Noctural dipping status and left ventricular hypertrophy: A cardiac magnetic resonance imaging study

We investigate the impact of dipper status on cardiac structure with cardiovascular magnetic resonance (CMR). Ambulatory blood pressure monitoring and 1.5T CMR were performed in 99 tertiary hypertension clinic patients. Subgroup analysis by extreme dipper (n=9), dipper (n =39), non-dipper (n =35) and reverse dipper (n =16) status was performed, matched in age, gender and BMI. Left ventricular (LV) mass was significantly higher for extreme dippers than dippers after correction for covariates (100 +/- 6g/m(2) vs 79 +/- 3g/m(2), P=.004). Amongst extreme dippers and dippers (n =48), indexed LV mass correlated positively with the extent of nocturnal blood pressure dipping (R=.403, P=.005). On post-hoc ANCOVA, the percentage of nocturnal dip had significant effect on indexed LV mass (P=.008), but overall SBP did not (P=.348). In the tertiary setting, we found a larger nocturnal BP drop was associated with more LV hypertrophy. If confirmed in larger studies, this may have implications on nocturnal dosing of anti-hypertensive medications.