N425 - EXAM 1

IABP: what does it do (2 main hemodynamic effects)?

Decreases afterload (deflates just before systole) and increases myocardial/coronary perfusion (inflates during diastole)

IABP: is it a temporary or permanent device?

Temporary use only

IABP: indications

• Cardiogenic shock

• refractory unstable angina/ischemia unresponsive to meds

• bridge to PCI, CABG, transplant, or recovery

• mechanical complications of MI as a stabilizing bridge

• hemodynamic support during high-risk PCI

IABP: when does the balloon inflate and deflate relative to the cardiac cycle?

Inflates at the dicrotic notch (start of diastole); deflates just before the systolic upstroke

IABP: what should you assess/document on the cannulated limb and how often?

Pulse, color, temperature, and sensation of the affected limb every 1-2 hours

IABP: positioning precaution for the cannulated leg

Keep the cannulated leg with minimal hip flexion; anticoagulation per protocol

IABP: why should the pump never be turned off for more than a few minutes?

Risk of thrombus formation on the balloon

IABP: variables that must be continuously monitored

• Position of balloon in aorta

• displacement volume

• inflation/deflation timing

• signal quality

• cardiac function
  hemodynamic variables

• circulating blood volume

• blood pressure

• vascular resistance

IABP complications: vascular/hematologic

Vascular injuries, thrombus and embolus formation, thrombocytopenia

IABP complications: which arteries can be occluded by the balloon and what should you monitor?

• left subclavian artery

• renal arteries

• mesenteric arteries

• check pulses, urine output, and bowel sounds

IABP complications: signs of improper inflation timing

Increased afterload so the heart can't pump effectively (decreased CO, less flow to the heart), chest pain, drop in BP, decreased perfusion; report to provider (timing may be adjustable depending on hospital)

IABP complications: signs of balloon leak and immediate action

s/s

• Pump alarms/stops

• BP decrease

• blood backing up into the tubing (coffee-grounds appearance)

• usually a failsafe

intervention

• catheter must be removed ASAP

IABP complications: 'mechanical complications' category includes what 3 things?

Improper timing of inflation, balloon leak, malfunction of balloon or console

Impella: what type of device is it and what does it do?

A tiny heart pump placed across the aortic valve into the LV that actively pumps blood from the LV to the aorta (true LV unloading, unlike IABP)

Impella: indications

• Cardiogenic shock

• hemodynamic support during high-risk PCI

• bridge to recovery, decision, transplant, or a longer-term device

• LV unloading/decompression in patients on ECMO or with severe LV failure/severe HF

Impella: what keeps the pump motor from clotting and what must be tracked closely?

• A heparinized dextrose purge-fluid solution

• purge pressure and flow must be tracked closely

Impella: how do you confirm the device hasn't migrated across the valve?

Monitor the placement signal (motor current/waveform)

Impella: anticoagulation monitoring

Strict ACT/PTT monitoring

Impella: signs of hemolysis to watch for

• Pink/red urine

• decreased hemoglobin

• increased LDH

Impella: who should reposition the device?

Do NOT reposition without the physician/interventional team

LVAD: definition

• A surgically implanted mechanical pump that assists or takes over the pumping function of the failing left ventricle → drawing blood from the LV to the aorta

  • via an internal pump connected to an external controller/battery pack (driveline exits through the abdominal wall)

LVAD: indication - bridge to transplant

Supports circulation while awaiting a donor heart

LVAD: indication - bridge to recovery

Supports the heart while it recovers, e.g. post-cardiotomy, myocarditis

LVAD: indication - destination therapy

Permanent support for patients who are not transplant candidates

LVAD: overall clinical picture for use

Support in patients with chronic heart failure until transplant, or support in severe heart failure for patients who are not transplant candidates and have exhausted all other medical options

Transvenous pacemaker: general indications

Emergency situation for rate control; rhythm disturbances; post-cardiac surgery for rate support or overdrive pacing of dysrhythmias; bridge until a permanent pacemaker is available

Transvenous pacemaker: symptomatic bradycardia - what symptoms indicate it's symptomatic?

Low blood pressure, altered mental status, chest pain, fatigue, shortness of breath

Transvenous pacemaker: specific rhythm indications

• High-grade AV block

• sick sinus syndrome

• complete heart block

Transvenous pacemaker precautions: what must be at the bedside at all times?

A spare battery and a backup generator

Transvenous pacemaker precautions: why wear gloves when handling exposed pacing wires, and what else should you do with exposed terminal ends?

Electrical current can precipitate dysrhythmias; insulate exposed terminal ends with a non-conductive material (e.g., tape or rubber cap) when not in use

Transvenous pacemaker precautions: other safety measures

Secure all connections; keep insertion site dry and monitor for infection; continuous ECG monitoring with pacer spikes visible; have emergency equipment (crash cart, atropine, transcutaneous pacer) at bedside; monitor entry site for bleeding/hematoma; assess distal circulation if femoral approach used

Transvenous pacemaker management: how do you confirm capture?

A pacer spike is immediately followed by a QRS complex/paced beat

Transvenous pacemaker management: how do you confirm sensing?

