Ratio of left atrial to left ventricular size: an anatomical marker of the diastolic left ventricular pressure-volume relationship.

Background: Classification of diastolic heart function is best defined by the degree of leftward and upward shift of the diastolic pressure-volume relationship (DPVR). Direct measurement of DPVR, however, requires invasive techniques. Increased left atrial (LA) size is a marker of left ventricular (LV) diastolic hypertension, and so, the LA/LV diameter ratio has the potential to mark the degree of upward and leftward shift in the LV-DPVR. We thus investigated the association of this novel marker with exposures known to induce diastolic dysfunction and with clinical evidence of diastolic dysfunction.
Methods and Results: Reports from 7,803 patients undergoing maximal exercise stress echocardiography were reviewed. Increased LA/LV diameter ratio predicted diminished exercise capacity (P < 0.001) in a multivariate regression analysis. Increased LA and decreased LV diameters were each independently associated with exercise capacity (P < 0.001, both). Increased LA/LV diameter ratio was associated with hypertension (P = 0.001), diabetes (P = 0.03) and with increased severity of LV hypertrophy (P< 0.001). Those with LA/LV diameter ratio > or = 1.0 were more likely to use loop diuretics, odds ratio = 2.5 [95% CI, 1.4, 4.5], compared to those with lower ratio values.
Conclusions: Increased LA/LV diameter ratio was observed in subjects with hypertension, diabetes and LV hypertrophy. Increased ratio predicted worse exercise capacity and was associated with more frequent loop diuretic use. These data are consistent with the hypothesis that this ratio is a noninvasive marker of the LV-DPVR.