Predictors of pacing-induced cardiomyopathy detection and outcomes demonstration after conduction system pacing upgrade on patients with long-term persistent atrial fibrillation.

OBJECTIVE: To identify the predictors of pacing-induced cardiomyopathy (PICM) and illustrate the safety and feasibility of conduction system pacing (CSP) upgrade on patients with long-term persistent atrial fibrillation (AF). METHODS: All patients with long-term persistent AF and normal left ventricular ejection fraction (LVEF) ≥50% were consecutively enrolled from January 2008 to December 2017, and all the patients with atrioventricular block (AVB) and high right ventricular pacing (RVP) percentage of at least 40%. The predictors of PICM were identified, and patients with PICM were followed up for at least 1 year regardless of CSP upgrade. Cardiac performances and lead outcomes were investigated in all patients before and after CSP upgrade. RESULTS: The present study included 139 patients, out of which 37 (26.62%) developed PICM, resulting in a significant decrease in the left ventricular ejection fraction (LVEF) from 56.11 ± 2.56% to 38.10 ± 5.81% (p< .01). The median duration for the development of PICM was 5.43 years. Lower LVEF (≤52.50%), longer paced QRS duration (≥175 ms), and higher RVP percentage (≥96.80%) were identified as independent predictors of PICM. Furthermore, the morbidity of PICM progressively increased with an increased number of predictors. The paced QRS duration (183.90 ± 22.34 ms vs. 136.57 ± 20.71 ms, p < .01), LVEF (39.35 ± 2.71% vs. 47.50 ± 7.43%, p < .01), and left ventricular end-diastolic diameter (LVEDD) (55.53 ± 5.67 mm vs. 53.20 ± 5.78 mm, p = .03) improved significantly on patients accepting CSP upgrade. CSP responses and complete reverse remodeling (LVEF ≥50% and LVEDD < 50 mm) were detected in 80.95% (17/21) and 42.9% (9/21) of patients. The pacing threshold (1.52 ± 0.78 V/0.4 ms vs. 1.27 ± 0.59 V/0.4 ms, p = .16) was stable after follow-up. CONCLUSION: PICM is very common in patients with long-term persistent AF, and CSP upgrade was favorable for better cardiac performance in this patient population.

[Changes in content of plasma brain natriuretic peptide in dilated cardiomyopathy in rabbits].

OBJECTIVE: To determine the changes in plasma brain natriuretic peptide (BNP) in adriamycin-induced dilated cardiomyopathy (DCM) in rabbit, and to evaluated the significance. METHODS: Twenty-two rabbits were randomly divided into control group (n=10) and model group(n=12). The DCM model was reproduced by injecting adriamycin via ear vein for 8 weeks. Echocardiogram was performed and plasma BNP were measured before administration, and at 8 th and 11 th week after the challenge. Indexes of hemodynamics and pathological changes were observed. RESULTS: Indexes of echocardiogram and hemodynamics of model group were consistent with pathologic changes of DCM. Plasma levels of BNP of the model group were increased significantly after administration of the drug(all P<0.01), though the values before the drug administration were approximately the same as in the control group. Plasma BNP levels were significantly higher in DCM group at the 11 th week than at the 8 th week (P<0.05). Plasma levels of BNP were positively correlated with and left ventricular end-diastolic volume(LVEDV), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic pressure(LVEDP) and negatively correlated with left ventricular systolic pressure(LVSP), and left ventricular ejection fraction (LVEF). CONCLUSION: Administration of intravenous adriamycin to rabbits results in DCM which in suitable for the conduction of research of neuroendocrine abnormality of heart. Overload of the left ventricle and increasing tension of left ventricular wall are key factors for regulating BNP excretion. Plasma BNP level is a good marker for evaluating degree of severity of cardiac function in DCM.