A 62-year-old white male with no significant medical history except for hypertension, presented to the emergency room of one of our community hospitals with a flu-like illness of 1 week duration and shortness of breath with hypoxia. His home medications were lisinopril 40 mg once daily and atenolol 50 mg daily. On initial presentation, his vitals were normal except for a pulse oximetry of 89% and a weight of 102 kg with body mass index (BMI) of 29.8 kg/m2. Even though he complained of low grade fever, his initial temperature was normal at 36.8°C. His cardiovascular system examination revealed a regular rhythm with normal venous pressure and heart sounds. The only positive finding in his physical examination was crackles in the back of the chest. His chest X-ray and CT scan showed multifocal bilateral infiltrates (). Initial ECG was within normal limits, with a normal PR interval of 160 ms. He was admitted to the hospital and started treatment with supplemental oxygen via a nasal canula and the antibiotics azithromycin and ceftriaxone. COVID-19 test by polymerase chain reaction (PCR) was returned positive later that day. Two days later, he developed crushing substernal chest pain with serial ECG changes suggestive of posterior myocardial infarction. Emergency coronary angiogram revealed occlusion of a large co-dominant proximal left circumflex artery (LCx), for which he promptly underwent primary percutaneous coronary intervention (PCI) with implantation of a drug-eluting stent, Xience Alpine, 3 × 15 mm (Abbott Vascular, Santa Clara, CA, USA), with excellent angiographic results (). Post-procedure, he was initiated on clopidrogel 75 mg/day in addition to aspirin 81 mg/day that was started previously. During the procedure, his respiratory distress worsened, requiring intubation and mechanical ventilation. He was transferred to our centre on the fifth day after the initial hospitalization because of worsening hypoxia and haemodynamic instability. Soon after arrival, he was placed on veno-venous extracorporeal membrane oxygenation (V-V ECMO). He was decannulated 3 days later while remaining on the ventilator. He was given a full 10-day course of hydroxychloroquine and also received the additional antibiotics piperacillin/tazobactam. Serum troponin I levels peaked at 40.47 ng/mL on day 5 of the hospitalization and then down-trended to <1 ng/mL (reference <0.03 ng/mL), though not completely reaching baseline. Other pertinent laboratory data included normal renal function, normal complete blood cell count with relative lymphopenia at 380 cells/mm3 and elevated lactate dehydrogensae (LDH) levels at 336 U/L (reference range 84–246 U/L) on admission. Interleukin-6 (IL-6) levels was at 14 pg/mL (reference range is <5 pg/mL) on day 3. C-reactive protein at 30.34 mg/dL (reference value <1), D-dimer levels of 33 976 ng/mL FEU (reference range <500) and ferritin levels at 1592 μg/L (reference range 20–300) were also elevated, on admission. On his 14th hospital day he had his first episode of asystole lasting 16 s. In the next 3 days, he had multiple sinus pauses without an escape rhythm, many lasting longer than 20 s (). These episodes occurred spontaneously without any negative chronotropic medications and without events causing an increase in intrathoracic pressure such as coughing, suctioning of the endotracheal tube, changing the patient’s position, etc. He had not been hypoxic or on any pressors or inotropes during this time. As expected, concomitant arterial pressure tracing also showed flatline, along with the episodes of asystole. At the end of each pause, the returning rhythm was atrial fibrillation that would spontaneously convert into normal sinus rhythm after several hours. His echocardiogram on the day when he had his first episode of asystole showed preserved left ventricular systolic function with an ejection fraction of 55–60% and posterior-lateral hypokinesia.\nInitially transcutaneous pacing was attempted but was not effective even at maximum outputs. The episodes continued for the next 2 days. As these episodes occurred some time after the index myocardial infarction and without provocation, the need for a permanent pacemaker was thought to be high. Because we wanted to minimize the number of procedures for the patient and reduce the risk of exposure for the healthcare staff during the implant and during the follow-up period, a decision to proceed with the implantation of a leadless pacemaker was made, without going through an interim temporary pacemaker.\nThe leadless pacemaker was inserted on the 17th hospital day after obtaining appropriate consent. Micra™ VR (Medtronic, Minneapolis MN, USA) was inserted in a standard fashion through the femoral vein (). Our pre-established COVID-19 protocol was followed, including adequate personal protective equipment and the procedure being performed in a designated, catheterization laboratory.\nOn completion of the procedure, the patient was transferred back to the COVID-19 unit, where he continued to remain on a ventilator for the next 10 days, followed by successful extubation.\nThe leadless pacemaker was interrogated wirelessly without added exposure risk to the staff on the day following the implantation and 5 days after the implant. Seven days post-implant the percentage of pacing was 3.4% and at 6 weeks post-implant it as 1.5%. A week after the implant, the patient underwent magnetic resonance imaging (MRI) of the brain due to mental status changes without any adverse effects on his pacemaker. He was successfully extubated 10 days after the leadless pacemaker implantation, and was eventually discharged on the 50th day of hospitalization to a rehabilitation facility, where he continues to recover gradually. His discharge medications included aspirin 81 mg/day, atorvastatin 80 mg/day, and metoprolol 12.5 mg twice per day.
A 47-year-old female with hypertension and hyperlipidemia was admitted to emergency department due to typical angina lasting 2 days. Her blood pressure was 150/80 mm Hg. On electrocardiogram (ECG), there was a sinus rhythm with heart rate of 67 bpm, along with ST depression of 0.5 mm on inferolateral derivations (). Echocardiography showed hypokinesis of mid-lateral wall with an ejection fraction of 48%. We detected slightly increased cardiac troponin level. Because of ACS (NSTEMI), acetylsalicylic acid (300 mg), ticagrelor (a loading dose of 180 mg and maintenance dose of 90 mg twice a day) and intravenous unfractionated heparin (10,000 IU) were given to the patient and then her coronary angiography was performed, which revealed a total occlusion of the distal ndLCx (). After the lesion was predilated with 2.0 × 15 mm sized balloon catheter, a drug eluting stent of 2.5 × 23 mm was implanted and full patency was achieved (). Thereafter, her symptoms dramatically improved. Since her heart rate was 67 beats/min, beta blocker therapy was not started. Approximately 10 h later, ECG showed first degree AVB without symptom (). Her therapy consisting of ASA, ticagrelor, ramipril and statin was continued unchanged. On the next (second) day, the patient experienced mild dizziness with complet AVB, without hemodynamic impairment (). Ticagrelor was stopped and prasugrel was initiated instead. On the third day, her ECG showed again first degree AVB without symptom (). On the fourth day, she had normal sinus rhythm without AVB and symptom (). On the fifth day, the patient was salubriously discharged from the hospital with therapy of ASA, prasugrel, rosuvastatin and ramipril. We did not observe any heart block and/or bradyarrhythmia during the 3 months of follow-up.