Agnieszka Liberska

Long-term outcomes of cardiac resynchronization therapy are worse in patients who require atrioventricular junction ablation for atrial fibrillation than in those with sinus rhythm

BACKGROUND The aim of the study was to assess the impact of atrial fibrillation (AF) with and without the need for atrioventricular junction (AVJ) ablation on outcomes in patients undergoing cardiac resynchronization therapy (CRT). METHODS A single center cohort of 200 consecutive CRT patients was divided into three groups: 1) AF with CRT pacing < 95% in which AVJ ablation was performed (AF-ABL, n = 40; 20%), 2) AF without the need for AVJ ablation (AF-non ABL, n = 40; 20%), 3) sinus rhythm (SR, n = 120; 60%). All patients were assessed before CRT implantation and at 6-month follow-up. Positive clinical response to CRT was considered alive status without the need for heart transplantation and improvement ≥ 1 NYHA after 6 months. The comparative analysis among all study groups with respect to response-rate and long-term survival was performed. RESULTS The 6-month response-rate in both AF-ABL and AF-nonABL was significantly lower than in SR (52.5 and 50 vs.77.5%, respectively; both p < 0.017), though there were no differences in baseline characteristics among study groups apart from higher baseline NT-proBNP levels in AF-ABL. However, after adjustment for this confounder, and despite optimal CRT pacing burden in study groups, the remote all-cause mortality during median follow-up of 36.1 months was significantly higher in AF-ABL than in SR (adjusted HR = 2.57, 95% CI 1.09-6.02, p = 0.03). What is more, no difference in long-term survival between SR and AF-nonABL was observed. CONCLUSIONS Despite the improvement of CRT pacing burden and thus response-rate up to the level of AF subjects without the need for ablation, the long-term survival of AF patients requiring AVJ ablation remains still worse than in SR.

Can we rely on machines? Device-detected atrial high rates correspond well with atrial arrhythmias in cardiac resynchronization recipients

AIMS The aim of the study was to verify in what proportion of patients, device-detected atrial high rate (AHR) episodes are indeed atrial arrhythmias (AAs). We investigated also the reasons for inappropriate arrhythmia classification and assessed if patients with misdiagnosed arrhythmias have distinct characteristics that would help to identify them. METHODS AND RESULTS The study population consisted of 304 consecutive patients implanted with cardiac resynchronization therapy defibrillators (CRT-Ds) and subsequently monitored via remote monitoring for a median follow-up (FU) of 30.5 months. Intracardiac electrograms of every recorded AHR episode were assessed and classified (AA vs. no AA) by two experienced cardiologists. During FU, 14 386 episodes of AHR were recorded and classified in 176 (57.9%) patients. In 89.2% of them, these episodes were true AA (94% atrial fibrillation, 62% de novo). The reasons for AHR misdiagnosis were atrial far-field signals (89.5%) and noise (10.5%). The mean per cent of day spent in AHR (54.9 vs. 5.86%; P < 0.001) and the occurrence of periods with low CRT pacing (82.8 vs. 55%; P = 0.003) were significantly higher in AA subjects than in those with misdiagnosed AHR. Episode duration of properly detected AHRs was longer than that of misdiagnosed AHRs. Higher per cent of time spent in AHR was an independent marker of appropriate arrhythmia detection [adjusted hazard ratio (HR) 1.04; P = 0.023]. CONCLUSION Nearly two-thirds of CRT-D patients had AHR episodes within 2.5 years after implantation. Almost 90% of AHRs were indeed AA. Misdetections were caused by far-field sensing or noise. A two-step diagnostic algorithm (>9% of time spent in AHRs and episode duration >36 s) allowed for proper detection of AA with a high hit-rate and specificity.

Device-related infective endocarditis in cardiac resynchronization therapy recipients — Single center registry with over 2500 person-years follow up

