Spontaneous Circulation
Spontaneous Circulation focuses on advanced ECG interpretation, cardiac pharmacology, hemodynamic assessment and resuscitation, and managing acute coronary syndrome. It is devoted to translating the best evidence-based treatments from critical care, resuscitation, and trauma for bedside use in the emergency department.

Wednesday, June 4, 2014

Unexpected Turns
She watched the Camry coming straight at her, obeying the laws that Newton laid out: a body in motion stays in motion until an external force intercedes.
Her husband, daughter, and the TV weatherman had told her not to go out. Ice had descended on the city earlier in the day, making even the walk to the garage precarious. But she needed milk to make a cake for the next day’s party, and the store was only three blocks away. Her plan was simple: store, milk, home. That might have worked if not for the Camry that became a hockey puck on the ice.
The next couple of hours were a blur but proceeded as readers would expect: 911, paramedics, backboard, cervical collar, ambulance, IV, medicine, stabilization bay, ultrasound, x-rays, more medicine, scanner, hospital bed. All she remembered from that first day through her fentanyl fog was someone saying, “Only a fractured hip. With surgery, this should all be a bad memory in a year.”
She had suffered an acetabular fracture and femoral head fracture. (Figures 1 and 2.)

Figure 1. Pelvic AP x-ray.

Figure 2. Still image from CT scan showing details of acetabular fracture and femoral head fracture.
The next morning she developed atrial fibrillation with a rapid ventricular rate. (Figure 3.) Surgery was postponed, and cardiology was consulted. She was asymptomatic and maintained normal blood pressure despite the rhythm change. The ECG showed diffuse ST-segment depression concerning for subendocardial ischemia, which could be attributed to her known coronary artery disease. She had suffered an NSTEMI about four years earlier, and had two stents placed in the proximal- and mid-RCA. She also had diffuse LAD and circumflex disease. The atrial fibrillation and rapid rate were felt to be secondary to adrenergic stimulation. This improved with additional pain control and beta-blockade, and she spontaneously converted to normal sinus rhythm.

Figure 3. ECG on hospital day 2 when the patient developed atrial fibrillation with rapid ventricular rate.
On hospital day 5, her physicians thought she was safe for surgery, and she underwent a successful ORIF of the posterior acetabulum and total hip arthroplasty. But then she developed chest pain, diaphoresis, and nausea on post-op day 1. Her heart rate slowed to 30 bpm, and she was hypotensive: 90 mm Hg systolic. She responded to a 1000 mL bolus of 0.9% saline and atropine. A 12-lead ECG was obtained.
She awoke the day after surgery hopeful, looking forward to beginning recovery. Breakfast done and waiting for physical therapy, it started. She felt hot and sweaty for several minutes before the chest pain began, followed by nausea. She knew something was wrong, and the seriousness was reinforced by the number of people in her room scurrying about. Her rate slowed to 30 bpm. Blood pressure was below 90 mm Hg systolic. The rapid response team gave her a 1000 mL bolus of 0.9% saline and atropine with good response. A 12-lead ECG was obtained. (Figure 4.)

Figure 4. ECG on the morning of hospital day 6 showing inferior STEMI.
The ECG shows Q-waves in the inferior leads with ST-segment elevation. The R:S ratio is >1 in the right precordial leads suggestive of a true posterior injury. Reciprocal changes are noted in leads I and aVL. A first-degree atrioventricular block was also present. These changes were diagnostic of an inferior ST-elevation myocardial infarction. The bradycardia and hypotension that the patient experienced is suggestive of Bezold-Jarisch reflex, a common epiphenomenon with inferior infarctions.
A STEMI is a clear indication for emergent revascularization, but factors here complicated the medical decision-making. She was at a very high risk of bleeding given her recent orthopedic surgery. Dual antiplatelet therapy and anticoagulation would exacerbate the bleeding risk, which would persist not only during the angiography but afterward if any intervention were performed. Nevertheless, she was treated with aspirin, and taken to the cardiac catheterization lab with the intention of defining the coronary anatomy and identifying the culprit lesion.
She was found to have diffuse disease in the LAD and circumflex coronary arteries but without high-grade obstructive disease. Patent left-to-right collaterals were also seen, as was a 100% occlusion of the ostium of the RCA. (Figure 5.)
Using balloon angioplasty, this was reduced to 30%, which reestablished flow. (Figure 6.) Unfortunately, a thrombectomy catheter could not cross the lesion. No stenting was performed. Any stent placed, whether bare metal or drug-eluting, would have required dual antiplatelet therapy that would have placed her at high risk of bleeding. The distal RCA was small in caliber, indicating chronic disease. Placing a stent would also have required additional contrast dye, which would have placed the patient at risk for contrast-induced nephropathy. A temporary pacemaker was placed given her episode of bradycardia.
She remained hemodynamically stable, and developed no decrease of her renal function. Troponin I peaked at 17 ng/mL. No other episodes of chest pain occurred. She recovered completely from her hip surgery over the following weeks. A month after her STEMI, she underwent PCI to the RCA ostia and mid LAD without any bleeding complications. She was discharged from the hospital on the first day of spring with snow still covering the ground.