A long-term evaluation of cryoballoon ablation in 205 atrial fibrillation patients: a single center experience.

BACKGROUND: Atrial fibrillation is the most prevalent cardiac arrhythmia with significant healthcare impact with regards to treatment costs, morbidity, and mortality. Many of the focal electrical activities that initiate and sustain atrial fibrillation have been found to reside within or near the pulmonary veins. Consequently, pulmonary vein isolation by catheter ablation has emerged as an effective method to eliminate the focal triggers associated with atrial fibrillation. METHODS: In this single-center study, 205 patients were ablated for atrial fibrillation using a cryoballoon catheter and followed-up long-term by retrospective chart examination to evaluate their post-procedural freedom from atrial fibrillation. RESULTS: Patients were followed for up to 6 years with a cohort median of 3 years of post-ablation evaluation. Overall, at 12, 24, and 36 months post-ablation, 71, 49, and 31% of evaluated patients were free of atrial fibrillation, respectively. We found the type of atrial fibrillation (paroxysmal vs. persistent) as an independent predictor for arrhythmia recurrence (HR 1.97; 95% CI: 1.24-3.13, P = 0.006). The cohort median atrial fibrillation-free survival time was 24 months (27 months for paroxysmal atrial fibrillation patients and 14 months for persistent atrial fibrillation patients). There were a total of 37 (18%) complications, 8 (3.9%) were categorized as major complications, all without permanent sequels. The most common complication was phrenic nerve palsy which occurred in 14 (6.8%) patients. CONCLUSION: Long-term outcomes in this study suggest that the pulmonary vein isolation using the cryoballoon technique is relatively an effective method especially in the treatment of paroxysmal atrial fibrillation.

Global myocardial contractile reserve assessed by high-dose dobutamine stress echocardiography predicts response to the cardiac resynchronization therapy.

BACKGROUND: Myocardial contractile reserve (CR) is a strong prognostic factor in patients with heart failure. The presence of significant myocardial fibrosis can lead to a reduced response to cardiac resynchronization therapy (CRT). We assumed that myocardial CR assessed by high-dose dobutamine stress echocardiography (DSE) would predict response to CRT. METHODS: Fifty-two consecutive symptomatic patients with heart failure (New York Heart Association [NYHA] class III), with depressed ejection fraction (EF) of the left ventricle (26.3 ± 6.9%) and dyssynchronous contractions (QRS duration 149.8 ± 23.8 msec) underwent DSE before CRT implantation. The difference in EF at rest and at peak (40 µg/kg per minute) DSE indicated global CR. Responders to CRT were defined by a decrease in left ventricular end-systolic volume of ≥15% and/or an increase in EF of ≥5% after 6 months of CRT. RESULTS: During high-dose dobutamine infusion, responders (28 patients, 54%) showed a greater increase in EF compared with nonresponders (Δ 11 ± 7% vs. Δ 2 ± 9%, P = 0.007). CR correlated moderately with an improvement in EF after 6 months of CRT (r = 0.50, P = 0.0009). Furthermore, responders showed significant improvement in clinical status, evaluated by a reduction in NYHA functional class (-0.8 ± 0.6 vs. 0.1 ± 0.4, P = 0.02), compared with nonresponders. A 7% exercise-induced increase in EF yielded sensitivity of 79% and specificity of 87% in predicting the response to CRT after 6 months. CONCLUSIONS: Myocardial CR assessed by high-dose DSE can play a potentially important role in identifying responders to CRT.

[Basic biological roles of galectins in tissue repair and tumor growth]. / Základné biologické úlohy galektínov v reparácii tkanív a raste nádorov.

Galectins are representatives of endogenous lectins - molecules specifically recognizing distinct sugar motifs. They play an important role in the processes of cell proliferation, differentiation, migration and extracellular matrix formation. Furthermore, galectins are able to transfer cellular signals and to participate in intercellular interaction. It has been proven that galectins play an important role in the formation of tumor and/or wound healing microenvironment. This review contains an overview of experimental and clinical studies dealing with biological roles of galectins in tissue repair and in its parallel - the tumor growth.

Extracellular matrix of galectin-1-exposed dermal and tumor-associated fibroblasts favors growth of human umbilical vein endothelial cells in vitro: a short report.

