Left ventricular electromechanical delay in patients with heart failure and normal QRS duration and in patients with right and left bundle branch block.
OBJECTIVE
We sought to define the reference values of intra-left ventricular (LV) electromechanical delay (EMD), and to assess the prevalence (and pattern) of intra-LV dyssynchrony in patients with heart failure (HF) and normal QRS and in patients with right and left bundle branch block.


RESULTS
We used tissue Doppler imaging echocardiography and a six-LV wall model to study LV EMD in 103 patients [41 with HF and normal QRS, 22 with right bundle branch block (RBBB), and 40 with left bundle branch block (LBBB)], and in 59 controls. In controls, the median intra-LV EMD was 17 ms, (inter-quartile range 13-30); 95% of controls had a value < or =41 ms. Patients showed a longer intra-LV EMD than controls: 33 ms (20-57) in patients with normal QRS, 32 ms (23-50) in RBBB patients, and 50 ms (30-94) in LBBB patients. Intra-LV dyssynchrony (defined as intra-LV EMD >41 ms) was present in 39, 36, and 60% of the patients, respectively. On average, HF patients showed the same pattern of activation as controls, from the septum to the posterior wall, but activation times were significantly prolonged. In RBBB patients the activation sequence was directed from inferior to anterior and in LBBB from anterior to inferior wall.


CONCLUSIONS
Left ventricular dyssynchrony was present in several patients with HF and normal QRS, and in patients with RBBB; conversely, 40% of LBBB patients showed values of LV EMD within the normal range. Left ventricular activation sequence was different between groups. Assessment of LV synchronicity by means of imaging techniques may be more important than QRS duration or morphology in selecting patients for cardiac resynchronization treatment.
Badano
Luigi P
LP
Cardiology Unit, Echo-lab, Department of Cardiopulmonary Sciences, A.O. Santa Maria della Misericordia, Piazzale S. Maria della Misericordia 15, 33100 Udine, Italy. lbadan@tin.it
Gaddi
Oscar
O
Peraldo
Carlo
C
Lupi
Gabriele
G
Sitges
Marta
M
Parthenakis
Frangisko
F
Molteni
Santo
S
Pagliuca
Maria Rosaria
MR
Sassone
Biagio
B
Di Stefano
Paola
P
De Santo
Tiziana
T
Menozzi
Carlo
C
Brignole
Michele
M
D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000503:physiopathology*; D002303:Cardiac Output, Low / Q000503:physiopathology*; D016022:Case-Control Studies; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D012016:Reference Values; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*