Authors:

S Laranjo¹ , S Alves¹ , I Rocha² , M Oliveira¹ , ¹Hospital Santa Marta, Department of Cardiology - Lisbon - Portugal , ²Cardiovascular Autonomic Function Lab, Faculty of Medicine of Lisbon - Lisbon - Portugal ,

Citation:

Reflex syncope (rS) is a common clinical entity resulting from an excessive reflex autonomic response, particularly during orthostatism. Treatment options are controversial and of limited effectiveness. Tilt training (TTr) is a form of therapy proposed to patients with recurrent forms of rS.  The aim of our study was to assess the effectiveness of TTr and to characterize hemodynamic and autonomic responses during a TTr program in patients (P) with rS refractory to conventional measures.

Methods: Between 2005 and May 2018 we enrolled 102P (57,8% female, age 46,13±18,28 yrs). All had orthostatic induced rS, refractory to conventional measures and documented by head-up tilt test. All P met the following inclusion criteria: 1) at least 2 syncopal episodes within the last 6 months or 1 syncope and 3 pre-syncopal episodes/year; 2) absence of known structural and/or electrical heart disease; 3) absence of other evident etiologies for syncope. The TTr program included 9 tilt sessions (3 times a week, 30 min; 60° – 6 sessions, 70° – 3 sessions), under ECG and blood pressure (BP) monitoring, combined with home orthostatic self-training (gradually extending time to 30 mn) and 10° head-up during sleep. Stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), baroreflex sensitivity (BEI) and heart-rate variability were computed. P were examined at 1 month and every 6 months thereafter. Treatment effects were assessed using telephone survey. Quality of life ("Impact of Syncope on Quality of Life" questionnaire) was evaluated before beginning the TTr program and at 6 months follow-up.

Results The average follow-up after TTr was 66.79±41.30 months. Most of the P did not present recurrent episodes of syncope (n=89; 86,3%) or pre-syncope (n=82, 80%). In the remaining P (14%), there was a significant decrease in the number of syncopes (5.1±2.7/patient/year 12 months before vs. 1.4±0.8/patient post-TTr; p=0.0059) and pre-syncope (11,4±6,2/patient/year 12 months before TTr vs. 4,5±2.6/patient post-TTr, p=0.0175). The TTr program was associated with a QoL improvement in the ISQL items, related to worry, fear and frustration with the difficulties experienced (?<0.05). Over the course of the TT program there was a significant increase in mean systolic BP, SV, TPR and CO. Simultaneously, a shift in autonomic nervous system response pattern was seen, associated with an increase of the baroreflex effectiveness index. There was a trend for a global increase in heart rate variability, with a significant decrease of the sympathovagal balance (LF/HF) índex. 

Conclusion: In refractory rS, TTr may be an effective therapeutic option with long-term benefits and a significant impact in QOL.  These results are associated with a significant modulation of autonomic nervous system function, leading to a more homeostatic response and a better baroreflex function.