224 Sympathetic nervous system and PRA are involved in the lack of aldosterone increase during HUT-induced vasovagal syncope

EP Europace, Jun 2005

Gajek, J., Zysko, D., Mazurek, W.

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224 Sympathetic nervous system and PRA are involved in the lack of aldosterone increase during HUT-induced vasovagal syncope

G. Russo 0 A. Porta 0 G. Buja 0 S. Cerutti 0 S. Iliceto 0 0 1Bassano del Grappa, Italy; 2University of Padua, Department of CaMiology , Padova , Italy; 3University of Milan, Department of Preclinic Sciences , Milan , Italy; 4polytechnic of Milan, Department 0 Bioengineering , Milan , Italy 46.84-21.9 years, 43% male). The early pre-established patterns of BP and HR were: O/71:drop in systolic BP > 20 mmHg (SO/H) or >10 mmHg drop in diastolic BP (DOH) within the first 5 minutes of orthostatism; PT: HR increase > 30 bpm within the first 5 minutes orthostatism with a HR > 120 bpm in the absence of hypotension; progressive decrease (PD): slow and continous fall in BP until the end of the test; Normal(NP): none of above abnormalities is present. Results: a normal initial response of BP and HR to orthostatism was the most prevalent in both negative HUT and B-H pts (76.9% and 64,4%, p<.05). Individual patterns showed the following values: NP HOS HOD PD PT - Purpose Neurally-mediated syncope (NMS) resuks from a complex interaction among autonomic afferent signals, cortical modulation, and bulbar integration. Upright tik test (UTT) offers the opportunity to study pathophysiological mechanisms leading to reflex syncope. The aim of our study was to evaluate the modifications of autonomic activity leading to tik-induced syncope by heart rate variability (HRV) analysis. Method We studied 40 patients with a mean age of 47.94-17yrs. Frequency domain analysis of heart rate variability (HRV) was performed on 2 periods of 300 beats recordings: at baseline, in supine position, and after 5 minutes of 60 ? tilt. Results UTT was positive in 26 patients (65%), the responses were vasodepressive in 10, mixed in 16. Baseline LF and I:IF components did not show significant difference between subjects with positive or negative test (normalized units, /:IF: 38.814-19 versus 36.944-19, p= NS; LF: 48.944-26 versus 50.844-22, p= NS). The patients with mixed reactions were characterized by higher values of HF at baseline (normalized units, 43.884-20 versus 25.844-14, p<0.02), and higher values of LF during tilt (624-16 versus 45.614-26, p<0.05), in comparison with patients with vasodepressive responses. During UTT, HRV parameters showed similar changes in patients with positive or negative test. However, subjects with mixed reactions were characterized by a reduction of I:IF during UTT (normalized units, from 43.884-20 to 28.284-12, p<0.005), whereas the others by an increase of the same component (normalized units, from 25.844-14 to 41.084-30, p<0.005). Conclusions In conclusion, baseline evaluation of HRV was not useful to identify patients with positive response to UTT. On the contrary, the modifications of HRV during UTT seem to indicate that patients with a cardioinhibitory response were characterized by an increase of sympathetic activity during the test, that could represent an essential factor to induce a stronger vagal reaction on the sinus node, whereas in subjects with vasodepressive responses there is a inadequate increase of the sympathetic drive, probably causing a failure of peripheral vasoconstriction. 223 The bradycardia-hypotension reaction during head-up tilt test in patients with syncope: prevalence and value of blood pressure and heart rate behavior during the early stage of the test G.A. Ruiz 1, R. Chirife 2, M.C. Tentori 2, D. Dasso 2, R. Gelpi 3, J.C. Peffetto 4 1Hospital Juan A. Fernandez, Florida, Argentina; 2Hospital Juan A Fernandez, Cardiology, Buenos Aires, Argentina; 3Facultad de Medicina. UBA, Instituto Fisiopatologia Cardiovascula, Buenos Aires, Argentina; 4Facultad de Ingenieria, UBA, Biomedicina, Buenos Aires, Argentina The blood pressure (BP) and heart rate (HR) behavior during the early stage of the tik test (TI?) define different orthostatic disorders: postural tachycardia (PT), orthostatic hypotension (systolic SO/H, diastolic DOH) and vasovagal reaction (Normal initial behavior followed by an abrupt and relatively late fall in ]3P with or without HR decrease). The mixed and cardioinhibitory responses are characterized by a bradycardiahypotension reaction (]3-H) and syncope. Objective: to assess the prevalence, sensitivity, specificity and predictive value of different pre-established patterns of ]3P and HR behavior during the early stages of HUT for a ]3-/7Ireaction. Methods: 442 pts with >1 syncope or mukiple presyncope episodes of unknown origin were included: 138 developed ]3-/7Ireaction during HUT (age 38.14-21.9 years, 50% male) while 304 pts had HUT (-) (age 64 12 9 10 9 SP (+) PV (-) PV SS: sensitivity,SP: specificity; PV: predictive value Conclusion: different early patterns of ]3P and HR defining different orthostatic intolerance disorders may precede an abrupt bradicardiahypotension reaction. The most prevalent one is the normal behavior of ]3P and HR in early TF. None of them has an elevated sensitivity or (+) predictive value. The mechanism leading to ]3-/7Ireaction is not unique. 