Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Dual Chamber Temporary Pacing Operations & Troubleshooting Indications for Dual Chamber Temporary Pacing Complete heart block Sinus bradycardia Bradycardia with congestive heart failure Atrial and/or ventricular ectopic arrhythmia Reentrant tachycardias During pulse generator replacement Indications for Dual Chamber Temporary Pacing Prior to the implant of a permanent pacemaker Temporary support of a patient after heart surgery Acute myocardial infarction complicated by heart block High rate burst stimuli for the treatment of some tachyarrhythmias The NASPE/BPEG Generic (NBG) Code Position I Category Chamber(s) Paced II III IV V Chamber(s) Sensed Response to Sensing Programmability Rate Modulation Antitachyarrhythmia Function(s) O = None O = None O = None O = None O = None A = Atrium A = Atrium T = Triggered P = Simple Programmable P = Pacing V = Ventricle V = Ventricle I = Inhibited M = Multiprogrammable S = Shock D = Dual (A+V) D = Dual (A+V) D = Dual (T+I) C = Communicating D = Dual (P+S) R = Rate Modulation Manufacturer’sS = Single Designation (A or V) Only S = Single (A or V) Note: Positions I through III are used exclusively for antibradyarrhythmia function Asynchronous Modes AOO VOO DOO DVI 1 2 3 Ap * Ap * * Vp Vs 4 Ap * * Vp = AV interval (140 ms) = PVARP (250 ms) = indicates cycle restarted by sensed or paced event * Vp 5 Ap * 6 Ap * * Vp Lower rate = 60 ppm V-A interval = 860 ms * Vp DDD Pacing Chamber Paced Chamber Sensed Action or Response to a Sensed Event D D D DDD Pacemaker Provides: AV Synchrony Rate Variability Results in: Changes in cardiac output Management of rhythm Improved quality of life Parameter Adjustments of the Temporary DDD Pacemaker Lower Rate A–V Interval Upper Rate Output Sensitivity Refractory Period (PVARP) ECG Function DDD Mode Timing Intervals in milliseconds (ms) V–A A–V 750 ms 250 ms V–V 1000 ms DDD / 60 / 250 / 125 / 155 Calculation of Atrial Escape Interval Atrial Escape Interval Lower Rate – A–V Interval = V–V (ms) – A–V (ms) = V–A (ms) (60 ppm) 1000 – 250 = 750 (60 ppm) 1000 – 150 = 850 (70 ppm) 850 – 200 = 650 Proper Atrial Sensing is the “Heart” of Physiologic Pacing A Pace / V Pace A–V Sequential Pacing V–A A–V 750 ms 250 ms V–V 1000 ms DDD / 60 / 250 / 150 A Pace / V Sense Atrial Pacing with Normal A–V Conduction DDD / 60 / 200 / 150 Programmed Lower Rate 1000 ms Actual V–V 960 ms A Sense / V Pace Atrial Synchronous Pacing Spontaneous Atrial Rate = 55 ppm DDD / 50 / 150 / 150 Spontaneous Atrial Rate = 110 ppm A Sense / V Sense Spontaneous P-Wave with Normal A–V Conduction Spontaneous Atrial Rate = 65 ppm Spontaneous P-R Interval = 160 ms DDD / 60 / 200 / 150 Timing Operations of DDD Pacing Ventricular Rate Upper Rate Atrial Tracking Lower Rate Atrial Rate Definitions PVARP – Post Ventricular Atrial Refractory Period Time after Vs or Vp when atrial rates are ignored A–V – Time from As or Ap to Vp in ms TARP – Total Atrial Refractory Period in ms Refractory Period Increase to prevent: – T-wave sensing – P-wave sensing Decrease to permit tachy pacing Wenckebach Operation Wenckebach Operation AV AV W PVARP AV W PVARP Upper Rate As AV PVARP Upper Rate As W AV PVARP Upper Rate As PVARP Upper Rate As Upper Rate As As Vp Vp W = Wenckebach Interval Vp Vp Vp 2 : 1 Block 2 : 1 Block AV AV AV AV PVARP PVARP PVARP PVARP Upper Rate Upper Rate Upper Rate Upper Rate As As Vp As As Vp As As Vp As As Vp Physiology of Retrograde Conduction 1. Loss of A-V synchrony due to a PVC 2. Sensed retrograde activation 3. A-V interval initiated PVC4. Prolongation of A-V interval 5. Ventricular pacing synchrononized to retrograde P-waves Pacemaker Mediated Tachycardia (PMT) Fast ventricular paced rhythm Synchronized to retrograde- conducted P-waves Not normal sinus tachycardia Thresholds Feature of the Temporary DDD Pacemaker Output Control Atrial Ventricular Pulse Amplitude (ma) Pulse Width (ms) Feature of the Temporary DDD Pacemaker Sensitivity 2.5 1.25 0.5 Troubleshooting Undersensing Failure of the pacemaker to sense intrinsic R-waves or intrinsic P-waves Undersensing Battery depletion Decreased QRS voltage Fusion beat Dislodged/fractured lead Inappropriate sensitivity setting Oversensing Inhibition of the pacemaker by events the pacemaker should ignore, e.g. EMI, T-waves, and myopotential Oversensing Myopotential inhibition EMI T-waves outside of refractory period Dislodged/fractured lead Inappropriate sensitivity setting No Output Pacemaker fails to emit stimuli at the programmed intervals No Output 1 AP VP 2 AS VP 3 AP VP 4 AP VP 5 AP VP No atrial output (on ECG) Battery depletion/pacemaker off Faulty cable connection Oversensing Dislodged/fractured lead Loss of Capture Electrical stimuli delivered by the pacemaker does not initiate depolarization of the atria or ventricle Loss of Capture Atrial Noncapture Ventricular Noncapture Fusion Inappropriate output setting Dislodged/fractured lead Increased resistance to conduction Tissue is refractory QRS complex not visible Faulty cable connection Ventricular Safety Pacing Ap Ap = Atrial Pace Vp = Ventricular Pace Ventricular Blanking at Atrial Rate Vp Programmed A-V Interval 12 ms Ventricular Safety Pace Interval 110 ms Programmed A-V Interval Ventricular Sensing within this period triggers a ventricular output at an A-V interval of 110 ms instead of programmed A-V interval. Ventricular Sensing during the remainder of the programmed A-V interval inhibits the ventricular output. If there is no sensed event, a ventricular output occurs at the programmed A-V interval. Ventricular Safety Pacing (VSP) 1 Ap * * Vs Vp 2 Ap * 3 4 Ap * Ap * Ap * * Vs Vp * Vs Vp * Vp * Vp = AV interval (160 ms) = PVARP (250 ms) = indicates cycle restarted by sensed or paced event Lower rate = 54 ppm Upper rate = 180 ppm V-A interval = 860 ms 5