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Cardiovascular Disease
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
A short PR interval does not always indicate an AV accessory bypass tract. Other causes of a short PR interval include small stature, increased sympathetic activity and a congenitally small AV node.
Paper 3
Published in Aalia Khan, Ramsey Jabbour, Almas Rehman, nMRCGP Applied Knowledge Test Study Guide, 2021
Aalia Khan, Ramsey Jabbour, Almas Rehman
On an ECG the PR interval corresponds with the time taken for excitation to spread from the sino-atrial (SA) node through the atrial muscles and the atrio-ventricular (AV) node down the Bundle of His into the ventricular muscle. A normal PR interval = 0.12–0.20 seconds.
The patient with acute cardiovascular problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
The PQRST complex has been described earlier in the chapter. Sinus rhythm has the following characteristics (see also Table 6.7): Rate of between 60–100 beats per minute.Regular.P wave is present.P-R interval is normal (between 0.12–0.20 seconds or three to five small squares on ECG paper).QRS complex follows the P wave (duration less than 0.12 seconds or 3 small squares on ECG paper.ST segment on isoelectric line.T wave is present.
Thyrotoxic periodic paralysis: a presentation of hyperthyroidism increasing in frequency around the world
Published in Journal of Endocrinology, Metabolism and Diabetes of South Africa, 2023
Laboratory results include a very low serum potassium level without any acid-base disturbance.21,22 Renal excretion of potassium is also low, thus excluding renal potassium wasting. A high urinary calcium-to-phosphate ratio has been proposed to distinguish thyrotoxic periodic paralysis patients from those with familial hypokalaemic periodic paralysis.5 Suppressed thyroid stimulating hormone levels with raised T3 and T4 levels are pathognomonic of the disease. Unsurprisingly, Graves’ disease is most commonly diagnosed in patients with thyrotoxic periodic paralysis; however, thyroiditis, toxic multinodular goitre and TSH-producing pituitary tumours have also been reported.21,22,24 The ECG may show U-waves, prolonged PR interval and both supraventricular and ventricular ectopic beats. The risk for life-threatening ventricular tachycardias or fibrillation remains high until the hypokalaemia is corrected.25,26
Electrocardiographic changes after breast reduction surgery
Published in Journal of Plastic Surgery and Hand Surgery, 2023
Ayca Ergan Sahin, Tugce Yasak, Burak Yılmaz, Ahmet Anil Sahin, Ali Rıza Demir, Ozlem Colak
In literature, the relationship between atrial conduction and PWD was demonstrated in previous researches. Dilaveris et al. [16] compared patients with a history of paroxysmal atrial fibrillation to healthy controls and their study showed that paroxysmal atrial fibrillation patients had higher PWD than healthy controls. According to the studies in literature, Centurión commented that PWD was associated with an abnormality in atrial conduction, and increased PWD might lead to AF shortly [17]. In another study, patients with atrial fibrillation had similarities with patients who had PR interval prolongation and therefore, the authors commented that prolongation in PR interval might be considered as a preliminary stage to atrial fibrillation [18]. Additionally in a meta-analysis, Cheng et al. [19] concluded that, PR interval prolongation should not be considered as a benign condition but an independent risk factor for atrial fibrillation and atrial arrhythmogenesis. On the other hand, the parameters such as TPe duration, TPe/QT ratio and TPe/QTc ratio are used in the evaluation of ventricular repolarization and ventricular arrhythmogenesis [20,21]. Therefore, the improvement is these parameters might be a sign of decreased ventricular arrhythmogenesis and marker of improved ventricular conduction.
Slow pathway elimination using antegrade conduction improvement with fast atrial pacing during AVNRT radiofrequency ablation: a proof-of-concept study
Published in Acta Cardiologica, 2022
Sok-Sithikun Bun, Ahmed Mostfa Wedn, Ahmed Taher, Philippe Taghji, Fabien Squara, Karim Hasni, Claudio De Zuloaga, Emile Ferrari
Older and recent studies showed the ‘improvement’ of anterograde conduction after SP ablation. In 1994, Strickberger et al. reported that the elimination of the conduction of the SP was associated with a shortening of the effective refractory period of the FP [5]. It has been hypothesised that a concealed retrograde conduction of conducted sinus impulses from the SP through the FP could be observed. Recently, SP ablation performed for symptomatic AVNRT in two patients with baseline PR prolongation before ablation, resulted after ablation in PR interval shortening [16]. In the same way, Prystowsky E recently reported an exclusive SP conduction at baseline that was converted after successful SP elimination to an exclusive antegrade FP conduction, corroborated with PR shortening (and abolition of concealed retrograde conduction within the FP) [17].