Comparison of time of reperfusion during anterior wall acute myocardial infarction to left ventricular volume one month and 20 months later

Use of real-time three-dimensional echocardiography to assess left ventricular systolic synchronization after dual-chamber pacing therapy

This study was designed to evaluate the left ventricular systolic synchronization in patients implanted with dual-chamber DDD mode cardiac pacemakers by real-time three-dimensional echocardiography (RT3DE). Twenty patients implanted with DDD mode cardiac pacemakers for 12 months and 20 healthy subjects underwent RT3DE. This method provided left ventricular end-diastolic volume (LEDV), left ventricular end-systolic volume (LESV), stroke volume (SV), left ventricular ejection fraction (LVEF), the mean value of the time to minimal systolic volume of the 16 left ventricular segments (Tmean), the standard deviation of Tmean (T-SD), the maximal difference of the time to minimal systolic volume of the 16 left ventricular segments (Tmax) and time-volume curves of the 16 left ventricular segments. Results showed that compared with the healthy group, LESV was significantly increased (P<0.05), SV and LVEF were significantly decreased (P<0.05) and T-SD and Tmax were significantly prolonged (P<0.05) in patients implanted with DDD mode cardiac pacemakers. The time to minimal systolic volume of the 16 left ventricular segments time-volume curves differed in patients implanted with DDD mode cardiac pacemakers. Asynchronization of the left ventricular systolic performance in patients implanted with DDD mode cardiac pacemakers was observed. The results showed that RT3DE is a quantitative method used to evaluate left ventricular systolic synchronization.

Use of radionuclide imaging in acute coronary syndromes

The triage of patients presenting to the emergency department (ED) with acute chest pain is a diagnostic challenge. Radionuclide myocardial perfusion imaging has been shown to have favorable diagnostic and prognostic value in this setting, with an excellent early sensitivity to detect acute myocardial infarction (MI) not achieved by other testing modalities. A normal resting perfusion imaging study has been shown to have a negative predictive value of over 99% to exclude MI. Observational and randomized trials of both rest and stress imaging in the ED evaluation of patients with chest pain have demonstrated reductions in unnecessary hospitalizations and cost savings compared with routine care. Perfusion imaging has also been used in risk stratification after MI, and for measurement of infarct size to evaluate reperfusion therapies. Novel "hot spot" imaging radiopharmaceuticals that visualize infarction or ischemia are currently undergoing evaluation and hold promise for future imaging of acute coronary syndromes.