Recently, leadless pacemaker has emerged as a new pacing strategy to avoid pocket and lead-related complications as compared with conventional pacemaker [1]. However, though the incidence of major complications was demonstrated to be low to 1.51% in Micra transcatheter pacing system (TPS) (Medtronic, Minneapolis, MN, USA) [2], cardiac perforation remains a major safety concern with the incidence of about 0.13–1.3% in studies [2, 3]. Herein, we presented a case of cardiac perforation with pericardial tamponade caused by accidently placing the delivery catheter into the coronary sinus.

A 83-year-old female (height, 148 cm; weight, 41.5 kg; body mass index, 18.9 kg∙m⁻²) suffered from sinus arrest of 5 s with paroxysmal atrial flutter and was admitted to our hospital for leadless pacemaker implantation. The patient received percutaneous coronary intervention with 2 stents implantation 1 month before admission and dual anti-platelet therapy of aspirin (100 mg/day) and clopidogrel (75 mg/day) were continued to the procedure day. During the procedure, the patient was received intravenous heparin 50u/kg before Micra TPS was introduced into the right femoral vein. Then the delivery catheter was directed across the tricuspid valve but it was accidently performed into the coronary sinus for several times. The device cup was advanced into the posterior branch of coronary sinus as confirmed by angiography (Fig. 1)(Additional files 1, 2). Simultaneously, pericardial effusion was detected at the left anterior oblique view (Fig. 1B, C). The delivery catheter was immediately pulled back to the right atrium. The patient was asymptomatic and remained hemodynamically stable (blood pressure 134/76 mmHg). After adjusting the direction of the catheter, it was finally successfully performed into the right ventricle and Micra leadless pacemaker was deployed at the apex of right ventricle (Fig. 2) with stable pacing parameters (R wave amplitude, 9 mV; threshold, 0.38 V/0.24 ms; impedance, 1000Ω). The patient’s condition remained stable until 2 h post-procedure, she was found pericardial tamponade with blood pressure dropped to 75/58 mmHg and heart rate increased to 96 beats per minute. Medium amount of pericardial effusion mainly distribution around the posterior wall of left ventricle was confirmed by echocardiogram (Fig. 3). The patient was emergently received pericardiocentesis and drainage of 270 ml bloody fluid. The symptoms were immediately relieved with blood pressure rise to 130/80 mmHg. Her dual anti-platelet therapy was suspended until no evidence of distinct pericardial effusion was detected after the drainage tube removal. Although no definite evidence was announced for application of rivaroxaban 5 mg in preventing embolic events, aspirin (100 mg/day) and rivaroxaban (5 mg/day) were initially prescribed afterwards concerning balance between ischemia (prevention of thrombosis in stents and thromboembolism due to atrial flutter) and bleeding risk in this elder female with low body mass index and extremely fragile state. The patient was discharged without pericardial effusion reconfirmed by echocardiogram. At 1-month follow-up, the pacing parameters remained stable and the patient was prescribed clopidogrel (75 mg/day), aspirin (100 mg/day) and rivaroxaban (5 mg/day) without pericardial effusion by echocardiogram. And the patient was followed-up without evidence of pericardial effusion, bleeding, thrombosis or thromboembolism at 3-month after discharge (Table 1).

Due to the different fixation way, cardiac perforation remains one of the severe complications of leadless pacemaker. It is recommended to implant leadless pacemaker at the septum of the right ventricle to minimize the incidence of cardiac perforation [2, 4], though it is not easy to be achieved in all patients, especially in small hearts or cor pendulum (drop hearts) cases. According to the literatures [2, 3], the risk factors for cardiac perforation in leadless pacemaker included female, low body mass index, history of myocardial infarction and lung diseases. Therefore, each patient should be carefully estimated before implantation, especially in cases with these risk factors.

Pericardial effusion caused by accidently placing a delivery catheter into the coronary sinus is rare but should be carefully considered in Micra TPS implantation, especially for those with periprocedural anti-platelet therapy.