Electrocardiogram (ECG) is one of the most common biological signals which play a significant role in the diagnosis of heart diseases. One of the most important parts of ECG signal processing is interpretation of QRS complex and obtaining its characteristics. R wave is one of the most important sections of this complex, which has an essential role in diagnosis of heart rhythm irregularities and also in determining heart rate variability (HRV). This paper employs Hilbert and wavelet transforms as well as adaptive thresholding method to investigate an optimal combination of these signal processing techniques for the detection of R peak. In the experimental sections of this paper, the proposed algorithms are evaluated using both ECG signals from MIT-BIH database and synthetic data simulated in MATLAB environment with different arrhythmias, artifacts, and noise levels. Finally, by using wavelet and Hilbert transforms as well as by employing adaptive thresholding technique, an optimal combinational method for R peak detection namely WHAT is obtained that outperforms other techniques quantitatively and qualitatively.
Background::
Anthracyclines, a widely used chemotherapy agent with a definite survival
improvement, can result in cardiac toxicity presenting with HF (heart failure).
Objective::
We aim to assess the predictive value of cardiac biomarkers assessment in combination
with myocardial two-dimensional strain echocardiography for early detection of cardiac toxicity in
patients who underwent Anthracycline-based chemotherapy.
Method::
Fifty-two consecutive adult patients scheduled to undergo the first course of
Anthracycline-based chemotherapy were subjected to the study. All the patients underwent highly
sensitive 2D echocardiographic evaluation before the treatment, 4 and 12 weeks after completion of
first-course chemotherapy. Longitudinal and segmental strains were measured. Serum levels of
High-sensitive cardiac troponin I (hscTn-I) and N-terminal-pro-BNP (NT-proBNP) were also
assessed before the initiation and 3 weeks after completion of first-course chemotherapy.
Result::
Fifteen patients (28.8%) revealed a decrease in LVEF (Left Ventricular Ejection Fraction)
throughout the evaluations, while just 5 patients met the criteria of cardiac toxicity (9.6%). AUC for
Global Longitudinal Strain (GLS) ROC curve at 4 weeks of follow-up was calculated to be 0.968.
Inferoseptal Systolic Longitudinal Strain (SLS) had the highest AUC value (AUC: 0.934) among
different wall SLS. LVESD (Left Ventricular End-Systolic Diameter) at first and second evaluation
could predict the risk of cardiac toxicity among LVESD, LVEDD (Left Ventricular End Diastolic
Diameter) and LVEDV (Left Ventricular End-Diastolic Volume). Among cardiac biomarkers, hscTnI
had higher sensitivity, while NT-proBNP had higher specificity for cardiac toxicity.
Conclusion::
This study has shown that hs-cTnI with good sensitivity can predict cardiac toxicity in
Anthracycline-based chemotherapy receiver. The use of strain with speckle echocardiography
method has a prognostic value; however, both longitudinal and segmental strain should be assessed.
Lateral and inferoseptal SLS (Segmental Longitudinal Strain) are specific markers of cardiac
toxicity in the course of anthracycline-related cardiac toxicity.
This case report underscores that crystal methamphetamine abuse is an important cause of multivessel coronary thrombosis and raises doubts about the therapeutic options. The patient was a 34-year-old smoker and crystal methamphetamine abuser with no significant medical history, who presented with retrosternal chest pain associated with cold sweats. Twelve-lead electrocardiogram revealed diffuse ST-segment elevation in I, II, AVL, AVF, and V 2-6 leads. He underwent urgent coronary angiography and it showed Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in coronary arteries and presence of a thrombus in the left anterior descending artery (LAD) and the right coronary artery (RCA). The patient underwent medical therapy with antiplatelet agents and anticoagulants. Repeat coronary angiography after three months of dual therapy with warfarin and aspirin did not show any thrombus or any significant lesion in the RCA and the LAD having TIMI grade 3 flow.
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