Cardiology

1
Cardiology

• SVT Algorithm
• Atrial Fibrillation/Atrial Flutter
• Pharmacology

2
SVT AlgorithmRegular/Narrow-Complex Tachycardia

• This algorithm is used for all patients with a
  heart rate of 150 or greater with narrow QRS
  complexes and pulses.
• Initial determination is whether the patient is
  Stable vs. Unstable.
• 4 Parameters for unstable patients
• Altered Mental Status/ALOC
• Hypotension
• Ongoing Chest Pain
• Other signs of shock (i.e. dyspnea, diaphoresis,
  etc.)

3
SVT Algorithm

• The difference in therapy between Stable and
  Unstable patients
• Stable Patients ? pharmacology first.
• Unstable Patients ? electricity first.
• The form of electricity is ? Cardioversion
• This will be covered in detail during the lab
  sessions.

4
SVTStable Patient

• Initiate oxygen therapy
• Initiate an IV line
• Obtain 12 lead ECG (if available)
• Attempt Vagal/Valsalva Maneuvers
• Drug of choice is Adenosine. Can be given up
  to 3 times if needed.
• 6 mg, rapid IVP, followed by a 20 ml bolus of NSS
• if no conversion
• 12 mg, rapid IVP, followed by a 20 ml bolus of
  NSS
• if no conversion
• 3) 12 mg, rapid IVP, followed by a 20 ml bolus of
  NSS

5
SVT Stable Patient

• After Adenosine if the rhythm does NOT change,
  the next drug of choice is either a Calcium
  Channel Blocker or a Beta Blocker.
• Calcium Channel Blockers
• Diltiazem (Cardizem) Calcium Channel Blocker of
  choice
• a) 15 to 20 mg (0.25 mg/kg) over 2 minutes, can
  be repeated in 15 minutes with 20-25 mg (0.35
  mg/kg)
• b) If patient converts hang a drip (100mg/100ml)
  and run at 1 mg/minute.

6
SVT Stable Patient

• If choosing a Beta-Blockade administer as
  follows
• Metoprolol 5mg q 5min, total 15minute
• Atenolol 5mg slow over 5min, repeat q10min
• Propanolol .1mg/kg slow IV push. Divide into 3
  equal doses and administer q3min lt 1mg/min.
• Esmolol .5mg/kg over 5 min over 1 min, follow
  with 4 minute infusion at 50ug/kg
• Labetalol 10mg IVP over 2 min, may repeat or
  double q10 min. Total dose 150mg.
• use B-blockers with caution in pulmonary
  disease or CHF

7
SVTStable Patient

• If unsuccessful, consider expert consultation.

8
SVTUnstable Patient

• If the patient meets the parameters of being
  unstable, perform immediate Synchronized
  Cardioversion at the listed energy levels listed
  later in this lecture.
• Remember that unstable patients cannot perform a
  Vagal/Valsalva maneuver.
• Remember to obtain IV access.
• If patient is still conscious sedate
  (versed/valium).

9
A-Fib/A-Flutter Irregular Narrow-Complex
Tachycardia

• Again treatment is reserved for those with heart
  rates above 150 with irregular narrow complex
  tachycardia.
• Determine if the patient is stable vs. unstable.
  Using the same guides as for SVT.
• If stable, consider expert consultation and if
  indicated control rate with
• 1) Calcium Channel Blockers
• 2) Beta Blockers
• If unstable, perform immediate synchronized
  cardioversion.

10
Treatment Modalities

• Adenosine
• Calcium Channel Blockers
• Beta Blockers
• Synchronized Cardioversion

11
Adenosine

• Generic Name Adenosine
• Trade Name Adenocard
• Classification Class IVb antiarrhythmic,
  endogenous nucleoside
• How Supplied 3 mg/ml

12
AdenosineMechanism of Action

• Found naturally in all body cells.
• Rapidly metabolize in the blood vessels.
• Slows sinus rate
• Slows conduction time through AV node
• Can interrupt reentry pathways through AV node
• Can restore sinus rhythm in SVT

13
AdenosineIndications

• First line medication for most forms of
  narrow-QRS supraventricular tachycardia (SVT)

14
AdenosineDosing (adult)

• Peripheral IV dose 6 mg rapid IV push over 1 to
  3 seconds. If no response within 1 to 2 minutes
  administer 12 mg. May repeat 12 mg dose once in
  1 to 2 minutes. Follow each dose immediately
  with a 20 ml NSS bolus. Recommended IV site is
  the antecubital fossa. Nothing lower.
• Use the injection port nearest the hub of the IV
  catheter. Constant ECG monitoring is essential.

