Implantable Cardioverter Defibrillator

Rebecca BoduchBiomedical Engineering

University of Rhode Island

Heart Disease

• Ventricular Tachycardia –– The heart had a rapid , regular heart rhythm– The rhythm originates in the lower chambers of

the heart

• Ventricular Fibrillation –– The heart rhythm is irregular, abnormal, and

chaotic

Information about Heart Conditions

• Ventricular tachycardia and fibrillation occur most often in patients that have damaged heart muscle or coronary artery disease

• When ventricular tachycardia has occurred the heart is pumping fast and in one continuous loop, thus causing the heart chambers little time to fill resulting in dangerously decreased amounts of blood being pumped to the body

• Ventricular fibrillation the heart is pumping chaotically and the chambers don’t contract properly, causing results in dangerously decreased blood flow

Normal Heart Rhythm

Ventricular Tachycardia Heart Rhythm

Ventricular Fibrillation Heart Rhythm

Implantable Cardioverter Defibrillator

• Implantable Cardioverter Defibrillator (ICD) has been proven to be an effective way of treating these heart conditions

• An ICD is implanted under the skin near the collarbone through open chest surgery

• There are leads that go from the implanted generator down onto the surface of or in the heart

• There can be different amounts on leads• These leads are responsible for detecting

and monitoring the heart rhythm

Implantable Cardioverter Defibrillator

• If an abnormal heart rhythm is detected, the ICD administers a shock to the heart, in order to “reset” the heart rhythm

• ICD’s have been proven to be an effective way in prevention of death, brain damage, and other complications associated with these heart conditions

Medication vs. Surgery

• Sudden Death from cardiac causes is the leading cause of death among people with congestive heart failure (CHF)

• A study was conducted to determine if the drug amiodarone or an ICD improves the prognosis for people living with heart conditions

• The study has 2521 patients who have either case 1 or case 2 CHF and also a left ventricle ejection fraction of less than 35%

Medication vs. Surgery

• The 2521 patients were divided into three groups

– 847 patients were treated with the conventional treatment plus placebos

– 845 patients were treated with the conventional treatment plus amiodarone

– 829 patients were treated with the conventional treatment plus a single lead ICD

• The study was conducted over a 5 year period and patients were followed up every 3 months

Conclusion

• The results of the study proved that an ICD was more effective.

• Having an ICD reduced the risk of death by 23%

• The study also showed that amiodarone had no added effect on the patient prognosis

• The study helped to prove in favor of ICD therapy

Hazard Ratio

References:

• "Amiodarone or an Implantable Cardioverter–Defibrillator for Congestive Heart Failure." The New England Journal of Medicine 352.3 (2005): 225-37. Print.

• "Implantable Cardioverter Defibrillator." American Heart Association. American Heart Association. Web. 5 Feb. 2010. <http://www.americanheart.org/presenter.jhtml?identifier=11227>.

• "Ventricular Tachycardia and Ventricular Fibrillation." New York- Presbyterian. Web. 5 Feb. 2010. <http://nyp.org/health/ventricular-tachycardia-fibrillation.html>.