The impact of biofilm formation on implantable cardiac devices

Introduction: biofilm is a culture of sessile bacteria, isolated from the external world, capable of internal communication and signalization, which allow for the development of phenotypic changes to adapt to hostile environments. Given its easy pathogenic dissemination, biofilms can develop in prosthetics and implantable medical devices, forming focal nosocomial infections. Objective: to comprehend biofilm formation mechanisms in implantable cardiac devices in an intra-hospital environment, as well as the treatment and prophylactic measures to treat this condition. Materials and methods: descriptive and observational exploratory study based on a literary review on biofilm formation, its consequences in a hospital environment, and infections caused by proliferation on implantable cardiac devices. In total, 28 articles were selected using the following descriptors: ((nosocomial) AND (cardiac)) AND (devices). Results: biofilm grows in an uneven form, being influenced by strain and environment. It has a high virulence when it comes to growing on implantable cardiac devices considering its ability to adhere to biotic and abiotic surfaces. Immunosuppression and the lack of surgical sterilization are factors that can contribute to complications associated with the use of these devices, such as infectious endocarditis. Conclusion: biofilm, due to its pathogenicity and virulence, is a serious though rare complication in patients that use implantable devices. There is evidence that contamination occurs mainly in surgical environments, making it necessary the application of more rigorous sterilization techniques.

Temporary device malfunction of an MR conditional cardiac resynchronization defibrillator when undergoing MRI without appropriate re-programming: a case report

Background Magnetic resonance (MR) imaging (MRI) for patients with implantable cardiac devices is becoming more routine, with the development of MR conditional devices allowing more patients access to the imaging they need. However, for this to be performed safely, strict protocols must be followed necessitating close collaboration between cardiology and radiology departments. We present a case where mandatory device re-programming of a cardiac resynchronization therapy defibrillator device into MRI mode was not performed pre-scan leading to temporary device dysfunction with no clinical consequences. Case summary A 72-year-old man presented to a device clinic for a routine device interrogation. An atrial tachycardia response episode was recorded at the same time as the patient reported having undergone an MRI scan at a local centre. The electrogram demonstrated temporary right ventricular loss of capture with standard output programming, and a short episode of oversensing on the atrial and ventricular channel which was not sustained for long enough to meet tachycardia detection. Discussion We demonstrate two potential electrophysiological effects of MRI on pacemakers, where the device had not been appropriately re-programmed pre-procedure. This illustrates that whilst MRI in patients with implantable cardiac devices is safe, strict protocols must be followed requiring robust multidisciplinary communication.