Case presentation:
A 83-year-old female (height, 148cm; weight, 41.5kg; body mass index,18.9 kg∙m−2) suffered from sinus arrest of 5 seconds with paroxysmal atrial flutter and was admitted to our hospital for leadless pacemaker implantation. The patient had percutaneous coronary intervention with 2 stents implantation 1 month before admission and dual anti-platelet therapy of aspirin (100mg/day) and clopidogrel (75mg/day) 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 was accidently performed into the coronary sinus for several times. The device cup was placed at the beginning of the posterior branch of coronary sinus as confirmed by angiography (Figure 1 ). Simultaneously, pericardial effusion was detected at the left anterior oblique view (Figure 1B, 1C ). But the patient was asymptomatic and remained hemodynamically stable (blood pressure 134/76mmHg). 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 (Figure 2 ) with good pacing parameters (R wave amplitude, 9mV; threshold, 0.38V/0.24ms; impedance, 1000Ω). At 2 hours post-procedure, the patient was found pericardial tamponade with blood pressure dropped to 75/58 mmHg. Medium amount of pericardial effusion mainly distribution around the posterior wall of left ventricle was confirmed by echocardiogram (Figure 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. The pacing parameters remained stable. Dual anti-platelet therapy was stopped for 5 days. No evidence of distinct pericardial effusion was detected after the drainage tube removal. Aspirin (100mg/day) and rivaroxaban (5mg/day) were prescribed afterwards. The patient was discharged without pericardial effusion reconfirmed by echocardiogram.