Intrathoracic Impedance and Fluid Monitoring The Heart Group, Lancaster, PA

1. Intrathoracic Impedance and Fluid Monitoring  The Heart Group, Lancaster, PA

2. CRT in Lancaster: June 2005 First CRT implant 11.13.98 >1,200 CRT device implants to date Patients with CRT devices routinely followed in the CHF clinic

3. Case 1: 20 Day Early warning Patient History 62 y.o. woman Diabetes, NICM, EF~35% HTN, DM, PAF, depression Sentry (prior PCD reached EOL) Medical Treatment Quinapril, carvedilol, spironolactone, bumetanide, digoxin, coumadin

5. Case 1, Lessons Poor correlation of impedance measurements with BNP Recognition of weight gain following “positive” OptiVol reading and after initiation of diuretic therapy Follow up: As of September weight increased 25 lbs. BNP 100, Chest X-ray NAD, no CHF signs and thoracic impedance below threshold

6. Case 2: True Positive Patient History 70 y.o. man with ICM EF ~ 30% DM, ablation for atrial flutter, hyperlipidemia Medical Treatment Lisinopril, metoprolol succinate, bumetanide, amiodarone, coumadin

8. Case 2, Lessons Utility of other telemetry data in determining etiology of decompensation AF preceded fall in impedance Loss of consistent BiV pacing due to rapid AF presumably lead to decompensation Poor correlation of BNP with impedance Follow up: August- seen in CHF clinic. Weight gain, BNP 728, impedance falling (not at threshold), diuretics increased

9. Case 3: False Positive Patient History 70 y.o. woman NICM EF ~ 20% DM, renal insufficiency, anemia, ASD repair 1990, prior MI, chronic AF Medical Treatment Carvedilol, bumetanide, digoxin, coumadin, hydralazine (intolerant of ACE and ARB), spironolactone

11. Case 3, Lessons Baseline established while patient “dry” lead to “misinterpretation” of OptiVol fluid index Did not change diuretics patient was dry

12. Summary Learning curve Thoracic impedance is highly sensitive to fluid changes Impedance data should be interpreted in the context of clinical findings Impedance measurements will be of significant benefit when used with other telemetry data Clinicians must routinely have access to impedance measurements Pitfalls Hematoma, pneumonia, baseline dehydration may cause “false positive” Vascular congestion during implant and initial stabilization period may cause “false negative”