2006 Volume 4 Issue 2 Pages 43-50
Background.We aimed to assess right ventricular (RV) function in patients with complete right bundle branch block (CRBBB) using noninvasive techniques.
Methods.The studied subjects were 29 consecutive patients with CRBBB aged over 40 years (mean: 66 years). Six patients had hypertension; the other 23 patients had no cardiovascular disorders. Twenty age-matched healthy subjects (mean: 68 years) served as the controls. The RV volumes at end-diastole (RVEDV) and end-systole were measured via apical four-chamber view, and the RV ejection fraction (RVEF) was calculated. The isovolumic contraction (ICT) and relaxation times (IRT) and the ejection time (RVET) were measured using the recordings of RV inflow or outflow velocities and the electrocardiogram. The total cardiac performance index (TEI index) was calculated as (ICT + IRT) / RVET.
Results.The patients with CRBBB were divided into two groups based on the mean + 2 standard deviations of RV TEI index (=0.40) in the controls: the low value group (23 patients with TEI index<=0.40) and the high value group (6 with TEI index>0.40). The RVEDV was larger and RVEF lower in the high value group compared to the low value group. The ICT and IRT were prolonged while the RVET was shortened in the high value group when compared with the low value group. Arrhythmic events, such as paroxysmal atrial fibrillation or multiple ventricular premature beats, frequently occurred in the high value group (50 %) as compared to the low value group (4 %, p<0.01).
Conclusions.RV dysfunction or arrhythmic events may occur in some patients with CRBBB, and the TEI index may be useful for the detection and evaluation of these patients.