That was the case whether the shock was needed or not, and in 38 percent of cases it wasn’t, the researchers added.
“I see two implications,” said study co-author Dr. Matthew Reynolds. “First, we need to do all we can to minimize these shock events, which are known to negatively affect patients’ quality of life, are undesirable clinically and, in our study, trigger costly medical interventions.”
These procedures include invasive measures to test the heart’s function, according to the study.
“Second, there is no standard approach to managing these events . . . so we need to develop a better understanding of which interventions are and are not helpful after these shock events,” added Reynolds. He directs economics and quality of life research at the Baim Institute for Clinical Research in Boston.
Implantable cardioverter defibrillators (ICDs) work by delivering a shock to restore a normal rhythm when the lower chambers of the heart (the ventricles) beat erratically.
Inappropriate shocks occur when the device mistakes an irregular heartbeat for ventricular arrhythmia, a condition that can cause the patient to die from cardiac arrest if not corrected. Cardiac arrest is when the heart suddenly stops beating.
“We found that shock events from implantable defibrillators frequently trigger a cascade of medical encounters, the costs of which appear similar whether the shocks were for appropriate or inappropriate reasons,” said Reynolds.
“Improving the reliability of implantable defibrillators, and programming them in a manner that minimizes shock events, is not only good for patients, but likely can also help save the health care system some money,” he explained.
Dr. Byron Lee is chair of arrhythmia research at the University of California, San Francisco. Reviewing the study, he said, “it’s not surprising to me that patients who are shocked by their ICD will seek medical attention. The shocks are painful and frightening.”
Aside from pain, anxiety and discomfort for the patient, there is the issue of money. The average cost of health care following a shock was nearly $5,600 for an appropriate shock and nearly $4,500 for an inappropriate shock, the researchers found.
Dr. Gregg Fonarow is a professor of cardiology at the University of California, Los Angeles. He said, “This study highlights the significant utilization of health care resources and hospitalizations that occur after ICD shocks.”
It was interesting that nearly half the patients who received an ICD shock received some form of health care related to the shock, and one in seven were hospitalized, said Fonarow, who was not involved in the study.
It is also notable that the costs were similar whether the ICD shock was appropriate or inappropriate, Fonarow added.
“These findings suggest that additional efforts are needed to ensure optimization of ICD programming, along with other strategies to reduce ICD shocks,” he said. “Such efforts may result in substantial reduction in health care use and cost savings.”
For the study, the researchers collected data on more than 10,000 patients with implanted defibrillators in the United States between 2008 and 2010. They used data sent by the device to the manufacturer, and linked it with patients’ medical records.
During that time, more than 900 patients, average age 61, experienced nearly 2,000 shocks.
The researchers also found that 46 percent of the patients received health care related to the shock. One in three were cared for in the emergency room or received only outpatient care.
One in seven, however, were admitted to the hospital.
The findings may be limited because all patients had ICDs from the same manufacturer, Medtronic. In addition, factors that may have biased the results, such as patient behavior and health status, were not available, the study authors noted.
Moreover, the researchers could not determine whether the treatment that the patients received was appropriate, only if the shock was appropriate or not.
The report was published online Feb. 14 in the journal Circulation: Cardiovascular Quality and Outcomes.