Heart Blocks Flashcards
VARIABLE PRI
Second Degree Heart block TYPE I (Mobitz I or Wenckebach)
Third Degree Heart Block
CONSTANT PRI
FIRST DEGREE HEART BLOCK
2ND DEGREE HEART BLOCK TYPE II (MOBITZ II)
first degree heart block
if the R is far from P, then you have a FIRST DEGREE
p wave normal in size and shape; one positive (upright) followed by QRS (1:1 relationship)
QRS usually 0.10 sec or less unless intraventricular conduction delay exists
prolonged PRI > .20 SECONDS but CONSTANT
EKG CHARACTERISTICS OF FIRST DEGREE HEART BLOCK
Rate: usually normal range but depends on underlying rhythm
Rhythm: Regular
P waves: normal in size and shape; one upright (positive) p wave before each QRS in leads II, III, and aVF
QRS: usually 0.10 sec or less unless an intraventricular conduction delay exists
PRI: CONSTANT; Prolonged ( > .20 seconds) but constant
FIRST DEGREE HEART BLOCK NURSING INTERVENTIONS
> In the setting of an acute MI, the patient should be monitored closely for increasing signs of block
> High serum Digoxin and amiodarone levels can cause 1st degree heart block (hypokalemia can also potentiate digoxin toxicity)
> Identify and treat possible causes (hold negative dromotropic medications and notify the MD)
Second-Degree Heart Block Type I Wenckebach or Morbitz I
*long, longer, longest, dropped QRS variable PRI
Second-Degree Heart Block Type I Wenckebach or Morbitz I (EKG Characteristics)
Rate- Atrial rate is greater than the ventricular rate Rhythm- The atrial rhythm is regular (P waves march out); The ventricular rhythm is irregular P Wave- Upright, normal in size and shape. Some P waves are not followed by a QRS complex (more P waves than QRS complexes) PRI- VARIES! Lengthens with each cycle (although the lengthening may be very slight), until a P wave appears without a QRS complex. The PR interval following the non-conducted QRS complex is shorter than the preceding PR interval. QRS- Usually 0.10 seconds or less
SECOND DEGREE HEART BLOCK TYPE I WENCKEBACK OR MOBITZ 1 NURSING INTERVENTIONS
* If the heart rate is slow, causing signs and symptoms to occur, treat as bradycardia
NURSING 1. Vital signs (including SPO2) 2. Assess for shock (cool clammy skin, ALOC) 3. Lower HOB for hypotension 4. Oxygen if hypoxic 5. Assess fir angina 6. IV access if symptomatic 7. 12 Lead EKG (if new onset) 8. identify and treat possible causes (hold negative chronotropic medications)
SECOND DEGREE HEART BLOCK TYPE I WENCKEBACH OR MOBITZ 1 PHARMACOLOGIC AND ELECTRICAL INTERVENTIONS
PHARMACOLOGIC:
> Possibly, Atropine (initial dose is 0.5 mg IVP) ELECTRICAL:
> Pacing (if symptomatic) * When this dysrhythmia occurs in conjunction with an acute MI, observe for increasing AV block
Second-Degree Heart Block Type II aka Mobitz 2
If some Ps dont get through then you have Mobitz II
block below the Bundle of His QRS will be > than 0.10 sec in duration
block in bundle of his (uncommon) QRS= NARROW
P waves march out (occur at regular intervals)
Variable PRI
SECOND DEGREE HEART BLOCK TYPE II AKA MOBITZ 2 EKG CHARACTERISTICS
RATE: The atrial rate is greater than the ventricular rate. Ventricular rate is often bradycardia
RHYTHM: The atrial rhythm is regular (P waves march out). The ventricular rhythm is regular
P WAVES: Upright, normal in size and shape. Some P waves are not followed by a QRS complex (more P waves than QRS complexes)
PRI: CONSTANT. Within normal limits and constant
QRS DURATION: Usually 0.10 secs or less
SECOND DEGREE HEART BLOCK TYPE II AKA MOBITZ 2 NURSING INTERVENTIONS
*If the heart rate is slow, causing signs and symptoms to occur, treat as a bradycardia
NURSING INTERVENTIONS
- Vital signs (including SPO2)
- Assess for shock (cool clammy skin, ALOC)
- Lower HOB for hypotension
- Oxygen if hypoxic
- Assess for angina
- IV access for possible BP support
- 12 Lead EKG if new onset
8. Identify and treat possible causes (hold negative chronotropic medications)
SECOND DEGREE HEART BLOCK TYPE II AKA MOBITZ 2 PHARMACOLOGICAL & ELECTRICAL INTERVENTIONS
PHARMACOLOGIC:
> Atropine will not be effective for Mobitz Type 2 or complete heart block
> Maybe a sympathomimetic such as Isuprel
ELECTRICAL:
> If patient is symptomatic, transcutaneous pacing should be instituted until a transvenous pacemaker insertion can be inserted
> Second degree AV block type II is usually an indication for a permanent pacemaker
3rd Degree Heart Block (EKG Characteristics)
Rate: The atrial rate is greater than the ventricular rate The ventricular rate is determined by the origin of the escape rhythm.
Rhythm: The atrial rhythm is regular (P waves march out); The ventricular rhythm is also regular; There is no relationship between the atrial and ventricular rhythms.
P Wave: Upright, normal in size and shape because they are coming from the SA node.
PRI: Varies! The atria and ventricles depolarize independently of each other
QRS: Narrow or wide depending on the origin of the escape rhythm
Narrow QRS – junctional escape rhythm Wide QRS – ventricular escape rhythm
3RD DEGREE HEART BLOCK NURSING INTERVENTION
*If the heart rate is slow, causing signs and symptoms to occur, treat as a bradycardia
NURSING INTERVENTION
- Vital signs (including SPO2)
- Assess for shock (cool clammy skin, ALOC)
- Lower HOB for hypotension
- Oxygen if hypoxic
- Assess for angina
- IV access fir possible BP support
- 12 Lead EKG if new onset
- Identify and treat possible causes (hold negative chronotropic medications)
