Effects of High-Dose Rocuronium on the QTc Interval During Anaesthesia Induction in Patients Undergoing Coronary Artery Bypass Graft Surgery

Abstract

Objective: Existing myocardial damage in coronary artery disease patients causes prolonged QT syndrome. The primary objective of this trial is to explore the effects of different doses of the muscle relaxant agent rocuronium (0.6 mg kg -1 and 1.2 mg kg -1) on QTc following anaesthetic induction. The second objective is to determine the incidence and kinds of arrhythmias. Methods:In this prospective and randomized trial, patients undergoing elective coronary artery revascularization surgery were included in one of two groups. Both groups took the same anaesthetic induction agents: midazolam and fentanyl. Rocuronium was administered in Group 1 (n=20) with dose of 0.6 mg kg -1 and in Group 2 (n=20) with a dose of 1.2 mg kg -1 for muscle relaxation. Heart rate, average arterial pressure and QTc were recorded before induction (T0), after induction (T1), after muscle relaxant (T2), and 2 minutes (T3) and 5 minutes after intubation (T4).Results: QTc was significantly longer 2 minutes after intubation (in Group 1 and Group 2, respectively, 447.9±28.3 and 466.1±37.8 ms) than at the beginning (respectively, 426.9±25.7, 432.0±35.5 ms) (p<0.01). In the intergroup comparison, average QTc values were similar in all trial periods (p>0.05). The prevalence of arrhythmias in between Group 1 (35%, n=7) and Group 2 (15%, n=3) was similar (p=0.06). Arrhythmias were recorded 2 minutes after intubation in both groups (n=10, 25%). Conclusion:In patients undergoing coronary artery revascularization surgery, rocuronium doses of 0.6 mg kg -1 and 1.2 mg kg -1 prolong the QTc interval after intubation. Cardiac arrhythmias related to long QTc arising after intubation should be taken into consideration.Key Words: Rocuronium, QTc, coronary artery disease Amaç: Koroner arter hastalarında, mevcut miyokard hasarının kendisi uzun QT sendromu oluşumuna neden olmaktadır. Ça-lışmanın esas amacı anestezi indüksiyonu sonrasında, roküronyu-mun 2 farklı dozunun (0,6 mg kg -1 ve 1,2 mg kg -1 ) QTc intervali üzerine etkilerini araştırmaktır. ikincil amacı ise aritmi sıklığı ve niteliğini saptamaktır.Yöntemler: Çalışmaya elektif koroner arter revaskülarizasyon cerrahisi geçirecek 40 olgu alındı. Olgular iki gruptan birine dahil edildiler. Gruplarda kullanılan midazolam ve fentanil' in indük-siyon dozları aynı idi. Group 1; 0,6 mg kg -1 , Group 2; 1,2 mg kg -1 doz roküronyum ile entübe edildiler. Kalp atım hızı, ortalama arter basıncı ve QTc, indüksiyon öncesi (T0), indüksiyon sonrası (T1), roküronyum sonrası (T2), entübasyon sonrası 2. dakika (T3) 5. dakikalarda (T4) kaydedildi. Bulgular:Grup içi karşılaştırmada, yalnızca entübasyon sonrası 2. dakikadaki ortalama QTc değerleri (Grup 1 ve Grup 2'de sı-rası ile, 447,9±28,3, 466,1±37,8 ms), başlangıca göre (sırası ile, 426,9±25,7, 432,0±35,5 ms) istatistiksel olarak anlamlı uzun bulundu (p<0,01). Gruplar arası karşılaştırmada, ortalama QTc tüm çalışma dönemlerinde benzerdi (p>0,05). Grup 1 (%35, n=7), ile Grup 2'de (%15, n=3) aritmi görülme sıklığı benzerdi (p=0,06). Her iki grupta da aritmiler (n=10, %25), en...

Long QT Syndrome and Perioperative Torsades de Pointes: What the Anesthesiologist Should Know

“…The non-depolarizing muscle relaxants vecuronium 84,152,163 , pancuronium 164 , rocuronium (0.6mg/kg and 1.2mg/kg) 153,165,166 , and cisatracurium 167 do not cause QTc prolongation. Anticholinesterase-anticholinergic antagonism of neuromuscular blockade with neostigmine (40mcg/kg) and glycopyrrolate (8mcg/kg) or atropine (20mcg/kg) has been shown to cause clinically significant QTc prolongation and should be avoided in patients with LQTS 168 .…”