Jonas Pettersson

Changes in high-frequency QRS components are more sensitive than ST-segment deviation for detecting acute coronary artery occlusion☆

OBJECTIVES This study describes changes in high-frequency QRS components (HF-QRS) during percutaneous transluminal coronary angioplasty (PTCA) and compares the ability of these changes in HF-QRS and ST-segment deviation in the standard 12-lead electrocardiogram (ECG) to detect acute coronary artery occlusion. BACKGROUND Previous studies have shown decreased HF-QRS in the frequency range of 150-250 Hz during acute myocardial ischemia. It would be important to know whether the high-frequency analysis could add information to that available from the ST segments in the standard ECG. METHODS The study population consisted of 52 patients undergoing prolonged balloon occlusion during PTCA. Signal-averaged electrocardiograms (SAECG) were recorded prior to and during the balloon inflation. The HF-QRS were determined within a bandwidth of 150-250 Hz in the preinflation and inflation SAECGs. The ST-segment deviation during inflation was determined in the standard frequency range. RESULTS The sensitivity for detecting acute coronary artery occlusion was 88% using the high-frequency method. In 71% of the patients there was ST elevation during inflation. If both ST elevation and depression were considered, the sensitivity was 79%. The sensitivity was significantly higher using the high-frequency method, p<0.002, compared with the assessment of ST elevation. CONCLUSIONS Acute coronary artery occlusion is detected with higher sensitivity using high-frequency QRS analysis compared with conventional assessment of ST segments. This result suggests that analysis of HF-QRS could provide an adjunctive tool with high sensitivity for detecting acute myocardial ischemia.

Creativity, innovation and lean sigma: a controversial combination?

The application of lean sigma is gaining momentum in drug discovery and development but it remains controversial because of perceptions that process improvement will suppress much-needed creativity and innovation. We review the conditions required to support creativity and innovation and the principles and benefits of lean sigma in a drug discovery environment. We conclude that it is desirable to create a unified climate that encourages and enables both innovation and continuous improvement and that this is possible if three key tensions are handled carefully and with due respect to the needs of research. These three potential traps occur in the interpretation of standardization, the role of variation and the choice of how to use liberated capacity.

Making medicinal chemistry more effective—application of Lean Sigma to improve processes, speed and quality

The pharmaceutical industry, particularly the small molecule domain, faces unprecedented challenges of escalating costs, high attrition as well as increasing competitive pressure from other companies and from new treatment modes such as biological products. In other industries, process improvement approaches, such as Lean Sigma, have delivered benefits in speed, quality and cost of delivery. Examining the medicinal chemistry contributions to the iterative improvement process of design-make-test-analyse from a Lean Sigma perspective revealed that major improvements could be made. Thus, the cycle times of synthesis, as well as compound analysis and purification, were reduced dramatically. Improvements focused on team, rather than individual, performance. These new ways of working have consequences for staff engagement, goals, rewards and motivation, which are also discussed.

Quantification of myocardial hypoperfusion with 99m Tc-sestamibi in patients undergoing prolonged coronary artery balloon occlusion.

Percutaneous transluminal coronary angioplasty provides an excellent opportunity to investigate the location and quantity of hypoperfusion during sudden complete occlusion of one of the major coronary arteries. Thirty-five patients referred for elective percutaneous transluminal coronary angioplasty were injected intravenously with 99mTc-sestamibi during balloon inflation. To visualize and quantify the hypoperfused region, a map of perfusion was constructed from that occlusion study and from the control study performed on the following day. Patients were divided into groups according to proximal or distal occlusion within each of the three coronary arteries. The region of myocardium supplied by each coronary artery varied in location and extended outside the typical borders for all arteries, but most prominently for the left circumflex coronary artery. The quantities of hypoperfusion varied within each artery group, but the average hypoperfusion was greater for the left anterior descending coronary artery than for either the right coronary artery or the left circumflex coronary artery. It is concluded that the quantities of hypoperfusion were highly variable within each artery group. Occlusion of the left anterior descending coronary artery was associated with the largest ischaemic region. The area of hypoperfusion extended outside the typical borders, most prominently for the left circumflex coronary artery.

