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Publications (2)8.03 Total impact

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    ABSTRACT: BACKGROUND: Although vasovagal syncope (VVS) is preceded by a surge of circulating catecholamines (epinephrine [Epi] and norepinephrine [NE]) of adrenal/renal and synaptic origin, prevention of VVS with β-adrenergic blockade has been ineffective except in "older" VVS patients. OBJECTIVE: We hypothesized that age-related differences of β-blocker effect may be due in part to differences in the relative magnitudes of Epi and NE release during an evolving faint, specifically, greater Epi/NE ratio in younger fainters compared to older patients. To assess this hypothesis, we measured changes in Epi/NE ratios in younger (<40 years) vs older (≥40 years) patients during head-up tilt-table test-induced VVS. METHODS: The study comprised 29 patients (12 patients ≥40 years [mean 56 ± 10.7 years] and 17 patients <40 years mean 25 ± 5.7 years]) with recurrent suspected VVS in whom 70° head-up tilt testing reproduced symptoms. Arterial Epi and NE concentrations were measured at baseline (supine), 2 minutes of head-up tilt, and syncope. RESULTS: Baseline Epi and NE concentrations and the Epi/NE ratio did not differ in younger and older groups (Epi: 90 ± 65 pg/mL vs 70 ± 32 pg/mL; NE: 226 ± 122 pg/mL vs 244 ± 183 pg/mL). However, Epi/NE ratio increased to a greater extent in younger fainters during head-up tilt and tended to be greater in younger patients at both 2 minutes (<40: 1.02 ± 1.29 vs ≥40: 0.40 ± 0.27, P = .11) and at symptoms (<40: 2.6 ± 1.26 vs ≥40: 1.6 ± 0.71, P = .03). At symptoms, Epi/NE ratio ≥2.5 was observed in 9 of 17 younger patients vs 1 of 12 older patients (P = .02). CONCLUSION: Epi/NE ratios tend to be greater in younger fainters, a finding that may account in part for the observation that β-blocker therapy is less effective in reducing VVS susceptibility in younger individuals.
    Heart rhythm: the official journal of the Heart Rhythm Society 07/2012; · 4.56 Impact Factor
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    ABSTRACT: Vasodepressor Cough Syncope.  Cough syncope is classified among the neural-reflex "situational" faints, but whether the clinical consequences in affected individuals result from reflex triggered bradyarrhythmia or vasodepressor-induced hypotension, or both, is often unknown. In this report we describe findings in a patient with a clinical history consistent with cough syncope, and in whom documented multiple asystolic spells were at first believed to be responsible for symptoms. However, pacemaker therapy initiated at an outside facility failed to suppress symptoms, and subsequent referral for more detailed autonomic study revealed the asystole to be due to sleep apnea, whereas cough-induced vasodepressor hypotension was the basis of syncope in this individual; the latter provided a pathophysiologic target for prevention of recurring symptoms. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1024-1027, September 2012).
    Journal of Cardiovascular Electrophysiology 04/2012; 23(9):1024-7. · 3.48 Impact Factor