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35. LVAD Woes: Lub-Dub, Lub-Dub, Lub-Dub…or Maybe Not!
Keywords
LVAD, left ventricular assist deviceDrivelineCongestive heart failureCardiomyopathyCase 1
A 57-year-old male with history of ischemic cardiomyopathy eventually necessitating LVAD placement presented with shortness of breath. He complained of progressively worsening orthopnea for 2–3 days, now with dyspnea at rest, with worsening bilateral lower extremity swelling. He takes warfarin daily and has not missed any doses. He also takes atorvastatin and insulin daily.
Pertinent Physical Exam
Except as noted below, the findings of the complete physical exam are within normal limits.
Vital signs: Mean arterial pressure (MAP) 63, temperature 98.6 °F/37C
General: Pale, appears ill but in no acute distress, awake, and alert
Cardiovascular: Whir of LVAD auscultated, unable to palpate extremity pulses
Respiratory: Bibasilar crackles, diminished breath sounds bilaterally
Extremities: Cool and dry, with 2+ pitting edema bilaterally to knees, no rashes or wounds
PMH
Ischemic cardiomyopathy s/p LVAD placement 2 years prior and an internal cardioverter-defibrillator (ICD) placement
Insulin-dependent diabetes mellitus, type II
Hyperlipidemia
SH
Former 1.5 pack per day smoker; quit 2 years ago
FH
Father with CAD at age 45; death from myocardial infarction at age 66
ED Management
Patient placed on cardiac monitoring; 2 large bore IVs placed
Pertinent Test Results
EKG showed sinus tachycardia with heart rate of 103 and no ST segment changes or T wave inversions
Test | Result | Units | Normal range |
|---|---|---|---|
Hgb | 10.1 ↓ | g/dL | (Male) 14–18 g/dL (Female) 11–16 g/dL |
Sodium | 132 | mEq/L | 135–148 mEq/L |
Creatinine | 1.1 | mg/dL | 0.6–1.5 mg/dL |
Troponin | 0.06 | ng/ml | <0.04 ng/ml |
INR | 2.4 | – | ≤1.1 |
Plan
Serial EKGs, troponins, and bedside and formal echocardiogram (echo) were performed and a consult to open heart surgery was placed. If the patient were to become hypotensive or to deteriorate clinically, we planned for administration of vasopressors.
Updates on ED Course
Bedside echo showed a dilated right ventricle and functioning LVAD. A CT pulmonary angiogram (CTPE) was ordered based on symptoms and right heart dilatation on echo and was negative for pulmonary embolism.
Open heart surgery came to see the patient and recommended medical management for right heart failure and admission to congestive heart failure service.
Repeat troponin trended up, now at 0.94 ng/ml 3 hours after the original troponin, concerning for subendocardial ischemia.
Case 2
A 61-year-old male with a history of ischemic cardiomyopathy, status-post LVAD placement 3 years prior as destination therapy, presented with chest pain and repeated ICD firing. His LVAD team recommended calling EMS for transport to the nearest LVAD center. EMS reported that his heart rhythm as ventricular tachycardia. They administered 150 mg of amiodarone prior to arrival without conversion to sinus rhythm. Home medications include dobutamine, torsemide, spironolactone, warfarin, amiodarone, hydralazine, and aspirin [1].
Pertinent Physical Exam
Except as noted below, the findings of the complete physical exam are within normal limits.
Vital signs: BP 122/80 (automatic cuff), RR 18, temperature 98.6 °F/37 °C, LVAD motor speed 10,000 rpm
General: Well-appearing, no distress, but anxious
Cardiovascular: Whir of LVAD auscultated, thrill palpated on arterial pulse examination
Respiratory: Clear breath sounds bilaterally
Extremities: Warm and dry, no edema
PMH
Ischemic cardiomyopathy with LVAD placement 3 years prior
ICD placement, with hospitalization within the last 2 weeks for CHF exacerbation
Chronic kidney disease, stage III
SH
No history of smoking or drug use; occasional alcohol use
FH
No family history of cardiac disease
ED Management
An EKG was obtained showing polymorphic ventricular tachycardia with a heart rate of 300 bpm. Amiodarone drip and prophylactic magnesium infusion were administered. Chemistries, CBC, troponin, and CXR were ordered.
