Cardiac Concepts: Review of the Lost Chapters

Blaze Amodei FP-C, CCP-C, TP-C

Objectives

• Basics review of cardiology and electrophysiology for the prehospital clinician

• The “false paradigm of a STEMI/NSTEMI dichotomy”

• 30,000 ft view of OMI/NOMI pattern presentation

• HAVE FUN

“In every situation, do what is right for the patient.” -Dr. John L. McDonald

Review the Basics

• Anatomy of the Heart

• Chambers, vessels, and valves

• Conduction system

• Basic ECG

• Einthoven’s Triangle, calibrations, Hexaxial reference plain

• Vectors and Axis (Why does it mater)

• P wave, QRS, T wave w/ intervals durations

Einthoven’s Triangle & Hexaxial reference plain

• Lets math it out and look at the camera angles

Calibration

Standard calibration:

10mm/mV @ 25mm/sec

ECG tracing

STEMI vs. NSTEMI

Only STEMI needs

emergent cathertization

right?

OMI or NOMI, that is the

Question….

Location, location, location…

Sensitivity & Specificity

• Classic Criteria

• LBBB/Paced Rhythms (SMSC)

• New RBBB w/ LAFB

• RV Infarction

• Posterior Wall MI

• High Lateral MI

• D-Winter

• aVR (Who knew….?)

• Hyper Acute T Waves

• Wellens Phenomenon

• Transient STEMI and/or Unrelieved pain w/NSTEMI

RBBB and LBBBRBBB

-The heart rhythm must originate above the ventricles (i.e.

sinoatrial node, atria or atrioventricular node) to activate

the conduction system at the correct point.

-The QRS duration must be more than 100 ms

(incomplete block) or more than 120 ms (complete block)

-There should be a terminal R wave in lead V1 (e.g. R,

rR', rsR', rSR' or qR)

-There should be a slurred S wave in leads I and V6

LBBB

-The heart rhythm must be supraventricular in

origin

-The QRS duration must be ≥ 120 ms[2]

-There should be a QS or rS complex in lead V1

-There should be a notched ('M'-shaped) R wave in

lead V6.

Fasicular blocks

LAFB:

LAD

q1 r3

I up

II down

III down

LPFB:

RAD

r1 q3

I down

II biphasic/up

III up

Pacemakers• Indications:

• Sinus node dysfunction: Symptomatic sinus bradycardia, sick sinus syndrome

• Conduction disturbances: 2nd type II or 3rd degree heart blocks

• Tachyarrhythmias: A-fib and VT

• Types:

• Permanent (Implanted)

• Temporary: Transcutaneus, transvenous, Transthoracic

Chambers paced:

A: Atria

V: Ventricles

D: Dual

Chambers sensed:

O: None

A: Atria

V: Ventricles

D: Dual

Mode of response:

O: None

I: Inhibited

T: Triggered

D: Dual

Wellens’ Syndrome: A look at a widow maker

Indicates LAD and coronary artery stenosis

2 Types:

Symmetric deeply inverted T waves in V2 and V3

Biphasic T waves in V2 and V3 (less common)

Either of the 2 T wave abnormalities described.

History of chest pain.

Normal / minimally elevated cardiac enzymes.

No pathological Praecordial Q waves.

Minimal / no ST elevation.

No loss of precordial R waves.

Don’t let BTWI fool you! 1. There is a relatively short QT interval (QTc < 425ms) 2. The leads with T-wave inversion often have very distinct J-waves.3. The T-wave inversion is usually in leads V3-V6 (in contrast to Wellens' syndrome, in which they are V2-V4)4. The T-wave inversion does not evolve and is generally stable over time (in contrast to Wellens', which always evolves). 5. The leads with T-wave inversion (left precordial) usually have some ST elevation 6. Right precordial leads often have ST elevation typical of classic early repolarization7. The T-wave inversion in leads V4-V6 is preceded by minimal S-waves8. The T-wave inversion in leads V4-V6 is preceded by high R-wave amplitude9. II, III, and aVF also frequently have T-wave inversion.

Winter is coming…. De Winter T waves

Diagnostic Criteria

-Tall, prominent, symmetric T

waves in the precordial leads

-Upsloping ST segment

depression >1mm at the J-point in

the precordial leads

-Absence of ST elevation in the

precordial leads

-ST segment elevation (0.5mm-

1mm) in aVR

-“Normal” STEMI morphology may

precede or follow the deWinter

pattern

Anterior STEMI equilvant without obvious ST elevation changes

KEY: ST depression and peaked T waves in the precordial leads.

Hyper Acute T wavesT waves should not exceed 10mm in precordial

leads and 5 mm in hexaxial leads but the ratio

is what counts.

Immediately after coronary artery occlusion

(and reperfusion) T wave amplitude increases

as the first significant finding

(If any one lead has a QRS to T wave ratio

greater than 0.36, it is acute STEMI with equal

accuracy. False negatives had a long time

between symptom onset and ECG, so that the

T-wave was no longer tall.)

aVR: What is it good for?

If due to ACS, this STE in aVR is associated not only with acute LM insufficiency, but

alternatively with 3 vessel disease, or with LAD insufficiency.

Previously thought elevation in aVR with diffuse depression = LM occlusion

When data in not communicated appropriately….

1) in patients with recognized STEMI (due to coronary occlusion, usually of the LAD) and is

associated with higher mortality than in patients without STE in aVR and

2) in patients without ischemic ST elevation, in which case there is always diffuse ST

depression of subendocardial ischemia (which can be due to supply-demand mismatch or

due to ACS).

