Usefulness of P-wave duration and heart rate recovery to identify exercise of indicated myocardial ischemia

Background:Although egzersize stres test (EST) is generally the first choice in diagnosis of ischemic heart disease, its sensitivity and specificity is limited.Egzersize induced p wave elongation and heart rate recovery are parameters which are not analysed in routine assessment of EST.The roles of both these parameters in prediction of ischemia had been shown previously.But until now there is no study investigating the predictive value of combined analysis of p wave elongation, heart rate recovery and ST segment change in detection of ischemia.So in this study we aimed to determine the additive value of p wave elongation and heart rate recovery in detection of ischemia during EST.Methods:A total of 441 patient who underwent EST and MPS Gated-Spect for evaluation of ischemia were screened retrospectively.Of these 441 cases, 369 patients who were found eligable for enrollment were analysed for p wave elongation and heart rate recovery according to ECG records during MPS Gated-spect.P wave duration change was calculated as [(p wave duration at recovery)-(p wave duration at rest)].P wave duration was analysed by 4 fold magnification in leads D2 and V5.Heart rate recovery was defined as [maximum heart rate- heart rate at the end of 1 minute of recovery phase].The patients were classified as ischemic or nonischemic according to presence of localized perfusion defects in MPS Gated-spect.Results:Among our study group the usual ST segment change was found to have a positive predictive value (PPV) of %55,2 and negative predictive value of %82,6 for ischemia detection.Both the PPV and NPV of p wave elongation were higher than ST segment change (%62,8 and %87,3).Heart rate recovery also revealed a higher NPV (%88,3) with an almost similiar PPV (%52,4) compared to ST segment change.When combining three of these parameters, PPV and NPV reached much higher values of %77,8 and %94,5.Conclusion:This study showed that adding the parameters of p wave duration change and heart rate recovery in evaluation of EST revealed a higher predictive value for ischemia detection than the usual EST analysis.