Practice News / Events

Beyond Discharge: Heart Rhythm Device Follow-up at Heart Clinic Arkansas
By Dr. Eleanor E. Kennedy

Expanded indications for heart rhythm devices have received much publicity in both the medical and lay press over that past year or two. For example, implantable cardioverter-defibrillators (ICDs) are now indicated for most patients with ejection fractions less than 35% because such devices are associated with reduction in both arrhythmic and total mortality. In addition, biventricular devices offer improvement in heart failure symptoms, rehospitalization rates, and quality of life for patients with prolonged QRS. But care for these patients does not end when they leave the hospital. Heart Clinic Arkansas offers a comprehensive Heart Rhythm Device Clinic for following patients with pacemakers, ICDs and biventricular devices with both regularly scheduled in-clinic appointments and remote at-home monitoring.

Tweaking the numbers
Most heart rhythm devices are implanted at “nominal” electrical impulse output settings which are designed to allow a substantial safety margin in terms of capture threshold, especially during the first three months as the lead tip “matures” at its point of contact with the myocardium. In most cases, output settings can be decreased substantially and safely at the 3-month point, a technique which has a significant favorable impact on battery life. On the other hand, if follow-up visits reveal that the capture threshold is increasing substantially, there may be a problem with the lead which can be evaluated in a timely manner. Prompt diagnosis of lead problems can be lifesaving in our patients who are pacemaker dependent.

To pace or not to pace
Evidence has accumulated that unnecessary right ventricular pacing is more than just needless drain on the battery. Such pacing may actually decrease cardiac pumping efficiency and result in increased hospitalizations for congestive heart failure. Our device clinic very carefully assesses AV conduction and sets parameters to facilitate intrinsic activation wherever possible. Longer battery life, better pumping. A win-win situation.

Coordination counts
Biventricular devices stimulate both the left ventricle and the right ventricle to allow more synchronized contraction of the ventricles and particularly the septal and lateral walls of the left ventricle. As a result, cardiac output increases with many secondary benefits in terms of improved functional status and subjective well-being, and decreased heart failure rehospitalization rates. As the biventricular devices offer many options in terms of coordinating AV intervals and even RV-LV intervals, the device clinic precisely optimizes these “coordination settings” using real-time echo-Doppler images to custom-program each patient’s device. Otherwise it’s like putting the wrong kind of oil in your car.

Shock and Stress
One of the most challenging aspects of life with an ICD is the pain and anxiety that may be associated with receiving shocks. The staff at Heart Clinic Arkansas has been trained to respond to calls from patients in this situation. Patients with certain ICDs which allow remote monitoring (more about this below) can download electrograms from their ICD’s memory, and we can see exactly why the patient received a shock. Although many shocks are of course due to severe ventricular arrhythmias which might have otherwise been life-threatening, some may be due to supraventricular tachyarrthmias or electromagnetic environmental noise or even a malfunction of the ICD system, usually the lead wire. Whatever the cause, further shocks can often be prevented or made less likely by taking appropriate measures, whether these be medication changes, reprogramming the device or replacing a lead.

Remote Control
Heart Clinic Arkansas has used traditional remote monitoring for its pacemaker patients for years. These are screening transtelephonic transmissions for assuring capture threshold safety margin and integrity of battery life and are the way most pacemaker battery ERI (Elective Replacement Indicator) or End of Life (EOL) is picked up. These checks may also tell us if there are gross sensing problems. Now we can offer more comprehensive remote at-home monitoring of our patients with ICDs as well, something which is especially important for our patient population, many of whom live at considerable distance from our clinic. This is an internet based system which is an efficient, safe, and convenient way for us to remotely monitor the condition of our patients and the performance of their devices. The comprehensive data received remotely is similar to what is typically obtained during an in-person visit.

How does the service work?
Patients can send data from their home or while traveling. The system we use contains the same servers and encryption software used for vital applications at most medical and financial institutions. Patients transmit data from their implanted device using a portable monitor on an agreed upon schedule. The monitor is easy to use, and the entire process takes only a few minutes. The patient simply pushes a button to turn on the monitor and then places the small, computer mouse-shaped antenna over their implanted device. The monitor reads device-related and physiologic data and then automatically dials a toll-free, pre-programmed number to send the information over a standard telephone connection. The monitor uses audible tones and indicator lights to confirm that the transmission was successful.

After-care
Heart Clinic Arkansas, through its’ Rhythm Device Clinic, offers comprehensive follow-up care to our many patients with implanted pacemakers, defibrillators, and biventricular devices. Through meticulous attention to detail, device settings can be chosen to optimize cardiac function and battery longevity. Through remote telemetry, patient symptoms can be assessed and responded to appropriately and in a timely fashion, allowing all to truly live better electronically.