[Spectral indices of heart rate variability in patients with vasovagal syncopes according to evidence of 5-min ECG].

AIM: To compare autonomic nervous system activity estimated by power spectral analysis of heart rate variability in patients with vasovagal syncopes and healthy volunteers. MATERIAL AND METHODS: Seventeen health volunteers and 25 patients with vasovagal syncope were included in the study. In 16 cases faints were induced by head-up tilt table test (HTT), in 9 cases--by bicycle exercise test (BET). Power spectral analysis of heart rate variability in 5-th min ECG records was performed in supine and upright position while breath was fixed. RESULTS: In supine position the data of low frequency (LF) and high frequency (HF) of spectral power in both groups of patients were significantly higher than in volunteers. During upright the HF of spectral power significantly decreased in patients and volunteers. In upright position LF of spectral power significantly decreased in patients with syncope induced by HTT, did not change in patients with syncope induced by BET, but significantly increased in volunteers. CONCLUSION: Patients with vasovagal syncope had abnormal autonomic nervous system activity: a high level of parasympathetic influence in supine position and poor reaction of sympathetic nervous system during upright.

[Comparative efficacy and tolerance of atenolol and midodrine in patients with vasovagal syncopes].

AIM: To compare efficacy and tolerance of atenolol and midodrine in patients with vasovagal syncopes (VVS). MATERIAL AND METHODS: The trial included 35 patients with recurrent VVS confirmed at long passive head-up tilt table test (HTTT) or maximal load bicycle exercise test (MET). These tests were also used for assessing efficacy of atenolol and midodrine in cases when syncopes occur in repeated tests. If recurrent induction of VVS was absent, efficacy of the drugs was assessed by long-term (up to 12 months) clinical observation. Long-term administration of atenolol and midodrine was continued in patients with effect by HTTT and/or MET. Eighteen patients were randomized to take atenolol in a daily dose up to 50 mg, seventeen--to take midodrine in a daily dose up to 15 mg. RESULTS: Efficacy of atenolol by HTTT and MET was 8%, midodrine--57% (p = 0.01). All the patients benefited from the drugs in their long-term regimen. Long-term administration of atenolol induced remission of VVS in 82% cases, midodrine--in 89% (insignificant). Overall efficacy of atenolol was 44%, of midodrine--70% (insignificant). In 5 of 6 patients resistant to atenolol and midodrine monotherapy, combined use of the drugs was effective. Treatment with atenolol, midodrine and their combination prevented VVS in 89% patients. Both short- and long-term courses of atenolol and midodrine were safe in terms of side effects. CONCLUSION: Atenolol and midodrine as well as their combination were highly effective and well tolerated in the treatment of VVS patients.

[Successful midodrin treatment for vasovagal syncopes accompanied by asystole]. / Uspechnoe lechenie midodrinom vazovagal'nykh obmorokov, protekaiushchikh s asistoliei.

Vasovagal syncopes (WS) are fainting fits whose manifestations are systemic vasodilation and bradycardia. The development of WS is frequently accompanied by short-term cardiac arrest. Recent data show that implantation of a cardiac pacemaker fails to prevent the development of fainting fits in these patients. On the basis of the pathogenesis of WS, the use of alpha-adrenomimetic midodrine is justifiable. The presented case demonstrates the successful use of the agent in the treatment of vasovagal syncope accompanied by asystole.

[Results of midodrin treatment of vasovagal syncope]. / Rezul'taty primeneniia midodrida dla lecheniia bolnykh vazovagal'nymi obmorokami.

AIM: To elicit efficacy of midodrin in patients with vasovagal syncope. MATERIAL AND METHODS: 50 patients with recurrent vasovagal syncope documented by head-up tilt tests or bicycle exercise stress tests participated in the study. These tests controlled the effects of midodrin if syncopes occurred again in repetition of the tests. In the other patients the effect of the drug was assessed clinically. All the patients received midodrin in daily dose up to 15 mg. RESULTS: Mirodrin effectively prevented syncope in 13 (72%) patients as shown by the tilt test, in 10 (59%) patients as shown by the exercise stress tests and in 14 (93%) patients as controlled clinically. Total efficacy of midodrin was 74% (37 of 50 patients). CONCLUSION: Midodrin demonstrated high efficacy in prevention of vasovagal syncope. Side effects were not serious therefore the drug is well tolerated.

[Long-term orthostatic and bicycle ergometry exercise tests in differential diagnosis of syncopal conditions of unclear origin]. / Vozmozgnosti dlitel'noi ortostaticheskoi i veloérgometricheskoi prob pri differentsial'noi diagnostike sinkopal'nykh sostoianii neiasnogo geneza.

AIM: To study efficiency of bicycle exercise test and long-term orthostatic test in differential diagnosis of syncopes. MATERIAL AND METHODS: The study included 113 patients suffering from recurrent syncopes of unclear origin. Twelve healthy volunteers were selected for assessment of the tests specificity. All the patients and controls were examined by means of long-term orthostatic test (LTOT) and bicycle exercise test (BET). RESULTS: Specificity of both tests was 100%. In LTOT syncopes were observed in 52 (46%) cases, including vasovagal syncopes (51 patients), epileptic seizure (1 patient). BET induced vasovagal syncopes in 54 (48%) patients. The results of both tests by inducing syncopes coincided in 30 (26%) cases. In 24 (21%) patients syncopes occurred only in BET while LTOT appeared uninformative. In 21 (18.6%) cases syncopes occurred only in LTOT while BET produced a negative result. 38 (34%) patients had syncopes neither in LTOT nor BET. Both tests induced syncopes in 75 (66%) patients. No complications were observed. CONCLUSION: LTOT and BET are safe and complementary methods in differential diagnosis of syncopes.