Chronotropic incompetence Symptoms, Causes, Pacemaker, Stress Test, Treatment

It is the condition of heart in which heart regulations are not able to cope with the metabolic demand. Basically in this condition heart fails to achieve maximum heart rate. It normally occur in patients already suffering from cardiovascular disease. The mortality rate is high in chronotropic incompetence. This condition appears during exercise, as during exercise the metabolism becomes fast and the oxygen demand is also increased but the heart is not able to cope with the demand. The heart beat remains normal and cardiac output also remain same. This condition can lead to sudden cardiac arrest.

Chronotropic incompetence Causes


The chrontropic incompetence can occur as a result of many factors like:
  • As a side effect or toxic effect of medication used for other problems.
  • If the dysfunction of sinus node occur, it will lead to chronotropic incompetence.
  • Can occur secondary to many ischemic heart diseases.
  • Chronotropic incompetence occur as a result of autonomic dysfunction.
  • If the left ventricle is not working properly, then it can cause chronotropic incompetence.
  • Atrial fibrillation is another cause reported behind chronotropic incompetence.
  • Hypo thyroidism is also the side cause behind it.
  • Increase age is also a factor behind this condition.

Chronotropic incompetence Symptoms, Causes, Pacemaker, Stress Test, Treatment

Chronotropic incompetence Symptoms


The following symptoms are associated with chronotropic incompetence:
  • Heart failed or make it delay to achieve maximum heart rate
  • Heart rate gets unstable during exercise or heavy weight lifting and climbing stairs.
  • Aging is associated with chronotropic incompetence.
  • Patient feels fatigue during any activity.
  • Patient feels heavy heart.
  • Sweating occurs.
  • Pain in chest area.
  • Stress at chest region.
  • Patient may become depressed and anxious.
  • Heavy breathing.
  • Sometimes the patient becomes faint and fall.
  • Decreased blood pressure is also reported along with normal heart beat.

Chronotropic incompetence Pacemaker

Recent studies show that the pace maker is not enough for chronotropic incompetence but are of some help. Electrical energy is supplied by the pace maker towards heart to make it beat properly according to demand. Pace makers are battery operated devices and sometimes cannot increased cardiac load, which require regular follow ups for monitoring its performance. This is its main drawback that it has to be monitored on regular basis. The pace makers when used in chronotropic incompetence, should be based on clinical symptoms which show decreased cardiac working during any hyper activity like exercise and climbing.

Chronotropic incompetence Stress Test

The chronotropic incompetence is checked or tested with exercise stress test. In which the heart rate response is checked during exercise. Results are considered as prediction of mortality and occurrence of coronary heart diseases due to chronotropic incompetence. The other stress test include thallium imaging. In this test, the thallous chloride 74 to 111 Bq is injected just 1 min before the ending of treadmill test. Then computed tomography imaging is performed to check the activity of heart as the salt of thallium emit photons, which are visible in computed tomography imaging.

Chronotropic incompetence Treatment

Treatment of Chronotropic incompetence mainly due to weakness or defect in cardiac muscles. So, basic aim of treatment is to increase heart out and ejection fraction. For this purpose cardio-selective beta-receptor agonist are used for sometime to adjust cardiac output. Some vasoconstrictors are also used in case of emergency but in long run surgical procedure might be main stay.
Chronotropic incompetence Symptoms, Causes, Pacemaker, Stress Test, Treatment Chronotropic incompetence Symptoms, Causes, Pacemaker, Stress Test, Treatment Reviewed by Simon Albert on May 05, 2017 Rating: 5
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