BACKGROUND/AIM: Stromal cells in the tumor microenvironment are primarily considered as sources of promalignant factors. The objective of our study was to define the effect of extracellular matrix (ECM) produced by normal dermal or cancer-associated fibroblasts exposed to adhesion/growth-regulatory lectin galectin-1 on human umbilical vein endothelial cells (HUVECs). MATERIALS AND METHODS: Fibroblasts were cultured for 10 days with lectin, followed by removing cellular constituents after an osmotic shock. Freshly-isolated HUVECs were placed on the ECM. In parallel, HUVECs were seeded on untreated and gelatin-coated surfaces as controls. A positive control for growth of HUVECs culture using medium supplemented with vascular endothelial growth factor completed the test panel. Cells were kept in contact to the substratum for two days and then processed for immunocytochemistry. RESULTS: HUVECs seeded on fibroblast-generated ECM presented a comparatively high degree of proliferation. Furthermore, contact to substratum produced by tumor-associated fibroblasts led to generation of a meshwork especially rich in fibronectin. CONCLUSION: Galectin-1 is apparently capable to trigger ECM production favorable for growth of HUVECs, prompting further work on characterizing structural features of the ECM and in situ correlation of lectin presence, ECM constitution and neoangiogenesis.

[Importance of EKG in patients wuth resynchronization therapy]. / Význam EKG u pacientov s resynchronizacnou liecbou.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves symptoms and survival in patients with chronic heart failure. The presence of electrocardiographic (ECG) signs of electrical dyssynchrony during ventricular contractions are an essential criterion for the implantation of CRT. Nevertheless, 1/3 proportion of patients who undergo CRT do not seem to respond favorably. Aim of study was to investigate the relevant ECG parameters prior to CRT (as well as their postimplantation changes) and to determine their relation to predicting favorable response to CRT. METHODS: 52 symptomatic patients (age 62.2 ± 10.5 years, 39 men) with severe left ventricular (LV) systolic dysfunction (ejection fraction 26.3% ± 6.9%) with QRS 120 ms underwent CRT implantation. In early pre- and postimplantation CRT period the following ECG parameters were recorded: QRS complex width and morphology (complete and atypical left bundle branch block, nonspecific intraventricular conduction delay), the size of R and S wave. After 6 months of CRT, responders were definied by improvement of LV ejection fraction > 5 % and/or reduction of end-systolic LV volume > 15 %. RESULTS: The incidence of left bundle branch block (complete or atypical) prior to CRT implantation was higher in responders compared to non-responders group (64% vs 35%, p = 0.036). After implantation of CRT, responders showed significant narrowing of the QRS complex, while non-responder`s QRS complex width remained unchanged (QRS -18 ± 22 ms vs 1 ± 27 ms, p = 0.018). Furthermore QRS complex reduction led to increase in LV ejection fraction (r = 0.47, p = 0.001) and to reduction of LV end-systolic volume (r = 0.42, p = 0.004). R and S changes between responders and non-responders did not differ (p = 0.598 respectively, P = 0.685). CONCLUSION: The presence of complete left bundle branch block before CRT implantation is associated with a better response to CRT compared to other myocardial intraventricular conduction disturbances. Post-implantation narrowing of QRS complex appears to be an early predictor of favorable response to CRT.

Complications of circumferential pulmonary vein isolation using the cryoballoon technique: Incidence and predictors.

BACKGROUND: Cryoballoon ablation technique for the treatment of atrial fibrillation (AF) is a complex procedure consisting of several procedural steps associated with significant risk of complications. The aim of this single-centre study was to give detailed analysis of the complication rate and corresponding risk factors of pulmonary veins cryoisolation (PVI) procedures. METHODS AND RESULTS: A total of 158 consecutive patients (71.5% men, aged 57 ± 9 years, 73.3% paroxysmal atrial fibrillation) were enrolled. Out of 632 pulmonary veins, 96.7% were targeted and isolated by 2-7 applications of cryothermal energy guided with intracardiac echocardiography and fluoroscopy. The additional ablation of cavotricuspid isthmus was performed in 14.6% of procedures. In total, 29 complications were recorded in peri-procedural or early post-procedural period, 8 (5.1%) of them being evaluated as major. No case of permanent injury, disability or death was registered. Multivariate logistic regression showed the persistence of pre-ablation AF as the risk factor of major complications (OR=5.0; ± 95% CI: 1.14-21.97, P=0.033); lower body height was the significant risk factor of any complications (OR=0.95; ± 95% CI: 0.91-0.99, P=0.026) with rapid increase of complication risk with body height ≤ 162 cm. Embolic complications were significantly associated with the pre-ablation AF, while patients with low body height had a trend towards increased risk of phrenic nerve palsy. CONCLUSION: Our study confirmed that the cryoballoon pulmonary vein isolation can be safely performed with low incidence of life-threatening complications which may be further decreased if the mentioned risk factors are handled appropriately.