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Assessing and responding to sudden deterioration in the adult
Published in Nicola Neale, Joanne Sale, Developing Practical Nursing Skills, 2022
You will have noticed that, unlike in sinus rhythm, in atrial fibrillation, ‘P’ waves cannot be identified. This is because the atria are ‘fibrillating’ rather than contracting, and the impulses are conducted through the atrioventricular node irregularly, so the QRS complexes appear irregularly. You will see that the QRS complexes occur more frequently as often uncontrolled atrial fibrillation leads to a more rapid heart rate. If you were feeling Mrs Patel’s pulse, it would feel irregularly irregular. This observation is an important indicator of atrial fibrillation and it should be reported. In this section, you have learned how to attach a cardiac monitor, how to observe a rhythm strip and how to recognise one common arrhythmia, atrial fibrillation.
Congestive Heart Failure
Published in Jahangir Moini, Matthew Adams, Anthony LoGalbo, Complications of Diabetes Mellitus, 2022
Jahangir Moini, Matthew Adams, Anthony LoGalbo
On ECG, there is usually the voltage criteria for LV hypertrophy. Extremely deep septal Q waves are often present along with asymmetric septal hypertrophy. Hypertrophic cardiomyopathy may produce a QRS complex in V1 and V2 that simulates an earlier septal infarction. There are usually abnormal T waves. Usually, there is a deep symmetric T-wave inversion. An ST-segment depression is common – especially with the apical obliterative subtype. The P wave is usually broad and notched. A biphasic P wave may indicate left atrial hypertrophy. There is increased incidence of a preexcitation phenomenon that is of the Wolff-Parkinson-White syndrome type that can cause palpitations. Bundle branch block is often seen. The 2-D Doppler echocardiography technique can determine the severity of hypertrophy and the amount of outflow tract obstruction, which are used to monitor effects of medical or surgical treatments. Cardiac catheterization is performed if invasive therapy is being considered. There is usually no significant stenosis of the coronary arteries. However, older patients may also have CAD. Genetic biomarkers do not identify people at high risk or affect treatment, though genetic testing may help in the screening of family members.
Bioelectric and Biomagnetic Signal Analysis
Published in Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam, Introduction to Computational Health Informatics, 2019
Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam
P-wave is a superimposition of P-wave from the right-atrium and P-wave from the left-atrium. The normal size of P-wave is less than 0.25 millivolts (2.5 mm of the ECG graph paper) with a duration of less than 0.12 seconds. The two P-waves are superimposed because the delay between Pleft and Pright is quite small. However, if the left-atrium enlarges, Pleft will be delayed causing P-wave to spread. If the right-atrium dilates, then both will superimpose causing the P-wave peak to become more pronounced and the spread of P-wave shortens.
Assessing cardiac safety among clients receiving methadone as part of opioid agonist maintenance therapy (OAMT) in Durban, South Africa
Published in Journal of Addictive Diseases, 2023
Dorcas Rosaley Prakaschandra, Andrew Scheibe, Monique Marks, Datshana Prakesh Naidoo
Standard resting 12-lead ECGs were recorded using a WelchAllyn CP50 405881 (WelchAllyn Inc) portable electrocardiographic recorder. Parameters analyzed were the PR interval, QRS interval, QT and QTc duration and heart rate. Abnormalities in P wave morphology, PR and ST-interval deviations were also documented. The QT interval was defined as the interval between the Q-wave and the end of the T-wave, and was measured in Lead II, together with the RR interval. Bazett’s formula (QTc = QT/✓ R–R)28 was used to calculate the QTc. QTc intervals were considered prolonged if they were >450 ms for men and >470 ms for women.29 Because the QT intervals differ according to gender, males and females were analyzed separately. ECGs were conducted at baseline and at 12 months.
The effects of methamphetamine on electrocardiographic parameters in male patients
Published in International Journal of Psychiatry in Clinical Practice, 2022
Bahadir Demir, Filiz Ozsoy, Ahmet Buyuk, Abdurrahman Altindag
12-lead ECG was performed with a Nihon-Kohden Cardiofax S branded device while all participants were in supine position and at rest. In these logs, the paper flow rate was 50 mm/s, the amplitude was 10 mm/Mv, the filter was 100 Hz and the alternating current filter was 60 Hz. ECG logs were evaluated by two experienced cardiologists. The electrocardiogram measurements obtained were transferred to a computer using a scanner and analysed with ×400% using Adobe Photoshop CS2 program (Adobe Systems Inc., San Jose, CA). Tp-e and QT intervals were obtained from V2–V5 derivations. The QT interval was calculated as the time from the beginning of the QRS to the point where it returns to the isoelectric line at the end of the T wave. Tp-e interval: The interval at the termination of the T wave peak was measured as Tp-e. For the R–R interval, the average of three consecutive shot complexes was measured. Bazzet's formula was used to calculate the heart rate and QTc interval. Those with U waves in their ECG were excluded from the study. Finally, the P wave dispersion was calculated by subtracting the minimum P wave duration from the maximum P duration.
Erroneous computer-based interpretations of atrial fibrillation and atrial flutter in a Swedish primary health care setting
Published in Scandinavian Journal of Primary Health Care, 2019
Thomas Lindow, Josefine Kron, Hans Thulesius, Erik Ljungström, Olle Pahlm
For the purpose of this study, atrial fibrillation was defined as an irregular supraventricular rhythm and absence of discernible P waves. Atrial flutter was defined as a supraventricular rhythm with regular flutter waves (F waves) with an atrial rate of 200–340/min and absence of an isoelectric baseline between discernible F waves. ECGs were re-assessed by one experienced ECG reader (TL, >10 years of experience of ECG interpretation including computer interpretation overreading) and one expert ECG reader (OP, >30 years of experience). ECGs with an incorrect diagnosis of atrial fibrillation or atrial flutter were assessed also by a third reader with vast experience in invasive electrophysiology studies, including ablation treatment for atrial fibrillation and atrial flutter (EL, >20 years of experience). A definitive rhythm diagnosis was determined by consensus. ECGs with an incorrect diagnosis were assessed for signal quality and for each ECG presence of either no, minor or major signal disturbances were noted.