Implementation of a zero fluoroscopic workflow using a simplified intracardiac echocardiography guided method for catheter ablation of atrial fibrillation, including repeat procedures

Objective: Pulmonary vein isolation (PVI) is the cornerstone of the interventional treatment of atrial fibrillation (AF). Traditionally, during these procedures the catheters are guided by fluoroscopy, which poses a risk to the patient and staff by ionizing radiation. Our aim was to describe our experience in the implementation of an intracardiac echocardiography (ICE) guided zero fluoroscopic (ZF) ablation approach to our routine clinical practice. Methods: We developed a simplified ICE guided technique to perform ablation procedures for AF, with the aid of a 3D electroanatomical mapping system. The workflow was implemented in two phases: (1) the Introductory phase, where the first 16 ZF PVIs were compared with 16 cases performed with fluoroscopy and (2) the Extension phase, where 71 consecutive patients (including repeat procedures) with ZF approach were included. Standard PVI (and redoPVI) procedures were performed, data on feasibility of the ZF approach, complications, acute and 1-year success rates were collected. Results: In the Introductory phase, 94% of the procedures could be performed with complete ZF with a median procedure time of 77.5 (73.5-83) minutes. In one case fluoroscopy was used to guide the ICE catheter to the atrium. There was no difference in the complication, acute and 1-year success rates, compared with fluoroscopy guided procedures. In the Extension phase, 97% of the procedures could be completed with complete ZF. In one case fluoroscopy was used to guide the transseptal puncture and in another to position the ICE catheter. Acute success of PVI was achieved in all cases, 64.4% patients were arrhythmia free at 1-year. Acute major complications were observed in 4 cases, all of these occurred in the redo PVI group and consisted of 2 tamponades, 1 transient ischemic attack and 1 pseudoaneurysm at the puncture site. The procedures were carried out by all members of the electrophysiology unit in the Extension phase, including less experienced operators and electrophysiology fellows (3 physicians) under the supervision of the senior electrophysiologist. Consequently, procedure times became longer [90 (75-105) vs 77.5 (73.5-85) min, p = 0.014]. Conclusions: According to our results, a ZF workflow of AF ablations can be successfully implemented into the routine practice of an electrophysiology laboratory, without compromising safety and effectivity.</p

DOX protects against the H₂O₂–induced cell death.

<p>A wide range of doxycycline concentrations (50 nM, 100 nM, 300 nM, 1 μM, 10 μM) were applied to H₂O₂ –stressed (0.3 mM, 3h) H9c2 cells. All concentrations of DOX significantly improved the cell viability (**P < 0.01).</p

Representative echocardiographic M-mode images of left ventricles of control, DOX, ISO and ISO+DOX groups.

<p>Representative echocardiographic M-mode images of left ventricles of control, DOX, ISO and ISO+DOX groups.</p

Mitochondrial depolarization and fragmentation in H9c2 cardiomyocytes.

<p><b>(A)</b> Mitochondrial fragmentation was induced in H9c2 cells after incubation with 400 μM H₂O₂ for 5 hours, at which time the mitochondrial filaments disappeared and fragmented mitochondria with lengths shorter than 2 μm were observed instead. Doxycycline reduced or completely prevented ROS—induced mitochondrial fragmentation at the concentration of 5 μM. <b>(B)</b> DOX protected H9c2 cells from apoptosis by preventing the depolarization of the mitochondrial membrane. Green and red fluorescence images of the same field were acquired using a fluorescent microscope equipped with a digital camera. The images were merged to demonstrate depolarization of Δψ in vivo, indicated by loss of the red component of the merged image. Some red fragments can also be seen, representing the fragmented mitochondria. Representative merged images of three independent experiments are presented (#P < 0.05, C vs. H₂O₂ and *P < 0.05, H₂O₂ vs. DOX+H₂O₂).</p

DOX favorably modulates the expression of Mfn-2, OPA-1 and the phophoryltaion of Drp-1.

