By Tommy Kirkham
Coronary bypass surgery is a procedure performed on patients who have a blockage or blockages in their coronary arteries caused by atherosclerotic plaques induced by coronary artery disease or from a myocardial infarction (heart attack) (Mayo, 2014).
Coronary bypass surgery is performed if the blockage induces symptoms of chest pain, shortness of breath and light-headedness with very light exercise or at rest (Mayo, 2014). Other factors that will also endorse the implementation of surgery include improper pumping of the left ventricle, blockage of the left main coronary artery, which supplies most of the blood to the heart, or if a stent or angioplasty procedure was ineffective (Mayo, 2014). Furthermore, if a heart attack patient isn’t responding to other forms of treatment, a coronary bypass may be performed (Mayo, 2014).
Following the surgery the patient is commonly discharged after one week in the hospital, the full recovery will take up to twelve weeks (Mayo, 2014). The patient may be symptom free for 10-15 years; however, he or she will likely have more blockages (including a block in the graft) in the future because the coronary bypass surgery is not treating the underlying disease creating the atherosclerotic plaques (CAD) (Mayo, 2014). The results of the surgery depend heavily on the patient’s lifestyle and health, which include factors like medications, smoking, diabetes, diet (specifically reducing LDL cholesterol), blood pressure and exercise (Mayo, 2014).
Aerobic exercise as early as one week following coronary bypass surgery is associated with early and long-term improvements in exercise capacity, cardiac output (CO) and parasympathetic nerve activity (PNA) as compared to individuals who did undertake a specialized exercise rehabilitation program (Takeyama et al. 2000). An effective exercise program for a patient following coronary bypass surgery consists of riding a cycling ergometer (or stationary bike) for 30 minutes twice a day for two weeks (Takeyama et al. 2000). The patient’s heart rate should match that of their anaerobic threshold as determined by a cardiopulmonary exercise test (Takeyama et al. 2000).
The autonomic nervous system consists of sympathetic and parasympathetic nerves. The sympathetic nerves serve to increase the heart rate and the parasympathetic nerves lower it. Athletes have high maximal heart rates and low resting heart rates. Exercise has a regulatory effect on the autonomic nervous system (He et al. 2015). An athlete, therefore, has a more balanced autonomic nervous system pre surgery. This could lead to a quicker recovery of autonomic nerve activity following surgery if the hormonal homeostatic control response is maintained following the procedure; an athlete already has a healthier heart.
The vagus nerve is a cranial nerve that plays a main role in the regulation of the parasympathetic innervations of the heart. That is to say that it functions to decrease the heart rate. Following coronary bypass surgery a high stress environment persists which induces an increase in heart rate (He et al. 2015). Exercise has also been shown to increase the activity of the vagus nerve, which would result in the lowering of the heart rate and represent a favorable prognosis following a heart attack and coronary bypass surgery (Heet al. 2015).
All of the information above serves to emphasize the importance of exercise on cardiovascular health. If you have a family history of coronary heart disease, and may be pre-disposed to undergoing a coronary bypass surgery, maintaining a healthy and active lifestyle not only serves as a preventive measure, but may also aid the rehabilitation process. Also, if you do undergo bypass surgery, there is mounting evidence showing the importance of exercise and activity in the rehabilitation process. Coming up with a comprehensive exercise prescription with medical health professionals is imperative to a healthy heart post-op.
References:
1. He X, Zhao M, Bi X, Sun L, Yu X, Zhao M, Zang W. Novel strategies and underlying protective mechanisms of modulation of vagal activity in cardiovascular diseases. British Journal of Pharmacology doi: 10.1111/bph.13010, 2015.
2. Mayo Clinic Staff. Coronary bypass surgery. http://www.mayoclinic.org/tests-procedures/coronary-bypass-surgery/basics/definition/prc-20023680. Oct. 23, 2012.
3. Takeyama J et al. Effects of physical training on the recovery of the autonomic nervous system activity during exercise after coronary artery bypass grafting. Jpn Circ J 64: 809-813, 2000.