Value of serial P wave changes in indicating left heart failure in myocardial infarction.

In order to evaluate ventricular failure in acute myocardial infarction, electrocardiographic left atrial overloading was correlated to several simultaneous clinical and radiological signs of left ventricular dysfunction in 200 consecutive patients. Analyses were made at three time periods after infarction. Left atrial overloading, measured by P terminal force, was significantly associated with the signs of left ventricular dysfunction, though in this unselected series of infarctions the prevalence of abnormal values was not high (46%). This finding is to be considered rather as a contributory sign than as a diagnostic one in the entire clinical picture. In an individual patient, however, conspicuous serial changes are helpful in indicating the direction of course of the haemodynamic disorder. The prognostic value of the P terminal force was found to be significant.