<p>Representative western blot analysis of Mfn-2, OPA-1, Drp-1 and pDrp-1^Ser616 and densitometric evaluation is shown. PhosphoDrp-1^Ser616 bands were normalized to the appropriate Drp-1 bands. Representative blots and bar diagrams of three independent experiments are presented. C: control animals, ISO: animals 8 weeks after ISO administration; ISO + DOX: animals treated with doxycycline, 8 weeks after ISO administration; DOX: animals treated with doxycycline for 8 weeks. Values are mean ± SEM. # P < 0.05 vs control, *P < 0.05 vs. ISO.</p

DOX reduces ISO–induced interstitial collagen deposition and protein nitrosylation in ISO–induced heart failure.

<p><b>(A)</b> Sections stained with Masson’s trichrome (scale bar: 500μm, magnifications 5-fold). Control: age-matched rats, DOX: age-matched animals treated with doxycycline for 8 weeks, ISO: age-matched animals 8 weeks after ISO administration, ISO+DOX: age-matched animals treated with doxycycline, 8 weeks after ISO administration. Values are mean ± SEM. #P < 0.05 (ISO vs. control group), *P < 0.05 (ISO+DOX vs. ISO group). <b>(B)</b> Representative immunohistochemical stainings for nitrotyrosine (NT, brown staining, scale bar: 500μm, magnifications 5-fold) in the myocardium of control: age-matched rats, DOX: age-matched animals treated with doxycycline for 8 weeks, ISO: age-matched animals 8 weeks after ISO administration, ISO+DOX: age-matched animals treated with doxycycline, 8 weeks after ISO administration. Values are mean ± SEM. #P < 0.05 (ISO vs. control group), *P < 0.05 (ISO+DOX vs. ISO group).</p

Effect of doxycycline on the Ventricular Weight/Tibia Length (VW/TL) ratio and on plasma BNP.

<p>Effect of doxycycline on the Ventricular Weight/Tibia Length (VW/TL) ratio and on plasma BNP.</p

Effects of doxycycline on the echocardiographic parameters.

<p>Effects of doxycycline on the echocardiographic parameters.</p

Pharmacological PARP-1 inhibition attenuated oxidative damage and cell loss in dorsal hippocampus.

<p>(A) PAS staining to evaluate structural alterations of the dorsal hippocampus and fissural vessels. *: Lateral cerebral ventriculus (scale bar: 200 μm). (B) NT and (C) HNE staining of CA1 regions for the evaluation of nitrosative damage and lipid peroxidation of pyramidal neurons in the dorsal hippocampus (scale bar 50 μm). (D) Representative micrographs of CA1 region of the dorsal hippocampus with Cresyl violet staining (scale bar 50 μm). (E) Pyramidal neuron number in the CA1 region of dorsal hippocampus. (F-H) Representative micrographs of immunostaining for (F) 8-oxG, (G) PAR and (H) GFAP (scale bar 50 μm) «: perivascular white matter damage. (I) TUNEL positive neurons and (J) numbers relative to pyramidal cells in the CA1 region of dorsal hippocampus (scale bar 50 μm). (F-H) ► points to positively stained cell. Data are presented as mean±S.E.M. ##p<0.01 vs. WKY-C; *p<0.05, **p<0.01 vs. SHRC.</p

Representative micrographs of fluorescent staining for AIF and NF-kB cellular distribution and MKP-1 expression.

<p>(A-D) Nuclear translocation of AIF in carotid artery walls of (A) WKY-C, (B) WKY-L, (C) SHR-C and (D) SHR-L animals (scale bar: 10 μm). (E-F) Cellular level of MKP-1 in (E) WKY-C, (F) WKY-L, (G) SHR-C and (H) SHR-L animals (scale bar: 25 μm). (I-L) Subcellular distribution of NF-kB in (I) WKY-C, (J) WKY-L, (K) SHR-C and (L) SHR-L animals (scale bar: 10 μm).</p