Cardiology Board Review

Jens Johansson PGY2ARMC Emergency Medicine

Tachycardia- Narrow Complex

Atrial Flutter• Regular 280-340• Block 2:1 (MC- 150 BPM), 3:1, 4:1 representing Atrium to Ventricle

conduction- can be variable-> Irregular rhythm. QRS narrow unless BBB present.

TX:• Unstable: Synchr Cardioversion (less success if chronic AF- anatomic

abnormality not fixed w/ cardioversion• Stable: CCB, BB, Amiodarone, Digoxin

Atrial Fibrillation• Disorganized atrial conduction with irregular conduction to

ventricles• No discernable p- wave with irregular QRS • QRS narrow unless BBB

TX:• Unstable: Synchr Cardioversion (less success if chronic AF or

permanent A-fib)• Stable: Rate control- BB, CCB, Digoxin, Amiodarone,

Anticoagulation-ASA, Heparin, Warfarin based on CHADS2 Score.

Multifocal Atrial Tachycardia• Often mistaken for A-fib, but 3 or more discernable p- waves,

Irregular rate, 100-180 BPM.• Narrow QRS, but can be wide QRS with BBB• 2/2 lung dz

TX: • Treat underlying lung dz, Rate control with CCB

Supraventricular Tachycardia• Reentry Tachycardia• Abrupt onset and termination differentiates from Sinus Tach• Precipitated by PAC or PVC (if AVRT)• Requires 2 different conduction pathways with different refractory times• Regular rate, p- waves absent, QRS narrow unless BBB

• Types:• AVNRT- Conduction pathways within AV node• AVRT- Conduction pathways between Atria and Ventricle• Atrial Reentry Tachycardia- Conduction pathways within atria

TX: • Unstable-Synchr. Cardioversion• Stable- Vagal maneuver, Adenosine, BB, CCB, Procainamide

• Preexitation Syndromes- WPW• Men> Women, 10% of Ebstein Anomaly (Tricuspid anomaly- atrialization of RV/ CHD)• Accessory pathway/ Bundle of Kent circumvents AV node, connect. atrium to bundle of His.

• Orthodromic SVT/ Narrow QRS (95%): • Antegrade conduction vie AV node/Retrograde via accessory pathway.

TX: • Unstable- Synchr. Cardioversion• Stable- CCB, BB, Adenosine, Procainamide

• Antidromic SVT/ Wide QRS and short PR (5%):• Antegrade conduction via accessory pathway, retrograde via AV node.• Wide QRS/ Delta wave. Can be indistinguishable from V-Tach.

TX:• Unstable: Synchr. Cardioversion• Stable: Procainamide, Amiodarone

• NO CCB/BB/Dig, Adenosine (blocks AVN, allowing conduction via accessory pathway)

Tachycardia- Wide Complex

Monomorphic Ventricular Tachycardia• Single ventricular ectopic focus with wide QRS 2/2 depolarization via myocardium (not as

rapid as His- Purkinje fibers). • Absent P- waves, rate >140, QRS> 160 mS

In favor of VT vs SVT w/ aberrancy:• Fusion beats- fusion of wide ectopic beats and normal QRS• Capture beats- Narrow QRS captured between wide QRS• AV dissociation• >50 yrs, cardiac dz

TX:• Unstable: Pulse- Synchronized cardioversion, Pulseless- unsynchronized defibrillation• Stable: Amiodarone, Procainamide, correct underlying etiology

Polymorphic Ventricular Tachycardia (Torsade de Pointes)

• Wide complex QRS, 180-240, wave like appearance.• Baseline EKG may show long QT

Prolonged QT:• Congenital: Jervell-Lange- Nielson, Romano-Ward• Meds: Antiarrhythmics 1A, IIIA, TCA, Phenothiazine, antipsychotics• Electrolyte: Hypo K, Hypo Mg• ICH

TX:Unstable: Pulse- Synchr cardioversion, Pulseless- DefibrillationStable: Mg, Overdrive pacing or Isoproterenol (incr HR-> Shorter QT)

Ventricular Fibrillation

• Hyperirritable ventricular myocardium 2/2 Ischemia, scarring, antiarrhythmics, a-fib, cardioversion.• Disorganized, irregular rapid waveform with no discernable P or QRS.

TX: • ACLS, Defibrillation, or will degenerate in to Asystole. • Epinephrine, Amiodarone, Mg

Cardiac Devices

Ventricular Pacing- TemporaryIndications:• Bradycardia with hemodynamic Instability• Bradycardia with significant escape rhythms• Overdrive pacing• Standby for:• Stable bradycardia• Acute MI with Sinus node dysfunction• Mobitz II or third degree block• Cardiac Ischemia with new LBBB or RBBB

• Transcutaneous pacer- pads to ant-post chest. Limited by body habitus.

