Systemic availability of oral verapamil and effect on PR interval in man.

: Transfersomes are bilayer vesicles composed of phospholipid and edge-activators, which are mostly surfactant. Transfersomes based drug delivery system has gained a lot of interest of the pharmaceutical researchers for their ability to improve drug penetration and permeation through the skin. Transdermal drug delivery via transfersomes has the potential to overcome the challenge of low systemic availability. However, this complex vesicular system has different issues to consider for developing a successful transdermal delivery system. One of the major ingredients, phospholipid has versatile sources and variable effect on the vesicle size and drug entrapment in transfersomes. The other one termed as edge-activator or surfactant has some crucial consideration of skin damage and toxicity depending upon its type and concentration. A complex interaction between type and concentration of phospholipid and surfactant was observed, which affect the physicochemical properties of transfersomes. This review focuses on the practical factors related to these two major ingredients such as phospholipid and surfactant. The origin, purity, desired concentration, the susceptibility of degradation, etc. are the important factors for selecting phospholipid. Regarding surfactants, the major aspects are type and desired concentration. A successful development of transfersomes based drug delivery system depends on the proper considerations of these factors and practical aspects.

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DETERMINANTS OF SYSTEMIC AVAILABILITY OF MORPHINE AND BUPRENORPHINE IN THE RAT

Journal of Pharmacy and Pharmacology ◽

10.1111/j.2042-7158.1981.tb11697.x ◽

1981 ◽

Vol 33 (S1) ◽

pp. 38P-38P

Author(s):

M. Mistry ◽

J.B. Houston

Keyword(s):

Systemic Availability

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PR interval as a predictor of syncope in tilt-up testing in adolescents and young adults

The Egyptian Heart Journal ◽

10.1186/s43044-021-00149-6 ◽

2021 ◽

Vol 73 (1) ◽

Author(s):

Juraj Jug ◽

Lada Bradić ◽

Rea Levicki ◽

Martina Lovrić Benčić

Keyword(s):

Heart Rate ◽

Vasovagal Syncope ◽

True Positive ◽

Ecg Monitoring ◽

Interval Prolongation ◽

Patient History ◽

Pr Interval ◽

Heart Rate Dynamics ◽

Testing Data ◽

Consciousness Disorder

Abstract Background Syncope, as the most frequent consciousness disorder, is very common in young individuals. The aim of this study was to analyze ECG parameters and clinical properties obtained during tilt-up testing in 12 to 30-year-old subjects. We enrolled a total of 142 patients from our outpatient clinic (39 males, 103 females) with a true positive tilt-up test and analyzed ECG records obtained during tilt-testing. Data were stratified according to the age, gender, and type of syncope. Results PR interval shortening preceding syncope was found in all syncope types, irrespective of the gender. All types of syncope were more frequent in women (72.5%). Mixed syncope type was found to be the most common (47.18%). Male and female subjects differed in initial heart rate (71.56 vs 76.23/min, p=0.05), as well as heart rate dynamics during tilt-up testing. A gender difference was also found in systolic blood pressure (116.92 vs 110.44 mmHg, p<0.01), time to syncope onset (20.77 vs. 16.44 min, p=0.03), and the total number of syncopal episodes in patient history (2.79 vs. 4.62, p<0.05). Subjects with cardioinhibitory syncope had the longest PR interval (average 154.3 ms). PR interval prolongation and loss of variability during tilt-up testing positively correlated with aging (r=0.22, p<0.05). Nodal rhythm was found in 8 patients. Conclusion PR interval shortening on ECG tracings during a tilt-up test can be found in all subtypes of vasovagal syncope, thereby contrasting previous reports that these changes are a hallmark of the cardioinhibitory type of syncope. PR shortening, if observed during ECG monitoring, could be a potential predictor of syncope.

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Abnormalities of the P Wave and PR Interval

Electrocardiogram in Clinical Medicine ◽

10.1002/9781118754511.ch37 ◽

2020 ◽

pp. 383-396

Author(s):

Matthew Borloz

Keyword(s):

P Wave ◽

Pr Interval

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Associations between left bundle branch block with different PR intervals, QRS durations, heart rates and the risk of heart failure: a register-based cohort study using ECG data from the primary care setting

Open Heart ◽

10.1136/openhrt-2020-001425 ◽

2021 ◽

Vol 8 (1) ◽

pp. e001425

Author(s):

Marc Meller Søndergaard ◽

Johannes Riis ◽

Karoline Willum Bodker ◽

Steen Møller Hansen ◽

Jesper Nielsen ◽

...

Keyword(s):

Heart Failure ◽

Primary Care ◽

Heart Rate ◽

Left Bundle Branch Block ◽

Bundle Branch Block ◽

Increased Risk ◽

Pr Interval ◽

Qrs Duration ◽

The Impact

AimLeft bundle branch block (LBBB) is associated with an increased risk of heart failure (HF). We assessed the impact of common ECG parameters on this association using large-scale data.Methods and resultsUsing ECGs recorded in a large primary care population from 2001 to 2011, we identified HF-naive patients with a first-time LBBB ECG. We obtained information on sex, age, emigration, medication, diseases and death from Danish registries. We investigated the association between the PR interval, QRS duration, and heart rate and the risk of HF over a 2-year follow-up period using Cox regression analysis.Of 2471 included patients with LBBB, 464 (18.8%) developed HF during follow-up. A significant interaction was found between QRS duration and heart rate (p<0.01), and the analyses were stratified on these parameters. Using a QRS duration <150 ms and a heart rate <70 beats per minute (bpm) as the reference, all groups were statistically significantly associated with the development of HF. Patients with a QRS duration ≥150 ms and heart rate ≥70 bpm had the highest risk of developing HF (HR 3.17 (95% CI 2.41 to 4.18, p<0.001). There was no association between the PR interval and HF after adjustment.ConclusionProlonged QRS duration and higher heart rate were associated with increased risk of HF among primary care patients with LBBB, while no association was observed with PR interval. Patients with LBBB with both a prolonged QRS duration (≥150 ms) and higher heart rate (≥70 bpm) have the highest risk of developing HF.

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