Smith Modified Sgarbossa criteria

- Concordant ST-segment

elevation ≥ 1 mm in any

lead (other than V1-V3)

- Concordant ST-segment

depression ≥ 1 mm in

lead V1 – V3

- Discordant ST/S Ratio >

0.25

Misdirections• BER: Benign Early Repolarization

• LVH: Left Ventricular Hypertrophy (Sick Gains Bro!)

• Pericarditis

• LV anuerysm

• Electrolyte Abnormalities (Goldilocks was just right)

• SVT with aberrancy

• Artifact or wandering baseline

• WPW and conduction abnormalities

• Hypothermia

• Neurocritical care

BER: Benign Early Repolarization-Widespread concave ST elevation, most prominent in the mid- to left precordial leads

(V2-5).

-Notching or slurring at the J-point “Fish Hook”.

-Prominent, slightly asymmetrical T-waves that are concordant with the QRS complexes

(pointing in the same direction).

-The degree of ST elevation is modest in comparison to the T-wave amplitude (less than

25% of the T wave height in V6)

-ST elevation is usually < 2mm in the precordial leads and < 0.5mm in the limb leads,

although precordial STE may be up to 5mm in some instances.

-No reciprocal ST depression to suggest STEMI (except in aVR).

-ST changes are relatively stable over time (no progression on serial ECG tracings).

Questions?Thank YOU!

If you would like references or additional resources I can link up with you offline

References• Pendell Meyers. EMCrit Podcast 250 – The OMI Manifesto Lecture by Pendell Meyers. EMCrit Blog. Published on June 27,

2019. Accessed on July 18th 2019. Available at [https://emcrit.org/emcrit/emcrit-podcast-250-the-omi-manifesto-lecture-by-pendell-meyers/ ].

• Scott Weingart. EMCrit Podcast 147 – Who Needs an Acute PCI with Steve Smith (Part II). EMCrit Blog. Published on April 12, 2015. Accessed on July 18th 2019. Available at [https://emcrit.org/emcrit/who-needs-an-acute-pci-ii/ ].

• Smith, S. (2012, January 5th). ECG Diagnosis of Acute STEMI-Equivalent in the Presence of Left Bundle Branch Block. Retrieved from https://vimeo.com/34634434.

• Smith, S. (2016, August 8th). Lecture: Acute Coronary Syndromes, Part (Overview and Non-STE-ACS) and Part 2 (STEMI) Retrieved from http://hqmeded-ecg.blogspot.com/2016/08/lecture-acute-coronary-syndromes-part.html.

• Mehta et al. Early versus delayed invasive intervention in acute coronary syndromes. The New England journal of medicine 2009;360:2165-75. The TIMACS (Timing of Intervention in ACS) Trial.

• Amsterdam et al. 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2014;130:e344-426.

• Macfarlane et al. Age, sex, and the ST amplitude in health and disease. J Electrocardiol. 2001;34 Suppl:235-41. (PMID:11781962)

• Smith et al. Electrocardiographic differentiation of early repolarization from subtle anterior ST-segment elevation myocardial infarction. Ann Emerg Med. 2012;60:45-56.

• Schmitt et al. Diagnosis of acute myocardial infarction in angiographically documented occluded infarct vessel: limitations of ST-segment elevation in standard and extended ECG leads. Chest. 2001 Nov;120(5):1540-6. (PMID: 11713132)

Ventilation Management

Casey Brown, FP-C

REACH Air Medical Services

Objectives

• Learn the basic functions of the ventilator

• Explain why this is a powerful tool in the critical care arsenal

• Give a hands-on demonstration and comparison between an Ambu-bag and ventilator.

Ventilator ZOLL 731 Series

Zoll 731 - Functions

• https://www.zoll.com/medical-products/ventilators/emv-plus

• Compressor driven

• SpO2 and EtCO2 pleth wave

• CPAP or BIPAP functions in NIPPV mode

Zoll 731 – Functions; continued

• O2 Source

– Used with high or low flow oxygen

– Increases tank usage time

• Can deliver up to 100% FiO2 with each breath

• Approximately 10 hour run time

– 2-hour charge for a 90% battery recharge

Why Use a Ventilator?

Ventilator Use

• Extra set of hands

• Allows for critical care

– Medication administration

– Titration

– Compressions

– OG/NG tube placement

– Tracheal suction

– Etc.

• Precise and volume-controlled breath

Ventilator Use, continued

• Deliver prescribed FiO2%

• Respiratory rate

• Airway compliance monitoring

– PIP measurements

Ventilator Use, continued

• Ventilate 5kg - >160kg

• NIPPV or CPAP/BIPAP

• Ventilate special patients

– ARDS

– Sepsis

– Facial Trauma

– Barotrauma

– ALL KINDS OF PATIENTS!!

• So we ask ourselves, “why not use a ventilator?”

Can Your AMBU Bag Do That?

• Ambu bag • Zoll 731

Basics of the Zoll 731

Basics of Zoll 731, continued

• SpO2 pleth wave with HR

• EtCO2 pleth wave with FiO2, PIP and PEEP

• Vt (set) and RR

• Mode

What do the Abbreviations Mean?

• SpO2

• EtCO2

• FiO2

• PIP

• PEEP

• Vt

• Vte

• RR

• Vm

• SIMV

Putting It All Together

• Effective Ventilation needs adequate

– PIP

– Vte

– PEEP

– FiO2

– RR

• Without a good RR

– No ventilation

• Without PEEP and FiO2• No oxygenation

• Without Vt• No air movement

References:

• https://www.zoll.com/-/media/public-site/products/ventilators/ems_emv_specsheetep_0095.ashx?la=es-es&hash=DD95835C9EB0743CC1A07C173D41C4A49318078A

• https://api.zoll.com/-/media/public-site/products/ventilators/9650-002360-01-sf_a.ashx

• http://www.rcjournal.com/guidelines_for_authors/symbols.pdf

It is Time to Practice!