The device appropriately senses the patient's intrinsic beats and does not fire inappropriately

Transvenous pacemaker management: what should be documented each shift and with any changes?

Rate, mode, mA (output), and sensitivity settings

Transvenous pacemaker setting - Rate: definition and typical value

Number of impulses delivered to the heart per minute; set to what the patient needs, usually 60-80 beats/min

Transvenous pacemaker setting - Rate: transcutaneous default

Defaults to 70, but the physician may change it

Transvenous pacemaker setting - Rate: dual chamber pacing

Controls both ventricular and atrial impulses

Transvenous pacemaker setting - Output (mA): definition and target

The amount of electrical current delivered; set above threshold (minimum mA needed for consistent capture), typically 2-3x threshold for a safety margin

Transvenous pacemaker setting - Sensitivity (mV): definition and goal

How well the device detects the patient's intrinsic cardiac activity; set so it senses native beats but is not so sensitive that it senses artifact (oversensing)

Transvenous pacemaker setting - Mode: Demand vs. Asynchronous

• Demand (synchronous) paces only when the intrinsic rate falls below the set rate

• Asynchronous is fixed-rate and fires regardless of intrinsic activity, used only in specific circumstances (e.g., no intrinsic rhythm)

Temporary pacemaker types

Transvenous, transcutaneous, substernal cardiac pacing wires (epicardial)

Permanent pacemaker: what does it simulate?

Normal physiologic cardiac depolarization and conduction

Permanent pacemaker: cardiac resynchronization therapy (CRT) - purpose

Corrects ventricular conduction delays (e.g., bundle branch block) in patients with severe HF, to resynchronize right/left ventricular contraction

Permanent pacemaker: indications

• Symptomatic bradycardia (sick sinus syndrome, sinus node dysfunction)

• second-degree AV block Type II

• third-degree (complete) AV block; post-MI conduction system damage causing significant AV block; cardiac resynchronization therapy

Permanent pacemaker: postoperative management

Monitor incision/generator pocket site for hematoma, infection, lead dislodgement; immobilize the affected arm/shoulder for 24-48 hours to prevent lead dislodgement; continuous ECG monitoring to confirm capture/sensing

Permanent pacemaker: patient education topics

Device identification card; avoid strong electromagnetic fields (certain power tools, MRI unless device is MRI-conditional); routine device interrogation/follow-up; report signs of infection or malfunction

Permanent pacemaker complication: infection (pocket or lead) - management

Antibiotics; may require device/lead extraction

Permanent pacemaker complication: lead dislodgement/fracture - result and management

Causes loss of capture/sensing; requires device interrogation and possible lead revision

Permanent pacemaker complication: pneumothorax - cause and management

• From subclavian vein access during implantation

• monitor respiratory status

• get chest x-ray

• may need chest tube

Permanent pacemaker complication: cardiac perforation/tamponade - signs

Hypotension, muffled heart sounds, JVD (Beck's triad)

Pacemaker malfunction: name the three main types

Failure to capture, failure to sense, failure to pace

Pacemaker malfunction: failure to capture - ECG finding

Pacer spike present but NOT followed by a QRS complex

Pacemaker malfunction: failure to sense (undersensing) - ECG finding and risk

Pacer spikes fire inappropriately and 'march through' the patient's own QRS/T waves; risk of R-on-T phenomenon causing VT/VF

Pacemaker malfunction: failure to pace - ECG finding

No pacer spike when one is expected

12-lead ECG: what defines a STEMI?

ST-segment elevation (compared to the normal isoelectric baseline) in two or more contiguous leads

12-lead ECG: evolution of an MI over time

Hyperacute T waves -> ST elevation -> Q wave development -> T wave inversion -> ST normalization (leaving pathologic Q waves as evidence of a prior infarct)

12-lead ECG: what is often seen in leads opposite the area of injury?

Reciprocal ST depression

12-lead lead group: Septal (V1, V2)

Wall = septal wall; artery = left anterior descending (LAD), septal branch

12-lead lead group: Anterior (V3, V4)

Wall = anterior wall; artery = LAD ('widow maker' when the occlusion is proximal)

12-lead lead group: Septal + Anterior (V1-V4)

Wall = anteroseptal; artery = LAD

12-lead lead group: Lateral (I, aVL, V5, V6)

Wall = lateral wall; artery = left circumflex

12-lead lead group: Inferior (II, III, aVF)

Wall = inferior wall; artery = right coronary artery (RCA)

12-lead lead group: Posterior MI - how is it identified?

Reciprocal changes in V1-V2 (ST depression, tall R waves); confirm with posterior leads V7-V9; artery = RCA or circumflex

12-lead lead group: Right ventricular MI - how is it identified?

Right-sided leads (V4R); wall = right ventricle; usually a proximal RCA lesion

Right-sided STEMI: how is it diagnosed?

12-lead ECG shows ST elevation in leads II, III, and aVF (inferior); a right-sided 12-lead (V4R) is recommended when this is noted on the initial 12-lead

Right-sided STEMI: key hemodynamic principle

The right ventricle is preload dependent

Right-sided STEMI: fluid management

Manage with fluids to promote adequate preload

Right-sided STEMI: why avoid nitroglycerin?

