Tp-e interval, Tp-e/QT and Tp-e/QTc ratio in hypertensive patients with primary aldosteronism

Dexmedetomidine and Perioperative Arrhythmias

The highly selective α2-adrenoceptor agonist dexmedetomidine is a commonly used sedative drug for patients undergoing anesthesia and intensive care treatment. Several studies have indicated that dexmedetomidine may have a potential role in preventing and treating perioperative tachyarrhythmias. However, the specific effect and mechanism of action of dexmedetomidine in this context remain unclear. Dexmedetomidine is known to regulate the electrophysiologic function of the myocardium by inhibiting the function of the sinus node and atrioventricular node, as well as affecting myocardial repolarization. This paper aims to provide a theoretical basis for the prevention and treatment of perioperative arrhythmias by summarizing the effects of dexmedetomidine on myocardial electrophysiologic function and its impact on different types of arrhythmias.

Genetic Testing for Antipsychotic Pharmacotherapy: Bench to Bedside

There is growing research interest in learning the genetic basis of response and adverse effects with psychotropic medications, including antipsychotic drugs. However, the clinical utility of information from genetic studies is compromised by their controversial results, primarily due to relatively small effect and sample sizes. Clinical, demographic, and environmental differences in patient cohorts further explain the lack of consistent results from these genetic studies. Furthermore, the availability of psychopharmacological expertise in interpreting clinically meaningful results from genetic assays has been a challenge, one that often results in suboptimal use of genetic testing in clinical practice. These limitations explain the difficulties in the translation of psychopharmacological research in pharmacogenetics and pharmacogenomics from bench to bedside to manage increasingly treatment-refractory psychiatric disorders, especially schizophrenia. Although these shortcomings question the utility of genetic testing in the general population, the commercially available genetic assays are being increasingly utilized to optimize the effectiveness of psychotropic medications in the treatment-refractory patient population, including schizophrenia. In this context, patients with treatment-refractory schizophrenia are among of the most vulnerable patients to be exposed to the debilitating adverse effects from often irrational and high-dose antipsychotic polypharmacy without clinically meaningful benefits. The primary objective of this comprehensive review is to analyze and interpret replicated findings from the genetic studies to identify specific genetic biomarkers that could be utilized to enhance antipsychotic efficacy and tolerability in the treatment-refractory schizophrenia population.

The impact of fever on myocardial repolarization parameters

BACKGROUND

It has been reported in the literature that the increase in body temperature shortens QT interval on electrocardiogram through heart rate modulation. However, the effects of fever on ventricular repolarization are not clearly known. This study elaborates on QT interval of isolated fever, corrected QT (cQT), Tp-e interval, the ratio of corrected Tp-e (cTp-e) and Tp-e/QT, and their impacts on arrhythmia potential.

METHODS

This prospective study was performed on 74 patients without any active and chronic diseases other than fever and upper respiratory tract infection. The study included patients at the age of 18-50 years suffering from fever above 38.2 °C. QT and Tp-e intervals of the patients were measured from their ECGs taken in febrile and afebrile periods. cQT and cTp-e values were calculated according to Bazett, Fridericia, and Framingham formulations.

RESULTS

QT and Tp-e intervals were observed to be shorter in the febrile period (p < 0.001 and p = 0.006 respectively). cTp-e was found to be longer in the febrile period according to Bazett, Fridericia, and Framingham formulations (p < 0.001, p = 0.002, p < 0.001, respectively). Tp-e/QT ratio was found to be higher in the febrile period than in the afebrile period (p < 0.001).

CONCLUSION

Although QT, cQT, and Tpe intervals were shorter, cTpe interval and Tpe/QT ratio were longer and higher in the febrile period, respectively. These findings may indicate that fever may create a proarrhythmic effect by causing variability in the transmural distribution of myocardial repolarization.