Dr. Ron’s Research Review – April 4, 2018

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This week’s research review focuses on Postural Tachycardia.

POTS is defined as the presence of chronic symptoms of orthostatic intolerance (≥6 months) accompanied by an increased heart rate (HR) ≥30 bpm within 10 minutes of assuming an upright posture and in the absence of orthostatic hypotension (blood pressure [BP] fall >20/10 mmHg). In children and adolescents, a higher threshold (≥40 bpm) should be used since they have a greater physiological orthostatic tachycardia.

Vitamin B12

A study investigated the association between vitamin B12 levels and postural orthostatic tachycardia syndrome (POTS) during adolescence when accelerated myelin synthesis increases the vitamin B12 need.  One hundred twenty-five patients (mean age 11.1 ± 2.3 years; 60% female) reporting short-term loss of consciousness and diagnosed with vasovagal syncope based on anamnesis with a normal distribution and 50 control subjects (mean age 10.94 ± 2.5 years, 62% female) were included in this study. Serum vitamin B12, folic acid, and ferritin levels were measured prospectively in addition to other tests. Vitamin B12 deficiency was defined as a serum level <300 pg/mL.(1-4) Vitamin B12 levels were significantly lower in the patient group compared with the control group (47.2% vs 18%, P < .001). In the patient group, children with the POTS pattern had significantly lower vitamin B12 levels compared with children without the POTS response (P = .03). Vitamin B12 deficiency in patients with POTS may lead to sympathetic nervous system baroreceptor dysfunction. (Öner et al., 2014)

Vitamin B1

This study examined the prevalence of vitamin B1 deficiency and assessed response to vitamin B1 supplementation in the deficient POTS patients. Medical records of 65 consecutive patients with POTS evaluated at our clinic were reviewed. In this cohort (mean age 32, range 13-54 years; 89% female), 6% had vitamin B1 deficiency, and one of four deficient patients experienced significant improvement of POTS after oral vitamin B1 supplementation.  A small subset of patients with POTS may have vitamin B1 deficiency. Testing for vitamin B1 deficiency and correcting the deficiency is recommended.  (Blitshteyn, 2017)

Melatonin

Patients with POTS (n = 78) underwent acute drug trials with melatonin 3 mg orally and placebo, on separate mornings, in a randomized crossover design. Blood pressure, HR, and symptoms were assessed while seated and after standing for up to 10 min prior to, and hourly for 4 h following study drug administration.  The reduction in standing HR was significantly greater 2 h after melatonin compared with placebo (P = 0.017). There was no significant difference in the reduction of systolic blood pressure between melatonin and placebo, either with standing or while seated. The symptom burden was not improved with melatonin compared with placebo.  Oral melatonin produced a modest decrease in standing tachycardia in POTS. (Green et al., 2014)

Dr. Ron

 


 

Articles

Vitamin B1 deficiency in patients with postural tachycardia syndrome (POTS).
            (Blitshteyn, 2017) Download
OBJECTIVE:  POTS is a heterogeneous disorder of the autonomic nervous system that can result from multiple etiologies. An increased prevalence of vitamin B12, vitamin D 25-OH and iron deficiencies has been observed in patients with POTS. This study examined the prevalence of vitamin B1 deficiency and assessed response to vitamin B1 supplementation in the deficient POTS patients. METHODS AND RESULTS:  Medical records of 65 consecutive patients with POTS evaluated at our clinic were reviewed. In this cohort (mean age 32, range 13-54 years; 89% female), 6% had vitamin B1 deficiency, and one of four deficient patients experienced significant improvement of POTS after oral vitamin B1 supplementation. CONCLUSION:  A small subset of patients with POTS may have vitamin B1 deficiency. Testing for vitamin B1 deficiency and correcting the deficiency is recommended.

Melatonin reduces tachycardia in postural tachycardia syndrome: a randomized, crossover trial.
            (Green et al., 2014) Download
BACKGROUND:  Postural tachycardia syndrome (POTS) induces disabling chronic orthostatic intolerance with an excessive increase in heart rate (HR) upon standing, and many POTS patients have a hyperadrenergic state. Medications that restrain HR are a promising approach to this problem. OBJECTIVE:  We tested the hypothesis that melatonin will attenuate the tachycardia and improve symptom burden in patients with POTS. METHODS:  Patients with POTS (n = 78) underwent acute drug trials with melatonin 3 mg orally and placebo, on separate mornings, in a randomized crossover design. Blood pressure, HR, and symptoms were assessed while seated and after standing for up to 10 min prior to, and hourly for 4 h following study drug administration. RESULTS:  The reduction in standing HR was significantly greater 2 h after melatonin compared with placebo (P = 0.017). There was no significant difference in the reduction of systolic blood pressure between melatonin and placebo, either with standing or while seated. The symptom burden was not improved with melatonin compared with placebo. CONCLUSION:  Oral melatonin produced a modest decrease in standing tachycardia in POTS. Further research is needed to determine the effects of regular night-time use of this medication in POTS.


 

Postural orthostatic tachycardia syndrome (POTS) and vitamin B12 deficiency in adolescents.
            (Öner et al., 2014) Download
OBJECTIVE:  Vitamin B12 is involved in the production of adrenaline from noradrenaline. It is the cofactor involved in catecholamine degradation and plays a role in myelin synthesis. The current study aimed to investigate the association between vitamin B12 levels and postural orthostatic tachycardia syndrome (POTS) during adolescence when accelerated myelin synthesis increases the vitamin B12 need. METHODS:  One hundred twenty-five patients (mean age 11.1 ± 2.3 years; 60% female) reporting short-term loss of consciousness and diagnosed with vasovagal syncope based on anamnesis with a normal distribution and 50 control subjects (mean age 10.94 ± 2.5 years, 62% female) were included in this study. Serum vitamin B12, folic acid, and ferritin levels were measured prospectively in addition to other tests. We defined vitamin B12 deficiency as a serum level <300 pg/mL.(1-4) RESULTS: Vitamin B12 levels were significantly lower in the patient group compared with the control group (47.2% vs 18%, P < .001). In the patient group, children with the POTS pattern had significantly lower vitamin B12 levels compared with children without the POTS response (P = .03). CONCLUSIONS:  Vitamin B12 deficiency in patients with POTS may lead to sympathetic nervous system baroreceptor dysfunction.

 

References

Blitshteyn, S (2017), ‘Vitamin B1 deficiency in patients with postural tachycardia syndrome (POTS).’, Neurol Res, 39 (8), 685-88. PubMed: 28531358
Green, EA, et al. (2014), ‘Melatonin reduces tachycardia in postural tachycardia syndrome: a randomized, crossover trial.’, Cardiovasc Ther, 32 (3), 105-12. PubMed: 24495468
Öner, T, et al. (2014), ‘Postural orthostatic tachycardia syndrome (POTS) and vitamin B12 deficiency in adolescents.’, Pediatrics, 133 (1), e138-42. PubMed: 24366986