AIM To assess incidence, predisposing factors and outcomes of cardiac device-related infective endocarditis (CDRIE) in patients undergoing cardiac resynchronization therapy (CRT). METHODS AND RESULTS High-volume, single-center cardiology database was screened to identify all CDRIE cases, based on modified Duke criteria, amongst 765 consecutive CRT implantations between 2002 and 2015 (70.8% de novo implantations, 13.7% and 15.5% up-grades from pacemaker and implantable cardioverter–defibrillator [ICD], respectively). During the median follow-up (FU) of 1207 days (range: 256–2664) overall 38 CDRIE (4.97%) cases were identified (incidence: 15/1000 person-years). Multivariate Cox regression model, incorporating significant baseline differences as covariates (model 1), demonstrated that both up-grade from ICD to CRT and higher baseline NYHA class were independently associated with increased risk of CDRIE (adjusted HR 4.29, 95%CI 1.93–9.57; and HR 2.43, 95%CI 1.32–4.49, respectively). In the second model (including all differences with P < 0.2) up-grade from ICD (HR 4.36, 95%CI 1.96–9.69), higher NYHA class (HR 2.04, 95%CI 1.11–3.75), hypertrophic cardiomyopathy (HR 5.85, 95% CI 1.46–23.52), lower baseline hemoglobin level (HR 0.68, 95%CI 0.50–0.94) and chronic obstructive pulmonary disease (HR 2.46, 95%CI 1.05–5.77) were all independently associated with higher risk of CDRIE. All-cause mortality in patients with CDRIE was significantly higher than in subjects without infective complications (68.4% vs. 33.7%, P < 0.001), and 50% of patients with CDRIE died during index hospitalization. CONCLUSIONS The prevalence of CDRIE in CRT recipients is almost 5% within 3.5 years post implantation. Up-grade from ICD and high baseline NYHA class flag up patients at high-risk of CDRIE. CRT-related infective complications are associated with very poor prognosis.

Do we need to monitor the percentage of biventricular pacing day by day

BACKGROUND Incidence and clinical significance of transient, daily fluctuations of biventricular pacing percentage (CRT%) remain unknown. We assessed the value of daily remote monitoring in identifying prognostically critical burden of low CRT%. METHODS AND RESULTS Prospective, single-centre registry encompassed 304 consecutive heart failure patients with cardiac resynchronization therapy defibrillators (CRT-D). Patients with 24-h episodes of CRT% loss<95% were assigned to quartiles depending on cumulative time spent in low CRT%: quartile 1 (1-8days), 2 (9-20days), 3 (21-60days) and quartile 4 (>60days). During median follow-up of 35months 51,826 transmissions were analysed, including 15,029 in 208 (68.4%) patients with episodes of low CRT%. Overall, mean CRT%≥95% vs. <95% resulted in a 4-fold lower mortality (17.3 vs. 68.2%; p<0.001). Fifty-four percent of patients experienced episodes of CRT% loss, despite 85.6% having mean CRT%≥95%. Mortality was lowest in quartile 1 (7.7%), while longer periods of CRT% loss resulted in significantly higher death rates (25.0 vs. 34.6 vs. 57.7%; quartiles 2-4 respectively, p<0.001), despite mean CRT% still being ≥95% in quartiles 1-3. Cumulative low CRT% burden was the independent risk factor for death (HR 1.013; 95% CI 1.006-1.021; p<0.001). Mortality rose by 1.3 and 49% with every additional day and quartile of CRT% loss, respectively. CONCLUSIONS Daily remote monitoring allows one to detect 24-h episodes of CRT% loss<95% in over two-thirds of CRT-D recipients during median observation of 3years. Cumulative low CRT% burden (in days) independently predicts mortality before mean CRT% drop.

Ferritin as a potential biomarker of efficacy of treatment of atrial fibrillation - preliminary report

BACKGROUND Complex mechanisms of responsible for originating and maintaining of atrial fibrillation (AF) are involved in pathophysiology of this arrhythmia. Inflammation substantially contribute to arrhythmic remodelling of atrial tissue.The aim of the present study is to assess an applicability of ferritin and high sensitive C-reactive protein (hs-CRP) as biomarkers of atrial fibrillation and their usefulness in evaluation of efficacy of cryoablation. MATERIALS AND METHODS The study population consisted of 40 patients who underwent first AF cryoablation procedure. The whole follow-up time was for 6 months. The efficacy of cryoablation was defined as lack of episodes of AF longer than 30 s reported either in patients medical documentation or present in standard or Holter ECG records. Concentrations of hs-CRP (latex method ) and ferritin (immunochemical method) were determined in standard way in hospital laboratory. RESULTS The recurrence of atrial fibrillation during follow-up was detected in 7 of 40 patients (efficacy 82.5%). Basal concentrations of hs-CRP and ferritin were significantly higher in patients who underwent ablation during AF. Ablation resulted in an increase of either hs-CRP or ferritin concentrations. After seven days, both hs-CRP and ferritin concentrations returned to basal level. The trend toward the higher concentration of hs-CRP was observed in AF recurrence subgroup in 30th and the 90th day after the procedure. Ferritin concentrations were significantly higher in recurrence subgroup after 30 and 90 days. CONCLUSION Our results suggest that the evaluation of ferritin serum level can be a potential tool for assessment of AF treatment efficacy.