The chest muscles, ribs, heart, lungs, and stomach are controlled directly and indirectly by spinal nerves. Misalignments can interfere with these nerves going to the heart and chest. Sometimes it may even produce tachycardia (too fast heart rate) and other arrhythmias (abnormal heart rate), pain that mimics heart problems, or changes in heart function and blood pressure.
Few people know about this connection to the spine, and therefore it is rarely diagnosed by medical doctors.