Effect of heart rate on left ventricular longitudinal myocardial function in type 2 diabetes mellitus

Background Left ventricular (LV) longitudinal myocardial dysfunction is considered a marker of preclinical LV dysfunction in patients with type 2 diabetes mellitus (T2DM). High heart rate (HR) is associated with cardiovascular outcomes, but the effect of HR on LV longitudinal myocardial function in T2DM patients is uncertain. Methods We studied 192 T2DM patients with preserved LV ejection fraction (LVEF), and 81 age-, sex-, and LVEF-matched healthy volunteers. HR was measured as the average HR during echocardiography, and high HR was defined as resting HR >= 70 beats/minute. LV longitudinal myocardial function was assessed as global longitudinal strain (GLS). The predefined cutoff for subclinical LV dysfunction was set at GLS < 18%. Results GLS in T2DM patients with high HR was significantly lower than that in T2DM patients with low HR (16.3% +/- 4.2% vs. 17.8% +/- 2.8%; P = 0.03), whereas GLS in normal subjects with high and low HR was similar (20.3 +/- 1.7% vs. 20.3 +/- 2.0%; P = 0.99). Multivariable logistic regression analysis showed that high HR (odds ratio: 1.04; 95% confidence interval: 1.01-1.07; P = 0.01) was independently associated with GLS < 18% in T2DM patients as well as HbA1c, T2DM duration, LVEF, body mass index, and mitral inflow E and mitral e' annular velocity ratio. One sequential logistic model evaluating the associations between GLS < 18% and clinical variables in T2DM patients showed an improvement with the addition of LVEF and E/e' (P < 0.001) and a further improvement with the addition of high HR (P < 0.001). Conclusion Compared with normal subjects, resting HR was associated with LV longitudinal myocardial function in asymptomatic T2DM patients with preserved LVEF. Our findings provide new insights on the management of T2DM patients.

Automated summary

High heart rate is independently associated with LV longitudinal myocardial dysfunction in asymptomatic patients with type 2 diabetes mellitus and preserved LV ejection fraction. The combination of heart rate with other clinical variables improves the assessment of LV function in these patients.