EKG: special tests

What tests do you order to assess rhythm?

ECG, Holter, Loop

What tests do you order to assess the hearts structure?

Echo, CT, MRI

What tests do you order to assess an obstruction?

Cath, CT, MRI, Stress test

What tests do you order to assess functional capacity?

Stress test, MUGA, Cardiac PET Stress

What are the 3 types of Ambulatory ECG monitoring?

• Holter monitor: 24-48 hrs -frequent/daily sx

• Event monitor: 2-4 wks -infrequent sx, weekly/monthly

• Implantable Loop Recorder: 3-4 yrs, rare sx

What are the indications for ordering ambulatory ECG monitoring?

palpitations, syncope/dizziness, afib, suspect afib, screen for pvcs, assess for silent ischemia

What is the primary noninvasive imaging modality for evaluation of cardiac anatomy & function?

TTE

What are the indications for ordering a TTE?

murmur, valve disorders, heart disease, endocarditis, HTN, pre-op, pericardial dz, cardiomyopathy, etc

What are the indications for a TEE?

dx endocarditis, cardiac embolus, aortic pathology, guide change in tx, nondx TTE, clinical decision making: anticoag vs cardioversion vs ablation in afib, guidance of PCI, blunt chest trauma

What are the absolute contraindications of a TEE?

perforated viscous, esophageal stricture, esophageal tumor, esophageal laceration/perforation, esophageal diverticulum, active upper GI bleed

When should you be wary ordering a TEE? (relative contraindications)

active PUD/esophagitis, recent upper GI bleed, sx hiatal hernia, esophageal varices, hx of: GERD, Barretts, GI surgery, neck radiation, dysphagia, esophageal surgery

What does a Echo contrast (Bubble study) check for?

R → L shunting, PFO, ASD, VSD, Pulm vasc AV shunts, estimate RVSP

What is used in a Bubble study?

agitated saline

What are the special contrast agents used in a Bubble study? What are they used for?

Optison, Definity, Lumason; improve image quality, assess masses and tumors, NOT for shunt detection

What are the contraindications to the contrast used in Bubble studies?

R → L or bidirectional cardiac shunts, hypersensitivity to perflutren, intra-arterial injection, hypersensitivity to blood or albumin (Optison only)

What are the two types of stress testing?

Treadmill, chemical (for those who can’t do treadmill)

What is monitored during stress testing?

RR (ECG) & BP response

Pros/cons of stress testing

Pro: less invasive, less expensive

Con: less accurate, won’t detect smaller blockages, chance for false ± results

What is stress testing used for?

dx CAD, monitoring pts w/ CAD, stratifying risk/surg clearance for pts w/ CAD, determining functional capacity

What are the indications for ordering a stress test?

anginal sx, strong cardiac risk factors, smoking hx, DM, HTN, HLD

*no longer recommended for routine CAD screening in otherwise healthy adults

What are the major risk factors for CAD?

C-reactive PTN, fibrinogen, lipoPTN A, homocysteine

What are the absolute and relative contraindications to stress testing?

Abs: AS, allergery to meds used, any acute heart/pulm/artery syndrome ex, MI, PE, ACS, aortic dissection

relative: high AV block, bradyarryhthmias, electrolyte imbalance, severe HTN, HOCM, severe stenosis, systemic illness, tachyarrythmias

What are the types of exercise stress tests?

Plain treadmill: starting point, low risk pts, EKG only

Stress echo: low risk pts, need info over cardiac wall motion, EKG + echo

Myocardial perfusion scan: uses radionuclide to evaluate perfusion & fxn, uses SPECT or PET to detect, w/ or w/o treadmill

What radionuclide agent is used in Myocardial Perfusion Scans?

Thallium or Technetium

What are the types of Pharm stress testing?

Pharmacologic: when pts cannot walk on treadmill

Dobutamine stress echo: uses dobutamin to stress, gets echo + EKG; contra in pts w/ astham or 2nd AV block

What are the protocols of stress testing?

-set speed/grade parameters

• Bruce: preferred, extensively validated

• Modified bruce: sedentary pts, risk stratification after ACS

• Naughton: postMI for risk determination, determine tx

• Athletic Ramp: more spee than grade, better for athletes

What do you compare when interpreting stress tests?

compare rest & stress images

“donut” = short axis; “horseshoes” = horiz/vert long axis

What are cardiac PET scans used for?

measure metabolic/perfusion rate, pinpoint area of bloackage/impairment, perfusion/viability mismatch, evaluate myocardial viability, help determine between CABG vs transplant

What does a MUGA scan assess?

blood-filled part of the ventricles, and how well blood is pumped out; LV function, EF, may detect areas of poor contractility post ischemia

What is a MUGA scan?

radionuclide ventriculograph (noninvasive); uses radioactive tagged RBCs + Gamma ray camera

What are the indications for ordering a MUGA scan?

chemotherapy or cardiotoxic therapy: evaluate baseline prior to tx; evaluate EF in pt w/ HF, evaluate for CAD in pts w/ COPD or obesity

What are the indications for doing a cardiac cath?

locate stenosis → place stents, hemodynamic assessment, ventriculogram (EF), biopsy, detect/repair congenital defects, repair/replace valves, ablation, ligate the left atrial appendage

What are the contraindications of a cardiac cath?

absolute: pt refusal

relative: abn electrolytes, febrile, acute renal filure, decomp HF, severe allergy to contrast, bleeding disorder, anticoag state, pregnant, severe HTN

Cardiac cath vs Cardiac CT angio vs Cardiac MRI

PCI: structure, obstruction, therapeutic, diagnostic; invasive

CCTA: structure, obstruction; non-invasive

CMR: structure, function; preferred over CCTA in younger pts or iodine/BB allergy

What is a CCTA used for?

direct visualization of coronary blockage w/o invasive testing; great option for pts when trying to avoid cathing

What are the indications of a CCTA?

strong suspicion conflicting w/ stress test, sx pts who are intermediate risk for CAD after initial risk stratification, pts w/ ECG uninterpretable for ischemic changes (LBBB), pts unable to exercise, pts w/ equivocal stress test results

What are the contraindications of CCTAs?

allergic to iodinated contrast, some BBs, very low CAD probability, high likelihood of CAD (should go straight to invasive), high Ca score

What Cardiac MRIs used for?

great for congenital anomalies, coronary artery aneurysm, aortic dz, pericardial dz, fibrosis, masses, CABG stenosis

not for detecting coronary stenosis!!

What are the contraindications of CMRs?

implanted medical devices, iron fragments in the eye, claustrophobia (relative)

What agents can be used in stress testing?

• Dipyridamole: vasodilation, inc myocardial BF in normal arteries but not in arteries distal to stenosis (“steal” phenomenon)

• Adenosine: same as Dipyri but has to be given continuous IV bc it rapidly degrades in the plasma

• Regadenoson: more slective adeosine agonist, fewer adverse effects, greater ease of administration