Possible heart disease?

Well, you're definitely experiencing heart palpitations. And if they're occurring pretty regularly for "no apparent reason," then the cause is underlying, and you should visit a cardiologist to find out what's causing them. Could be an arrhythmia, like atrial fibrillation, or ventricular tachycardia. If you want a quick way to bring your heart rate down, gulp down a couple gles of ice cold water during one. Works every time for me with my heart palpitations. Do see a cardiologist soon though. He could prescribe you a beta-blocker to prevent your irregular heart palpitations altogether, and your life wouldn't be so "interrupted" or bothered by them anymore. Meanwhile, avoid caffeine altogether, and cut back on sugar and sweets. And stop smoking, if you do. These only aggravate and worsen heart conditions. And start drinking lots of water throughout the day, you'd be surprised by how well it keeps your heart rate down.