Non-invasive myocardial work in aortic stenosis: validation and improvement in left ventricular pressure estimation.

AIMS: The non-invasive myocardial work index (MWI) has been validated in patients without aortic stenosis (AS). A thorough assessment of methodological limitations is warranted before this index can be applied to patients with AS. METHODS AND RESULTS: We simultaneously measured left ventricular pressure (LVP) by using a micromanometer-tipped catheter and obtained echocardiograms in 20 patients with severe AS. We estimated LVP curves and calculated pressure-strain loops using three different models: (i) the model validated in patients without AS; (ii) the same model, but with pressure at the aortic valve opening (AVO) adjusted to diastolic cuff pressure; and (iii) a new model based on the invasive measurements from patients with AS. Valvular events were determined by echocardiography. Peak LVP was estimated as the sum of the mean aortic transvalvular gradient and systolic cuff pressure. In same-beat comparisons between invasive and estimated LVP curves, Model 1 significantly overestimated early systolic pressure by 61 ± 5 mmHg at AVO compared with Models 2 and 3. However, the average correlation coefficients between estimated and invasive LVP traces were excellent for all models, and the overestimation had limited influence on MWI, with excellent correlation (r = 0.98, P < 0.001) and good agreement between the MWI calculated with estimated (all models) and invasive LVP. CONCLUSION: This study confirms the validity of the non-invasive MWI in patients with AS. The accuracy of estimated LVP curves improved when matching AVO to the diastolic pressure in the original model, mirroring that of the AS-specific model. This may sequentially enhance the accuracy of regional MWI assessment.

[Occurrence of arrhythmias related to treatment of myocardial infarction]. / Forekomsten av arytmi ved behandling av hjerteinfarkt.

BACKGROUND: Percutaneous coronary catheter intervention (PCI) reduces mortality in ST-elevation myocardial infarction (STEMI) more than fibrinolysis. However, it remains uncertain whether PCI reduces the incidence of early post-infarction arrhythmias. MATERIAL AND METHODS: We compared the incidence of arrhythmias in two groups of consecutive STEMI-patients who underwent continuous ECG monitoring. One group was treated with PCI in 2006-07, while a historic control group received thrombolysis in 1996-98. RESULTS: 93 (38%) PCI patients and 97 (53%) of the thrombolysed patients (p = 0.001) had arrhythmias. 27% of the patients in the PCI group were treated for arrhythmias vs. 34% of the thrombolysed (n.s.). Significantly fewer PCI-treated patients had atrial fibrillation (5% vs. 16%), AV-block II/III (0% vs. 6%) and asystole (0% vs. 5%), but an increased frequency of ventricular tachycardia was recorded (10% vs. 5%). 41% of all arrhythmic and 63% of treated events occurred in the first hour after PCI; corresponding results for thrombolysis were 23% and 28% (p = 0.000). Mortality was greater in the thrombolysed group (11% vs. 2%, p = 0.006), but patients were older, had more risk factors and larger emit ions of cardiac enzymes. After adjustment for the confounding effects of age, gender, score for ST-elevation and infarct localization, there was still a reduction in total arrhythmias in the PCI-treated group (odds ratio 0.37, 95% confidence interval 0.19-0.73, p = 0.004). INTERPRETATIONS: PCI-treatment seems to reduce early post-STEMI arrhythmias, but a non-randomized design and the use of historical controls, reduce the strength of this conclusion.