Neurohumoral Markers of Cardiac Autonomic Denervation after Surgical Ablation of Long-Standing Persistent Atrial Fibrillation.

Although the autonomic nervous system has an evident impact on cardiac electrophysiology and radiofrequency ablation (RFA) is the conventional technique for treating persistent atrial fibrillation, the specific effects of RFA have been insufficiently studied to date. Here, we investigated whether RFA affects neurohumoral transmitter levels and myocardial 123I-metaiodobenzylguanidine (123I-MIBG) uptake. To perform this task, we compared two groups of patients with acquired valvular heart disease: patients who had undergone surgical AF ablation and patients with sinus rhythm. The decrease in norepinephrine (NE) level in the coronary sinus had a direct association with the heart-to-mediastinum ratio (p = 0.02) and a negative correlation with 123I-MIBG uptake defects (p = 0.01). The NE level decreased significantly after the main surgery, both in patients with AF (p = 0.0098) and sinus rhythm (p = 0.0039). Furthermore, the intraoperative difference between the norepinephrine levels in the ascending aorta and coronary sinus (ΔNE) of -400 pg/mL was determined as a cut-off value to evaluate RFA efficacy, as denervation failed in all patients with ΔNE < -400 pg/mL. Hence, ΔNE can be utilized to predict the efficacy of the "MAZE-IV" procedure and to assess the risk of AF recurrence after RFA.

Pulmonary Veins Morphometric Characteristics and Spatial Orientation Influence on Its Cryoballoon Isolation Results.

The aim of this paper is to evaluate the effect of pulmonary vein (PV) morphometric characteristics and spatial orientation on the results of cryoballoon ablation (CBA). Methods: A randomized, prospective, single-center controlled study was conducted, enrolling 230 patients with drug-refractory atrial fibrillation (AF). We compared procedural and long-term outcomes in patients who underwent their first procedure of pulmonary vein isolation (PVI) for AF with either radiofrequency ablation (RFA) (n = 108) or CBA (n = 122) and assessed their interaction with the different pattern of PV anatomy, morphometric characteristics, and spatial orientation. The primary efficacy endpoint was any documented atrial arrhythmia recurrence (AF, atrial flutter, or atrial tachycardia) lasting over 30 s during a 12-month follow-up after a 90-day blanking period and discontinuation of antiarrhythmic drugs. The procedure's endpoint was the achievement of PVI. Before the intervention, all patients underwent computed tomography (CT) to assess the PV anatomical variant, maximum and minimum diameters of the PV's ostia, their cross-sectional area, orifice ovality index, and PV tilt angles. Results: The mean follow-up period was 14 months (12; 24). Long-term efficacy in the cryoablation group was 78.8% and in the RFA group­83.3% (OR = 0.74; 95% CI 0.41−1.3; p = 0.31). The RFA results did not depend on PV anatomy. The «difficult¼ occlusion of the right inferior PV (RIPV) occurred in 12 patients and was associated with a more horizontal PV position in the frontal plane; the mean tilt angle was −15.2 ± 6.2° versus −26.5 ± 6.3° in the absence of technical difficulties (p = 0.0001). In 11 cases (9%), during ablation of the right superior PV (RSPV), phrenic nerve injury (PNI) occurred and was associated with the maximum and minimum RSPV diameter, 20.0−20.4 mm (OR = 13.2; 95% CI: 4.7−41.9, p < 0.05) and 17.5−20 mm (OR = 12.5; 95% CI 3.4−51, p < 0.05), respectively. Patients with arrhythmia recurrence were characterized by significantly larger diameters and ovality of the left superior PV (LSPV). The spatial orientation of the PV does not affect the long-term results of cryoablation. Conclusion: Preprocedural evaluation of PV morphology and orientation using cardiac CT might help choose the optimal technology for the individual patient.

Influence of Internal Thoracic Artery Harvesting on Sternal Osteoblastic Activity and Perfusion.

The purpose of this study was to assess the sternal osteoblastic activity and perfusion in the early period after a coronary artery bypass graft (CABG) using single-photon emission computed tomography (SPECT) and three-phasic dynamic scintigraphy (3PDS) with 99mTc methylene diphosphonate (MDP). METHODS: The study group consisted of 57 male patients that were 57.3 ± 6.6 years of age. Thirty-six of them were randomized into two groups: in group I (n = 18), the internal thoracic artery (ITA) was skeletonized, and in group II (n = 18), the ITA was pedicled. All the patients in groups I and II underwent an off-pump CABG using 1.7 ± 0.3 grafts, including one anastomosis of the ITA to the left anterior descending coronary artery. The control group III (n = 21) consisted of patients that underwent mitral valve repair surgery, in whom the sternotomy without the ITA harvesting was performed. The 3PDS and SPECT of the thorax with 99mTc MDP were performed 2 weeks after surgery. RESULTS: The sternal phosphates uptake in group I was approximately twice as high as in group II and approximately 1.5 times higher than in group III (p < 0.05). The MDP uptake asymmetry after the ITA skeletonization was the same as in the group with both intact ITAs. In contrast, after the pedicled ITA harvesting, the osteoblastic activity of the ipsilateral side of the sternum was lower than in the contralateral one. There was no statistically significant difference in scintillation count in the xiphoid process between groups I and II (p > 0.05); however, we observed a significant difference in the manubrium and body (p < 0.05). CONCLUSION: The main factor that improved the sternal perfusion after a CABG was the preservation of branches supplying the sternum using the skeletonization technique of ITA harvesting.

