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Assessing and responding to sudden deterioration in the adult
Published in Nicola Neale, Joanne Sale, Developing Practical Nursing Skills, 2022
The P wave is indicative of atrial activity. It shows us depolarisation of the left and right atria. It is concerned with atrial contraction. If a P wave is present, it indicates atrial activity. If no P waves are present, this would indicate a more serious situation of a broad, prolonged complex.
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.
The patient with acute cardiovascular problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
P wave: this is a small rounded wave that is seen on the ECG during atrial depolarisation. P waves should always be present, as this indicates SA nodal depolarisation (sometimes referred to as ‘firing’) and that the subsequent wave of depolarisation is simultaneously spreading across the atrial myocardium. The PR interval is the time between the beginning of the P wave and the first deflection of the QRS complex. This is 0.2 seconds (or seen as 5 small squares on ECG paper).
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.
Influence of relative wall thickness on electrocardiographic voltage measures in left ventricular hypertrophy: a novel factor contributing to poor diagnostic accuracy
Published in Postgraduate Medicine, 2020
Ning Ye, Guo-Zhe Sun, Ying Zhou, Shao-Jun Wu, Ying-Xian Sun
A recent study [8] demonstrated that isolated left atrial dilation has indeterminately moderate effects on P-wave duration and voltage. In contrast, left atrial concentric hypertrophy consistently increased P-wave amplitude, with duration unaffected. These findings provided a potential explanation regarding the limited utility of current P-wave criteria in the detection and diagnosis of left atrial enlargement in clinical practice. However, insufficient data have been reported in relation to the independent influence of left ventricular geometry on ECG voltage for ascertaining LVH. A general consensus has been established regarding the use of echocardiographic relative wall thickness (RWT) when defining concentric and eccentric changes [9]. Hence, we subsequently proposed an original hypothesis suggesting that RWT itself could potentially influence the diagnostic performance of ECG indices by affecting QRS voltages, independent of the left ventricular mass index (LVMI). The influence of RWT on Cornell, Sokolow-Lyon and Peguero-Lo Presti voltage were examined, after which the effects identified were evaluated in regard to the diagnostic performance in detecting LVH in a large general Chinese population.