15
AdenosinePrecautions

• Facial flushing
• Coughing/dyspnea, bronchospasm
• Nausea
• Headache
• Hypotension
• Chest pressure
• Lightheadedness
• Paresthesias

• Dysrhythmias at time of rhythm conversion
• Use with caution in patients with emphysema,
  bronchitis
• Avoid in patients with asthma
• Discontinue in any patient who develops severe
  respiratory difficulty

16
AdenosineContraindications

• Poison/drug-induced tachycardia
• Asthma
• 2nd or 3rd degree AV Block
• Sick sinus syndrome (except in clients with a
  functioning artificial pacemaker)
• Atrial flutter/atrial fibrillation
• Ventricular tachycardia

17
AdenosineSpecial Considerations

• Must be injected into the IV tubing as fast as
  possible. Failure to do so may result in
  breakdown of the medication while still in the IV
  tubing.
• Adenosine may cause fatal cardiac arrest,
  sustained ventricular tachycardia requiring
  resuscitation, and non-fatal MI. Transient or
  prolonged episodes of asystole have been reported
  with fatal outcomes in some cases.
• If central line is in place may only require 3 mg
  for IV administration.

18
AdenosineOnset of Action

• SECONDS!!!!!

19
Calcium Channel Blockers

• Generic/Trade Name Verapamil (Calan, Isoptin,
  Verelan), Diltiazem (Cardizem)
• Classification Calcium channel blocker (calcium
  antagonist).
• How Supplied Verapamil injection 5mg/2ml
• Diltiazem injection 5 mg/ml monovial 100
  mg freeze-dried powder for injection 10 mg, 25
  mg

20
Calcium Channel BlockersMechanism of Action

• Inhibit movement of calcium ions across cell
  membranes in the heart and vascular smooth
  muscle, resulting in
• Depressant effect on the hearts contractile
  function (negative inotropic effect)
• Slowed conduction through the AV node (negative
  dromotropic effect)
• Dilation of coronary arteries and peripheral
  arterioles
• Decreased myocardial oxygen demand

21
Calcium Channel BlockersIndications

• SVT
• Patients with normal LV function (diltiazem?
  Class I)
• Patients with impaired LV function (diltiazem ?
  Class IIb)
• Atrial Tachycardia
• Patients with normal LV function (diltiazem?
  Class IIb)
• Patients with impaired LV function (diltiazem ?
  Class IIb)

22
Calcium Channel BlockersIndications

• Atrial flutter/fibrillation for rate control
• Patients with normal LV function (diltiazem,
  verapamil ? Class I)
• Patients with impaired LV function (diltiazem ?
  Class IIb)
• Pre-excited atrial fibrillation (WPW)
• 1) Patients with normal LV function (diltiazem,
  verapamil ? Class III)

23
Calcium Channel BlockersIndications

• Junctional Tachycardia
• Verapamil, diltiazem ? Class indeterminate
• Inappropriate Sinus Tachycardia
• 1) Verapamil, diltiazem ? Class indeterminate

24
Calcium Channel BlockersDosing

• Verapamil
• 2.5 5 mg IV bolus over 2 minutes (administer
  over 3 to 4 minutes in elderly or if BP is within
  the lower range of normal). May repeat with 5 to
  10 mg in 15 to 30 minutes (if no response and BP
  remains normal or elevated).
• Maximum dose 20 mg

25
Calcium Channel BlockersDosing

• Diltiazem
• 15 to 20 mg (0.25 mg/kg) over 2 minutes. If
  needed, follow in 15 minutes with 20 to 25 mg
  (0.35 mg/kg) IV over 2 minutes.
• Maintenance infusion 1 mg/min, titrated to heart
  rate.

26
Calcium Channel BlockersPrecautions

• Avoid calcium channel blockers in patients with
  wide-QRS tachycardia unless it is known with
  certainty to be supraventricular in origin.
• Calcium channel blockers decrease peripheral
  resistance and can worsen hypotension.
• IV calcium channel blockers and IV beta-blockers
  should not be administered together or in close
  proximity (within a few hours) may cause severe
  hypotension.

27
Calcium Channel BlockersContraindications

• Wide-QRS tachycardia of uncertain origin
• Poison/drug induced tachycardias
• Digitalis toxicity (may worsen heart block)
• Atrial fibrillation/flutter with an accessory
  bypass tract (WPW)
• Severe CHF

• Sick sinus syndrome (bradycardia-tachycardia
  syndrome) except with a functioning ventricular
  pacemaker.
• Hypotension (SBP lt 90 mmHg)
• Cardiogenic shock
• 2nd or 3rd degree AV block

28
Calcium Channel BlockersSpecial Considerations

• Diltiazem depresses myocardial contractility to a
  lesser degree than verapamil and causes less
  hypotension.
• During administration, monitor closely for
  hypotension and AV block.

