Usefulness of Doppler tissue imaging for the assessment of right and left ventricular myocardial function in patients with dual-chamber pacing.
The aim of the study was to evaluate by Doppler tissue imaging (DTI) the combined effects of atrio-ventricular (AV) delay and heart rate (HR) changes on global and segmental right (RV) and left (LV) ventricular diastolic function in 15 patients with dual-chamber pacemakers paced in the DDD mode. RV and LV inflow velocities and regional systolic and diastolic pulsed-wave (PW) DTI parameters were analyzed at four different pacing modes: (1) HR 70 beats/min, AV delay 125 ms; (2) HR 70 beats/min, AV delay 188 ms; (3) HR 89 beats/min, AV delay 125 ms; (4) HR 89 beats/min, AV delay 188 ms. For each pacing mode selected, RV diastolic filling velocities always prevailed over LV ones. As for RV and LV adaptation to the four different stimulation protocols, a higher paced rate and a prolonged AV delay caused across both the AV valves a decrease of E wave and of E/A ratios. The intersegmental comparison of PW-DTI parameters outlined that RV free wall exhibited significantly higher peak systolic (Sm) and early-diastolic (Em) wall velocities, and longer systolic ejection time. Considering separately RV and LV segmental physiology at the four programmed pacing modes, an increase in HR determined a progressive shortening of systolic ejection times in all the segments analyzed. Moreover, in each region the Em/Am ratio decreased with higher HR and longer AV delay. Conversely, Em encountered a progressive reduction in RV free wall, while remaining quite unchanged in all the LV regions. Both ventricles shared a similar pattern of global and regional adaptation to programmed HR and AV delay modifications, consisting in a progressive greater contribution of late diastole to ventricular filling at higher HR and more prolonged AV delay. However, at a regional level the right ventricle exhibited higher systolic and diastolic wall velocities than all left ventricular regions.
D'Andrea
A
A
Department of Cardiology, Second University of Naples, Naples, Italy. adandrea@synapsis.it
Ducceschi
V
V
Caso
P
P
Galderisi
M
M
Mercurio
B
B
Liccardo
B
B
Sarubbi
B
B
Scherillo
M
M
Cotrufo
M
M
Calabro
R
R
D000368:Aged; D000704:Analysis of Variance; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D001283:Atrioventricular Node / Q000000981:diagnostic imaging / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D002304:Cardiac Pacing, Artificial; D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D016277:Ventricular Function, Left / Q000502:physiology*; D016278:Ventricular Function, Right / Q000502:physiology*