A sea of troubles: upgrade of ICD to CRT-D in a patient with ischemic cardiomyopathy

This is a case describing a 54-year-old Chinese male with ischemic cardiomyopathy (ICM) coexisting with electrical and mechanical dyssynchrony and an implantable single-cavity cardioverter-defibrillator (ICD). The patient was admitted to our hospital for upgrade to cardiac resynchronization therapy defibrillator (CRT-D). Many difficulties were encountered during the process of ICD upgraded CRT-D, which including the left subclavian venous anomalous, the left brachiocephalic stenosis, coronary sinus (CS) Thebesian valve (TV), phrenic nerve stimulation, screw loosening, and mechanical dyssynchrony resulting from atrial tachycardia. Each of these difficulties may be encountered during an operation, but all difficulties are rare at the same time. Therefore, this case has clinical education value.