Noninvasive long-term ECG monitoring vs. loop recorder implantation for the atrial fibrillation management.

OBJECTIVE: The objective of the study was to estimate the efficacy of a noninvasive ambulatory ECG monitoring (NIAM) in comparison with implantable loop recorder (ILR) in patients with atrial fibrillation (AF). METHODS: Thirty-two patients 58 [47; 73] years of age with AF were included in the study. Patients were randomized into two groups: in group I (n = 15), "Reveal XT" ILR was used for invasive ECG monitoring up to 3 months; in group II (n = 17), "Spyder" device was used for NIAM up to 14 days. RESULTS: In both groups, at least one AF episode was detected during 14 days of monitoring. The overall count of AF episodes was 25 in NIAM group and 28 in ILR group. The mean time between AF start and its registration by a physician was 8 hr in NIAM group and 20 hr in ILR group (p = .005). The diagnostic value parameters of NIAM were as follows: sensitivity-80.1%, specificity-73.1%; positive predictive value-74.1%; and negative predictive value-79.2%. The same parameters in ILR group were comparable with NIAM: sensitivity-78.6%; specificity-69%; positive predictive value-71%; and negative predictive value-77%. At the same time, continued monitoring with ILR for longer than two weeks did not lead to a significant change in the sensitivity and specificity of the method. CONCLUSION: In patients with paroxysmal AF, the diagnostic value of both NIAM and ILR is comparable. An increase in the duration of ECG monitoring for longer than two weeks does not provide additional diagnostic information.

Micromorphology of Skeletonized and Pedicled Internal Thoracic and Radial Arteries.

The objective of the study was to estimate the internal thoracic arteries (ITA) and radial arteries (RA) micromorphologic features by light microscopy after harvesting them using the skeletonization and pedicled methods in patients undergoing coronary artery bypass grafting. The micromorphologic characteristics of ITA and RA were studied by luminous microscopy in 61 patients undergoing coronary artery bypass grafting. A total of 122 ITA and RA segments harvested during surgery, fixed in formalin, and stained with hematoxiline and eosin were evaluated. The mean intima-media thickness of ITA was 9.2 and 134.7 µm and that of RA was 9.1 and 334.2 µm, respectively. In the distal segment of ITA the media-intima relation was 1.5 times bigger than in the proximal segment. None of ITA specimens contained atherosclerotic plaques or lipid inclusions. Atherosclerotic plaques were found in 3 (5%) RA specimens. Other degenerative changes were detected in 30%-74.2% of the specimens: splitting of internal elastic lamina, reduced tortuosity of the internal elastic lamina, and thickening and detachment of the intima; their incidence was associated with the skeletonization of the vessels. In conclusion, the incidence of ITA and RA degenerative changes varies from 30%-74.2% and its increase is associated with the skeletonization of the vessels, which is statistically significant. The media of the RA is 2.5 times thicker than that of the ITA (P < 0.01). This fact shows that RA has higher spasmogenic potential than that of ITA. The distal segment of the ITA has 1.5 times bigger media-intima relation than the proximal segment. Therefore, in case of enough graft length, it is recommended to avoid the distal segment and cut it off.

Mechanical function of left atrium and pulmonary vein sleeves before and after their antrum isolation.

BACKGROUND AND OBJECTIVE: Pulmonary vein (PV) sleeves are established as the main substrate taking part in the mechanisms of atrial fibrillation (AF) initiation. However, we have extremely few data concerning their physiological role in the heart contractility. The aim of the study was to estimate the mechanical function of the left atrium (LA) and PV sleeves before and early after their isolation. MATERIALS AND METHODS: A total of 17 patients with a mean age of 57.4±8.3 years who underwent PVs isolation due to AF were enrolled in the study. A day before the procedure a computed tomography (CT) of the LA and PVs and dopplerography of transmitral flow were performed. During the procedure the mechanical function of the LA and PV sleeves were estimated by transesophageal echocardiography and manometry in the left heart chambers. RESULTS: During the invasive study the patterns of the heart chambers and PV sleeves pressure were identified. These patterns confirmed the active role of the PV sleeves in LA filling and active LA relaxation during left ventricular systole. After PV isolation an alteration of transmitral blood flow and increase of LA pressure were registered. However, diastolic dysfunction was ruled out by LV manometry, thereby testifying LA mechanical function disturbance. The change in PV hemodynamics also occurred as a result of the decrease in PV sleeves contractility, revealed by manometry and paired CT scans. CONCLUSIONS: The PVs take an active part in left atrial filling by contraction of their sleeves. Antrum isolation of the PVs leads to the deterioration of their contractility and LA reservoir function.

