The roots of Russia's invasion of Ukraine go back decades and run deep. The current conflict is more than one country fighting to take over another; it is — in the words of one U.S. official — a shift ...

Ventricular fibrillation (VFib or VF) and ventricular tachycardia (v-tach or VT) are two types of heart arrhythmia that occur in the heart’s lower chambers, called the ventricles. The ventricles ...