QT Measurement Techniques and Anesthesia Management
QT Measurement Techniques and Anesthesia Management
In studies, the effects of drugs used for anesthesia and analgesia on QT distance were
 evaluated in isolation. However, drugs are administered in combination with each other during
 anesthesia induction. Therefore, drugs interact in terms of positive and undesirable effects.
 In addition, most of the studies examining anesthesia and QT distance have been conducted in
 non-cardiac surgery. The target group in this study is the adult patient group who will
 undergo cardiac surgery. The primary aim of our study is to investigate the effect of two
 different types of anesthesia induction techniques on QT distance in patients undergoing
 open-heart surgery. QT evaluation will be performed after endotracheal intubation after
 anesthesia induction.
Long QT syndrome (LQTS) is a cardiac conduction disorder characterized by the prolongation
 and extension of ventricular repolarization. This prolonged repolarization may cause re-entry
 circuits when sympathetic activity is added and may cause syncope, dizziness, torsades de
 pointes (TdP), ventricular fibrillation (VF), ventricular tachycardia (VT), or sudden cardiac
 death (1). LQTS is divided into two groups as congenital and acquired. Drug-induced LQTS is
 the most common cause of the acquired form. It is known that some drugs used during
 anesthesia and analgesia management have effects on the QT distance (2).

 The QT interval is the most commonly used ECG indicator for arrhythmias, representing the
 action potential duration (3). The prolonged QT interval is a risk marker frequently used in
 patients with a predisposition to the development of TdP, a type of polymorphic VT or VF
 variant. Often the QT distance is computed with the corrected QT (QTc) Bazett formula (QTc =
 QT / √RR). However, non-torsadogenic VT / VF cannot be evaluated with QTc alone, and this has
 led to the need for new additional biomarkers.

 A new marker called "Index of cardio-electrophysiological balance (iCEB)" shows the balance
 between depolarization and repolarization of the action potential. The iCEB calculated by
 dividing the QT interval by the QRS duration (QT / QRS); In addition to drug-induced long QT
 and TdP, it is also superior in detecting conduction slowdowns, QT shortening, and associated
 non-TdP-like VT / VF induced by drugs, especially drugs used in anesthesia management, and is
 now shown as a potential risk predictor in drug-induced arrhythmias ( 3,4). The secondary aim
 of our study is to evaluate the effects of drugs used in anesthesia management on QT distance
 with Bazett and iCEB techniques.

 The expected benefit from the research is to determine the effects of two different
 anesthesia induction techniques, in which anesthetic drugs are applied in combination, on the
 QT prolongation induced by drugs, and to detect QT prolongations in different periods of
 anesthesia with different QT measurement methods. No study-specific risk is considered.

 This study was planned prospectively and randomized. If the patients who will undergo
 open-heart surgery in the cardiovascular surgery operating rooms are evaluated in terms of
 both anesthesia methods after the preoperative routine evaluation and meet the conditions for
 participation in the study, the research project will be explained to the patients. If
 accepted by the patients, verbal and written consent will be obtained and the patients will
 be included in the study. Anesthesia management and grouping will be determined by the
 randomization program.

 A total of 60 adult patients in both groups who will undergo open-heart surgery will be
 included in the study. Using the randomization program, the patients will be divided into two
 groups of 30 people. While 2-3 mg/kg propofol and 1-2 mg/kg ketamine will be used for
 anesthesia induction in the first group, 0.15 mg/kg midazolam and 10-15 mcg/kg fentanyl will
 be used for anesthesia induction in the other group. Patients with bundle branch block in
 their preoperative ECG, patients with arrhythmia, allergies specific to known drugs, and
 patients with electrolyte disorders will not be included in the study.

 Age, gender, body weight, and height of the patients will be recorded. Patients will be
 questioned in terms of additional diseases and medicines they use. Preoperative blood sodium,
 potassium, and calcium values will be evaluated and recorded in terms of electrolyte
 imbalance.

 Patients will be taken to the operation room and rested for 1 minute by preoxygenation. Then,
 12-lead ECG will be taken to evaluate the QT length with the Bazett formula (QTc = QT / √RR)
 and the iCEB formula (QT / QRS), and the average arterial pressure, heart rate, oxygen
 saturation of the patient will be recorded simultaneously. ECG measurements will be analyzed
 on lead II and lead V5.

 Afterward, the same parameters will be re-recorded after the completion of anesthesia
 induction suitable for the groups and the bispectral index value falls below the BIS value of
 40.

 Third and lastly, the same parameters will be recorded 2 minutes after the patients are
 intubated.
Inclusion Criteria:

 • Adult patients who will undergo open-heart surgery

 Exclusion Criteria:

 -  Under the age of 18 years

 -  Bundle branch block in preoperative ECG

 -  Arrhythmia in preoperative ECG

 -  allergies specific to known drugs

 -  Electrolyte disorders