Evaluation of post-radiofrequency myocardial injury by measuring cardiac troponin I levels

Successful caudal vena cava and pulmonary vein isolation in healthy horses using 3D electro-anatomical mapping and a contact force-guided ablation system

BACKGROUND

Recently, treatment of equine atrial tachycardia by three-dimensional electro-anatomical mapping (3D EAM) and radiofrequency catheter ablation (RFCA) has been described. Myocardial sleeves in the caudal vena cava and pulmonary veins are a potential trigger for initiation and perpetuation of atrial tachycardia and atrial fibrillation in the horse. Isolation of these myocardial sleeves by RFCA may be an effective treatment for these arrhythmias.

OBJECTIVES

To describe the feasibility of 3D EAM and RFCA to isolate caudal vena cava and pulmonary veins in adult horses using 3D mapping and a contact force (CF)-guided ablation system.

STUDY DESIGN

In vivo experiments.

METHODS

3D EAM and RFCA was performed in five horses without cardiovascular disease under general anaesthesia, using the CF-guided system CARTO®3. Point-by-point RFCA aimed for isolation of caudal vena cava and pulmonary veins. Radiofrequency energy was delivered in power-controlled mode with a target power of 45 W, CF between 10 and 15 g and 30 mL/min irrigation rate, until an ablation-index of 450-500 was reached.

RESULTS

In the right atrium, myocardial sleeves of the caudal vena cava were isolated (n = 5). In the left atrium, isolation of ostium II (n = 3), ostium III (n = 1) and ostium I, II and III en bloc (n = 1) was performed. Successful isolation was confirmed by entrance and exit block.

MAIN LIMITATIONS

Horses were euthanised at the end of the procedure, so long term effects such as potential reconnection of isolated veins could not be studied.

CONCLUSIONS

This is the first description of 3D EAM and RFCA with CARTO®3 in horses, thereby showing the technical feasibility and successful caudal vena cava and pulmonary vein isolation. CF measurement allowed monitoring of catheter-tissue contact, resulting in efficient acute lesion creation as confirmed by entrance and exit block. This is a promising treatment for cardiac arrhythmias in horses.

The efficacy of radiofrequency ablation in the treatment of pediatric arrhythmia and its effects on serum IL-6 and hs-CRP

The aim of this study was to investigate the efficacy of radiofrequency ablation in the treatment of pediatric arrhythmia and to assess the changes in serum interleukin-6 (IL-6) and hs-CRP levels after treatment. Hundred and six children with tachyarrhythmia who were admitted to Xuzhou Children's Hospital from November, 2014 to December, 2015 were recruited for study. The efficacies of radiofrequency in the treatment of different types of arrhythmia were analyzed. Successful ablation was found in 104 cases (98.11%) and recurrence was found in 7 cases (6.73%). Among 62 cases of atrioventricular reentrant tachycardia (AVRT), successful ablation was found in 60 cases (96.77%) and recurrence was found in 3 cases (4.84%). Among 33 cases of atrioventricular nodal reentrant tachycardia (AVNRT), successful ablation was found in 33 cases (100%) and recurrence was found in 2 cases (6.06%). Among 5 cases of ventricular tachycardia (VT), successful ablation was found in 5 cases (100%) and no recurrence was found. Among 4 cases of atrial tachycardia (AT), successful ablation was found in 4 cases (100%) and recurrence was found in 1 case (25%). Among 2 cases of atrial flutter (AFL), successful ablation was found in both (100%) and recurrence was found in 1 case (50%). After operation, the levels of IL-6 and hs-CRP were increased and were continually increased within 6 h after operation. The levels of IL-6 and hs-CRP at 24 h after operation were reduced but still higher than preoperative levels. The duration of radiofrequency and ablation energy were positively correlated with the levels of IL-6 and hs-CRP, while the number of discharges was not significantly correlated with either. In conclusion, radiofrequency ablation is a safe and effective treatment for pediatric arrhythmia. Postoperative monitoring of IL-6 and hs-CRP levels is conducive to understanding postoperative myocardial injury and inflammatory response.

