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Ayman M. Kamaly, MD Professor of
Anesthesiologists Do it … Do it … while you sleep !!
Overview : 1958: 1958: 1 st Battery operated pacing devices. 1980: 1980: Implantable Cardioverter- ICDs defibrillator (ICDs). Today: Today: > 2000 pacemaker models, produced by 26 companies.
Epidemiology: No reliable Egyptian data. USA data: > 250,000 adults & children are undergoing Cardiac Rhythm Management Device (CRMD) implantation annually. Aging, advances in CRMD technology & expanding indications for pacing, will lead to growing numbers of patients with CRMD.
not uncommon This will increase the chances to be confronted with patients having CRMD (not uncommon). comorbid diseases Those patients often have significant comorbid diseases and need procedures of varying complexities. primary medical problems understanding these devices Our ability to care for these patients requires attention to their primary medical problems, as well as understanding these devices.
Permanent Pacemaker Indications: Symptomatic Sinus Bradycardia. S A Node Disease. Symptomatic A V Node Disease. Hypertrophic Obstructive Cardiomyopathy (HOCM). Dilated Cardiomyopathy (DCM). Long Q T Syndrome. Bryce et al, Ann Intern Med. 2001; 134:
How CRMD Works?! Basic: Basic: Track the native electrical rhythm. When doesn't sense a heart beat within a normal beat-to-beat time, it stimulates the ventricle. More complex: More complex: Sense &/or stimulate both; atrium and ventricle. Much More Complex:Rate Modulation Much More Complex: Rate Modulation
Rate Modulation Sensors
Generic Pacemaker Code (NASPE/ BPEG, Revised 2002) NASPE NASPE: North American Society of Pacing & Electrophysiology, BPEG BPEG: British Pacing & Electrophysiology Group. * = When 2 atria or 2 ventricles are paced.
Asynchronous: (AOO, VOO, & DOO) Fixed (preset rate) rate pacemaker. Discharges irrespective of the native heart rate. Hazard Hazard: Competes with the native intrinsic rhythm arrhythmias induction. Examples and Types of Pacing Modes:
Single Chamber Atrial Pacing (AAI, AAT) Atrium is paced and the impulse passes down the conducting pathways, thus maintaining A-V synchrony. A single lead in the Rt. Atr., which senses the intrinsic P wave and causes inhibition or triggering of the pacemaker. Useful in sinus arrest & sinus bradycardia (adequate AV-conduction) Inappropriate for chronic AF & long ventricular pauses.
Single Chamber Ventricular Pacing (VVI, VVT) VVI: The most widely used pacing mode. ventricle is sensed & paced. It senses the intrinsic R wave and thus inhibits the pacemaker function. Indications: Complete HB with chronic AF, Af, & long ventricular pauses.
Dual Chamber AV Sequential Pacing (DDD, DVI, DDI, and VDD) Using 2 leads (Rt. Atr. & Rt. vent.) 1 st : atrium is stimulated to contract, After an adjustable PR interval, ventricle is stimulated (preserve normal AV contraction sequence), indications: AV block, SA node disease. In DDD system, both the atrium and ventricle can be sensed and paced. Advantages: mimic SR, so beneficial when atrial contraction is important for ventricular filling (e.g. A.S.)
Effect of the Magnet Application on Pacemaker Function. Magnet-activated switches Magnet-activated switches were incorporated into pacemakers to produce pacing behavior that demonstrates remaining battery life. Never intended to treat pacemaker emergencies or prevent EMI effects
can be EMI Thus, magnets can be used to protect the pacemaker- dependent patient during EMI, (diathermy/cautery). Magnet application results in a non-sensing asynchronous mode with a fixed pacing rate (magnet rate). not without risk Use of magnet during surgery is not without risk. Asynchronous pacing may trigger malignant rhythm.
Not All Pacemakers Switches to a Continuous Asynchronous Mode When a Magnet is Applied. surprise programme In programmable pacemakers, in the presence of EMI, generator may unpredictably reprogrammed with a new surprise programme. should be considered programmable Most current devices should be considered programmable unless known otherwise.
Anesthesiologists You Sleep.. We Care !!
