Vol 41 # 3 September 2009 - Kma.org.kw

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September 2009 KUWAIT MEDICAL JOURNAL 211 Table 1: Baseline clinical characteristics of patients with ICD lead failure Pt. No. Age Sex Diagnosis LVEF % Indication 1 2 3 4 5 6 7 8 27 62 62 42 14 55 58 66 M F M M F M F M Idiopathic VT/VF, SCD DCM , HF Ischemic CMP, S/P CABG Ischemic CMP, S/P CABG Long QT Ischemic CMP DCM Ischemic CMP 65 25 30 25 65 35 23 20 Idiopathic VT/VF Survivor of SCD Primary prevention Syncope and inducible VT Primary prevention Primary prevention Spontaneous VT Primary prevention Primary prevention M = Male, F = Female, VT= Ventricular tachycardia, VF= Ventricular fibrillation, Pt. = Patient, SCD- Sudden Cardiac Death, DCM = Dilated cardiomyopathy, HF = Heart Failure, CABG = Coronary Artery Bypass Graft, LVEF = Left Ventricular Ejection Fraction, CMP = Cardiomyopathy warn physicians. Lead malfunction is defined as lead failure that requires lead replacement. Lead failure is diagnosed if noise oversensing is present that is not related to cardiac cycle, lead impedance is out of normal range and/or sensing failure evidenced a drop in ventricular sensing signal less than two millivolt or lead fracture is seen on X-ray. Eight patients were included after having signed an informed consent form. This study was approved by the local ethical committee. RESULTS A total of eight defibrillator leads failed during follow-up. Lead failure was diagnosed at a mean time of 47.1 ± 29.1 months (range: 16 - 60.1 months) after ICD implantation. Six patients had a defibrillator device and two patients had bivent-ICD. Baseline clinical characteristics of patients with lead failure are listed in Table 1. There were five male and three female patients with a mean age of 48.3 ± 18.9 years (range: 14 - 66 years) at the time of diagnosis of lead failure. Four patients had the device implanted as primary prevention of sudden cardiac death due to ischemic cardiomyopathy and one for long QT syndrome. One patient had the device implanted for syncope and inducible ventricular tachycardia on electrophysiological study. The other two patients had the device implanted after resuscitation from spontaneous ventricular tachycardia / ventricular fibrillation. The affected lead models are listed in Table 2. All patients except one had the leads implanted through left subclavian venous access. Diagnosis of lead failure was made by clinical presentation as inappropriate shocks in four patients due to noise oversensing on a ventricular electrogram during sinus rhythm (Fig. 1A and 1B) and was discovered during routine follow-up in the remaining four patients who were asymptomatic. Routine device testing revealed high lead impedance out of normal range (Fig. 2A), noise registration on stored electrogram and drop in ventricular sensing signals in two patients (Fig. 2B). In other two patients routine testing revealed increased lead pacing threshold and sudden increase in lead impedance out of normal range without noise oversensing (Fig. 2C). None of the patients had radiographic signs of lead fracture except patient no. 8 in whom the lead failure was due to Twiddler’s syndrome. All patients underwent new lead implantation without complications. DISCUSSION The annual rate of ICD lead failure requiring intervention increases with time and reaches Table 2: Clinical presentation and follow-up of patients with ICD lead failure Pt. No. Venous Site Lead Model ICD Implant Implant to fracture (Months) 1 2 3 4 5 6 7 8 Left subclavian Left subclavian Left subclavian Left subclavian Left subclavian Left subclavian Right subclavian Left subclavian Medtronic 6947 Medtronic 6949 Medtronic 6945 Medtronic 6949 Medtronic 6943 Medtronic 6944 Medtronic 6948 Guidant 0185 Single Chamber Device Biventricular device Single Chamber Device Dual chamber device Single Chamber Device Dual chamber device Biventricular Device Single Chamber Device 89 16 85 20 49 54 48 16 Clinical presentation at follow-up High impedance sensing failure, noise over sensing Inappropriate shocks Inappropriate shocks High impedance Inappropriate shocks High impedance Inappropriate shocks High impedance and loss of capture (Twiddler’s Syndrome) Pt. = Patient, ICD = Implantable cardioverter-defibrillator
212 Mode of Detection of Transvenous Defibrillation Lead Malfunction in Implantable Defibrillators September 2009 Fig. 1A: Shows inappropriate shock during sinus rhythm from noise artifact causing far field sensing and short V-V intervals on ventricular electrogram Fig. 1B: Noise on the ventricular electrogram from patient with far field sensing during sinus rhythm from one of the episodes stored by the device 20% in ten year old leads [5-7] . It is encountered in all types of lead models. In addition, a growing number of insulation defects have to be expected with increasing time after implantation [8,9] . The mechanism leading to lead failure could be related to multiple leads implanted, specific lead designs and chronic pressure on the lead from ligature Fig. 2A: Device interrogation indicating defibrillator lead impedance out of normal range used to fix the lead [10] . Higher activity as in young patients could also result in chronic mechanical stress on the lead leading to higher lead failure as in two of our patients (patient no. 1 and 5). In addition subclavian crush syndrome could also be a cause of lead failure [11] . There are many reports on higher lead complication rate with subclavian venous puncture [12] . All patients with lead failure were implanted with subclavian technique. Lead failure was diagnosed by inappropriate shocks in four patients. All were due to artifact sensing and detection consistent with other reports [7,13-15] . In the present study the number of inappropriate shocks ranged from four to ten. Routine ICD follow-up lead to diagnosis of lead failures in the other four patients emphasizing the need for continuous follow-up of old leads including sense / pace parameters, lead impedance, far field sensing and possibly high voltage coil impedance. Novel and innovative ways to better help improve cardiac patient care by providing timely diagnosis of patient conditions without the need of a face-to-face visit mainly by Telemedicine, the provision of healthcare
Page 1 and 2: VOLUME 41 NUMBER 3 KMJ KUWAIT MEDIC
Page 3 and 4: Kuwait Medical Journal (KMJ) Publis
Page 5 and 6: Instructions for Authors Acknowledg
Page 7 and 8: AN ADDED FEATHER TO THE KMJ’S CAP
Page 9 and 10: 186 Swine-origin Influenza A (H1N1)
Page 11 and 12: 188 Population Health Genomics in M
Page 29 and 30: 206 Evaluation of Dermatology Resid
Page 31 and 32: 208 Evaluation of Dermatology Resid
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Page 51 and 52: 228 Blunt and Penetrating Thoracic
Page 55 and 56: 232 Small Bowel Tumors: Insidious a
Page 57 and 58: 234 Small Bowel Tumors: Insidious a
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Page 65 and 66: 242 Severe Diabetic Ketoacidosis Pr
Page 67 and 68: 244 Acquired Hemophilia in a Child:
Page 75 and 76: 252 Neurosarcoidosis as a First Pre
Page 79 and 80: 256 Urosepsis Simulating Congenital
Page 81 and 82: 258 Rituximab in Severe Refractory
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262 Selected Abstracts of Articles
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264 Selected Abstracts of Articles
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266 Forthcoming Conferences and Mee
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272 KUWAIT MEDICAL JOURNAL Septembe
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274 WHO-Facts Sheet September 2009
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