Beyond dyssynchrony in cardiac resynchronisation therapy

Independent and incremental prognostic value of Doppler-derived left ventricular total isovolumic time in patients with systolic heart failure

BACKGROUND

A prolonged total isovolumic time (T-IVT) has been shown to be associated with worsening survival in patients submitted to coronary artery surgery. However, it is not known whether it has prognostic significance in patients with chronic systolic heart failure (HF).

AIM

To determine the prognostic value of T-IVT in comparison with other clinical, biochemical and echocardiographic variables in patients with chronic systolic HF.

METHODS

Patients (n=107; age 68±12 years, 25% women) with chronic systolic HF, left ventricular ejection fraction (EF)<45%, and sinus rhythm, underwent a complete Doppler echocardiographic study, that included tissue Doppler long axis velocities and total isovolumic time (T-IVT), determined as [60-(total ejection time+total filling time)]. Plasma N-terminal pro-B natriuretic peptide (NT-pro-BNP) was also measured. The associations of dichotomous variables selected according to the Receiver Operator Characteristic analysis were assessed using the Cox proportional hazard model.

RESULTS

Follow-up period was 37±18 months. Multivariate predictors of events were T-IVT≥12.3% s/min, mean E/Em ratio≥10, log NT-pro-BNP levels≥2.47 pg/ml and LV EF≤32.5%. On Kaplan-Meier analysis, patients with prolonged T-IVT, high mean E/Em ratio, increased NT-pro-BNP levels and decreased LV EF had a worse outcome compared with those without. The addition of T-IVT and NT-pro-BNP to conventional clinical and echocardiographic variables significantly improved the chi-square for the prediction of the outcome from 33.1 to 38.0, (P<0.001).

CONCLUSIONS

Prolonged T-IVT added to the prognostic stratification of patients with systolic HF.