Did the Coexistence of a Pacemaker Probe, a Prominent Eustachian Valve and Induced Hypothermia Lead to Severe Pulmonary Embolism in a Resuscitated Patient after STEMI?

A 79-year old man collapsed in a shopping center. Five minutes later, the called emergency medical service found the patient pulseless and started cardiopulmonary resuscitation for approximately three minutes. Ventricular fibrillation was detected, the second shock was successful and return of spontaneous circulation (ROSC) could be established using low dosages of noradrenaline. Respiration was secured by intubation and the electrocardiogram (ECG) showed a sinus bradycardia with ST-elevations in the inferior leads. The cardiologist on duty scheduled the patient for immediate coronary angiography. The femoral access was chosen to also introduce a pacemaker (PM) probe due to the bradycardia and expected reperfusion arrhythmias. Corresponding to the ECG a fresh occlusion of the medial right coronary artery was found without significant lesions of the left coronary artery. The lesion could be recanalized and stented without complications, CKmax rose up to 1698 U/L the next day. The heart rate after PCI was around 50 bpm with infrequent PM activity: Frequency threshold was set at 40 bpm. Dual antiplatelet therapy (DAPT) was initiated after the patient was transferred to the intensive care unit. Hypothermia was induced with a core body temperature of 33°C for 24 hrs., then warming-up 0.2°C/h. Sinus bradycardia still was present with sporadic PM activity during the hypothermic period as well as in the night after warming. The PM probe was left in place. Two days after warming both, oxygen saturation and arterial blood pressure dropped. Echocardiography showed a prominent thrombus in the right atrium (RA) and a CT-scan revealed a severe pulmonary embolism (Figure 1). Deep vein thrombosis could be excluded via ultrasonography. To better understand the origination of the RA thrombus, a transesophageal echocardiography was conducted displaying a massively thrombotic coat of the pacemaker probe (Figures 2a and 2b). To prevent further embolism, we retrieved the PM probe using an Amplatz ev3 GooseNeck® snare kit introduced via a F-18 Cordis® sheath: therefore, the probe was retracted into the inferior caval vein (ICV) under transesophageal echocardiographic monitoring at first. Then the left ICV was punctured to introduce the snare, the tip of the probe was grabbed and pulled back into the sheath. Afterwards both were drawn out to show thrombotic material adhering to the probe (Figure 3). In the RA, a prominent Eustachian valve was unmasked after removal of the probe (Figure 2b). Additionally, thrombolytic therapy with 100 mg alteplase was given. Hemodynamics stabilized and the patient was weaned from catecholamines as well as ventilation. Still in the ICU, the patient improved hemodynamically and no permanent PM was necessary. Due to hypoxic brain damage within the resuscitation event, the patient was *Corresponding author: Dr. Christian Schach, Clinic and Polyclinic for Internal Medicine II, Department of Cardiology, University Hospital Regensburg, FranzJosef-Strauss-Allee 11, Germany, Tel: ++49 941 944 7268; Fax: ++49 941 944 7235; E-mail: [email protected]