Sinus tachycardia: don't blame the whistle-blower

Sinus tachycardia due to sympathetic activation may be the ultimate response to support cardiac output. Abrupt heart rate reduction in this condition may be deleterious as is illustrated by two cases. Both patients were referred in cardiogenic shock after inappropriate treatment with a beta-blocking agent, initiated as a symptomatic treatment of a sinus tachycardia.Thus even if beta-blocking agents provoked a paradigm shift in the understanding of heart failure and became a cornerstone of the treatment, therapy should be initiated with knowledge of the underlying condition.