Acid reflux can cause heart palpitations.
More Info: Acid reflux is one of the many causes of heart palpitations. Discover through which nerves stomach acid may stimulate heart palpitations. 
The Normal Heartbeat
The heart is a muscle that pumps blood throughout the body. When the heart beats, it contracts to push the blood through the chambers of the heart. For most people the heart beats 60-100 times per minute. Electrical impulses from a part of the heart called the SA node tell the heart when to contract depending on the body's needs. For example, when you exercise, your body requires more oxygen. The heart will contract faster to supply the need. 
What is a Heart Palpitation?
A heart palpitation is a blanket term for infrequent and sporadic changes in heart rhythm. When they occur they can feel like the heart is beating too fast, has skipped a beat, is pounding harder than normal, or is fluttering. They can be felt in the chest, throat, or neck.
For healthy people, most heart palpitations are innocuous, but for others, they could be a signal of an underlying medical condition. 
What Causes Heart Palpitations?
Many things can cause an irregular heartbeat including stress, anxiety, strenuous exercise, caffeine, nicotine, fever, hormone changes, medications that contain stimulants, dehydration, low potassium, low blood sugar, anemia, overactive thyroid, and acid reflux.
Acid Reflux and Heart Palpitations
Acid reflux occurs when the digestive juices in the stomach reflux into the esophagus causing discomfort and pain. The association between acid reflux and heart palpitations may lie with the vagus nerves.
The vagus nerves run throughout the organs of the neck, thorax, and abdomen. Theses nerves have a variety of functions including slowing the rate of the heartbeat, and stimulating peristalsis and gastrointestinal secretions. 
It is difficult to find literature on the subject, but some experts have surmised that due to the interconnection of the vagus nerves with the heart and stomach, refluxed stomach acid irritates the vagus nerves in turn causing a heart palpitation. 
Treatment of Heart Palpitations Caused by Acid Reflux
As long as cardiac disease and other medical issues have been ruled out, the goal of treatment is to control the acid reflux. This involves lifestyle changes such as quitting smoking, avoiding foods that cause flare-ups, avoiding alcohol and caffeine, and losing weight. Medications may be necessary such as antacids, proton-pump inhibitors, or H2 blockers.