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Evaluation of 24h blood pressure by telemetry in Yucatan miniature swine: Absence of dipping
Author(s) -
Myrie Semone B,
McKnight Leslie L,
Van Vliet Bruce N,
Bertolo Robert F
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.737.33
Subject(s) - blood pressure , zoology , hemodynamics , diurnal temperature variation , heart rate , diastole , medicine , endocrinology , biology , atmospheric sciences , geology
A “non‐dipping” blood pressure (BP) profile is regarded as an independent risk factor for various cardiovascular events and target organ damage. In the present study, we investigated the dipping phenomenon in Yucatan miniature swine. Piglets (∼1000g, N=6) were weaned at 31 days old and then fed standard chow ad libitum. At 8 mo, BP telemeters (DSI model D70) were implanted via the femoral artery to measure hemodynamics and locomotor activity in unrestrained pigs. Following 8 days of recovery, heart rate (HR) and indices of locomotor activity showed pronounced diurnal variation, both being significantly (P<0.05) greater in the daytime than nighttime (HR: 84.4 vs 75.7 bpm; Activity index: 2.6 vs. 0.5). In contrast, BP indices showed little diurnal variation, the values being unimodally distributed over the 24 h period. The phenomenon of BP dipping was absent, with nighttime BP actually being slightly higher than the daytime BP (mean: 110 vs. 113 mmHg; systolic: 130 vs. 134 mmHg; diastolic: 91 vs. 94 mmHg). During a 7‐day salt challenge (from 0.5 % to 5.0 % salt diet), BP rose from 110 mmHg to 119 mmHg indicating that the pigs were moderately sodium sensitive. However, BP dipping was absent on either diet. Our results demonstrate that in this swine model, BP dipping is absent and unaffected by locomotor activity and/or dietary sodium. (Supported by CIHR).