Arrhythmia Surgery Flashcards

1
Q

“Cut and Sew” MAZE Lesions

A
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2
Q

Determinants of Cryoablation Lesion Size

A
  1. Probe Temperature
  2. Thermal Conductivity
  3. Tissue Temperature
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3
Q

Cryoablation Advantages and Disadvantages

A

Advantages

  1. Freezing is a safer energy source - preserves ECM structure

Disadvantages

  1. Risk of coronary stenosis
  2. Time consuming (1-3min per lesion)
  3. Less safe/effective on beating heart (thromboembolism/heat sink)
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4
Q

Determinants of Radiofrequency Ablation Lesion Size

A
  1. Electrode-Tissue Contact Area
  2. Interface Temperature
  3. Current and Voltage (Power)
  4. Duration
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5
Q

Biopolar Radiofrequency Advantages and Disadvantages

A

Advantages

  1. Create trasnmural lesions on the beating heart
  2. Limits collateral injury

Disadvantages

  1. Access needed for tissue to be sandwiched between the two poles
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6
Q

Cox-Maze IV Lesion Sets

A
  1. Pulmonary Vein Isolation (bipolar RF)
  2. Right Atrial Lesion Set (beating heart; bipolar RF + unipolar or cryoablation endocardially down to the TV annulus)
  3. Left Atrial Lesion Set (arrested; amputation of the LAA; bipolar RF to connect the PVV lesions + unipolar or cryoablation endocardially down to the MV annulus)
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7
Q

Pulmonary Vein Isolation Lesion Sets

A
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8
Q

Rx-free Freedom from Symptomatic AF

A

Paroxysmal AF

  • 6-months - 90%
  • 1-year - 90%
  • 2-years - 90%
  • 10-years - 85%

Persistent AF

  • 6-months - 90%
  • 1-year - 90%
  • 5-years - 80%
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9
Q

Pulmonary Vein Isolation and LA Lesion Sets Without the Mitral Annular Lesion Increase the Risk of…

A

Atrial Flutter

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10
Q

Freedom from AF with Complete MAZE vs. LA Lesion Sets Only

A

Freedom from AF

  • Complete Cox-MAZE IV - 85%
  • LA Lesions Only - 75%

Drug-free Freedom from AF

  • Complete Cox-MAZE IV - 80%
  • LA Lesions Only - 50%
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11
Q

Freedom from AF for Surgical vs. Catheter Pulmonary Vein Isolation

A

at 1-year

Surgical - 65%

Catheter - 35%

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12
Q

Indications for Surgical MAZE

A
  1. Symptomatic patients with documented AF undergoing concomitant cardiac surgery
  2. Asymptomatic patients with documented AF undergoing concomitant cardiac surgery if low risk
  3. Symptomatic patients with documented AF and failed (or not candidates for) catheter ablation
  4. Symptomatic patients with documented AF with CHADS > 2 but contraindications to anticoagulation, especially if they have already suffered a neurologic event
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13
Q

3 Letter International Pacemaker Code

A

Paced” / “Sensed” / “Algorithm” / “Rate Response

CRT-P ⇒ biventricular pacer

CRT-D ⇒ biventricular pacer-defibrillator

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14
Q

ACC/AHA Guideline Indications for PPM Insertion

A

Class I (symptomatic…)

  1. AVB (second or third degree)
  2. Sinus bradycardia/block/arrest (positive tilt table test SA asystole > 3sec
  3. Tachy-Brady syndrome

Class II

Symptomatic patients with…

  1. Bifascicular/Trifascicular block
  2. Hypertensive carotid sinus syndrome

Asymptomatic patients with…

  1. Complete AVB
  2. Mobitz II
  3. Congenital AVB
  4. Sinus bradycardia < 40 requiring Rx
  5. VT requiring overdrive pacing

Class III

  1. Syncope NYD

Asymptomatic patients with…

  1. Sinus bradycardia/block/arrest
  2. BBB
  3. Mobitz I
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15
Q

AVB

A

1º AVB

  • P-R interval > 200ms

2º AVB

  • Mobitz I (Wenckebach)

Progressive P-R interval increase followed by dropped QR

  • Mobitz II

Dropped QRS without P-R progression

3º AVB

  • Complete AV dissociation
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16
Q

Etiologies of Sinus Node Dysfunction

A
  1. CAD
  2. Cardiomyopathy
  3. Reflex Abnormalities
    1. Carotid Sinus Hypersensitivity
    2. Vasovagal Syncope
    3. Micturition-Induced and Deglutition Syncope
17
Q

R” - Rate Responsiveness

A

Increases the lower rate setting in response to increase metabolic demand

Measured by…

  1. Body Vibration
  2. Respiratory Rate (minute ventilation)
18
Q

Componants of DDD Algorithm/Settings

A
  1. Lower Rate Limit
  2. Upper Rate Limit
  3. AV Delay

HR between rates → 1:1 pacing of the ventricle unless the ventrticle depolarizes prior to the delay length

