Find me if you can: lessons learned using the novel cartofinder algorithm in a routine workflow for catheter ablation of atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Background

CARTOFINDER allows for a simultaneous and automated detection of repetitive focal and rotational activations during electroanatomical mapping using a multi-electrode catheter in patients with atrial fibrillation (AF).

Aim

This study aimed to validate the CARTOFINDER algorithm for the detection of potential drivers for AF under routine clinical conditions and to access the effects of PVI and additional substrate modification on regions of interests (ROI) from CARTOFINDER mapping.

Methods

Forty-four consecutive patients underwent AF ablation for persistent AF using a 3D-mapping system with the novel integrated CARTOFINDER module. All patients presented with persistent AF and mapping was performed using a multi-electrode catheter. The ablation workflow was divided into the following steps: 1. 3D reconstruction of the right (RA) and left atrium (LA). 2. Identification of the individual ROIs separated for focal and rotational activity in the RA and LA. 3. Ablation index guided pulmonary vein isolation (PVI). 4. Repeat mapping for ROIs in the RA and LA. 5. Direct current electrical cardioversion. 6. Confirmation of persistent PVI and bipolar ultra-high density mapping of the RA and LA followed by substrate modification if there was evidence for local bipolar low-voltage in the LA.

Results

Acute PVI was achieved in all patients (100%). In 28% of these patients additional LA substrate modification was performed. AF termination was observed in 4 patients. Mean procedure duration was 137 ± 30 min, mapping time for ROIs in the RA was 8 ± 5 min and 11 ± 5 for the LA, respectively. A mean number of 149 ± 82 ROIs were revealed from CARTOFINDER. In the LA, focal activity was predominantly observed inside the LA appendage (LAA) and in close relationship to the pulmonary vein ostia. The majority of rotational activities was found along the mitral valve annulus. In the RA, the majority of ROIs was found at the septum and in close relationship to the RA appendage. During re-mapping for ROIs after AF ablation we observed the elimination of ROIs close to the linear ablation set for PVI. In addition, rotational activity could not be re-identified at repeat mapping.

Conclusions

ROIs could be discriminated and visualized utilizing CARTOFINDER in all patients. These ROIs might potentially be an additional and individual ablation target beyond PVI in patients with persistent AF.

The histone deacetylase inhibitor SAHA acts in synergism with fenretinide and doxorubicin to control growth of rhabdoid tumor cells

BACKGROUND

Rhabdoid tumors are highly aggressive malignancies affecting infants and very young children. In many instances these tumors are resistant to conventional type chemotherapy necessitating alternative approaches.

METHODS

Proliferation assays (MTT), apoptosis (propidium iodide/annexin V) and cell cycle analysis (DAPI), RNA expression microarrays and western blots were used to identify synergism of the HDAC (histone deacetylase) inhibitor SAHA with fenretinide, tamoxifen and doxorubicin in rhabdoidtumor cell lines.

RESULTS

HDAC1 and HDAC2 are overexpressed in primary rhabdoid tumors and rhabdoid tumor cell lines. Targeting HDACs in rhabdoid tumors induces cell cycle arrest and apoptosis. On the other hand HDAC inhibition induces deregulated gene programs (MYCC-, RB program and the stem cell program) in rhabdoid tumors. These programs are in general associated with cell cycle progression. Targeting these activated pro-proliferative genes by combined approaches of HDAC-inhibitors plus fenretinide, which inhibits cyclinD1, exhibit strong synergistic effects on induction of apoptosis. Furthermore, HDAC inhibition sensitizes rhabdoid tumor cell lines to cell death induced by chemotherapy.

CONCLUSION

Our data demonstrate that HDAC inhibitor treatment in combination with fenretinide or conventional chemotherapy is a promising tool for the treatment of chemoresistant rhabdoid tumors.