BBC NEWS | Health | Heart risk of watching football
Writing in the New England Journal of Medicine, the researcher said: "Apparently, of prime importance for triggering a stress-induced event is not the outcome of a game - a win or a loss - but rather the intense strain and excitement experienced during the viewing of a dramatic match, such as one with a penalty shoot-out."
Researchers studied the effects on German fans of watching their home team compete in the 2006 World Cup finals.
Six of the seven games in which the German team participated were associated with an increase in the number of cardiac emergencies.
The largest number occurred during a June 30 quarter-final in which Germany defeated Argentina in a dramatic penalty shoot-out.
The next game, Germany's semi-final loss to Italy, produced almost as many heart attacks.