Comparison of teaching the basic electrocardiographic concept of frontal plane QRS axis using the classical versus the orderly electrocardiogram limb lead displays

This study compares the effectiveness of teaching the calculation of frontal plane QRS axis with the use of the classical versus the orderly electrocardiographic limb lead display. Eighty-three students from two environments were randomized into two groups and were taught to determine frontal plane axis with one of the methods. The accuracy and time to determine the axis were tested on 10 electrocardiograms. In the United States the group using the classical display achieved 4.2 (+/-2.7) correct answers, whereas those using the orderly method achieved 6.8 (+/-3.0) (p = 0.0006). The classical group used 9.2 (+/-2.8) minutes to complete the test, whereas the orderly group needed 7.2 (+/-2.0) minutes (p = 0.015). The results achieved in Sweden were similar. The use of the orderly electrocardiographic limb lead display results in greater diagnostic accuracy in less time than the classical display when determining the frontal plane QRS axis.

High-frequency electrocardiogram as a supplement to standard 12-lead ischemia monitoring during reperfusion therapy of acute inferior myocardial infarction.

BACKGROUND Resolution of ST-segment elevation in the electrocardiogram (ECG) is used as a reperfusion sign during thrombolytic therapy in acute myocardial infarction. Analysis of high-frequency QRS components (HF-QRS) might provide additional information. The study compares changes in HF-QRS (150-250 Hz) to ST-segment changes in the standard ECG during thrombolytic therapy. METHODS Twelve patients receiving intravenous thrombolytic therapy were included. A continuous 12-lead ECG recording was acquired for 4 hours. RESULTS After 1 hour of therapy, 3 patients showed ST-elevation resolution as well as an increase in HF-QRS. These changes in ST and HF-QRS occurred simultaneously. No other patient showed significant changes in ST or HF-QRS after 1 hour. After 2 and 4 hours, there was less concordance between the standard and high-frequency ECGs. CONCLUSIONS In patients with early ST-elevation resolution, the standard and high-frequency ECGs show similar results. Later changes are more disparate and may provide different clinical information.

Pharmacokinetics and tolerability of semaglutide in people with hepatic impairment

To investigate whether the pharmacokinetic characteristics of semaglutide were altered in people with hepatic impairment, assessed using Child–Pugh criteria, vs those with normal hepatic function.

Serial changes in the high-frequency ECG during the first year following acute myocardial infarction.

Background:  Previous studies have shown reduced high‐frequency QRS components (HF‐QRS) after acute myocardial infarction (MI). The purpose of this study was to investigate serial changes in HF‐QRS during the first year following acute MI.

Increased sensitivity for the diagnosis of healed myocardial infarction using vectorial information in the 12-lead ECG

The aim of this study was to use the vectorial information in the conventional 12-lead electrocardiographic (ECG) recording and to investigate whether this information, in combination with well-known ECG criteria, could increase the diagnostic performance for healed anterior or inferior myocardial infarction. A total of 1,458 subjects were included in the study; 272 patients with anterior myocardial infarction, 356 patients with inferior myocardial infarction, and 830 subjects classified as normal. New 12-lead vectorcardiographic criteria for anterior and inferior myocardial infarction were developed and used in combination with well-known ECG criteria. The combined criteria showed a sensitivity of 80.0% and 72.4% for the diagnosis of anterior and inferior myocardial infarction, respectively. The corresponding sensitivities for the conventional ECG criteria were significantly lower. In conclusion, the addition of vectorial parameters into ECG interpretation programs could be of value.

Determination of the ability of high-frequency ECG to estimate left ventricular mass in humans, determined by magnetic resonance imaging.

Background:  Previous studies have shown a significantly higher correlation between left ventricular mass index (LVMi) and high‐frequency QRS components (HF‐QRS) than between LVMi and QRS amplitudes in the standard frequency range in rabbits. The purpose of the present study was to compare ECG measurements from standard and high‐frequency ranges with left ventricular mass (LVM) and LVMi determined by magnetic resonance imaging in humans.