Palpitations, or abnormal heart rhythm is usually associated with symptoms like chest discomfort, shortness of breath, dizziness or light-headedness.
When experiencing these symptoms, is very important to examine the hearts function and structure completely.
Since the CAD (blocked heart arteries) was excluded, you may need to be performed an ECG and echocardiogram to check for heart muscle condition and if there are some valvular changes.
If these test came fine, you should be performed blood tests for thyroid gland functioning (hyperthyroidism) and testing catecholamines and metanephrines in plasma or through a 24-hour urine collection, for pheochromocytoma, an adrenal gland tumor.
Palpitations are indeed symptom of panic disorders, but, can be symptom of anemia, too.
Anemia is manifested with all of the above mentioned symptoms, chest pains, dizziness, shortness of breath, fatigue, palpitations.
Best wishes!