Myocardial injury during radiofrequency and cryoablation of typical atrial flutter

PURPOSE

Cardiac enzyme elevation after radiofrequency (RF) catheter ablation of atrial flutter (AFL) is common. Some studies found that cryoablation (CRYO) of AFL, compared to RF, is associated with higher levels of troponin, a finding that may indicate CRYO causes a greater amount of myocardial injury than RF. However, other investigations found no significant differences between troponin levels after CRYO versus RF. We have in a randomized study compared the post-procedural troponin I levels in RF and CRYO and the possible relation to procedural outcome and complications.

METHODS

We randomized 153 patients with cavotricuspid isthmus (CTI)-dependent AFL to CRYO or RF (78 CRYO; 75 RF). RF was performed with a 3.5-mm open-irrigated-tip catheter, and CRYO was performed with an 8-mm-tip catheter. Troponin I levels were measured before and 6 h after ablation.

RESULTS

Acute procedural success was achieved in 71/75 patients in the RF and in 72/78 patients in the CRYO. Troponin I levels were significantly elevated in both groups (baseline 0.012, 6th hour 0.35 ng/ml; p < 0.001). Troponin I levels were similar for RF and CRYO. Troponin I levels were higher in patients with acute failure compared to patients with acute success (0.48 ± 0.4 and 0.34 ± 0.16 ng/ml, p = 0.029); however, there was no difference between patients with or without late recurrence. There were no major complications in any group.

CONCLUSION

RF and CRYO for CTI-dependent AFL resulted in similar amounts of procedural myocardial injury. Troponin I levels had no prognostic value for late recurrence of AFL and there were no complications related to high troponin I levels.

Nonsymptomatic myocardial injury after radiofrequency and cryoablation: a study of children and patients with congenital heart disease

The aim of this study was to investigate the degree of myocardial injury following catheter radiofrequency (RF) ablation (RFA) or cryoablation and its clinical significance in children and patients with congenital heart disease. Cardiac troponin T (cTnT) or cardiac troponin I (cTnI), creatine kinase (CK), and its cardiac isoenzyme MB (CK-MB) were measured in 269 patients who underwent catheter ablation (216 RFA, 53 cryoablation) just before the procedure and again 6 hours after the end of the procedure. Follow-up studies included echocardiography and 12 lead electrocardiographics (ECGs). No clinical, ECG, nor ECG signs of ischemia were detected. Biomarkers were increased in 57.7-75.5 %. A linear regression analysis illustrated the ablation target site and the number of RF applications as a function of higher cTnI and cTnT levels, with the maximum increase due to ventricular ablation and higher numbers of RF applications. No significant difference in cTnT levels after RFA or cryoablation were observed for AV nodal reentrant tachycardia procedures and no significant differences were observed after nonirrigated tip or irrigated tip RFA in atrial wall or ventricular wall ablation. Elevations in both troponin T and troponin I levels were commonly observed after ablation, especially in ventricular wall ablation as well as with increasing numbers of radiofrequency applications. However, unlike in patients with acute coronary syndrome, these elevated levels had no specific significance. Reference values for each ablation target site were proposed in order to potentially detect additional subclinical injuries to the coronary arteries.

Remote magnetic versus manual catheters: evaluation of ablation effect in atrial fibrillation by myocardial marker levels

Background

A remote magnetic navigation (MN) system is available for radiofrequency ablation of atrial fibrillation (AF), challenging the conventional manual ablation technique. The myocardial markers were measured to compare the effects of the two types of MN catheters with those of a manual-irrigated catheter in AF ablation.

Methods

AF patients underwent an ablation procedure using either a conventional manual-irrigated catheter (CIR, n = 65) or an MN system utilizing either an irrigated (RMI, n = 23) or non-irrigated catheter (RMN, n = 26). Levels of troponin T (TnT) and the cardiac isoform of creatin kinase (CKMB) were measured before and after ablation.

