In May of 2016, a 55-year-old male with history of hypertension, hyperlipidemia, and coronary artery disease (CAD) status after angioplasty of left anterior descending (LAD) artery 2 years ago presented to the emergency room (ER) with substernal chest pain. His cardiac enzymes were not elevated and electrocardiogram (EKG) showed normal sinus rhythm at a rate of 62 bpm with borderline AV conduction delay and right bundle branch block (RBBB) pattern (). The patient was only taking aspirin and had discontinued his statin due to muscle ache and metoprolol because of fatigue. His chest pain was relieved with sublingual nitroglycerin in the ER. In view of his significant history of CAD and typical anginal symptoms, patient underwent cardiac catheterization. It revealed 90 percent stenosis of the left mid circumflex coronary artery which was successfully stented with a drug-eluting stent. Right coronary artery (RCA) showed 50–60% stenosis while LAD showed patent stent. The patient recovered very well. After calculating the GRACE score, the patient was discharged on aspirin and ticagrelor as per the ACC guidelines. He was also prescribed rosuvastatin and metoprolol. Two months after PCI, the patient presented to his primary cardiologist due to worsening fatigue and intermittent dizziness. His metoprolol was stopped. In November, 2016, he was brought by emergency squad to the hospital due to worsening dizziness and diaphoresis at rest. He denied any h/o chest pain, palpitations, nausea, or loss of consciousness. The patient had stopped ticagrelor 1 day prior to this admission since he ran out of it. The patient requested a second opinion on this admission. On physical examination, his blood pressure was 126/66 mmHg and heart rate was regular at 42 beats per minute. The neck was supple with no carotid bruits and cardiac auscultation revealed 2/6 ejection systolic murmur in the left sternal border. Patient's EKG revealed second-degree type II atrioventricular (AV) block which was new (). His cardiac enzymes, thyroid stimulating hormone, serum potassium, and magnesium were within normal range. The patient did not receive ticagrelor further during the admission. Cardiac catheterization revealed RCA stenosis of 60–70% but no intervention was required as this was not the cause of the new onset heart block. We considered starting patient on oral theophylline on admission had the heart block not resolved within 24 hours. His second-degree heart block resolved 2 days after discontinuation of ticagrelor and his EKG showed sinus bradycardia (heart rate = 54 bpm) with borderline AV conduction delay with RBBB pattern () which was similar to his baseline EKG. Clopidogrel was started as an alternative P2Y12 platelet receptor inhibitor and aspirin was continued. He was discharged after an event monitor was placed.
A 51-year-old male patient, with a history of hypertension and hyperlipidemia, presented to the emergency department with an anterior ST-elevation myocardial infarction (). A loading dose of both ticagrelor (180 mg) and aspirin (ASA, 250 mg i.v.) was administered and the patient sent to the cath-lab for primary percutaneous coronary intervention (PCI) on the left anterior descending coronary artery (Figures -). After revascularization, medical therapy included beta-blockers (carvedilol 6.25 mg b.i.d.), statins (atorvastatin 80 mg), and angiotensin II receptor antagonists (telmisartan 80 mg). Dual antiplatelet therapy was continued with ticagrelor (90 mg b.i.d.) and ASA (100 mg). At the echocardiography, performed the day after the revascularization, the ejection fraction was critically reduced (EF: 25%) with akinesia of the anteroseptal wall. Titration of carvedilol was performed during the following two days without significantly reducing the heart rate at target (90 bpm with 12.5 mg carvedilol b.i.d.). Ivabradine was then administered at 5 mg b.i.d. Few hours after the first dose, the patient presented with severe symptomatic bradycardia () and sinus arrest. Atropine and adrenaline i.v. were administered and both ivabradine and ticagrelor suspended and this latter changed with prasugrel. Any other similar event was not reported during the following days and the national competent authority was finally informed.