Subjects and methods
This study was performed on 30 patients with history of dual chamber
pacemaker implantation (at RV apical position) more than 6 months
duration and 30 healthy volunteers as controls. Subjects were included
in this study after obtaining their written informed consent and
acquiring the approval of the local Ethics Committee.
Inclusion criteria : 1) patients with implanted dual chamber
pacemaker more than 6 months duration 2) the ventricular lead placed in
the apex of RV (confirmed by fluoroscopy). 3) patients should have LV EF
> 50%. 4) ventricular pacing should be at least
> 90%.
Exclusion criteria: 1) position of ventricular lead outside the
apex of RV. 2) pacemakers implanted less than 6 months duration before
enrollment. 3) bad echocardiographic window. 4) previous cardiac surgery
(e.g. valve replacement, CABG). 5) history of IHD or previous PCI. 6)
myocardial disease as hypertrophic cardiomyopathy, restrictive
cardiomyopathy. 7) significant valvular lesions.
Methods: All the subjects underwent detailed history taking,
clinical examination and 12- lead ECG. A transthoracic echocardiography
was done using vivid E9, general electric health care (GE Vingemed,
Norway) equipped with a harmonic M5S variable frequency (1.7 – 4 MHz)
phased-array transducer with the patient in the left lateral position
based on American Society of Echocardiography (ASE) recommendations.