BACKGROUND/AIMS: The Q-T(c) interval is prolonged in a substantial fraction of patients with cirrhosis, thus indicating delayed repolarisation. However, no information is available in mild portal hypertensive patients. We therefore determined the Q-T(c) interval in cirrhotic patients with hepatic venous pressure gradient (HVPG) < 12 mmHg. METHODS: Forty-four patients with cirrhosis and HVPG < 12 mmHg underwent a haemodynamic study. They were compared with 36 cirrhotic patients with clinically significant portal hypertension (HVPG> or = 12 mmHg) and controls without liver disease. RESULTS: The fraction with prolonged Q-T(c) interval (> 0.440 s(1/2)) was similar in the two cirrhotic groups (49 vs 50%, ns) and significantly above that of the controls (5%, P < 0.005). Q-T(c) was normal in patients with normal HVPG. Likewise, mean Q-T(c) was 0.449 and 0.447 s(1/2) in the two cirrhotic groups (ns), values which are significantly above that of the controls (0.410 s(1/2), P < 0.01). In the mild portal hypertensive group, the Q-T(c) interval was inversely related to indicators of liver function, such as indocyanine green clearance (r = -0.34, P < 0.02). CONCLUSIONS: Delayed repolarisation of the myocardium already occurs in a substantial fraction of patients with cirrhosis with only a mild increase in portal pressure. The prolonged Q-T(c) interval may be related to liver dysfunction and to the presence of portal hypertension.