الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
HF remains the leading cause of hospitalization in patients over 65 years of age. AF is the most common sustained heart rhythm disturbance. AF is an independent predictor of mortality. AF is present in 10–50% of patients with CHF, with the highest incidence occurring in those having NYHA functional class IV. CHF is also an independent predictor of AF. The increased risk associated with AF in CHF patients is probably due to multiple reasons. Excessive ventricular rate, loss of atrial contraction and irregular ventricular filling times all contribute to clinical hemodynamic deterioration in CHF patients. AF may also be a marker of more advanced disease in CHF patients.
AVN ablation and subsequent permanent pacing is a well-established treatment option in patients with chronic, drug-refractory AF. AVN ablation and permanent pacing may improve quality of life and exercise capacity and may be superior to pharmacologic therapy in controlling symptoms of AF. However, recent studies have shown detrimental effects of long-term right ventricular (RV) pacing. Left ventricular (LV) dilatation (remodeling) with a decrease in LV ejection fraction after long-term RV pacing has been reported. The underlying cause of these adverse effects is unknown but may be related to induction of LV dyssynchrony after long-term RV pacing, with subsequent deterioration of LV function.
This study was designed to assess probable merits of BiV and LV-only pacing compared to RV pacing or continued pharmacological rate control in patients with medically refractory rapid permanent AF & LV systolic dysfunction after AV node ablation.
48 patients with permanent rapid AF with resting ventricular rate more than 90/m despite at least 2 rate controlling pharmacological agents, LVEF < 45 % and NYHA class II, III or IV symptoms were randomized to:
• Group A: 12 patients submitted to AVN ablation & RV pacing.
• Group B: 12 patients submitted to AVN ablation & LV coronary sinus pacing.
• Group C: 12 patients submitted to AVN ablation & BiV pacing.
• Group D: 12 patients submitted to pharmacological rate control.
At baseline and after 6 months, 12 lead ECG, LV systolic & diastolic function, LV dyssynchrony (M-mode, standard Doppler and tissue Doppler imaging), functional status (NYHA class, ETT) & QOL were assessed.
Continued pharmacological rate control (group D) resulted in progressive LV remodeling which was significant as early as the first month of follow up manifested as increase of LVEDD ,LVESD ,LVEDV & LVESV while systolic function indices(EF & FS) deteriorated later at 3 months. RV pacing showed a non significant trend towards LV volume reduction early after implantation (within 3 months).This was followed by significant deterioration of LVEDD, LVESD, LVEDV & LVESV. Systolic function indices (EF & FS) actually improved at 1 month predominantly due to a reduction of LVESD & LVESV followed by no further change thereafter. On the other hand , Groups B & C showed significant reverse remodeling of LV volumes as well as significant improvement of systolic function indices (EF & FS) at 1,3 & 6 months following LV based pacing compared to baseline. Systolic function indices (EF & FS) showed significant improvement in group C compared to group B starting at 3 months while end systolic dimension & volume showed significant improvement in group C compared to group B later at 6 months.