A device, a system, and a method for diagnosis and treatment of e.g., mitral valve regurgitation. The system includes a catheter that is configured to deflect and/or steer a distal tip of the catheter inside a patient's body, a guide wire that is configured to guide the catheter in an enclosed in vivo space within the patient's body, a proximal device handle that is configured to allow the non-parallel spiral cable to switch back and forth between flexibility modes, and a treatment device that is independent of, yet still within, an instrument channel of the catheter, wherein the distal tip of the catheter further includes an inflatable balloon which may be an asymmetrical intussuscepted shape, and may be attached within a section of the distal tip of the catheter, wherein the distal tip further includes a visualization device for directly viewing an in vivo space within the patient.