A diagnosis of Holiday heart syndrome derives from a good history and physical examination, the history being the more significant aspect. Healthcare providers have to exercise tact to solicit the patient's alcohol history, especially since not all patients are willing to divulge this information. The other part of the puzzle is ruling out any other potential causes of the presenting symptoms. Ensuring the patient doesn't already have a diagnosis that would explain the symptoms is essential. The physical exam is more straightforward. The cardiac exam may reveal an atrial arrhythmia. It is important to note that some atrial arrhythmias are intermittent and may not be present on examination. Repeat cardiac examination may be necessary if there is suspicious of this diagnosis. Additionally, signs and symptoms of heart failure may be present depending on the extent and duration of the disease. 

Routine laboratory tests may reveal evidence suggestive of alcohol use. For example, complete blood count (CBC) may show macrocytic anemia via an elevated mean corpuscular volume (MCV). Sometimes an elevated white blood cell count (WBC) may be seen as alcoholics have decreased immunity and tend to get sick more often. Complete metabolic panel (CMP) may show 2:1 aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio. One may also show diffuse elevation in liver function tests (LFTs). Magnesium and thiamine are commonly low in alcoholics. One of the most straightforward tests to remember and order is the blood alcohol level, which of course will be positive if the patient has alcohol in their system. Urine tests also exist including ethyl glucuronide (EtG) and ethyl sulfate (EtS), which are both biomarkers signifying the breakdown of alcohol. If the patient doesn't have alcohol in their system, there are still several other tests that may aid in the diagnosis. Gamma-glutamyl transferase (GGT) may be high in these patients. Another blood test to identify alcohol use is phosphatidyl ethanol (PEth), a marker. This is typically measured in blood and can indicate moderate to heavy drinking.  Carbohydrate-deficient transferrin (CDT) is useful to identify patients who have relapsed following a period of abstinence.

Electrocardiogram (ECG) or cardiac monitoring reveals an atrial arrhythmia. A chest x-ray may show cardiomegaly. An echocardiogram should be performed to evaluate for any structural abnormalities and to assess cardiac function. Liver disease is often a feature Holiday heart syndrome as alcohol damages the liver. Therefore, ultrasound of the liver may reveal liver cirrhosis. 

If the patient is unstable and has atrial fibrillation, cardioversion is the recommendation. If the patient is stable, the therapeutic indication is for arrhythmia treatment. It is important to note that medical therapy does not improve this disease absent alcohol cessation or moderation. The previous thinking was that complete alcohol cessation was needed to see a reversal of the disease process, but recent studies have shown that as long as alcohol intake reduces to less than 80 mg per day, it may result in reversible cardiac changes. The patient must be encouraged to join alcoholics anonymous (AA) and other support groups. 

Differential diagnosis includes the following:

• alcoholism
• arrhythmia
• cirrhotic cardiomyopathy
• dilated cardiomyopathy
• psychiatric problems

If diagnosed early and treated with alcohol cessation, the prognosis for holiday heart disease is good as the disease is reversible. If left untreated, it may culminate in severe cardiomyopathy, valvular disease, and ultimately death. Some patients may develop end-stage liver disease which also has a poor prognosis. 

Complications of the holiday heart syndrome include:

• New or worsening heart failure 
• Life-threatening arrhythmias
• Community-acquired pneumonia
• Thromboembolism
• Death

The patient should obtain referrals to Alcoholics Anonymous or a similar support group, psychiatrist, psychologist, and depending on the extent of the disease, a cardiologist. 

Healthcare providers must educate their patient on the effects of alcohol misuse. Although alcoholics may have many other problems beyond what appears on the surface, Holiday heart syndrome typically presents with several other problems, including financial hardship, family stress, work stress, and even drug use. It is essential to identify the source of alcohol use and recommend discontinuation. Many patients may be reluctant to quit alcohol because to them alcohol is a means to escape an underlying bigger problem. 

The biggest pitfall to the diagnosis of Holiday heart syndrome is that there is no definitive diagnostic test. Therefore, one can never be entirely sure that holiday heart syndrome is, in fact, the diagnosis and responsible for the atrial arrhythmias. Prevention of the disease is straightforward and requires avoidance of excessive alcohol use.

Managing holiday heart syndrome requires an interprofessional team of healthcare professionals that includes a nurse, laboratory technologist, pharmacist and a number of physicians in different specialties including psychiatry and cardiology. Without proper management the morbidity and mortality from holiday heart syndrome are high. The moment the triage nurse has admitted  a patient with an arrhythmia and excessive alcohol use, the emergency department clinician is responsible for coordinating the care which includes the following:

• Ordering alcohol levels in blood and urine, or other metabolites
• Monitor the patient for signs and symptoms of respiratory depression, suicidal ideations, signs, and symptoms of heart failure, and alcohol withdrawal
• Monitor and replete thiamine before giving glucose in alcoholics to avoid neurologic deficits
• Consult with the pharmacist about the initiation of CIWA protocol in at-risk individuals
• Consult with a pharmacist about starting a benzodiazepine if tremor or seizure history is present
• Consult with a nutritionist if the patient appears malnourished
• Consult with a toxicologist and nephrologist on further management, which may include dialysis
• Consult with the cardiologist regarding arrhythmia management
• Consult with the intensivist about ICU care and monitoring while in hospital
• Review medication reconciliation as many drugs interact with alcohol

The management of holiday heart syndrome does not stop in the emergency department. Once the patient is stabilized, one has to determine how and why the patient ingested large amounts of alcohol. Consult with a mental health counselor if this was an intentional act and assess risk factors for-self harm. [Level 1] Further, the possibility of addiction and withdrawal symptoms is a consideration. Only by working as an interprofessional team can the morbidity of alcohol ingestion be decreased. [Level 5]