Left atrial functions in the early period after cryoballoon ablation for paroxysmal atrial fibrillation

Introduction

In patients with paroxysmal atrial fibrillation (PAF), functional changes are observed in the left atrium (LA) after pulmonary vein isolation (PVI) with catheter ablation. Although previous studies have investigated the altered mechanical functions of LA with radiofrequency (RF) ablation, changes in LA functions in the early period after cryoablation have not been clearly demonstrated.

Methods

Thirty three patients (mean age: 57±11; 54.5% men) with PAF underwent cryoablation procedure with second generation cryoballoon (CB-2). All patients were in sinus rhythm before and after the procedure. LA dimensions, LA strain parameters (LAsr-LAscd-LAsct) and left ventricular diastolic function parameters were evaluated by Doppler echocardiography before and 3 months after the procedure.

Results

Acute procedural success was achieved in all cases. No major complications were occurred. A significant recovery in LA reservoir strain (p=0.009) was observed. No significant change was demonstrated in remaining echocardiographic parameters.

Conclusion

LA reservoir strain is an indicator of left atrial compliance and significant improvement in mechanical functions may occur even in the early period after cryoballoon ablation in patients with PAF in contrast to LA function deterioration observed in RF ablation.

Funding Acknowledgement

Type of funding sources: None.

EGM characteristics of intramural outflow tract ventricular arrhythmias

Funding Acknowledgements

Type of funding sources: None.

Introduction

Successful ablation of outflow ventricular premature contractions (VPC) depends on the identification of earliest activation. Annotation of bipolar (bi) EGMs can be challenging for especially multicomponent EGMs. Universally, annotation of earliest depolarization which depends on maximum dV/dt of unipolar (uni) EGMs and uni-QS morphology identify site of origin for VPC. However, identification of uni-QS morphology has limitations due to low spatial resolution. Additionally, time difference between bi- and uni-EGM can be observed and may be associated with deeper origin. Aim of this study is to compare EGM characteristics at successful ablation site in RVOT and RVOT+LVOT VPC ablation cases.

Methods

In this retrospective study, 40 patients who underwent successful RFA for RVOT and RVOT+LVOT VPCs were included. Local activation time (LAT), duration and voltage data of each bi- and uni-EGM at the successful ablation sites from RVOT and RVOT+LVOT cases were analyzed.

Results

28/40 (70%) of patients were ablated from RVOT and in 12/40 (30%) required both side ablation. All patients had acute PVC suppression. Bi-EGM-QRS onset was earlier (36.2±13.8 ms vs 28.8±7.3 ms, p=0.03), duration of bi-EGM was shorter (58.2±19.6 ms vs 83.8±22.3 ms, p=0.003) and Bi-voltage amplitude was higher (3.1±2.4 mV vs 1.2 ±0.9 mV, p=0.01) for patients with RVOT only ablation. Mean Bi-Uni EGM difference was 5.6±5.1ms in the RVOT group vs 13.5±5.4 ms in RVOT+LVOT group (p<0.001). Uni-QS morphology was recorded in 3.6±4.5 vs 3.3±1.9 cm2 in RVOT and RVOT+LVOT group respectively (P=0.80). In 11/40 (28%) of patients uni-QS was not identified at successful ablation site.

Conclusion

QS in uni-EGM was not a perfect predictor for successful ablation sites. Analysis of bipolar voltage amplitude and duration with Bi-uni EGM time difference may identify deeper source.

Effects of obesity on survival in patients with implantable cardioverter defibrillator

Background

Studies have shown that increased body weight and obesity may be associated with an increased risk of arrhythmic events. However, studies conducted in patients with implantable cardioverter-defibrillator (ICD) have found that low body mass index (BMI) is associated with higher mortality. The aim of this study is to evaluate the effect of obesity on the risk of arrhythmic events, hospitalization and death in patients receiving ICD therapy for primary or secondary prevention.

Methods

The study was designed as a single-center prospective and observational. Patients with BMI <30 kg/m2 were classified as non-obese and patients with ≥30 kg/m2 as obese. The primary endpoints were all-cause mortality, cardiac mortality, and cardiac rehospitalization.

Results

Among the total of 340 patients, 78.2% were male, 21.8% were female, and the mean age of the patients was 60.9 years. Among all patients, there were 30.6% normal weight, 47.4% overweight and 22.1% obese patients. AF recording was significantly higher in obese patients compared to the normal weight patient group (p=0.02). Shock, appropriate shock, and liquid load sensing were statistically higher in obese than non-obese patients (p=0.042, p=0.011 and p=0.007). In the primary prevention group, all-cause mortality and cardiac mortality rates were lower in the obesity group (p=0.022, p=0.037).

