Prediction of vasovagal syncope from heart rate and blood pressure trend and variability: experience in 1,155 patients.

BACKGROUND Vasovagal syncope (VVS) is a complex fainting disorder commonly triggered by orthostatic stress. OBJECTIVE We developed an algorithm for VVS prediction based on the joint assessment of RR interval (RR) and systolic blood pressure (SBP). METHODS Simultaneous analysis of RR and SBP trends during head-up tilt as well as their variability represented by low-frequency power (LFRR and LFSBP) generated a cumulative risk that was compared with a predetermined VVS risk threshold. When cumulative risk exceeded the threshold, an alert was generated. Prediction time was the duration between the first alert and syncope. In the first 180 sec of head-up tilt, baseline values were established, following which VVS prediction was possible. An analysis was performed using 1,155 patients who had undergone head-up tilt for syncope: 759 tilt-positive and 396 tilt-negative patients. In the tilt-test protocol, at syncope or after 35 min, the patient was returned to supine. RESULTS In tilt-positive patients, VVS was predicted in 719 of 759 patients (sensitivity 95%), whereas 29 false alarms were generated in 396 tilt-negative patients (specificity 93%). Prediction times varied from 0 to 30 min but were longer than 1 min in 49% of patients. CONCLUSION Predicting impending syncope requires use of simultaneous blood pressure and heart rate, which may shorten diagnostic testing time, free patients from experiencing syncope during a diagnostic tilt-test, and have application in risk-guided tilt training and in an implanted device-to-trigger pacing intervention. The prospects for relieving patient discomfort are encouraging.

[1]  R. García-Civera,et al.  Early application of an implantable loop recorder allows effective specific therapy in patients with recurrent suspected neurally mediated syncope. , 2006, European heart journal.

[2]  Rose Anne Kenny,et al.  Guidelines on management (diagnosis and treatment) of syncope--update 2004. , 2004, Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology.

[3]  J. Vesin,et al.  Autonomic Imbalance Assessed by Heart Rate Variability Analysis in Vasovagal Syncope , 1994, Pacing and clinical electrophysiology : PACE.

[4]  E Vicaut,et al.  Prediction of head-up tilt test result by analysis of early heart rate variations. , 1997, Circulation.

[5]  B. Wallin,et al.  Sympathetic outflow to muscles during vasovagal syncope. , 1982, Journal of the autonomic nervous system.

[6]  R. Hainsworth,et al.  Orthostatic tolerance in patients with unexplained syncope , 1994, Clinical Autonomic Research.

[7]  S. Romano,et al.  Shortened head-up tilting test guided by systolic pressure reductions in neurocardiogenic syncope. , 2002, Circulation.

[8]  T. Bowker,et al.  Age and hemodynamic responses to tilt testing in those with syncope of unknown origin. , 2003, Journal of the American College of Cardiology.

[9]  T. Lewis.  A Lecture on VASOVAGAL SYNCOPE AND THE CAROTID SINUS MECHANISM , 1932, British medical journal.

[10]  A. Natale,et al.  Circulatory and catecholamine changes during head-up tilt testing in neurocardiogenic (vasovagal) syncope. , 1994, The American journal of cardiology.

[11]  D. Eckberg,et al.  The vasovagal response. , 1991, Clinical science.

[12]  H Kaufmann,et al.  Consensus statement on the definition of orthostatic hypotension, pure autonomic failure and multiple system atrophy , 1996, Clinical Autonomic Research.

[13]  S Cerutti,et al.  Cardiac autonomic patterns preceding occasional vasovagal reactions in healthy humans. , 1998, Circulation.

[14]  W. Kapoor,et al.  [Guidelines on management (diagnosis and treatment) of syncope. Update 2004. Executive summary]. , 2004, Revista espanola de cardiologia.

[15]  T. Ichida.  World Medical Association declaration of Helsinki , 1991, Gastroenterologia Japonica.

[16]  Jean-Marc Vesin,et al.  Observer of autonomic cardiac outflow based on blind source separation of ECG parameters , 2000, IEEE Transactions on Biomedical Engineering.

[17]  P Bie,et al.  Hypotension induced by passive head-up tilt: endocrine and circulatory mechanisms. , 1986, The American journal of physiology.

[18]  T. Bowker,et al.  Usefulness of tilt test-induced patterns of heart rate and blood pressure using a two-stage protocol with glyceryl trinitrate provocation in patients with syncope of unknown origin. , 1999, The American journal of cardiology.

[19]  P. Vardas,et al.  Autonomic Nervous System Activity During Tilt Testing in Syncopal Patients, Estimated by Power Spectral Analysis of Heart Rate Variability , 1997, Pacing and clinical electrophysiology : PACE.

[20]  A. Malliani,et al.  Heart rate variability. Standards of measurement, physiological interpretation, and clinical use , 1996 .

[21]  G Noll,et al.  Progressive withdrawal of muscle nerve sympathetic activity preceding vaso-vagal syncope during lower-body negative pressure. , 1996, Clinical science.

[22]  D. Gold,et al.  Impairment of physical and psychosocial function in recurrent syncope. , 1991, Journal of clinical epidemiology.

[23]  U. Scherrer,et al.  Observer of the human cardiac sympathetic nerve activity using noncausal blind source separation , 1999, IEEE Transactions on Biomedical Engineering.

[24]  MicheleBrignole,et al.  Mechanism of Syncope in Patients With Isolated Syncope and in Patients With Tilt-Positive Syncope , 2001 .

[25]  G. Breithardt,et al.  Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. , 1996 .

[26]  M. Brignole,et al.  'The Italian Protocol': a simplified head-up tilt testing potentiated with oral nitroglycerin to assess patients with unexplained syncope. , 2000, Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology.

[27]  R. García-Civera,et al.  Mechanism of Syncope in Patients With Isolated Syncope and in Patients With Tilt-Positive Syncope , 2002 .

[28]  R. Sutton,et al.  A comparison of non-invasive continuous finger blood pressure measurement (Finapres) with intra-arterial pressure during prolonged head-up tilt. , 1995, European heart journal.

[29]  D L Eckberg,et al.  Vagal and sympathetic mechanisms in patients with orthostatic vasovagal syncope. , 1997, Circulation.

[30]  Y. Zotterman,et al.  Depressor Reflexes from the Heart , 1948 .

[31]  F. Ruschitzka,et al.  Dysfunctional Baroreflex Regulation of Sympathetic Nerve Activity in Patients With Vasovagal Syncope , 2003, Circulation.

[32]  M. Frenneaux,et al.  Baroreflex sensitivity in patients with vasovagal syncope. , 1997, Circulation.

[33]  R. Spiegel.  World Medical Association Declaration of Helsinki , 2005 .