الفهرس 
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Abstract
SUMMARY
ight ventricular apical lead placement became standard
practice secondary to the ease of site accessibility and lead
stability.
Long-term RVA pacing is detrimental causing reduced LV
function and adverse cardiac remodeling, as well as increased
incidence of HF, AF and death. Patients with a reduced baseline
LVEF and high amount of RVA pacing are at highest risk.
CRT has changed the clinical management of patients with
drug-refractory HF. Various randomized controlled trials have
shown significant improvements in symptoms, LV function and
long-term survival. The optimal placement of an LV lead in a
tributary of the CS to be coincident with the latest activated areas
of the left ventricle is one of the most challenging technical
aspects of CRT device implantation, this maximizes the
haemodynamic benefits of CRT and provides superior long-term
outcome.
The aim of the study is the assessment of CS lead function
(pacing threshold, sensing threshold and lead impedance) in
patients with newly implanted CRT systems over a follow up
period of 6 months to determine possibility of using LV pacing
instead of RV pacing in patients requiring percutaneous
permanent cardiac pacing for symptomatic bradycardia and
having normal LV function.
This is a prospective study included 50 consecutive
patients with congestive heart failure who received CRT systems
at Ain Shams university hospitals from September 2013 to
February 2014 according to the latest ESC guidelines.
Their ages ranged from 22 to 77 year old with mean 55.04
± 12.62 years including 90% males.
Thirty-three (66%) patients had DCM and 17 (34%) had
ICM. All patients were receiving maximally tolerated medical
therapy for heart failure.
The mean EF was 25.02 ± 6.9 %, LVEDD 70.90 ± 9.7.
LV lead function parameters including LV lead impedance,
R wave and pacing threshold were stable over 6 month follow up
and parameters were comparable to the RV lead.
Patients who received LV pacing via the posterolateral
branch had a lower BMI and lower LV impedance at 2 week
follow up versus those who received LV pacing via other
branches.
LV lead function parameters were similar between patients
with and those without viability at implantation site.
LV lead function parameters were comparable between
patients with DCM versus those with ICM at all-time points.
The long-term performance of CS lead revealed a stable
course over 6 month follow up.