A case of unexpected early battery depletion caused by lithium cluster formation in implantable cardioverter-defibrillator.

Device failure from unexpected battery depletion is uncommon but can be life-threatening. Lithium cluster formation at the cathode is a novel mechanism of sudden implantable cardioverter-defibrillator (ICD) battery depletion that was first reported in 2014. We report a rare case of a 78-year-old woman with an ICD battery failure due to lithium cluster formation. Although she had never received ICD therapy, the battery voltage had dropped from 2.9 V to 2.54 V (end of life) unexpectedly for only 2 days. The prevalence of this rare phenomenon was reported to be 0.004% in 2014. However, it had gone up to 0.21% in October 2016. Both device manufacturers and clinicians should be aware of this phenomenon, and remote monitoring systems and vibratory patient notifier alerts should be considered for early detection and early treatment. <Learning objective: Lithium cluster formation is a novel mechanism of premature ICD battery depletion that was first reported in 2014. Although the prevalence of this rare phenomenon was first reported as 0.004% in 2014, according to the data of St. Jude Medical, it had gone up to 0.21% in October 2016. We should be aware of this rare but important phenomenon and use remote monitoring systems and vibratory patient notifier alerts for early detection and treatment.>.