AV-node isolation in atrial fibrillation vs AV-node ablation by pace and ablate strategy

Funding Acknowledgements

Type of funding sources: None.

Introduction

AV-node ablation (AVNA) is a common therapy option for rate control strategy of permanent atrial fibrillation. However, this therapy has numerous side-effects as bundle branch blocks and absence of escape rhythm. We have invented a new technique that isolates the AV node instead of ablation.

Methods

Our study includes 60 patients with 40 being treated with AVNA and 20 being treated with AV-node isolation (AVNI). In AVNI patient´s AV-node region was mapped using 3D navigation system. Ablation was performed around the previously mapped HIS-cloud regions isolating the atrium from the AV-node. In all cases in AVNI group ablation was performed with irrigated tip ablation catheter.  Procedure time, ablation points, fluoroscopy time and total DAP, escape rhythm and delta QRS among other data were measured and compared in these two methods. Statistical analysis was performed by SPSS software 27.0.

Results

No complications appeared in this study. In the AVNI group more ablation points were used (p < 0.01) but there was no significant difference in total procedure time (p = 0.730). With AVNI highly significantly less fluoroscopy time (1.4 vs. 4.7 minutes) and total DAP (40.75 vs. 382.85 µGym²) was achieved (p < 0.01). Moreover, the median change in QRS width was 0 ms in the AVNI group vs. 26 ms in the AVNA group (p < 0.01). Immediately postoperative the escape rhythm of the AVNI group was significantly higher than in the AVNA group (MRang = 37.38 vs. MRang = 27.06, p = 0.023).

Conclusion

AV-node isolation using 3D navigation mapping system is a safe and effective alternative to classic AVNA procedure with less radiation exposure and potential preservation of escape rhythm, which is a major benefit in case of a pacemaker failure.

Figure 1. 3D Navigation pictures after successful AVNI with NavX-System (left panel) and CARTO 3-System (right panel). His cloud with yellow points. The Tricuspid annulus could be defined with different color (green on the left panel) or with the tag points (white points on the right panel). Modified left lateral to posterior view. Abstract Figure.

Postoperative Betreuung von Patienten nach alloprothetischem Herzklappenersatz

Despite enormous progress concerning material and design, patients with artificial heart valves still face a considerable risk of serious complications (e. g. hemorrhage, thromboemboli, redos) which sum up to 5-20% within the first 10 postoperative years depending on type and position of the implanted prosthetic valve. Nowadays technical defects of mechanical valves are negligible and relevant complications are most frequently the consequence of inappropriate oral anticoagulation therapy. To avoid these complications a strict control of both the anticoagulation therapy and the functional integrity of the prosthetic valve is mandatory. Therefore with the aim of risk minimization the patient should be enabled to cooperate by means of methods which are easy to handle in his everyday environment. We present a reliable method for early detection of prosthetic valve dysfunction which can be applied daily with minimal effort by the patient himself.

Home Monitoring of Patients after Prosthetic Valve Surgery - Experimental Background and First Clinical Attempts

PURPOSE

The purpose of this study was to investigate whether: 1. sound phenomena may be used to detect prosthetic valve dysfunction; 2. clinical and experimental data permit conclusions about alterations in the functional state of mechanical valves; 3. patients can record and pass on signals via Internet.

METHODS

1. We implanted bi-leaflet valves in pigs. By gradually influencing the motion of the tilting discs prosthetic dysfunction could be generated. 2. Thrombosis and lysis of bi-leaflet valves was studied in sheep. This process was documented using echocardiography and acoustically by the Fast Fourier Transformation. 3. Thirty devices were set up and handed out to patients following mechanical valve replacement. All patients regularly sent data to the hospital via Internet, regardless of their location at the time. The data were evaluated by comparing them with the reference file.

RESULTS

Animal experiments proved that changes in prosthetic function led to a significant change in sound phenomena. In contrast to echocardiography alterations at an early stage (onset of thrombosis) could be reliably verified. The sensitivity was greater than in echo-control analysis. All patients regularly recorded and passed on their signals. Surveys revealed high acceptance and easy handling of the devices.

CONCLUSIONS

Online registration of sound phenomena seems to be suitable for the detection of changes in prosthetic function. This led to the development of the first hand-held device for home monitoring of valve function. Registration of flow, frequency spectrum, and ECG envisaged at the next level opens up potential applications for Internet-based, remote monitoring of cardiac patients.

Aortic Dissection After Previous Coronary Artery Bypass Grafting

Aortic dissection after coronary artery bypass grafting (CABG) is a rare but potentially fatal complication. The aim of this study was to identify the reasons. Between 1991 and 2000 in our institution CABG was performed on 22,732 patients. In the same time interval 12 (0.5 degree/00) patients presented with an aortic dissection after previous CABG. Age: 59.1 +/- 5.9 years, gender: 10/2, only Stanford A dissections, 4 chronic and 8 acute dissections, mortality: 3, all acute. 2 died of cardiac complications (left heart failure), 1 of other complications (gastrointestinal ischemia). The time interval between CABG and dissection was 2.5 +/- 3.6 years. Two dissections were intraoperative, another 5 were within the first year; the longest time interval was 10 years. In 5 cases the entry originated from a central anastomosis, 1 originated from the aortic cannulation site, and 1 from the site of the cross clamping. In 5 cases the entry was not directly related to the previous operation (1 was located in close proximity to the left coronary ostium, 2 between aortic valve annulus and the coronary ostia and 2 between the distal coronary arteries in the ascending aorta). Pathological changes of the aorta were not described at the time of CABG; only in 1 case a mild aortic regurgitation and dilatation (47 mm) at the time of the first operation was described. As our results suggest an aortic dissection presenting after CABG must be considered to be a rare complication of the previous operation. Considering the severity of this complication satisfying results can be achieved.

Aortic valve surgery following previous coronary artery bypass grafting. Impact of calcification and leaflet movement

We reviewed the reports of 27 patients who had an aortic valve replacement after previous coronary artery bypass grafting. The aortic valve disease -- mainly aortic stenosis -- showed a rapid rate of progression. In the time interval between coronary artery bypass grafting and aortic valve replacement of 4.6+/-2.2 years the peak-to-peak pressure gradient of the aortic valve rose from 20.2+/-14.3 to 63.0+/-22.7 mmHg. As there is a great interest to identify the patients with a high risk of a rapid progression because of a high mortality of an aortic valve replacement as the second cardiac operation following a coronary artery bypass grafting we also reviewed the cardiac catheterisation films and found a high incidence of calcification and impaired aortic valve motion (81.5% of the patients had already calcified aortic valves and 81.5% had a impaired valve motion) at the time of coronary artery bypass grafting. We concluded that if a patient has to be operated for coronary artery disease an aortic valve replacement should be considered not only according to hemodynamic criteria but also when the aortic valve is calcified or its leaflets' motion is impaired.