Conclusion

Our findings showed that although cardiac arrhythmic events are more common in obese patients, mortality and hospitalization events are less common in obese patients. These findings are consistent with the reverse epidemiology that has been demonstrated previously between obesity and mortality

Funding Acknowledgement

Type of funding sources: None. Events obtained from device controlSurvival normal weight and overweight

Effect of general and local anesthesia on the vagal response characteristics during ganglionated plexus ablation

Funding Acknowledgements

Type of funding sources: None.

Background

The effect of different anesthetics on the function of the autonomic nervous system (ANS) is not well known. As a relatively new treatment option, ganglionated plexus (GP) ablation aims to modify the behavior of the cardiac ANS to prevent some/all of the autonomic processes occurring in vasovagal syncope (VVS) by using endocardial ablation techniques.

Purpose

The purpose of this study was to determine the effects midazolam and propofol on the vagal response (VR) characteristics during GP ablation in patients with vasovagal syncope (VVS).

Methods

Forty consecutive patients undergoing GP ablation for VVS were divided to receive local anesthesia with midazolam (group 1, n = 29) or general anesthesia with propofol (group EA, n = 11). All GP sites were detected by using previously defined fragmented electrogram based strategy. VR was defined on 3 levels: 1) R-R interval increased by 50% (level 1); 2) R-R interval increased by 20-50% (level 2); and 3) R-R interval increase lower than 20% (level 3).

Results

Baseline characteristics and mean follow-up times were comparable between groups. In both groups, the left superior GP (LSGP) was the most common GP site at which a VR was observed. However, there was a significant difference between groups for level of VR. While ablation on the LSGP caused a level 1 VR in 89.6% of cases in group 1, level 1 VR was seen in 22.2% of cases in group 2 (p < 0.0001). Similarly, ratio of level 1 VR during ablation on the left inferior GP (LIGP) was significantly lower in group 2 (44.8% vs 9%, p = 0.034). Once cut-off for VR was decreased to level 2, the ratio of (+) VR increased to 90.9% during ablation on the LSGP in group 2. Level 2 VR was detected in 45.4% of cases during ablation on the LIGP. Ratio of positive VRs in any level was lower than 20% during ablation on the right superior and inferior GPs in both groups. During a mean follow-up time of 12.1 ± 7 months, all but 2 (5%) of 40 patients were free of syncope.

Conclusions

The autonomic nervous tone might be affected in different ways by local and general anesthesia. Propofol may reveal a shift in the sympathovagal balance toward sympathetic predominance which may cause a blunting on VR during GP ablation. Further randomized, controlled and multicenter studies should be performed to confirm these findings.

Why is neuromodulation effect of pulmonary vein isolation not same in all cases?

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiac ganglionated plexi (GPs) of the autonomic system are primarily located in major epicardial fat pads adjacent to the left atrium and pulmonary vein junctions. These structures may play a central role in both the initiation and maintenance of atrial fibrillation (AF). Previous studies reported modification of GPs during pulmonary vein isolation (PVI) may increase rate of sinus node and AF-free survival. However, a deficiency certainly existed why is modification of GPs observed in some patients during PVI but not in others?

Purpose

We aimed to evaluate ratio of ablation points within classical antral circumferential ablation lines for PVI and distribution of 4 major atrial ganglionated plexus.

Methods

Thirty-eight consecutive patients undergoing ablation of GP for vagally mediated bradyarrhythmias were evaluated. All GP sites were detected by using previously defined fragmented electrogram based strategy which is a validated tool when compared with a combination of spectral analysis and high frequency stimulation to detect GPs. Estimated ablation lines for antral circumferential ablation was defined as a circumferential isolation line performed ≥1 cm away from the pulmonary vein ostium as identified by 3D electroanatomical reconstruction (Figure 1). The total number of ablation points in each GP sites and ratio of ablation points within estimated antral circumferential ablation lines were recorded.

Results

The great majority of ablation points were detected at the insertion of the right pulmonary veins. Number of ablation points in each GP site in descending order is as follows: (1) the right superior GP = 13.6 ± 6; (2) the left superior GP = 10.5 ± 5; (3) the right inferior GP = 5.9 ± 4; and (4) the left inferior GP = 2.5 ± 3. The ratio of ablation points within estimated antral circumferential ablation lines was higher in right-sided GPs (50.5%±24 for the right superior GP and 30.2%±31 for the right inferior GP vs 18.3%±24 for the left superior GP and 11.6%±26 for the left inferior GP. Figure 2 demonstrates total number of ablation points and the ratio of ablation points within estimated antral circumferential ablation lines in each GP site.

Conclusions

The present study shows that individual variability of distribution of GPs and how antral ablation was done during PVI might be the main contributors of neuromodulation effect. Further randomized, controlled and multicenter studies should be performed to confirm these findings. Abstract Figure 1