Abstract
The heart rate regularization is crucial for proper treatment of patients with atrial fibrillation and congestive heart failure. The standard resynchronization can be applied, but in patients with narrow QRS this procedure is of no use.
The aim of our study is to assess the efficacy of direct His-bundle pacing in patients with congestive heart failure and chronic atrial fibrillation using dual chamber ICD implanted for prevention of sudden cardiac death.
Methods
The study population included 78 patients with CHF and chronic AF: group A - 56 pts treated with direct His-bundle pacing using atrial port of dual chamber ICD and group B - 22 patients implanted with single chamber ICD as recommended by the guidelines. The patients in group B constituting clinical controls were derived from the Heart Failure Outpatients Clinic with established clinical status and pharmacotherapy.
Results
The demographic data, clinical characteristics and echocardiography measurements at baseline and during follow-up were presented in the table:
Table 1 Group A Group B P value Age (years) 69.7±6.9 66.7±11.3 n.s. Sex (% of male sex) 84.0 86.4 n.s. Ventricular pacing (%) – 46.3±31.2 – His-bundle pacing (%) 81.7±9.2 – – pre post pre post pre vs. post LVEDD (mm) 66.9±4.9 59.9±4.7 64.8±8.0 64.7±8.1 <0.01 n.s. EF (%) 29.6±3.8 43.6±5.9 28.1±6.1 28.8±7.3 <0.01 n.s. NYHA class 2.7±0.6 1.4±0.6 2.5±0.6 2.0±0.2 <0.05 n.s. B-blocker dose (metoprolol equivalent dose) 104.6±41.6 214.3±82.6 78.3±56.6 103.1±49.2 <0.001 <0.05
During 12-months of follow-up the mean values of NYHA functional class, EF and LV dimensions did not change in group B but significantly improved in group A. The physiological His-bundle based pacing enabled optimal beta-blocker dosing. The studied groups had no tachyarrhythmia at baseline so the presumable atrial fibrillation-related harm depends on the rhythm irregularity.
Conclusions
His-bundle-based pacing in CHF-chronic AF patients contributes to significant echocardiographic and clinical improvement. Standard single-chamber ICD implantation in CHF-chronic AF patients yields only SCD prevention without influence on remodeling process. The CHF-patients with narrow QRS and chronic AF benefit from substantially higher beta-blockade which can be instituted in His-bundle pacing group.
UNDERTREATMENT IN PATIENTS WITH DUAL CHAMBER PACEMAKERS AND ATRIAL FIBRILLATION DETECTED