224 Sympathetic nervous system and PRA are involved in the lack of aldosterone increase during HUT-induced vasovagal syncope J. Gajek 1, D. Zysko 2, W. Mazurek 2 1Medical University of Wroclaw, Department of Cardiology, Wroclaw, Poland; 2Medical University of Wroczaw, Department of Cardiology, Wroczaw, Poland Background: the lack of significant increase of alddosterone concentration immediately after the vasovagal syncope (VVS) during head-up tilt test (HUT) indicates on syncope recurrence during long term follow-up. The aim of the study was to assess the influence of autonomic nervous system and plasma renin activity on the lack of aldosterone concentration increase in patients with HUT-induced VVS. Methods: the study was carried out in 30 patients (22F, 8M) aged 36,64-15,4 years with VVS. The concentration of aldosterone, plasma renin activity, norepinephrine and epinephrine were assessed in baseline conditions, immediately after the syncope and 10 minutes after syncope. ECG Holter monitoring was performed in all patients. HRV parameters (mRR, SDNN, RMSSD, pNN50, TP, LF, HE, ]3) were assessed in 2 minutes intervals: before the test (period 1), 2 minutes after the beginning of HUT (period 2), at the end of passive phase of HUT (period 3). The delayed aldosterone concentration was defined as an increase immediately after syncope less than 20% comparing to the baseline values or less than 20% increase 10 minutes after HUT comparing to the values after syncope. The studied patients were divided into groups with (group I, n=8) and without (group II, n=22) delayed aldosterone increase. Results: there were no differences between the studied groups with regard to HRV parameters in baseline and neurohumoral factors. mRR (ms) SDNN rMSSD pNN50 (ms) (ms) (%) TP (ms) LF (ms) HF (ms) B Table Group I peliod2 797?162 46?14 period3 749?155 42?17 p <0,05 NS In both studied group the HRV parameters: mRR, SDNN, rMSSD, pNN50, LF, HF decreased and the parameter B increased in the period 2 and further tilting led to the significant decrease of mRR, rMSSD, LF in group I and mRR in group II in period 3. Conclusions: in the vasovagal patients with delayed aldosterone the pattern of the activation of autonomic nervous system during tilt testing differs from that present in patients without this phenomenon. 225 Repeated tilt testing in children and adolescents with tilt-positive neurally mediated syncope H. Ector 1, H. Heidb chel 2, R. Willems 2, T. Reybrouck 2 1University Hospital Gasthuisberg, Department of Cardiology, Leuven, Belgium; 2Univ Hospital Gasthuisberg, CaMiology, Leuven, Belgium In this study we have included 75 patients, age < 18 years, with: (i) apparent neurally mediated syncope and: (ii) a positive diagnostic tilt test without any pharmacological provocation. The mean age was 13.6 4- 2.8 years (median 13.8): 30 males (13.6 4- 2.7 years; median 13.8, min 6, max 17) and 45 females (13.6 4- 2.8 years; median 13.9, min 6, max 17). The response to the diagnostic tilt test was: type 1 (mixed) in 22 patients; type 2A (cardioinhibitory + bradycardia) in 1; type 2B (cardioinhibitory + asystole) in 22; type 3 (vasodepressor) in 30. For all 74 patients the tilt test was positive after 19 4- 10.6 minutes (median 17). For the 4 types of syncope, the duration in minutes of the diagnostic tilt test was: type 1 (mixed): 17.5 4- 10, median 15; type 2A (cardioinhibitory): 20 (1 patient); type 2B (cardioinhibitory + asystole): 18.1 4- 11.9, median 15; type 3 (vasodepressor): 20.7 4- 10.4, median 18. There was no significant difference between the 4 subtypes of syncope. Type 2B (cardioinhibitory + asystole) response occurred in 22 patients. The duration of asystole was 8.3 4- 4.9 seconds (median 6.9, min 3, max 20): males: 7.9 4- 4.5 (median 7.1); females 8.6 4- 5.4 (median 6.9). The head-up tilt test was repeated day after day: one session per day. The response became negative already at the second session in 40 patients (53%); at session 3 in 19 (25%); at session 4 in 6 (8%); at session 5 in 5 (7%); at session 6 in 2 (3%); at session 7 in 1 (1%); at session 8 in 2 (3%). For all 74 patients the mean session value of the first negative tilt test was 2.9 (SD 1.3, median 2). For obtaining the first negative test, there was no difference between the 4 subtypes of tilt response. Conclusion: in 53% of the young with neurally mediated syncope, already the second consecutive tilt test became negative. For an additional 25% the third session was the first negative test. So, only 22% of patients remained tilt-positive for 3 or more sessions. Negativation of tilt testing could be obtained for every patient. In tilt-positive children with neurally mediated syncope a subnormal orthostatic tolerance can be remedied by a program of repeated tilt testing. 