Key result
Coronary flow velocity reserve in healthy men exhibits significant diurnal variation, being lowest at 7 AM (3.23) compared to 9 PM (4.41, p=0.001).
Why the study?
Does coronary flow velocity reserve exhibit diurnal variation in healthy men?
Observational (n=15)
No
Does coronary flow velocity reserve exhibit diurnal variation in healthy men?
Coronary flow velocity reserve exhibits diurnal variation in healthy men, being lowest in the morning, which may relate to the known morning peak in cardiovascular events.
Answers are grounded in this paper and cite their sources.
Small study shows lower morning CFVR in healthy men; leaves open relevance to event timing or time-specific testing.
Background. A number of cardiovascular diseases show diurnal variation. However, it is unknown whether coronary circulation exhibits diurnal variation.Methods. The flow velocities in the left anterior descending coronary artery of 15 healthy men were measured by transthoracic Doppler echocardiography both at rest and during intravenous infusion of adenosine triphosphate at 7 AM, noon, 5 PM and 9 PM. Coronary flow velocity reserve (CFVR) was calculated as the ratio of hyperemic to basal mean diastolic flow velocity. CFVR at 7 AM was significantly smaller than that at 9 PM (p=0.001; 7 AM, 3.23 ± 0.66; noon, 3.89 ± 0.86; 5 AM, 3.46 ± 0.65; 9 PM, 4.41 ± 1.11, respectively). CFVR at 5 PM was also significantly smaller than that at 9 PM (p=0.008).Conclusions. Diurnal variation in CFVR exists in healthy men. This finding may be related to the diurnal variation in cardiovascular events.
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Toyoda et al. (2007) conducted an observational in Healthy (n=15). Time of day (diurnal variation) vs. 9 PM was evaluated on Coronary flow velocity reserve (CFVR) (p=0.001). Coronary flow velocity reserve in healthy men exhibits significant diurnal variation, being lowest at 7 AM (3.23) compared to 9 PM (4.41, p=0.001).
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