Heart Failure
Heart failure is a condition in which your heart can't pump enough blood to meet your body's needs. Heart failure doesn't mean that your heart has stopped or is about to stop working. It means that your heart can't cope with the demands of everyday activities.
Heart failure causes shortness of breath and fatigue that tends to increase with physical exertion. Heart failure also can cause swelling in the feet, ankles, legs, abdomen, and veins in the neck.
Arrhythmia
An arrhythmia is a problem with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.
Some people describe arrhythmias as fluttering or thumping feelings or skipped beats in their chests. These feelings are called palpitations.
Some arrhythmias can cause your heart to suddenly stop beating. This condition is called sudden cardiac arrest (SCA). SCA causes loss of consciousness and death if it's not treated right away.