Diagnostic Tool In Clinical Cardiology Research Articles

Machine Learning in Electrocardiography and Echocardiography: Technological Advances in Clinical Cardiology.

Electrocardiography (ECG) and echocardiography are the most widely used diagnostic tools in clinical cardiology. This review focuses on recent advancements in applying machine learning (ML) in ECG and echocardiography and potential synergistic ML integration of ECG and echocardiography. ML algorithms have been used in ECG for technical quality assurance, arrhythmia identification, and prognostic predictions, and in echocardiography to recognize image views, quantify measurements, and identify pathologic patterns. Synergistic application of ML in ECG and echocardiograph has demonstrated the potential to optimize therapeutic response, improve risk stratification, and generate new disease classification. There is mounting evidence that ML potentially outperforms in disease diagnoses and outcome prediction with ECG and echocardiography when compared with trained healthcare professionals. The applications of ML in ECG and echocardiography are playing increasingly greater roles in medical research and clinical practice, particularly for their contributions to developing novel diagnostic/prognostic prediction models. The automation in data acquisition, processing, and interpretation help streamline the workflows of ECG and echocardiography in contemporary cardiology practice.

Which Cardiac Structure Lies Nearby? Revisiting Two-Dimensional Cross-Sectional Anatomy

Two-dimensional (2D) transthoracic echocardiography is one of the most used diagnostic tools in clinical cardiology. Similarly, 2D transesophageal echocardiography is considered an indispensable tool for cardiologists and cardiac anesthesiologists worldwide. However, because of their tomographic nature, both techniques display only thin cut planes of a given area of the heart, which are far from representing the "anatomic reality." It is widely accepted that experienced echocardiographers are able to reconstruct mentally a three-dimensional image of any cardiac structure on the basis of their interpretation of multiple tomographic slices. However, this may not be the case with less experienced echocardiographers. In particular, the authors noticed that less experienced echocardiographers are almost totally unaware of which structures lie "nearby" a given 2D tomographic plane, that is, what is adjacent in the elevation plane. In this article, the authors report the use of three-dimensional transesophageal echocardiographic images to discover which structures are located nearby (i.e., "behind" and "in front") the corresponding 2D cross-sections. The authors believe that this novel use of three-dimensional echocardiography is a unique aid to disclose what cannot be seen in a given 2D cross-section, thereby expanding our understanding of 2D echocardiographic anatomy. This may be an effective method to encourage all to "think" in three dimensions, even when they use 2D echocardiography.

Electrocardiogram Alteration and its Association with Khat Chewing: A study in Jimma Town, Ethiopia

Background: The electrocardiogram has become the most commonly performed cardiovascular test and an essential diagnostic tool in clinical cardiology. Increasing evidences suggest that long-term khat chewing may have powerful implications on the cardiovascular system. However; very few studies have focused on the association between khat chewing and ECG alteration. Objective: To asses Electrocardiogram alteration and its association with khat chewing in Jimma town, Southwest Ethiopia. Method: In this study, a cross-sectional, house-to-house survey on the representative sample of 342 persons, age ≥ 18 years, was conducted in Jimma town, southwestern Ethiopia, from March to April 2016. Sociodemographic characteristics, khat chewing history and ECG record (by standard 12-lead) data were collected. Kebeles, household, one member of a family in each household was chosen by the lottery method. Collected data was checked for its completeness and coded then entered to Epi-data 3.1 version and then exported to SPSS version 20 window for analysis. Descriptive statistics, binary and multivariate logistic regression analyses were applied to compute the variables. Results: There was a significant statistical association between age, khat chewing and ECG alteration. The most prevalent altered ECG finding was high heart rate 28(47.46%), followed by myocardial infarction 12(20.34%). Conclusion: This work and previous studies demonstrated that age, chronic khat chewing and increase in systolic blood pressure have effect on ECG alteration. Recommendation: Health promotion interventions should aim to prevent cardiovascular system diseases. Policy makers should design strategies to control the production, usage and distribution of khat.

