Hello and thank you for using HCM. I carefully read your question and i understand your concern. I will try to explain you something and give you my opinion. I must explain you that hypertension and rhythm problems are two different issues. A person might have hypertension and not have arrhythmia or might have arrhythmia without hypertension. I fact, as you explain i suppose you take metoprolol. This is a medication that lower your heart frequency and your blood pressure. You might experience and feel your heart beats for different reasons. It might be a sinus tachycardia, an extra-sistolic beat or other arrhythmia like paroxysmal atrial fibrillation. All of this gives you this sensation like your heart is beating harder, like all you body beats to. It gives you an anxiety sensation, dificulties in breathing deeply. But it is difficult to say what is it without monitoring it. So i sugest you to make a blood analyses, an electrocardiogram, echo-cardiograph and of course a holter rhythm monitoring to see your rhythm tendency. The flu might be the reason of your symptoms. When the body suffers an infection the heart rises its frequency becouse of increased body needs and our immunitary system and every think comes back to normality when this situation is over. So my opinion is that you should not worry. Monitor this symptoms for some days and only if they persist after you are fully recovered from the flu just do what i told you before. Hope I was helpful. BEST REGARDS