Pertinent Test Results
Test | Result | Units | Normal range |
|---|---|---|---|
WBC | 4.2 | K/uL | 3.8–11.0 K/uL |
Hgb | 10.6 | g/dL | (Male) 1418 g/dL (Female) 11–16 g/dL |
Platelets | 146 | K/uL | 140–450 K/uL |
Sodium | 134 | mEq/L | 135–148 mEq/L |
Potassium | 3.6 | mEq/L | 3.5–5.5 mEq/L |
Bicarbonate | 24 | mEq/L | 21–34 mEq/L |
BUN | 28 | mg/dL | 6–23 mg/dL |
Creatinine | 2.1 | mg/dL | 0.6–1.5 mg/dL |
Glucose | 146 | mg/dL | 65–99 mg/dL |
Magnesium | 2.3 | mg/dL | 1.6–2.6 mg/dL |
INR | 2.4 | – | ≤1.1 |
Troponin | 0.06 | ng/ml | <0.04 ng/ml |
Plan
An electrophysiology consult was placed and synchronized cardioversion with procedural sedation was planned.
Updates on ED Course
Patient was sedated with propofol and was successfully cardioverted with 360 J 1 hour after his presentation to ED. The postcardioversion EKG showed normal sinus rhythm with QTc prolongation (588 ms). Postcardioversion LVAD display showed 10,000 RPM and cardiac output of 4.7 L/min. The patient was admitted to the heart failure service after remaining hemodynamically stable postcardioversion.
Learning Points
Priming Questions
- 1.
How do you evaluate patients with LVADs? How do you assess vital signs?
- 2.
What kind of complications do patients experience with LVADs?
- 3.
How is management of a coding patient with an LVAD different from standard ACLS?
Introduction/Background
- 1.
Types of LVADs:
All LVADs are designed to assist left ventricular output in patients with severe cardiomyopathy. In each case, the implanted pump, which is powered by an external power source and controller, transfers blood from the left ventricular apex to the aortic outflow tract. The controller is connected to the pump via the driveline, a surgically implanted tunneled power cable [2].
LVAD
Public domain image
There are two general types of LVADs: Pulsatile flow and continuous flow. Pulsatile flow LVADs mimic a physiologic systole and diastole, while continuous flow (as it sounds) continuously moves blood from the LV to the aorta. Continuous flow increases diastolic pressure and decreases pulse pressure. Continuous flow models are most often used for their improved safety profile compared to pulsatile flow devices [2].
Axial flow pump devices (including the commonly used HeartMate II®, Thoratec Corporation, Pleasanton, CA) use a curved rotor blade (impeller), which draws blood in a nonpulsatile fashion from the LV to the aortic outflow tract.
Centrifugal pump devices use “centrifugal force” to generate continuous, nonpulsatile flow. The newest devices, such as the HeartMate III® (Thoratec Corporation, Pleasanton, CA) rely on an electromagnet to suspend the rotor and thus decrease rotor contact with the pump casing, with the goal of reducing shear flow and hemolysis. A two-year follow-up study in patients with HeartMate III® implantation showed lower rates of reoperation for pump malfunction and pump thrombosis but no difference in survival compared to axial flow devices [3].
Types of LVADS
From New England Journal of Medicine: Mark S. Slaughter, M.D., Joseph G. Rogers, M.D., Carmelo A. Milano, M.D. et al. Advanced Heart Failure Treated with Continuous-Flow Left Ventricular Assist Device. 361;23, p 2244 Copyright © 2009, Massachusetts Medical Society. Reprinted with permission from Massachusetts Medical Society
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