Catheter ablation for atrial fibrillation after an unsuccessful surgical ablation and biological prosthetic mitral valve replacement: a pilot study.

BACKGROUND: Patients with mitral valve (MV) disease and atrial fibrillation (AF) undergo simultaneous prosthetic valve replacement and radiofrequency (RF) ablation procedure; however, this combinational procedure restores sinus rhythm (SR) in only 68-82% of the cases. In patients with ineffective surgical ablation, the use of a biological prosthetic valve might not only be a good choice to perform safe catheter ablation procedure in the left atrium (LA), but also provide a way to discontinue administration of oral anticoagulants. The objective of this study was to assess the efficacy of catheter ablation for AF after MV replacement with a biological prosthesis and an ineffective surgical ablation procedure. METHODS: Ten consecutive patients aged 48 ± 7 years were enrolled in this study. All patients had long-persistent AF associated with a rheumatic valve disease, which was treated by MV replacement with a biological prosthesis and a surgical RF ablation procedure. In the late postoperative period, all the patients had recurrent hemodynamically significant AF, which required repeated cardioversions. From 1 year to 3 years after the surgery, catheter ablation was performed, including reisolation of pulmonary veins (PVs) with the ablation of ganglionic plexi or linear lesions on the roof of the LA and mitral isthmus. The efficacy was assessed at 3 months, 6 months, and 12 months after the procedure. RESULTS: Restoration of SR during ablation was achieved in all of the cases. In 6-9 months, all the patients were free of arrhythmia. LA stunning manifested by the absence or decrease of the "A" wave in the transmitral flow and the retrograde wave in the PV flow was observed in nine patients with SR. In five of the patients, LA contractile function was restored in 1-6 months. Prosthetic valve dysfunction was not detected in any of the patients. CONCLUSION: Catheter ablation is an effective method for AF treatment following an ineffective surgical RF ablation procedure and biological prosthetic MV replacement. The use of bioprosthetic MVs allows for performing safe catheter ablation without subsequent prosthetic dysfunction.

'Electrical exclusion' of a critical myocardial mass by extended pulmonary vein antrum isolation for persistent atrial fibrillation treatment.

UNLABELLED: The aim of the study was to compare the efficacy of pulmonary vein antrum isolation (PVAI), extended PVAI and ganglionic plexi (GP) ablation in persistent AF. METHODS: One hundred and twenty patients 56.2 ± 8.8 years old were randomized into three groups: GP ablation (n = 37), PVAI (n = 42), and extended PVAI (n = 41). The following parameters were studied: sinus rhythm restoration, vagal reactions, fluoroscopy time, procedure duration, lesion surface area. In 16 months after the procedure, echocardiography and Holter monitoring were performed. RESULTS: Significant differences were found in the amount of X-ray exposure, procedure duration, lesion surface area and vagal reactions. In all the cases, atrial mechanical function worsened after the procedure. However, there were no significant differences between the groups. Sixteen months after the procedure, sinus rhythm without antiarrhythmic therapy was maintained in 38% of patients in GP group, in 56% of patients in PVAI group and in 69% of patients in extended PVAI group. CONCLUSIONS: In persistent AF, the extended PVAI is more effective than PVAI and GP ablation. After the PVAI or extended PVAI, abnormalities of the left atrial mechanical function occurred if the lesion area exceeded 25% of the total LA surface area.

High-amplitude pace mapping increases safety of radiofrequency catheter ablation of parahisian ectopic foci.

BACKGROUND: The objective of the study is to assess the efficacy of high-amplitude pace mapping in terms of the atrioventricular (AV) block risk after radiofrequency catheter ablation (RCA) of parahisian ectopic foci. METHODS: Twenty patients aged 38 ± 14 years with no structural heart disease underwent RCA of parahisian ectopic foci. All the patients were randomized into two groups: Group I (n = 11) had RCA performed in the region defined as ectopic focus by electrophysiology study and Group II (n = 9) had high-amplitude pacing performed in the region of "perfect" mapping. RCA was done only at the sites where high-amplitude pacing revealed the absence of His bundle capture. RESULTS: In group I, the efficacy of RCA was 54.5% and it was 100% in group II (P = 0.0195). Group II had no complications; in group I there were 27% of AV blocks (P = 0.0893). The late recurrence of ectopic activity was comparable in both groups: 3 (27%) and 2 (22%), respectively (P = 0.7953). In all the cases of recurrent ectopic activity and in all the cases of ineffective primary procedure, group I had effective reablation procedures performed using high-amplitude pace mapping. The overall efficacy in terms of repeated procedures was 90%. CONCLUSION: High-amplitude pace mapping increases primary and secondary efficacy of parahisian ectopic foci RCA and decreases the risk of AV block development. (PACE 2012;35:1458-1463).