Lightning-induced pacing system malfunction: a case report

Background Atmospheric electrical discharge is an extremely powerful natural phenomenon which can have dangerous and lethal effects on the human body. However, there is no evidence to indicate whether and, if so, to what extent the electric current travelling through the body can affect proper pacemaker function. Case summary An 80-year-old patient admitted to emergency department after being struck by a lightning bolt while riding a bike. The patient had a DDD pacemaker implanted 4 years prior to the incident. The ECG on admission depicted pacemaker spikes and native sinus rhythm at 50–60 b.p.m. On the 3rd day after admission the patient developed recurrent pacing-induced tachycardia. Pacemaker interrogation showed high pacing thresholds (failure to pace in the atrial channel). When the patient’s condition stabilized she was transferred to the tertiary hospital for transcutaneous lead extraction. The extracted pacing system was sent to Biotronik for thorough evaluation. Discussion Injuries due to a lightning strike are considered a rare occurrence but being struck by lightning with a pacemaker or an ICD is even less common. In the present case, the cause of cardiac arrhythmia was most probably electrical burn at the endocardial-electrode interface and a sudden elevation of the pacing threshold leading to transient pacing failure in both PM channels. To the best of our knowledge, in this case presentation we first described permanent lightning-induced pacemaker dysfunction.

Pacemaker Dysfunction due to a Large Thrombus on Ventricular Lead

Background: Pacemaker lead–related thrombosis is a rare but severe complication in patients with pacing lead implantation in the right ventricle. We present a case with recurrent syncope after single-chamber implantable cardioverter defibrillator (ICD) implantation. Pacing lead–related thrombosis was observed during open-heart surgery. This induced intermittent pacemaker dysfunction and recurrent syncope. Case Presentation: A 67-year-old male patient presented with frequent episodes of syncope and a history of dilated cardiomyopathy and paroxysmal ventricular tachycardia. Normal coronary angiography was found, and therefore a single-chamber ICD was implanted into the right ventricle to prevent cardiac events in 2013. However, he was referred to our hospital because of recurrent syncope 3 to 4 years after ICD implantation. A comprehensive investigation was performed to find out the etiology for the recurrent syncope. Pacing lead thrombosis was finally observed during open-heart surgery, which can introduce intermittent pacemaker dysfunction. After the thrombus was removed and the lead was separated from the posterior leaflet of the tricuspid valve, the ICD functioned normally after reprogramming. Oral anticoagulant was prescribed after discharging. During the 1-year follow-up period, this patient was free of syncope. Conclusions: This case illustrated that pacemaker lead–associated thrombosis should be considered when the cardiac implantable electronic device fails to prevent patients from having cardiac events. Oral anticoagulant might be important for preventing thrombosis among patients with ICD implantation into the right ventricle.

Gene Therapy Approaches to Biological Pacemakers

Bradycardia arising from pacemaker dysfunction can be debilitating and life threatening. Electronic pacemakers serve as effective treatment options for pacemaker dysfunction. They however present their own limitations and complications. This has motivated research into discovering more effective and innovative ways to treat pacemaker dysfunction. Gene therapy is being explored for its potential to treat various cardiac conditions including cardiac arrhythmias. Gene transfer vectors with increasing transduction efficiency and biosafety have been developed and trialed for cardiovascular disease treatment. With an improved understanding of the molecular mechanisms driving pacemaker development, several gene therapy targets have been identified to generate the phenotypic changes required to correct pacemaker dysfunction. This review will discuss the gene therapy vectors in use today along with methods for their delivery. Furthermore, it will evaluate several gene therapy strategies attempting to restore biological pacing, having the potential to emerge as viable therapies for pacemaker dysfunction.