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QT prolongation and sudden cardiac death in patients with alcoholic liver disease
C P Day1, O F James, T J Butler
1Department of Academic Cardiology, Medical School, University of Newcastle, Newcastle upon Tyne, UK.
Insights
Cardiovascular death is a major risk for alcoholics. Prolonged QT intervals in alcoholic liver disease patients indicate higher mortality risk, especially from sudden cardiac death.
Area of Science:
- Cardiology
- Hepatology
- Clinical Electrophysiology
Background:
- Cardiovascular disease is the leading cause of mortality in alcoholics.
- Alcohol's potential protective effect against ischemic heart disease may be linked to arrhythmias rather than coronary atheroma.
- QT interval abnormalities are recognized markers for arrhythmia and sudden cardiac death risk.
Purpose of the Study:
- To investigate the relationship between QT intervals and mortality in patients with alcoholic liver disease.
- To determine if QT interval prolongation is associated with increased risk of death, particularly sudden cardiac death, in this population.
Main Methods:
- Simultaneous 12-lead electrocardiographic recordings were obtained from 69 patients with alcoholic liver disease and 40 healthy controls.
- Patients abstained from alcohol for at least 7 days prior to testing.
- QT intervals were corrected for heart rate using Bazett's (QTc) and cube root (QTcub) formulae; QTcub was found to be rate-independent.
- Patients were followed for up to four years to ascertain mortality and cause of death.
Main Results:
- Alcoholic patients exhibited longer maximum QT intervals (QTcub 450 ms) compared to controls (QTcub 439 ms; p=0.016), independent of electrolyte variations.
- Patients who died (n=14) had significantly prolonged QT intervals (QTcub 471 ms) compared to survivors (QTcub 446 ms; p=0.007).
- This difference was primarily driven by 6 patients with sudden cardiac deaths, who had markedly prolonged QT intervals (QTcub 493 ms).
Conclusions:
- QT interval prolongation is present in some patients with alcoholic liver disease and is linked to an adverse prognosis.
- Prolonged QT intervals are particularly associated with an increased risk of sudden cardiac death in this patient group.
- QT interval measurement should be incorporated into the initial assessment of alcoholic patients, especially those being evaluated for liver transplantation.
Abstract:
Cardiovascular death is the most important cause of mortality in alcoholics, yet alcohol may protect against ischaemic heart disease. This could be explained if deaths were a consequence of alcohol-related arrhythmias rather than of coronary atheroma. In many conditions, abnormalities of the QT interval are markers of arrhythmia and for risk of sudden death. We examined the relation between QT intervals and mortality in patients with alcoholic liver disease. Simultaneous 12-lead electrocardiographic recordings were obtained from 69 patients with histologically proven alcoholic liver disease (without evidence of structural heart disease), and from 40 healthy non-drinking controls matched for age and sex. Patients were abstinent for at least 7 days before investigation to exclude acute effects of alcohol. QT intervals were corrected for rate with Bazett's and cube root formulae to define QTc and QTcub, respectively. Unlike QTc, QTcub was independent of rate. Patients were followed for up to four years. For those who died, the cause was determined from case records and postmortem reports. Maximum QT intervals were longer in alcoholics than in controls (QTcub 450 vs 439, p = 0.016). This difference was not explained by variations in electrolytes. QT intervals were prolonged in the 14 patients who died compared with survivors (QTcub 471 vs 446, p = 0.007). This difference was mainly due to the long QT intervals in the 6 patients with sudden cardiac deaths (QTcub 493). The only other factor independently associated with death was sex. QT interval prolongation occurs in some patients with alcoholic liver disease and is associated with an adverse prognosis, especially sudden cardiac death. QT measurement should be included in the initial assessment of alcoholic patients, particularly in those considered for liver transplantation.