226 Can the clinical characteristics of neurally mediated reflex syncopes predict the test outcome? N.R. Petix 1, A. Del Rosso 2, V. Guarnaccia 2, P. Bartoli 2 1Florence, Italy; :S. Giuseppe and S.Piero Igneo Hospital, Cardiology, Empoli-Fucecchio, Italy Background: the impact of the clinical characteristics of the various types of neurally mediated reflex syncopes on the head-up tik test (HUT) outcome have not been investigated in detail. The aim of this study was to assess whether the clinical spectrum of neurally mediated reflex syncopes can influence the outcome of the test. We studied 254 consecutive pts (133 m, mean age 59 4- 19 years) undergoing HUT potentiated with nitroglycerin (300 mcg) for suspected neurally mediated reflex syncope. The relationship between clinical spectrum and sex, age, the number of syncope and presyncope, history of trauma, presence of prodromal symptoms and hemodynamic values of HUT was analyzed. On the basis of the modalities of presentation of neurally mediated reflex syncope we recorded 102 pts with typical vasovagal syncope (VVS) (Gr.A: 45 m, mean age 51 4- 20 years), 19 pts with situational syncope (Gr.B: 15 m, mean age 60 4- 19 years) and 133 pts with syncope of unknown origin, without organic heart disease or other clinical features suspected for cardiac syncope, i.e. with atypical presentation (Gr.C: 73 m, mean age 62 4- 18 years). The pts of Gr.A showed a significantly lower age and a lower prevalence of trauma than the pts of Gr.B and C. HUT was positive in 68 pts (67%) with typical VVS, in 7 pts (37%) with situational syncope and in 68 pts (51%) with atypical syncope. By logistic regression analysis, the modalities of presentation of typical VVS were significantly associated with positive HUT (Wald c2 11.1, p = 0.001, Exp (b) 2.6, IC 95% 1.5 - 3.6). Moreover, in the pts of Gr.A an higher likelihood of positive HUT was observed in the 76 pts with the age < 50 years (Wald c2 7.8, p = 0.005, Exp (b) 4.05, IC 95% 1.04 6.11) than those with the age _> 50 years. In Gr.B and Gr. C no clinical variable was a predictor of positive HUT. In conclusion: a) in the pts with the age < 50 years an history of typical VVS syncope resuked predictive of the HUT outcome; b) in pts with situational or atypical presentation of syncope no clinical feature was predictive of the HUT outcome; particularly, in the pts with atypical modalities of presentation of syncope the diagnostic yield of HUT was low. POSTER HALL New technology in ICD therapy 228 M o r p h o l o g y discrimination in ICDs: improved arrhythmia discrimination with a potential risk of underdetection of ventricular tachycardia D.A.M.J. Theuns, M. Rivero Ayerza, M.E Scholten, A.S. Thornton, L.J. Jordaens Erasmus Medical Centre, Department of Clinical Electrophysiology, Rotterdam, Netherlands Introduction: To reduce inappropriate therapy for supraventricular tachycardia (SVT) in implantable cardioverter-defibrillators (ICDs), electrogram morphology discrimination (MD) has been developed to improve arrhythmia classification without compromising device safety. Aim: The aim of this study was to determine the effectiveness of arrhythmia discrimination by the MD algorithm. Methods: Eighty patients (68 male, 59 4- 13 years, LVEF 30%) received an ICD with a beat-to-beat algorithm for electrogram morphology analysis. Morphology detection was programmed at nominal setting: template match score of at least 60% in more than 5-out-of-8 beats; tachyarrhythmias with match-scores below this limit are classified as VT. For safety reasons, the MD algorithm was either programmed in "monitor mode" or parallel in a "2-out-of-3 mode" with classical detection algorithms (onset and stability). Stored electrograms of tachyarrhythmias were used to assess the sensitivity of the MD algorithm alone and in the "2-out-of-3 mode". Results: During a 9 4- 5 months follow-up, 29 patients (36%) had 413 tachyarrhythmias with stored electrograms. Of these episodes, 323 (78%) were classified as VT, and 90 (22%) as SVT by the investigators. At nominal setting, the MD algorithm correctly identified 213 of 323 episodes as VT, yielding a sensitivity of 66%. The template matchscore for the 110 underdetected episodes of VT was 72 4- 12%. The MD algorithm combined with sudden onset and stability increased the sensitivity to 98%. In a "2-out-of-3 mode", the classification of SVT was met in 66 of 90 episodes, resuking in a specificity of 73%. The MD algorithm correctly identified 92% of episodes with SVT.

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Gajek, J., Zysko, D., Mazurek, W.. 224 Sympathetic nervous system and PRA are involved in the lack of aldosterone increase during HUT-induced vasovagal syncope, EP Europace, 2005, 45-46, DOI: 10.1016/eupace/7.Supplement_1.45-b