Abstract 9923: Feasibility of New Real-Time 3-Dimensional Echocardiographic Imaging in a Mitral Valve Stenosis Model: A Comparison With 2D Imaging

Introduction: This study investigated the feasibility and accuracy of real-time three-dimensional echocardiography (RT3DE) in assessing the severity of simulated mitral stenosis in a pumped porcine heart model. Hypothesis: RT3DE is accurate for assessing mitral stenosis. Methods: Eight porcine hearts were used to simulate mitral stenosis. Four different sized inner-diameter tubes (9,11,13 and 15mm) were used to create stenotic mitral valve orifice areas. These tubes were inserted into vinyl tubing which was then connected to a pulsatile pump. A balloon was secured to the end of the tubing entering the left ventricle, and the model was sutured at the mitral annulus. The heart was submerged in a water tank and the pump set at 60 bpm with stroke volumes ranging from 30-70 mL in 10 mL increments. At each increment, images were acquired in 2D echo and RT3DE using a GE Vivid 7 ultrasound system. Data were analyzed using GE EchoPAC PC. Results: A comparison of true area and measured orifice areas were analyzed for both 2D echo and RT3DE. Linear regression analysis showed excellent correlation 2D and RT3DE acquired areas and true areas (2D: r 2 =0.9; RT3DE: r 2 =0.9). It was found that while RT3DE presented significantly similar mean values for all areas tested (P<0.05), 2D-measured areas were consistently larger than expected values (P<0.05). Conclusions: RT3DE has the potential to be an accurate, noninvasive diagnostic tool in clinical cardiology that overcomes imaging limitations present in 2D echo.

6-minute walking test in patients after cabg - assessment of exercise capacity

Abstract Introduction: The 6-minute walk test is a well established diagnostic tool in clinical cardiology to determine exercise tolerance, prognostic measure, control and modify the implemented treatment. Aim: Assess exercise tolerance in patients with coronary artery disease after surgical coronary artery bypass grafting using 6-minute walk test in correlation with selected concomitant risk factors for coronary artery disease. Material and methods: Analysis of medical records of 100 randomly selected patients, diagnosed by coronary angiography and coronary heart disease, scheduled for CABG. Patients were evaluated using exercise tolerance as measured by 6MWT before and 12 months after CABG. The results were correlated with the selected risk factors. Results: The study group showed improvement in 6MWT distance of 43.17 m (± 104.41) at 12-months after CABG. In order to analyze which risk factors influenced the observed changes of the 6MWT distance, the obtained results were correlated with factors such as the age of patients, sex, hypertension and smoking. There was no effect of these parameters on shortening or lengthening the distance. Conclusions: 1. From selected coronary artery disease risk factors only hypertension adversely affected the 6MWT distance before CABG. 3. The CABG operation caused significant improvement of exercise tolerance in patients with worse baseline exercise tolerance.

Computerized Interpretation of ECGs

Since the introduction of the string galvanometer by Willem Einthoven more than a century ago, the ECG has become the most commonly performed cardiovascular test and an essential diagnostic tool in clinical cardiology.1–3 The transition from analogue to digital ECGs resulted in automated computer analysis of the ECG (ECG-C) assuming a larger role in the diagnostic interpretation.3 Yet, as the ECG-C has evolved into a necessary tool of modern medical practice, many physicians remain unaware of the hazards of relying on these preliminary diagnostic interpretations. The ECG-C clinical use should always be with the understanding that they are preliminary interpretations and require reading and confirmation by qualified electrocardiographer.3 With an increased reliance on these readings for point-of-care decision making, clinicians must remain mindful of many limitations of the ECG-C.2,3 Article see p 76 Multiple prior investigations on the ECG-C interpretation have demonstrated erroneous interpretation, resulting in unnecessary, potentially harmful medical treatment, and inappropriate use of medical resources.4–7 A large international study compared the performance of 9 ECG-C programs with that of cardiologists in interpreting ECGs in clinically validated cases of various cardiac disorders.4 The percentage of ECGs correctly classified by the ECG-C was lower than that for the cardiologists.4 The median sensitivity of the computer programs was also significantly lower than that of the cardiologists in diagnosing left ventricular hypertrophy, right ventricular hypertrophy, anterior myocardial infarction, and inferior myocardial infarction.4 The median total accuracy level (the percentage of correct classifications) was 6.6% lower for the computer programs (69.7%) than for the cardiologists (76.3%; P <0.001).4 More contemporary analysis of the accuracy of ECG-C similarly concluded that there are frequent errors in the interpretation of the cardiac rhythm. In evaluating the ECG-C interpretation of the cardiac …

