Cardiac work in progress Flashcards
Can adenosine be used to exclude VT?
not necessarily, it may aid in the diagnosis of SVT but in young fit individuals with no coronary or structural pathologies you may see adenosine sensitive VT.
This may be seen in:
- Right Ventricular Outflow Tachycardia
- Facicular VT
- Some ischemia-related VT’s
How may you identify VT in a wide complex tachycardia?
- AV dissociation
- fusion beats
- capture beats
other classifications attempt to increase the chances of SVT or VT. This is not a definitive tool.
How effective is Amiodarone in treating VT?
Amiodarone this drug is less effective than many believe — perhaps only about 30% of cases of VT are successfully cardioverted. It’s evidence rating was downgraded in the last ILCOR guidelines.
what are the different types of av blocks and there definition?
1st degree block
prolongation of PR interval (>0.2s)
2nd degree Mobitz type I (Wenckebach) block
- progressive lengthening of PR interval with eventual dropped ventricular conduction
2nd degree Mobitz type II (Hay) block
- intermittent dropping of ventricular conduction
2nd degree (2:1 type) block
- alternate p-wave not conducted to ventricles
3rd degree block (complete heart block)
- complete dissociation between atria and ventricular
What are the values for normal and extreme axis?
Normal axis -30 to 90+ degrees
Extream axis -90 to 180+ degrees
What are the placement for V1-V6
V1: 4th intercostal space (ICS), RIGHT margin of the sternum
V2: 4th ICS along the LEFT margin of the sternum
V4: 5th ICS, mid-clavicular line
V3: midway between V2 and V4
V5: 5th ICS, anterior axillary line (same level as V4)
V6: 5th ICS, mid-axillary line (same level as V4)
Posterior leads are indicated in which patients? What is the placement of the leads?
St elevation in V1-3
V7– Left posterior axillary line, in the same horizontal plane as V6.
V8– Tip of the left scapula, in the same horizontal plane as V6.
V9– Left paraspinal region, in the same horizontal plane as V6.
In inferior infarction what is an indicator that r) sided heart failure is likely?
ST Elevation III > II
ST elevation in V4r
Although traditionally V4r has been the paramedic go to for R) sided involvement III > II has a stronger association.
Reciprocal changes:
What are they indicative of?
What leads should let be looking at:
These changes are indicative of a STEMI which is transmural. Some leads may have reciprocal aspects of the heart but not all:
Septal = v1/2 (posterior)
Anterior = v3/4 (posterior/maybe some in II, III, aVF)
Lateral = v5/6 (reciprocal changes in II, III, aVF)
Inferior = II, III, aVF (reciprocal changes in I, aVL)
Posterior = v6/7/8 (reciprocal changes in v1-4)
You have ST elevation in aVR and V1 with widespread ST depression. What are your considerations?
LAD mi should be a consideration in these patients. This however may also be seen in pt’s with aortic stenosis and/or poor perfusion to the heart.
https://litfl.com/st-elevation-in-avr/
De Winters T wave:
ECG findings:
al Significance of de Winter T Waves:
ECG findings:
- Tall, prominent, symmetrical 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
- Reciprocal ST segment elevation (0.5mm – 1mm) in aVR
- Typical STEMI morphology may precede or follow the De Winter pattern
Clinical Significance of de Winter T Waves:
- The de Winter pattern is seen in ~2% of acute LAD occlusions and is often under-recognised by clinicians
- Key diagnostic features include ST depression and peaked T waves in the precordial leads
- Unfamiliarity with this high-risk ECG pattern may lead to delays in appropriate treatment (e.g. failure of cath lab activation), with attendant negative effects on morbidity and mortality
Where do we look for Wellen’s Syndrome?
What dose it look like?
What is it indicative of?
Location:
In T-wave of V2-3
Morphology:
biphasic (a) or deeply inverted (b) T waves.
Use:
- high risk for extensive anterior wall MI within the subsequent days to weeks
- Indicative of LAD stenosis with high risk of significant MI
What is t-wave inversion in avl indicative of?
mid-segment LAD lesion. This is indicative of a high risk ECG finding.
Ref: Hassen GW, Costea A, Smith T, et al. The neglected lead on electrocardiogram: T wave inversion in lead aVL, nonspecific finding or a sign for left anterior descending artery lesion?. J Emerg Med. 2014;46(2):165-170. doi:10.1016/j.jemermed.2013.08.079
Brugarda sundrome
Def:
Cause:
Significance:
Def:
Brugada Syndrome is an ECG abnormality with a high incidence of sudden death in patients with structurally normal hearts.
Cause:
Cardiac Na+ channel abnormality. 50% of these are random malformations but may also present in familiar clusters. These changes may be as a result of
Fever, Ischaemia, Multiple Drugs (cardiac and non cardiac), Metabolic imbalances (Hypokalaemia, Hyperkalaemia, Hypothermia)
Post DC cardioversion
Pattern:
- Coved ST segment elevation >2mm in >1 of V1-V3 followed by a negative T wave.
- This is the only ECG abnormality that is potentially diagnostic.
Significance:
Often the first sign is cardiac arrest
What are the characteristics of WPW
- short PR interval
- slurred upstroke QRS
