"The patients I see suffer from dyspnea and have difficulties doing their daily activities. Their heart rates increase does not reflect their level of exercise."
Dr. Schubert (Germany)
In the current pacemaker population many patients do not receive the appropriate heart rates for their daily activities.
The main limitation is related to the fact that the accelerometer alone in a pacemaker cannot detect all the movements.
Walking up a flight of stairs or riding a bicycle are just a few examples illustrating the limitations of the accelerometer.
At the end it will leave the patient chronotropically incompetent.
Chronotropic incompetence is real and can be treated. Physicians throughout Europe see the difference in daily practice when they use the ALTRUA™ MV blended sensor to restore their patients’ chronotropic response to daily exercise. In many cases these patients seem completely transformed and are able to do their daily activities they used to do.
Click here to find more ALTRUA™ patient cases
Chronotropic incompetence refers to the inability of the heart to regulate its rate appropriately in response to physiologic stress4. There are a variety of definitions of chronotropic incompetence. In general, the diagnosis ranges from failure to achieve 70% to 85% of Age-Predicted Maximum Heart Rate (APMHR) as defined by the Wilkoff model. Clinics specialized in the treatment of cardiac diseases should use the definition they feel comfortable with.
* Percentage of age-predicted maximum heart rate (APMHR)
1. Sinus node disease manifests as symptomatic bradycardia with or without bradycardia-dependant tachycardia. Symptom-rhythm correlation must have been: spontaneously occurring drug induced where alternative drug therapy is lacking
2. Syncope with sinus node disease, either spontaneously occurring or induced at electrophysiological study
3. Sinus node disease manifests as symptomatic chronotropic incompetence: spontaneously occurring drug induced where alternative drug therapy is lackingRead more about the ESC guidelines
It is important to monitor paced patients even if not previously diagnosed with chronotropic incompetence. The prevalence of CI in the pacemaker population is anywhere from 34% to 42% at initial pacemaker implant. The Gwinn study found that the prevalence of chronotropic incompetence does increase over time in pacemaker patients6.
Percentage of patients with CI
Especially pacemaker patients that use beta blockers should be monitored closely for CI. Pacemaker patients often use beta blockers to treat a variety of conditions including arrhythmias, heart failure, hypertension and angina. Therapy with beta blockers leads to a reduction in resting and exercise heart rates. The majority of pacemaker patients being treated with beta blockers were found to be chronotropically incompetent (85%)7.
To recognise the symptoms of chronotropic incompetence in paced patients,
it is useful to verify the histograms in the pacemaker diagnostics on a regular basis.
Chronotropically incompetent patients are typically being paced at the lower rate limit.
See 2 examples below, click to enlarge