Radionuclide Imaging in Patients with Ischemic Heart Failure

Nuclear imaging procedures are well-established diagnostic tools in clinical cardiology, providing noninvasive information about myocardial perfusion, cardiac function and metabolism. Scintigraphic parameters provide relevant information that aids in everyday clinical decision making for referring physicians. In patients with coronary artery disease, the presence of myocardial necrosis, postischemic stunning and hibernation can determine left ventricular dysfunction leading to ischemic heart failure. The prognosis of these patients is still poor and the long-term results of medical management remain discouraging. It is now well established that ventricular dysfunction is often a reversible process and ventricular function may improve following myocardial revascularization. Patients with extensive areas of hibernation treated medically have a worse prognosis as compared to those who undergo revascularization with a similar extent of viable myocardium. Therefore, an accurate non-invasive assessment of myocardial viability with the preoperative differentiation between hibernation and stunning and irreversibly necrotic tissue is important for clinical decision-making to select patients candidates for revascularization. Radionuclide imaging techniques evaluating myocardial perfusion, cell membrane integrity, ventricular function and cardiac metabolism have demonstrated clinical utility in the assessment of myocardial viability and in predicting improvement of ventricular function and prognosis after coronary revascularization. Keywords: radionuclide cardiac imaging, ischemic heart failure, myocardial viability

Non-invasive diagnostic procedures for heart failure: echocardiography, myocardial perfusion scintigraphy and radionuclide ventriculography

Even though the diagnosis of heart failure can often be made at bedside from the patient's history and a thorough physical examination, some mechanical examinations are needed to objectify the clinical symptoms. Due to the chronic and progressive character of heart failure with repeated periods of clinical treatment, non-invasive and reproducible methods are of great importance. Thanks to technical progress in data-acquisition and -processing, echocardiography has become one of the most important diagnostic tools in clinical cardiology. Many questions associated with the diagnosis and treatment of heart failure can be answered with the aid of the wide spectrum of echocardiography, including morphological description in conventional M- or B-Mode and functional analysis based on Dopplertechnique. On the other hand well-established nuclear techniques like myocardial perfusion scintigraphy and radionuclide ventriculography profit from recent technical development. In addition, the modification, specification and standardisation of examination protocols improve the diagnostic reliability of nuclear medical techniques. Performed by a specialist, both principles of examination--ultrasound and scintigraphy--are valid in the diagnosis of heart failure and in therapy-management.

Behaviour of implantable coronary stents during magnetic resonance imaging.

BACKGROUND: Magnetic resonance imaging (MRI) becomes more and more a routine diagnostic tool in clinical cardiology. In patients undergoing MRI, metallic implants may be harmful by motion or heating under certain circumstances. Many cardiac patients have implanted intracoronary stents. However, the safety of these metallic implants and especially their temperature behaviour during MRI has not been sufficiently tested. METHODS: This study investigated motion and temperature changes of 14 different stents for intracoronary application in two clinical scanners at field strengths of 1.0 and 1.5 T. At 1.5 T these studies were repeated after implantation of the stents into the coronary arteries of excised porcine hearts. Furthermore, the clinical status of 33 patients was assessed after a cardiac MR study and compared with a group of 33 patients matched for age, sex and risk factors for restenosis. RESULTS: No visible motion of the stents was observed. Furthermore, using a highly sensitive infrared camera any significant heating of the stents during MRI could be excluded. The rate of clinical events was not different in patients after MRI as compared with the control group. CONCLUSION: It is concluded that MRI is safe in patients with the currently available intracoronary stents.

Nuclear medicine studies of the heart.

Nuclear imaging techniques are well established diagnostic tools in clinical cardiology, providing noninvasive information about myocardial perfusion, function and metabolism. The cost-effectiveness of radionuclide imaging in the diagnostic work-up of patients with coronary artery disease has been demonstrated. Additionally, the documented prognostic value of scintigraphic parameters is of clinical importance to guide decision making. Advances in technology, new radiotracers and new applications contribute to continuous growth in the field of nuclear cardiology. Multi-headed gamma camera systems lead to higher spatial resolution and sensitivity of cardiac single photon emission tomography (SPECT), and they also provide the opportunity for attenuation correction or electrocardiographic gating of SPECT images. Objective quantitative values of perfusion, function and metabolism are derived from scintigraphic data by use of improved software and hardware. With the latest developments in tracer technology, imaging of myocardial necrosis, receptor systems and autonomic innervation has become a reality and will lead to new clinical applications in the future.

Phonocardiography and mechanocardiography as the old-fashioned, but indispensable diagnostic tools in clinical cardiology.

Phonocardiography and mechanocardiography are indispensable diagnostic tools in clinical cardiology though several limitations are inherently present. They should not be abandoned even in the era of echocardiography, and they are so rewarding in so many cases that we have to consider properly what we can expect and what we cannot prior to answering to the patient's question, Now, what else are you going to examine, doctor?