Thanks for your question on Healthcare Magic. I can understand your concern. No, these symptoms are not due to thickening of blood. Since you are having heart murmur, we should definitely rule out arrhythmia (rhythm disturbances in heart) in your case. So consult cardiologist and get done 1. Ecg 2. 2d echo 3. Holter monitoring (24 hours continuous recording of ecg). If all these are normal then no need to worry for arrhythmia or other heart diseases. Sometimes uncontrolled stress and anxiety can also cause similar symptoms. So avoid stress and tension, be relax and calm. Don t worry, you will be alright. But first rule out heart diseases like arrhythmia. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.