Nitro reduces preload, which can cause severe hypotension in a preload-dependent RV - do NOT give nitro for a confirmed right-sided MI

Right-sided STEMI: how to manage symptomatic bradycardia/AV block

Treat aggressively with atropine and/or temporary pacing

Left-sided STEMI: management components

• remember MONA (morphine, oxygen, nitrates, aspirin)

• Reperfusion

• dual antiplatelet therapy

• anticoagulation

• beta blockers

• ACE inhibitors

• statins

• nitrates are generally appropriate

• monitor for shock

MI complication - Dysrhythmias: signs/symptoms

Sinus bradycardia, sinus tachycardia, atrial dysrhythmias, ventricular dysrhythmias, AV block

MI complication - Dysrhythmias: anticipated treatment

Antidysrhythmics, pacing, ICD, correct electrolytes

MI complication - Heart failure: left-sided S/S

Mild dyspnea, restlessness, agitation, slight tachycardia initially

MI complication - Heart failure: right-sided S/S

JVD, hepatic congestion, lower extremity edema

MI complication - Heart failure: anticipated treatment

Diuretics, afterload/preload reduction, inotropes, oxygen, treat underlying ischemia

MI complication - Cardiogenic shock: S/S

Hypotension, tachycardia, cool/clammy skin, decreased urine output, altered LOC

MI complication - Cardiogenic shock: anticipated treatment

Aggressive management: inotropes/vasopressors, IABP/Impella, emergent revascularization

MI complication - Septal wall rupture (VSD): S/S

New loud systolic murmur; heart failure and cardiogenic shock; rare but associated with high death rate

MI complication - Septal wall rupture (VSD): treatment

Emergency surgical repair

MI complication - Pericarditis: S/S

Mild to severe chest pain that increases with inspiration, coughing, or upper body movement, relieved by sitting forward; pericardial friction rub; diffuse ECG changes

MI complication - Pericarditis: treatment

High-dose aspirin; avoid NSAIDs/steroids post-MI

MI complication - Sudden cardiac death: S/S

May have no warning signs, OR chest pain, palpitations, dyspnea

MI complication - Sudden cardiac death: anticipated workup/treatment

• Cardiac catheterization, PCI, CABG

• exercise stress test

• antidysrhythmic drugs

• if tamponade develops → emergent pericardiocentesis or surgical drainage

Stable angina: S/S

Occurs with exercise/exertion; pain relieved within 5 minutes of rest or nitro

Acute Coronary Syndrome (ACS): definition

Prolonged myocardial ischemia

ACS - Unstable angina

Chest pain not resolved by rest or 3 doses of nitro; no ST elevation

ACS - NSTEMI

Elevated troponin levels; ongoing ischemia can cause cell death after about 20 minutes

ACS - STEMI diagnosis tip

Compare the current 12-lead ECG to a prior 12-lead ECG

Beck's Triad (cardiac tamponade) - list all 3 signs

• Hypotension

• Jugular venous distention (JVD), 3)

• Muffled/distant heart sounds

Management of stable VT (with pulse)

1. amiodarone

2. synchronized cardioversion if unstable

Management of pulseless VT/VFib

• CPR

• SHOCK

  • Immediate defibrillation (unsynchronized),

  • epinephrine first-line

    • 1mg q 3 minutes AFTER 2 shocks

  • then amiodarone/lidocaine

Management of SVT

Vagal maneuvers first, then adenosine; if unstable, synchronized cardioversion

Management of Torsades de Pointes (TdP)

IV magnesium sulfate is first-line; correct electrolytes (K+, Mg2+); stop QT-prolonging drugs; defibrillate if pulseless or it degenerates to VF

Management of asystole

CPR, epinephrine per ACLS algorithm, identify and treat underlying cause (H's and T's) - NOT a shockable rhythm

Management of symptomatic 3rd-degree (complete) heart block

• Atropine

• transcutaneous pacing as a bridge

  • prepare for emergent transvenous/permanent pacemaker

ACLS VF/pulseless VT algorithm - step 1-2

Confirm no pulse, begin high-quality CPR and attach monitor/defibrillator; if VF/pulseless VT confirmed, defibrillate immediately (unsynchronized shock)

ACLS VF/pulseless VT algorithm - steps 3-5

Resume CPR immediately for 2 minutes and establish IV/IO access; give epinephrine every 3-5 minutes; reassess rhythm after each 2-minute cycle and defibrillate again if still VF/VT

ACLS VF/pulseless VT algorithm - steps 6-7

Consider amiodarone or lidocaine after the 2nd/3rd shock if refractory; continue CPR-shock-drug cycles and identify/treat reversible causes (H's and T's)

ACLS Asystole/PEA algorithm - key point about shocking

Asystole/PEA is NOT a shockable rhythm

ACLS Asystole/PEA algorithm - steps

High-quality CPR, establish IV/IO access, give epinephrine every 3-5 minutes, continue CPR and reassess rhythm every 2 minutes, identify/treat reversible causes (H's and T's); if rhythm becomes shockable, switch to the VF/VT algorithm