29
Calcium Channel BlockersOnset of Action

• Verapamil IV 2 to 5 minutes
• Diltiazem IV ½ to 1 hour

30
Calcium Channel BlockersDurations

• Verapamil IV 2 hours
• Diltiazem IV 1 to 3 hours

31
Calcium Channel BlockersDrug Interactions

• Beta-blockers may have additive negative
  inotropic and chronotropic effects.
• In some cases, coadministration of verapamil or
  diltiazem may prolong bleeding time.
• Concurrent use of amiodarone and diltiazem can
  result in bradycardia and decreased cardiac
  output by an unknown mechanism.
• Verapamil has bee found to significantly inhibit
  elimination of alcohol, resulting in elevated
  blood alcohol concentrations that may prolong the
  intoxicating effects of alcohol.

32
Beta Blockers

• Generic/ Atenolol (Tenormin)
• Trade Names Esmolol (Brevibloc)
• Labetalol (Normodyne, Trandate)
• Metoprolol (Lopressor)
• Propranolol (Inderal)
• Classification Beta-blockers

33
Beta Blockers

• How Supplied
• Atenolol injection 5mg/10m
• Esmolol injection 100 mg/10 ml single-dose
  vial
• Labetalol injection 5 mg/ml in 20 ml ampule
  20, 40, 60 ml multi-dose vials
• Metoprolol injection 1 mg/ml in 5 ml ampule
• Propranolol injection 20 mg/5 ml unit-dose
  containers 40 mg 5 ml unit dose containers

34
Beta BlockersMechanism of Action

• Slows sinus rate
• Depresses AV conduction
• Reduces blood pressure
• Decreases myocardial oxygen consumption
• Reduces the incidence of dysrhythmias by
  decreasing catecholamine levels
• Reduces risk of sudden death in patients with an
  acute coronary syndrome

35
Beta BlockersIndications

• Non-ST segment elevation MI or unstable angina
  (Class I)
• Adjunctive agent with fibrinolytic therapy
• To reduce incidence of VF in post-MI patients who
  did not receive fibrinolytics (atenolol,
  metoprolol, propranolol)

36
Beta BlockersIndications

• To slow the ventricular response in (esmolol)
• SVT (Class I)
• Atrial fibrillation or atrial flutter (Class I)
• Multifocal atrial tachycardia (Class IIb)
• Inappropriate sinus tachycardia (Class IIb)
• Control of blood pressure in hypertensive
  emergencies (labetalol)

37
Beta-BlockersDosing (adult)

• Atenolol
• 5 mg IV over 5 minutes followed by another 5 mg
  IV dose 10 minutes later. Monitor BP, heart
  rate, and ECG closely.
• If patient tolerates full IV dose (10 mg), begin
  oral atenolol therapy 10 minutes after last IV
  dose

38
Beta BlockersDosing (adults)

• Esmolol
• 0.5 mg/kg over 1 minute, followed by a
  maintenance infusion at 50 mcg/kg/min for 4
  minutes. If the response is inadequate,
  administer a 2nd bolus of 0.5 mg/kg over 1 minute
  and increase the maintenance infusion to 100
  mcg/kg/min.
• Preferred by many physicians in the management of
  narrow-QRS tachycardias because it is
  short-acting (half-life 9 minutes)

39
Beta BlockersDosing (adults)

• Labetalol
• 5 to 20 mg slowly IV push over 2 minutes.
  Additional doses of 10 to 40 mg may be
  administered until a desired supine BP is
  achieved or a total of 150 mg has been
  administered.
• May be administered by IV infusion. Mix two 20
  ml vials in 160 ml of IV solution. The
  resulting concentration contains 200 mg/200 ml IV
  solution (1 mg/ml). Administer at a rate of 2
  ml/min to deliver 2 mg/min.

40
Beta BlockersDosing (adults)

• Metoprolol
• 5 mg slow IV push over 5 minutes x 3 as needed to
  a total dose of 15 mg over 15 minutes. Closely
  monitor BP, heart rate, and ECG
• In patients who tolerate the full IV dose (15
  mg), begin oral metoprolol therapy 15 minutes
  after last IV dose.

41
Beta BlockersDosing (adults)

• Propranolol
• 1 mg slow IV push. Repeat every 5 minutes to a
  maximum of 5 mg. Usual dose required is 2 to 4
  mg. Do not push faster than 1 mg/min to diminish
  the possibility of lower BP and causing cardiac
  standstill. Monitor BP, heart rate, and ECG
  closely.