Results

Mean procedure times and total ablation times were longer employing the remote magnetic system. In all groups, there were pronounced increases in markers of myocardial injury after ablation, demonstrating a significant correlation between total ablation time and post-ablation levels of TnT and CKMB (CIR r = 0.61 and 0.53, p < 0.001; RMI r = 0.74 and 0.73, p < 0.001; and RMN r = 0.51 and 0.59, p < 0.01). Time-corrected release of TnT was significantly higher in the CIR group than in the other groups. Of the patients, 59.6% were free from AF at follow-up (12.2 ± 5.4 months) and there were no differences in success rate between the three groups.

Conclusions

Remote magnetic catheters may create more discrete and predictable ablation lesions measured by myocardial enzymes and may require longer total ablation time to reach the procedural endpoints. Remote magnetic non-irrigated catheters do not appear to be inferior to magnetic irrigated catheters in terms of myocardial enzyme release and clinical outcome.

High-sensitivity troponin T as a marker of myocardial injury after radiofrequency catheter ablation

Background

The aim of our study was to monitor radiofrequency catheter ablation-induced myocardial damage by measuring high-sensitivity cardiac troponin T (hs-cTnT).

Methods

Serum concentrations of hs-cTnT (Elecsys 2010 system, Roche) were measured in 73 healthy blood donors and serially in 27 patients who had samples taken both before and 24 h after radiofrequency ablation (RFA) for atrioventricular nodal re-entry tachycardia (AVNRT), atrial fibrillation (AF) or right atrial flutter (AFL).

Results

Significant increases of hs-cTnT were seen in patients after RFA (AVNRT: P = 0.0115, AF: P = 0.0011, AFL: P = 0.0009). Postprocedural serum hs-cTnT correlated with the number of radiofrequency applications and with the duration of RFA procedure. Spearman's coefficient of rank correlation ( r) were as follows: hs-cTnT versus RFA duration: r = 0.771 ( P < 0.001); hs-cTnT versus number of pulses: r = 0.708 ( P < 0.001). Patients with the diagnosis of AVNRT had lower serum hs-cTnT concentration after RFA compared with AFL ( P < 0.0001) and AF ( P < 0.0001) patients.

Conclusions

Our data indicate that RFA causes a significant increase of serum hs-cTnT concentration that could be used to monitor myocardial injury.

Difference in Humoral Biomarkers for Myocardial Injury and Inflammation in Radiofrequency Ablation versus Cryoablation

BACKGROUND

Markers of myocardial injury and inflammation have been shown to be elevated following radiofrequency (RF) ablation. This study aimed to compare RF ablation and cryoablation for their impact on markers for myocardial injury and inflammation.

METHODS

Nineteen patients received catheter ablation for atrial flutter by either cryoablation (10 patients) or open-irrigated RF ablation (nine patients). Venous blood samples for troponin T (TnT), creatinkinase (CK), and the cardiac isoenzyme MB (CKMB) were obtained before, at six hours after the end of ablation, and the following day. C-reactive protein (CRP) levels were measured before ablation and the following day.

RESULTS

Bidirectional isthmus block was achieved in all patients. Cryoablation showed significantly higher TnT following ablation (0.85 microg/l +/- 0.39 microg/l) compared to RF ablation (0.36 microg/l +/- 0.24 microg/l; p= 0.01) with declining levels the following day (cryoablation: 0.58 microg/l +/- 0.20 microg/l; RF ablation 0.34 microg/l +/- 0.21 microg/l; p= 0.03). We observed equal findings for CK and CKMB, both significantly higher in cryoablation. RF ablation led to a nonsignificant rise in CK and CKMB. CRP was elevated significantly higher following RF ablation (12.3 mg/dl +/- 4.1 mg/dl) compared to cryoablation (6.9 mg/dl +/- 4.0 mg/dl; p= 0.01).

CONCLUSIONS

We show reduced inflammation despite higher markers for myocardial injury in cryoablation. The difference in biomarkers reflects different lesion formation in cryoablation and RF ablation. Cryoablation shows less systemic inflammatory reaction. This might be due to less endothelial damage and surface thrombosis in cryoablation.