Case Studies St. Jude Medical

Single Chamber ECG Analysis Programmed Parameters Mode………………………………………….. VVI Base Rate……………………………………….. 70 ppm Magnet Response…………………….. Battery Test Hysteresis Rate………………………………… Off ppm T Temporary programmed value 1.0 Second 7 Mar 2000 23:20

Single Chamber ECG Analysis Answer ECG #1 VVI Normal Capture and Sensing

Single Chamber ECG Analysis

Single Chamber ECG Analysis Answer ECG #2 VVI Normal Capture and Sensing with initiation of Hysteresis

Single Chamber ECG Analysis

Single Chamber ECG Analysis Answer ECG #3 VVI Loss of Ventricular Sensing

Single Chamber ECG Analysis 1.0 Second

Single Chamber ECG Analysis

Single Chamber ECG Analysis Answer ECG #4 VVI Normal Capture and Sensing

Single Chamber ECG Analysis

Single Chamber ECG Analysis

Single Chamber ECG Analysis Answer ECG #5 VVI Normal Capture Ventricular Undersensing

Single Chamber ECG Analysis

Single Chamber ECG Analysis

Single Chamber ECG Analysis Answer ECG #6 VVI Loss of Ventricular Capture Normal Sensing

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AVD 200 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #1 Loss of Atrial Capture Normal Atrial Sensing Normal Ventricular Capture Ventricular Sensing Unknown

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 150 ms Min. PV 75 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #2 Normal Atrial Capture Normal Atrial Sensing Normal Ventricular Capture Ventricular Sensing Unknown

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 150 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #3 Normal Atrial Capture Possible Psuedofusion on 4th atrial output Atrial Sensing Unknown Loss of Ventricular Capture Normal Ventricular Sensing Functional Loss of Ventricular Sensing

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 200 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #4 Normal Atrial Capture Atrial fusion on 3rd atrial output Normal Atrial Sensing Normal Ventricular Capture Normal Ventricular Sensing

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 200 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #5 Normal Atrial Capture Atrial Sensing Unknown Normal Ventricular Capture Fusion on 2nd ventricular output Normal Ventricular Sensing

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 200 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #6 Normal Atrial Capture Atrial Sensing Unknown Normal Ventricular Capture Fusion on 2nd ventricular output Ventricular Sensing Unknown

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 200 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #7 Normal Atrial Capture Normal Atrial Sensing Normal Ventricular Capture Normal Ventricular Sensing

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 200 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #8 Normal Atrial Capture with one beat showing functional loss of atrial capture Atrial Undersensing Normal Ventricular Capture Ventricular Sensing Unknown

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 200 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #9 Normal Atrial Capture Normal Atrial Sensing Normal Ventricular Capture Normal Ventricular Sensing

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 200 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #10 Normal Atrial Capture Normal Atrial Sensing Normal Ventricular Capture with two beats of functional loss of capture Ventricular Undersensing

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 150 ms PV 150 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #11 Atrial Capture Unknown Normal Atrial Sensing Normal Ventricular Capture Ventricular Sensing Unknown

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 150 ms Min. PV 88 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #12 Normal Atrial Capture Normal Atrial Sensing Normal Ventricular Capture Ventricular Sensing Unknown Initiation of a Pacemaker Mediated Tachycardia (PMT) with following a PVC

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 150 ms Min. PV 88 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #13 Loss of Atrial Capture initiating a Pacemaker Mediated Tachycardia (PMT) Normal Atrial Sensing Normal Ventricular Capture Ventricular Sensing Unknown

Dual Chamber ECG Analysis Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 150 ms Min. PV 88 ms PVARP 250 ms

Dual Chamber ECG Analysis Answer ECG #14 Normal Atrial Capture Atrial Sensing Unknown Normal Ventricular Capture Normal Ventricular Sensing The retrograde P-wave after the PVC is not seen because it falls in PVARP just like it should

