PURPOSE: The impact of left atrial volume (LAV) in patients with wide QRS duration (QRSD) and left ventricular mechanical dyssynchrony (LVMD) on response to cardiac resynchronization therapy (CRT) has not been well described. We hypothesized that LAV has predictive value in patients with CRT.
METHODS: We studied 108 consecutive patients (male 78, female 30, age 69.9± 9.7 years) with CRT [left ventricular ejection fraction (LVEF) ≤; 35%, NYHA class III-IV, and QRSD≥ 120ms]. Patients with atrial fibrillation were excluded. There were 69 patients with ischemic dilated cardiomyopathy and 39 patients with non-ischemic dilated cardiomyopathy. LAV was measured in apical four chamber view by Simpson's rule. The time difference (TPW-TDI) between QRS onset to the end of LV ejection by pulsed wave Doppler (PW) and QRS onset to the end of the systolic wave in the basal segment with the greatest delay by tissue Doppler imaging (TDI) was measured before CRT and at the last follow-up after CRT (15 ± 10.9 months). TPW-TDI > 50ms was defined as LVMD. Positive response to CRT was defined as a decrease of left ventricular end systolic volume ≥15% after CRT.
RESULTS: LAV was significantly smaller in CRT responders versus non-responders, both at baseline and after CRT (Table). There was no significant difference in LAV between patients with TPW-TDI > 50ms and ≤; 50ms at baseline, but LAV in patients with TPW-TDI >50ms was smaller compared to patients with TPW-TDI ≤; 50ms after CRT. There was no significant difference in LAV between patients with QRSD ≥ 150ms and < 150ms at baseline and after CRT (p= NS).
CONCLUSION: LAV had an important predictive value and should be considered when we design new research protocol in patients with CRT.
CLINICAL IMPLICATIONS: LAV may help predict a positive response to CRT.
DISCLOSURE: Jacob Koruth, None.