Atrial HR below lower limit → atrial pacing at the lower limit rate

Atrial HR above upper limit → ventricle paced at upper limit (Wenchebach appearance)

19
Q

Anticoagulation for AFib Trials

A

Warfarin vs. DOAC for non-valvular AFib

  1. RE-LY (2009 NEJM) - Dagatroban
  2. ROCKET-AF (2011 NEJM) - Rivaroxiban
  3. ARISTOTLE (2011 NEJM) - Apixaban
20
Q

MAZE Energy Sources

A
  1. Radiofrequency
  2. Cryoablation
  3. High-Intensity Focused U/S
  4. Laser
21
Q

Normal ECG Intervals

A
  1. PR Interval 120-200ms (3-5 small boxes)
  2. QRS Duration < 120ms (3 small boxes)
  3. QT < 400ms
22
Q

Indications for DDD pacing in elderly patients

A
  1. Pacemaker Syndrome
  2. HTN
  3. CHF
23
Q

Magnet Mode

A

VOO

24
Q

Best PPM mode for Trasnplant Patients with SA Node Dysfunction

A

AAIR

25
Q

Treatment of Acute Bradycardia

A
  1. Atropine
  2. Dobutamine
  3. Isoproterenol
  4. Temporary Pacing
26
Q

Anatomical Vascular Approaches to PPM Insertion

A
  1. Cephalic Vein
  2. Axillary Vein
  3. Subclavian Vein
  4. External Jugular
  5. Internal Jugular
27
Q

Complications of PPM Insertion

A

Perioperative Complications

  1. Pneumothorax
  2. Hemothorax
  3. Major Vessel Injury (Arterial)
  4. Lead Displacement
  5. Venous or Cardiac Perforation
  6. Air Embolism
  7. VT/VF

Late Complications

  1. Infection/Erosion
  2. Lead Entrapment
  3. Device Dysfunction
  4. Lead Fracture (impedance < 300 → insulation #; > 1000 poor conduction)
  5. Subclavian Crush
  6. Twiddler’s Syndrome
  7. Pacemaker-Mediated Tachycardia
28
Q

Implant Parameters

A

R-wave amplitude > 5mV

P-wave amplitude > 2mV

Impedance 400 - 1000 ohms

Thresholds < 1.0V at 0.5ms

(No diaphragmatic stimulation at 10V)

29
Q
A
30
Q

Pacemaker-Mediated Tachycardia

A

PVC conducted retrograde through the AV node causing retrograde depolarization of the atrium sensed by the pacemaker triggering inappropriate pacing of the ventricle at the upper rate limit

Limiting the upper rate limit setting or increasing the postventricular atrial refractory period to 300-350ms after the QRS may correct this

31
Q

Pacemaker Syndrome

A

Loss of AV synchrony in VVI mode (contraction of the atrium against a closed AV valve; eleviated in DDD mode)

32
Q

Sensing Problems

A
  1. Undersensing
  2. Oversensing
  3. Crosstalk
  4. Far-Field Sensing
  5. Exit Block (reduced by steroid-eluting leads)
33
Q

Mode Switching for Paroxysmal AFib

A

VVIR → when upper rate limit is exceeded

DDDR → when atrial rate belwo the upper rate limit

Requires

  1. Bipolar leads
  2. High sensitivity setting to detect low-amplitude AF
34
Q

Trials Demonstrating Benefits of ICD Therapy

A
  1. AVID
  2. MUSST
  3. MADIT-I (EP Inducable VT, with clinical non-sustained VT and PMHx of MI)
  4. MADIT-II (PMHx of MI and EF < 30%)
  5. SCD-HeFT
  6. COMPANION

No Benefit of ICD Therapy

  1. CABG-Patch (CABG vs. CABG+ICD)
  2. DINAMIT (ICD Post-MI)
35
Q

Indications for ICD Implantation

A

Secondary Prevention

  1. Clinical VT/VF, EP Inducable VT/VF, Absence of MI, Unsuitable for Rx or Ablation
  2. Clinical VT/VF, EP Inducable VT/VF, PMHx of MI

Primary Prevention

  1. ICM, LVEF < 35%, NYHA Class II or III, > 40d post-MI
  2. ICM, LVEF < 30%, NYHA Class I, > 40d post-MI
  3. Non-ICM, LVEF < 35%, NYHA Class II or III
36
Q

Causes of VT Refractory to Defibrillation

A
  1. Iatrogenic Pneumothorax
  2. Myoardial Ischemia
  3. Electromagnetic Dissociation
  4. Inappropriate ICD Lead Location
37
Q

Criteria for Class I Indication for CRT

A
  1. LVEF < 35%
  2. NSR
  3. Optimal Medical Therapy
  4. LBBB with QRS > 150ms
  5. NYHA Class II, III or ambulatory IV