42
Beta-BlockersPrecautions

• Atenolol
• Use with caution in patients with impaired renal
  function

43
Beta BlockersPrecautions

• Esmolol
• In clinical trials 20 to 50 of patients
  experienced hypotension, SBP lt90 mmHg and/or DBP
  lt 50 mmHg. Monitor patients closely, especially
  if pretreatment BP low. Decrease of dose or
  termination of infusion reverses hypotension,
  usually within 30 minutes.
• Infiltration and extravasation may result in skin
  sloughing and necrosis.
• Administer with caution in patients with impaired
  renal function
• Fatal cardiac arrests have occurred in patients
  receiving esmolol and verapamil

44
Beta BlockersPrecautions

• Labetalol
• Use with caution in patients with impaired
  hepatic function.
• Symptomatic postural hypotension is likely to
  occur if patients are tilted or allowed to assume
  the upright position within 3 hours of receiving
  IV labetalol

45
Beta BlockersPrecautions

• Metoprolol
• Use with caution in patients with impaired
  hepatic functions

46
Beta BlockersPrecautions

• Propranolol
• Use with caution in patients with impaired
  hepatic or renal functions

47
Beta BlockersContraindications

• Heart rate lt 60 beats/minute
• AV block greater than first degree
• Moderate to severe heart failure
• Cardiogenic shock
• Use with caution in conjunction with medications
  that slow conduction and in those that decrease
  myocardial contractility

48
Beta BlockersSpecial Consideration

• In general, patients with bronchospastic disease
  should not receive beta-blockers.

49
CardiologyDiazepam

• Generic Name Diazepam
• Trade Name Valium
• Classification Anticonvulsant and sedative.
  Benzodiazepine.
• How Supplied Ampules and prefilled syringes
  containing 10 mg in 2 ml of solvent.

50
DiazepamMechanism of Action

• Suppresses the spread of seizure activity through
  the motor cortex of the brain.
• It does not appear to abolish the abnormal
  discharge focus.
• It induces amnesia

51
DiazepamIndications

• Major motor seizures.
• Status epilepticus
• Premedication before cardioversion
• Skeletal muscle relaxant
• Acute anxiety states

52
DiazepamContraindications

• Should not be administered to any patient with a
  history of hypersensitivity to the drug.

53
DiazepamPrecautions

• Because of its relatively short-action, seizure
  activity may recur.
• Flumazenil (Romazicon), a benzodiazepine
  antagonist, should be available to use as
  antidote if required.
• Injectable diazepam can cause local venous
  irritation.
• To minimize irritation, it should only be
  injected into relatively large veins and should
  not be given faster than 1 ml/min.

54
DiazepamSide Effects

• Hypotension
• Drowsiness
• Headache
• Amnesia
• Respiratory depression
• Blurred vision
• Nausea/vomiting

55
DiazepamDosage

• In the management of seizures, the usual dose is
  5 to 10 mg IV.
• In acute anxiety reactions, the standard dosage
  is 2 to 5 mg administered intramuscularly.
• To induce amnesia prior to cardioversion, a
  dosage of 5 to 15 mg is given IV.

56
Midazolam

• Generic Name Midazolam
• Trade Name Versed
• Classification Benzodiazepine, sedative and
  hypnotic
• How Supplied Ampule and vials containing 5 mg/ml.

57
MidazolamMechanism of action

• Potent but short-acting benzodiazepine used
  widely in medicine as a sedative and hypnotic.
• It is 3 to 4 times more potent than diazepam.
• Has impressive amnestic properties.

58
MidazolamIndications

• Premedication before cardioversion and other
  painful procedures.

59
MidazolamContraindications

• Should not be administered to any patient with a
  history of hypersensitivity to the drug.
• It should not be used in patients who have
  narrow-angle glaucoma.
• Should not be administered to patients in shock,
  with depressed vital signs, or who are in
  alcoholic coma.

60
MidazolamPrecautions

• Intubation equipment must be available prior to
  the administration of midazolam.
• Vital signs must be continuously monitored during
  and after drug administration.
• Has more potential than the other benzodiazepines
  to cause respiratory depression and respiratory
  arrest.
• Flumazenil (Romazicon), should be available to
  use as antidote if required

61
MidazolamSide Effects

• Laryngospasm
• Bronchospasm
• Dyspnea
• Respiratory depression
• Respiratory Arrest
• Drowsiness
• Amnesia

• Altered mental status
• Bradycardia
• Tachycardia
• PVCs
• Retching

62
MidazolamDosage

• For sedation ? typically .1 to 2. mg are
  administered by slow IV injection.
• Best to dilute midazolam with NSS or D5W.

63
Synchronized CardioversionIndications

• All tachycardias (rate gt 150bpm) with serious
  signs and symptoms related to the tachycardia

64
Synchronized CardioversionTechnique

• Premedicate whenever possible (if time permits)
• Engage sync mode before each attempt, looking for
  sync markers on the R wave.
• Clear the patient before each and every shock.
• For SVT and A-Flutter, start with lower energy
  levels. If initial dose fails, increase in
  stepwise fashion.
• For A-Fib, use 100 to 200J initial monophasic
  shock, or 100 to 120J initial (selected) biphasic
  shock, and then increase in stepwise fashion.
• Deliver monophasic shocks in the following
  sequence 100J, 200J, 300J, 360J.