Beyond Heart Rhythms: New Directions for Implantable Devices

  • Fred Kusumoto
  • Nora Goldschlager


Implantable cardiac devices have become firmly entrenched as important therapeutic tools for a variety of conditions. Pacemakers are the only available treatment for symptomatic bradycardia not due to reversible causes. Large randomized studies have demonstrated a small but statistically significant reduction in atrial fibrillation associated with pacing modes that maintain atrioventricular synchrony. In contrast, pacing mode appears to have a less dramatic effect in patients with atrioventricular block. Cardiac resynchronization with specialized left ventricular leads has been shown to reduce symptoms and improve survival in patients with symptomatic heart failure, systolic dysfunction, and widened QRS complexes. The implantable cardioverter defibrillator has become the standard therapy for protecting patients against sudden cardiac death. Two recent trials, Multicenter Automatic Defibrillator Trial II (MADIT II) and the Sudden Cardiac Death Heart Failure Trial (SCD-HEFT), demonstrated that the ICD is associated with a significant survival benefit for patients with reduced ejection fraction (< 0.30–0.35) particularly if heart failure symptoms are present. Finally the implantable loop recorder has become an important diagnostic tool for the patient with unexplained syncope. This brief overview summarizes the indications and follow-up of the wide array of implantable cardiac devices available to the clinical cardiologist.

Key Words

implantable devices pacemakers 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Steimle AE, Stevenson LW, Chelimsky-Fallick C, Fonarow GC, Hamilton MA, Moriguchi JD, Kartashov A, Tillisch JH. Sustained hemodynamic efficacy of therapy tailored to reduce filling pressures in survivors with advanced heart failure. Circulation 1997;96:1165–1172.PubMedGoogle Scholar
  2. 2.
    Adamson PB, Magalski A, Braunschweig F, Bohm M, Reynolds D, Steinhaus D, Luby A, Linde C, Ryden L, Cremers B, Takle T, Bennett T. Ongoing right ventricular hemodynamics in heart failure. Clinical value of measurements derived from an implantable monitoring system. J Am Coll Cardiol 2003;41:565–571.PubMedGoogle Scholar
  3. 3.
    Bourge R. Presentation at the 2005 Annual Scientific Meeting of the American College of Cardiology, Orlando FL.Google Scholar
  4. 4.
    Wang L, Yu CM, Chau E, et al. Impedance based prediction of CHF admission precedes symptoms in heart failure patients. Heartrhythm 2004;1:679 (abstract).Google Scholar
  5. 5.
    Foreman B, Fishel RS, Odryzynsky NL, et al. Intra-thoracic impedance; a surrogate measure of thoracic clued- Fluid Accumulation Status Trial J Card Fail 2004;10:251 (abstract).Google Scholar
  6. 6.
    Ohlsson A, Kubo S, Steinhaus D, Connelly DT, Adler S, Bitkover C, Nordlander R, Ryden L, Bennett T. Continuous ambulatory monitoring of absolute right ventricular pressure and mixed venous oxygen saturation in patients with heart failure using an implantable hemodynamic monitor: Results of a 1 year multicenter feasibility study. Eur Heart J 2001;22:942–954.CrossRefPubMedGoogle Scholar
  7. 7.
    Kjellstrom B, Linde C, Bennett T, Ohlsson A, Ryden L. Six years follow-up of an implanted SvO2 sensor in the right ventricle. Eur J Heart Fail 2004;6:627–634.PubMedGoogle Scholar
  8. 8.
    Adamson PB, Smith AL, Abraham WT, Kleckner KJ, Stadler RW, Shih A, Rhodes MM; InSync III Model 8042 and Attain OTW Lead Model 4193 Clinical Trial Investigators. Continuous autonomic assessment in patients with symptomatic heart failure: Prognostic value of heart rate variability measured by an implanted cardiac resynchronization device. Circulation 2004;110:22389–22394.Google Scholar
  9. 9.
    Scharf C, Cho YK, Bloch KE, Brunckhorst C, Duru F, Balaban K, Foldvary N, Liu L, Burgess RC, Candinas R, Wilkoff BL. Diagnosis of sleep-related breathing disorders by visual analysis of transthoracic impedance signals in pacemakers. Circulation 2004;110:2562–2567.CrossRefPubMedGoogle Scholar
  10. 10.
    Defaye P, Pepin JL, Poezevara Y, Mabo P, Murgatroyd F, Levy P, Garrigue S. Automatic recognition of abnormal respiratory events during sleep by a pacemaker transthoracic impedance sensor. J Cardiovasc Electrophysiol 2004;15:1034–1040.CrossRefPubMedGoogle Scholar
  11. 11.
    Scharf C, Sowelam S, Cho YK, et al. Long-term monitoring of sleep apnea using an implanted device. Heart Rhythm 2005;2:S44 (abstract).CrossRefGoogle Scholar
  12. 12.
    Garrigue S, Bordier P, Jais P, Shah DC, Hocini M, Raherison C, Tunon De Lara M, Haissaguerre M, Clementy J. Benefit of atrial pacing in sleep apnea syndrome. New Engl J Med 2002;346:404–412.CrossRefPubMedGoogle Scholar
  13. 13.
    Ward WK, Wood MD, Slobodzian EP. Continuous amperoteric monitoring of subcutaneous oxygen in rabbit by telemetry. J Med Eng Technol 2002;26:158–167.PubMedGoogle Scholar
  14. 14.
    Janle EM, Kissinger PT. Monitoring physiological variables with membrane probes. Acta Astronaut 1998;43:87–89.CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  1. 1.Electrophysiology and Pacing Service, Division of Cardiovascular Disease, Department of MedicineMayo ClinicJacksonville
  2. 2.Cardiology Division, Department of MedicineSan Francisco General HospitalSan Francisco
  3. 3.Department of MedicineUniversity of CaliforniaSan Francisco
  4. 4.Electrophysiology and Pacing Service, Division of Cardiovascular DiseaseMayo ClinicJacksonville

Personalised recommendations