Just to clarify V-Tach's answer.
Interventional & Invasive are generally considered synonymous. An interventional cardiology fellowship is generally 1 year after a cardio fellowship, although many places are expanding this to two years. An interventionalist gets training in percutaneous coronary interventions including coronary stenting and coronary angioplasty. Some places even train them for peripheral vascular stenting, such as renal artery stents and carotid stents. Other interventions can also be learnt (again, depending on where you train) such as PFO closure.
Electrophysiology (EP) is 1, sometimes 2 yrs after general cardio. They specialize in diagnosis and treatment of arrhythmias. The EP studies they do involve localization of lesions and radiofrequency catheter ablation of the same. Additionally, they also learn placement of devices such as pacemakers, biventricular pacers, and implantable cardioverter-defibrillators.
General cardiologists do not undergo this specialized training. However, they can still perform transesophageal echocardiograms and diagnostic catheterizations. They also learn interpretation of transthoracic echocardiograms and, sometimes, nuclear cardiology studies.