The utility of shock coil and left ventricular tip-right ventricular coil impedance as a predictor of pneumothorax in cardiac resynchronization therapy implantation.

A high defibrillation threshold (DFT) infrequently occurs during device implantation. The major cause of high DFT is pneumothorax. However, there are few data about shock coil and left ventricular tip-right ventricular coil (LV tip-RV coil) impedance as a marker of a high DFT caused by pneumothorax. A 65-year-old man, diagnosed with dilated cardiomyopathy, was referred for cardiac resynchronization therapy (CRT) defibrillator implantation with single shock coil lead. The shock coil impedance was high and LV tip-RV coil impedance was normal just before DFT test. Then, high DFT was detected. Afterwards, pneumothorax was found. After the treatment of the pneumothorax, the shock coil impedance decreased. However, the LV tip-RV coil impedance did not change. This discrepancy can be a useful predictor of the high DFT caused by pneumothorax. With these markers, we can predict high DFT and consequently can treat pneumothorax earlier without the unnecessary shock delivery. <Learning objective: Cardiac resynchronization therapy (CRT) implantation is widely performed. Pneumothorax is one of the complications of CRT implantation. High defibrillation threshold (DFT) is known as a predictor of the pneumothorax. However, the predictor of this complication has not fully been evaluated. The high shock coil impedance combined with normal left ventricular tip-right ventricular coil impedance can be a useful predictor of the high DFT caused by pneumothorax.>.