglycerin was found to be 71% and 75% in patients with vasovagal and situational forms of syncope respectively. The sensitivity of TTT potentiated with clomipramine was higher in patients with vasovagal forms (92%), but sub-optimal in patients with situational forms. Interestingly, sensitivity increased to 87% and 100% respectively, in patients with both vasovagal and situational syncopes, indicating a more complex and severe form of reflex syncope. Our findings show that TTT supports a likely diagnosis of reflex syncope – reflex syncope was observed in 36% and 30% of cases with nitroglycerin TTT and clomipramine TTT respectively (3). We conclude that a negative response makes a diagnosis of reflex syncope less likely and suggests that other causes should be investigated (of which possible orthostatic or cardiac syncope).
More generally, the latest guidelines offer the following, current and appropriate indications for TTT:
*Not yet established: the indication of TTT for selecting cases of cardioinhibitory forms of syncope that would be candidates for pacing therapy.
1- Moya A, Sutton R, Ammirati F, Blanc JJ, Brignole M, Dahm JB, Deharo JC, Gajek J, Gjesdal K, Krahn A, Massin M, Pepi M, Pezawas T, Ruiz Granell R, Sarasin F, Ungar A, van Dijk G,Walma E, Wieling W. Guidelines for the Diagnosis and Management of Syncope (Version 2009) Eur Heart J 2009; 30: 2631–2671 2- Podoleanu C, Maggi R, Brignole M, Croci F, Incze A, Solano A, Puggioni E, Carasca E. Lower limb and abdominal compression bandages prevent progressive orthostatic hypotension in the elderly. A randomized placebo-controlled study. J Am Coll Cardiol 2006; 48: 1425-32 3- Furukawa T, Maggi R, Solano A, Croci F, Brignole M. Effect of Clinical Triggers on Positive Responses to Tilt-Table Testing Potentiated with Nitroglycerin or Clomipramine. Am J Cardiol 2011, June 2nd issue (in press)
Michele Brignole, MD FESC Department of Cardiology, Ospedali del Tigullio, Lavagna, Italy mbrignole@ASL4.liguria.it
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