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.