Third-degree atrioventricular block in an adolescent following acute alcohol intoxication

Syncope and Total Atrioventricular Block Associated With Alcohol Consumption in a Healthy Young Man

Association between alcohol intake and atrioventricular block is rare. This case describes a previously healthy 27-year-old man experiencing syncopes preceded by moderate alcohol intake. An implantable loop recorder demonstrated episodes of total atrioventricular block coinciding with an additional syncope after alcohol intake, resulting in pacemaker implantation. (Level of Difficulty: Intermediate.).

Alcohol intake and bradyarrhythmia risk: a cohort study of 407 948 individuals

AIMS 

There is a paucity of epidemiological evidence on alcohol and the risk of bradyarrhythmias. We thus characterized associations of total and beverage-specific alcohol consumption with incident bradyarrhythmias using data from the UK Biobank.

METHODS AND RESULTS 

Alcohol consumption reported at baseline was calculated as UK standard drinks (8 g alcohol)/week. Bradyarrhythmia events were defined as sinus node dysfunction (SND), high-level atrioventricular block (AVB), and permanent pacemaker implantations. Outcomes were assessed through hospitalization and death records, and dose-response associations were characterized using Cox regression models with correction for regression dilution bias. We studied 407 948 middle-aged individuals (52.4% female). Over a median follow-up time of 11.5 years, a total of 8 344 incident bradyarrhythmia events occurred. Increasing total alcohol consumption was not associated with an increased risk of bradyarrhythmias. Beer and cider intake were associated with increased bradyarrhythmia risk up to 12 drinks/week; however, no significant associations were observed with red wine, white wine, or spirit intake. When bradyarrhythmia outcomes were analysed separately, a negative curvilinear was observed for total alcohol consumption and risk of SND, but no clear association with AVB was observed.

CONCLUSION 

In this predominantly White British cohort, increasing total alcohol consumption was not associated with an increased risk of bradyarrhythmias. Associations appeared to vary according to the type of alcoholic beverage and between different types of bradyarrhythmias. Further epidemiological and experimental studies are required to clarify these findings.

QTc prolongation in adolescents with acute alcohol intoxication

In adults, alcohol intoxication is associated with prolongation of the QT interval corrected for heart rate (QTc). The QTc is influenced by age and sex. Although alcohol intoxication is increasingly common in adolescents, there are no data on the prevalence of QTc prolongation in adolescents with alcohol intoxication. This study aimed to determine the prevalence of QTc prolongation in adolescents with alcohol intoxication and identify at-risk adolescents. In this observational study including adolescents aged 10-18 years, heart rate and QT interval were automatically assessed from an electrocardiogram (ECG) at alcohol intoxication using a validated algorithm. The QTc was calculated using both the Bazett formula (QTc_B) and Fridericia formula (QTc_F). If present, an ECG recorded within 1 year of the date of admission to the emergency department was obtained as a reference ECG. A total of 317 adolescents were included; 13.3% had a QTc_B and 7.9% a QTc_F longer than the sex- and age-specific 95th-percentile. None of the adolescents had a QTc_B or QTc_F > 500 ms, but 11.8% of the adolescents with a reference ECG had a QTc_B prolongation of > 60 ms, while no adolescents had a QTc_F prolongation of > 60 ms. QTc prolongation was mainly attributable to an increase in heart rate rather than QT prolongation, which underlies the differences between QTc_B and QTc_F. Male sex and hypokalaemia increased the likelihood of QTc prolongation.Conclusion: QTc prolongation was seen in approximately 10% of the adolescents presenting with alcohol intoxication, and although no ventricular arrhythmias were observed in this cohort, QTc prolongation increases the potential for malignant QT-related arrhythmias. Clinicians must be aware of the possibility of QTc prolongation during alcohol intoxication and make an effort to obtain an ECG at presentation, measure the QT interval, and give an adequate assessment of the findings. We advocate admitting adolescents with alcohol intoxication and QTc prolongation. During hospital admission, we recommend limiting exposure to QTc-prolonging medication, increasing potassium levels to a high-normal range (4.5-5.0 mmol/L) and obtaining a reference ECG at discharge.

Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm

The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.

Alcohol and Heart Disease in the Forensic Setting

The impacts of chronic high levels of ethanol consumption on cardiovascular structure and function are reviewed as they pertain to forensic pathology practice. Both hypertrophy and remodeling of the myocardium as well as physiological revision of electrical conduction through the heart can occur in a progressive fashion. A discussion about the likely underappreciated spectrum of structural heart disease that may be seen in individuals with chronic alcohol dependence is presented. Finally, brief reference to the collision between alcohol, cardiovascular disease, and forensically relevant scenarios is provided.