Acute non-selective β-adrenergic blockade reduces prolonged frequency-adjusted Q–T interval (QTc) in patients with cirrhosis

Background/Aims: Earlier studies have shown a prolonged frequency-adjusted Q–T interval (QTc>0.440 s1/2) in a substantial fraction of patients with cirrhosis. The effect of β-blockade on QTc is unknown, and its determination was the aim of the study. Methods: Seventeen patients with cirrhosis received 80 mg propranolol orally during a haemodynamic investigation with measurements at baseline and 90 min after propranolol ingestion. Results: β-Blockade reduced cardiac output (−21%, P<0.001), heart rate (−20%, P<0.001), and the hepatic venous pressure gradient (HVPG, −17%, P<0.02). The mean QTc=0.460 s1/2 was prolonged compared to 0.410 s1/2 in age-matched controls (P<0.01). Whereas QTc decreased during β-blockade in the cirrhotic patients (from 0.460 to 0.440 s1/2, P<0.01), no effect was found in the subgroup with normal QTc (0.429 vs. 0.422 s1/2, ns), and a reduction was seen in the patients with prolonged QTc (from 0.488 to 0.456 s1/2, P<0.01). The percentage decrease in QTc was related to the reduction in HVPG (r=0.48, P=0.03) and cardiac output (r=0.56, P=0.02). Conclusions: Acute non-selective β-blockade reduces prolonged QTc towards normal values in patients with cirrhosis. The clinical significance of QTc reduction in arrhythmia is a topic for future research.