How to Deal with a Patient with CRMD
Stepwise Approach Patient with a CRMD: 1. Routine preoperative evaluation: CAD (50%) HTN (20%) & DM (10%), Assess: (1) severity, (2) current functional, status (3) medication. CXR, (continuity of leads) ECG, (Spike) Bioch (s. K + ) I.Preoperative Evaluation:
2.Confirm whether a patient has a CRMD: Focused history Focused history: interview, medical records, CXR, ECG. Inquire about the initial indication for the pacemaker & pre-implantation symptoms (dizziness, fainting). scars palpate Focused physical examination (check for scars, palpate for device). Preoperative Evaluation (Cont.):
3. Define the type of CRMD. ID card Obtain manufacturers ID card from patient. CXRX-Ray code If no other data is available: CXR (X-Ray code). 4. Determine patient dependency on CRMD pacing. VVI No spontaneous ventricular activity when programmed to VVI mode at the lowest programmable rate. Preoperative Evaluation (Cont.):
5. Evaluation of CRMD function. INTERROGATED Get the device INTERROGATED (by Cardiologist) & get a copy !! Preoperative Evaluation (Cont.):
pacing mechanical Ensure that the electrical pacing impulse creates a mechanical systole (preph. pulse) !! If VVI mode: if intrinsic HR is > set rate, slow down HR (carotid massage or Valsalva manoeuvre), while ECG is monitored. Preoperative Evaluation (Cont.): 5.Evaluation of CRMD function (Cont.)5.Evaluation of CRMD function (Cont.)
II.Preoperative Preparation 1. If Intraop. EMI is likely to occur : Reprogram to Asynchronous mode. Deactivate all Rate Responsive !! Activity rate responsive: shivering and fasciculations Minute ventilation rate responsive: (RR & V t ) should be kept controlled Temperature rate responsive Temp kept constant. Disable Antitachyarrhythmia functions if present (if CRMD is ICD). Temporary pacing and defibrillation equipment should be immediately available (all CRMD).
2. Evaluate the possible effects of anesthetic techniques on CRMD function. CXR to document the position of the Coronary Sinus lead, if CVL placement is planned, (CS lead displacement). II.Preoperative Preparation (Cont.)
III.Intraoperative Management (Cont.) 2. Anesthetic Technique: Should be dictated by patients underlying physiology &/or procedure. truly pacemaker dependant Agents suppresses AV or SA node (potent opiates or dexmedetomidine) may render patient truly pacemaker dependant. Myoclonic movements, can inhibit or trigger stimulation, (according to programmed pacing modes): Succ. Ch. Succ. Ch.: fasciculation, Etomidateketamine Etomidate & ketamine: myoclonic movements. Nitrous Oxide ??!
3. EMI–Induced CRMD Potential Dysfunction A.Electrocautery: AvoidUnipolar (χ χ) Avoid Unipolar (χ χ). UseBipolarorultrasonic harmonic) Use Bipolar or ultrasonic (harmonic) () If unipolar used: Grounding plate: as far as possible from the pacemaker site, notpass through or near the CRMD Assure that the current does not pass through or near the CRMD Not15 cm Distance: Not within 15 cm of pacemaker. 1-second10 seconds Frequency: 1-second every 10 seconds (to prevent repeated asystolic periods). cutCoag Pure cut is better than Coag. Asynchronous Asynchronous Mode (magnet or programmer). Emergency Tools Emergency Tools: Temporary pacing (transvenous, trans - cutaneous), Atropine, Isupril should be ready. III.Intraoperative Management (Cont.)
B.Nature of Procedure: Lithotripsy (ESWL): Lithotripsy (ESWL): Avoid beam focusing near the generator. Rwave If triggers on the R-wave, disable atrial pacing. Radiology: Radiology: Do Not affect Plain X-ray & CT: Do Not affect pacemaker function Contraindicated MRI: Contraindicated Generally III.Intraoperative Management (Cont.) 3.EMI–Induced CRMD Potential Dysfunction (Cont.)
Radio-therapy: Radio-therapy: Safe (Surgically relocate CRMD outside radiation field ECT: ECT: ECT itself safe (little current flows within the heart) Succinylcholine and seizure (!!!) Reprogram to asynchronous mode. External pacemaker should be available. III.Intraoperative Management (Cont.) 3.EMI–Induced CRMD Potential Dysfunction (Cont.) B.Nature of Procedure (Cont.):
ACLS Follow existing ACLS guidelines (energy level & paddle placement). Minimize the current flow through the generator & lead system by positioning the paddles : 1. As far as possible 1. As far as possible from the pulse generator, 2. Perpendicular to the major axis 2. Perpendicular to the major axis of the generator and leads to the extent possible by placing them in ananterior–posterior location. IV.Emergency Defibrillation or Cardioversion.
ICU Setup ICU Setup (Continuous ECG monitor, backup pacing & defibrillation). Assure that all CRMD settings are restored: Interrogate CRMD; (cardiologist/manufacturer) V.PostoperativeManagement V.Postoperative Management
Thanks for your Attention !! Oh.. Thank God … Hes Done Oh.. Thank God … Hes Done