• Transvenous pacer- via Cordis catheter to IJ or SC.

Pacemaker- PermanentIndications:

Third degree block, Sick sinus, Severe CHF

Generator: generates impulse

Lead: deliver impulse

EKG:• Pacer spikes before P and QRS if paced. • Wide QRS/ LBBB pattern.• Demand pacemaker may not have spikes if rhythm is nml

Failure:• Generator- device or battery• Lead- fracture, dislodging, migration of lead• Myocardium- fibrosis, electrolyte imbalance

Pacer Failure on EKG• Rate less than preset= Generator failure• Bradycardia but absent spikes= Failure to pace• Impulses fires inappropriately despite nml rhythm= failure to sense• Impulse/ spike without causing P or QRS= failure to capture• Pacer falsely senses activity of heart therefore and inhibits pacing= Oversensing• Pacer incorrectly misses activity of heart and therefore sends impulses= Undersensing

CXR• Pacer with thin coil to atrium, single ventricle or both ventricles • Defibrillator with thicker shocking coil in atrium and ventricle

Interrogation/ Trouble shooting• Use manufacturer specific magnet held close to Pacemaker.• Most pacers will switch from demand to fixed mode (preset rate for each pacer) with use

of any magnet.• IECD will turn off with magnet.

AICD (Automatic Inplantable Cardioverter Defibrillator)• Delivers defibrillatory shock to apex of right ventricle if VF or VT• Almost always combined with pacemaker

Indications:• High risk for dysrhythmia• Sever CHF• Brugada Syndrome• Hypertrophic CardiomyopathyFailure:• Generator• Sensing• Lead• Inappropriate discharge: Can turn off AICD with magnet

Hypertension

Hypertensive Urgency• Elevation of BP without acute end- organ injury.• Potentially harmful if sustained, usually DBP >130 mmHg.

TX:• Gradual reduction in BP over 24 hrs with Outpatient PO meds:

HCTZ, or BB (CAD), Lisinopril (CHF, RF, DM).• Outpatient evaluation of labs for end- organ damage.

Hypertensive Emergency

Hypertension with acute end- organ damage, usually >130 mmHg• Hypertensive encephalopathy, ICH, Ischemic stroke• Renal Failure• ACS, CHF, Pulm edema• Aortic Dissection• Retinal hemorrhage/papilledema• PIH

TX:• Reduce MAP by 20% over next hour with IV meds:• Nicardipine (incr HR), Nitroglycerine (incr HR), Esmolol (short acting, easily

titrated), Labetalol (for PIH, worsen bronchospasm), Sodium Nitroprusside (poss, cyanide tox, give w/ BB for elev of HR), Enalapril (avoid in Renal Artery stenosis)

Hyperadrenergic Syndromes

• Cocaine• Methamphetamine• Pheochromocytoma

TX: • Avoid Beta Blockers- allows unopposed alpha stimulation on blood

vessels-> further elevation of BP.• Caution with cardioversion of dysrhythmia if hyperadrenergic state

since irritable myocardium.• Phentolamine (alpha blocker) for Pheochromocytoma and Cocaine• Benzo’s

Aortic Emergencies

Aortic DissectionTear of aortic intima with blood leaking in to media

• Abrupt, excruciating pain epigastrum/ chest radiating through to back• If aortic branch vessel occlusion:

• Neuro deficits, paraplegia, CHF, ACS, Abdominal pain, flank pain/RF, syncope• Tamponade, HTN, unequal pulses, aortic insufficiency

• CXR: wide mediastinum, pleural effusion, apical cap, media separated from calcified intima, blurred aortic knob.• TEE, CT, CT Aortogram, MRITypes:

• Debakey I: ascending/descending, II: ascending, III: descending• Stanford A: Ascending , B: Descending

TX:• Start IV BB for HR control (Esmolol, Labetalol). Add Vasodilator (Nitroprusside) if needed to

bring BP down to SBP ~100. Analgesia (morphine to reduce sympathetic output.• Surgery for ascending dissection, Medical mgmt. for descending dissection.

AAA• True aneurysm, >3cm or incr diameter by 50%. Rupture risk incr @ 5cm.• MC abdominal and infra- renal. Grows 4 mm/yr once over 3cm. Most commonly

asymptomatic until rupture.• White, smoker, hypertensive male with CAD.• If pain, sudden onset in flank, abdomen, chest, back, often pulsatile mass,

hypotensive, unequal pulses.

Imaging: Abd XR, US, CT contrast, angiogram, MRI

TX:• Immediate Surgery consultation/OR• Optimize BP (not to low/ not to high: BP meds/ pressors) • Crossmatch PRBC’s• IVF