ICD ECG Analysis ECG #1

ICD ECG Analysis ECG #1

ICD ECG Analysis Answer ECG #1 T-Wave sensing longer decay delay Threshold start higher

Twiddler‘s Syndrome Presented with left hemi-diaphragmatic stimulation from atrial lead

Twiddler‘s Syndrome Courtesy of Dr. F. Venditti, Lahey Clinic, MA` Operative Color Picture- Twiddler’s Syndrome Courtesy of Dr. Ferdinand Venditti, Chief of Cardiology at the Lahey Clinic. Twiddler’s syndrome with lead twisted in the pocket. While the general advise is to never hold a lead with mechanical forceps or a hemostat as this may damage the lead, when the lead is as twisted as this one, it should not be re-advanced into the patient. Hence, it is being held with an instrument. This lead has been subjected to excessive stresses such that even if straightened and re-advanced into the patient, it is likely to have mechanical problems at some later date. Hence, if the pocket has to be entered due to Twiddler’s Syndrome, the lead should be removed and replaced with a new lead. Slide Series: X-Ray-99.ppt Courtesy of Dr. F. Venditti, Lahey Clinic, MA` 63

Rib-Clavicle Crush Rib-Clavicle Crush - Dual Unipolar DDD pacing - X-Ray These are cone down views of a PA chest x-ray obtained just prior to discharge after the pacing system was implanted and again 22 months later when the patient presented with an open circuit on the atrial channel. The measured lead impedance as > 1990 ohms. Both leads had been implanted via subclavian venipuncture using a relativiely medial approach. While one was totally transected, the other appeared to be functioning normally. However, as both leads were literally in the same tract and hence, both were subjected to similar external forces, both leads were replaced with the pulse generator moved to the other side of the body. In this patient, a diligent search had been made for the cephalic vein at the original implantation. Only when it could not be found was the subclavian approach utilized. At the revision procedure, the patient did not have a detectable cephalic vein in the right antecubital fossae and there was only a thin whisp of a vein on venography. Hence, subclavian venipuncture was again utilized. This antedated the appreciation of accessing the axillary vein although in the revision procedure, attempts were made to stay as lateral as possible. Slide Series: X-Ray-99.ppt

Rib-Clavicle Crush Rib-Clavicle Crush - Scanning EM of Internal insulation The same lead shown in the X-ray and the gross picture of the extracted lead was dissected in the Reliability lab. The external conductor was carefully removed leaving the internal insulation and internal conductor coil. The insulation demonstrates abrupt breaks which expose the internal (proximal) conductor to the distal conductor. Make-break contact between these two conductors generated voltage transients leading to episodes of oversensing. Persistent contact may result in a total short circuit and noncapture despite the presence of an output. The measured impedance will be < 250 ohms. Based on this scanning electron microscopic picture, the insulation is cracked through and through in multiple places from external stress on the lead. The insulation between these cracks is totally normal. Slide Series: X-Ray-99.ppt

Rib-Clavicle Crush Original lead damaged by rib-clavicle crush. New lead placed via cephalic vein cutdown

Myopotential Oversensing

Evaluation of Oversensing Reproduce while monitoring EGM / Event Markers Try to eliminate with reduced sensitivity Provocative maneuvers

Ventricular Fusion

Ventricular Pseudofusion

Loss of Capture due to Intrinsic Rise in Capture Threshold Metabolic abnormalities Hyperkalemia ( ­ K+ ) Congestive Heart Failure Changes in time of day sleep >> wake Exercise and heart rate Pharmacologic agents Flecainide Bipolar VVI with 2nd degree Wenckebach exit-block due to hyperkalemia (serum K 7.3 mEq/L). Upon correction of elevated potassium level, capture threshold was 1.3 V @ 0.8 ms

Hysteresis Slower rate and pauses ONLY follow native beats First escape cycle followed by pacing at higher rate Management Education Disable if causing problems Programming Base Rate: 115 ppm Hysteresis Rate: 65 ppm