What Should Psychiatrists and Cardiologists Know About Depression and Cardiovascular Disease?

Evidence from two systematic reviews has confirmed the strong link between depression and Ischaemic Heart Disease (IHD), heart failure and Myocardial Infarction (Rugulies 2002 & Van der Kooy 2007).

Patients with cardiovascular disease (CVD) are reported to have a higher risk of developing depression than the general population. Similarly, patients with depression are also more likely to develop CVD than those who are not and this is independent of traditional risk factors. The classic study by Frasure-Smith et al., an 18-month follow-up study showed that patients who develop depression after an acute myocardial infarction (AMI) have a 3.6-fold increase in mortality rates (after controlling for other confounders). The increase in rate was approximately the same as that of the strongest another predictor of mortality after MI, heart failure.

There are 3 possible hypotheses:

1. Dysregulation of the Autonomic Nervous System as evidenced by reduced heart rate variability
2. Abnormalities in Serotonin metabolism in depression enhances platelet aggregation in coronary arteries. (5HT2A receptor mediates platelet aggregation)
3. Stress-Diathesis Model: Depression is known to overstimulate the HPA axis resulting in sustained release of adrenaline leading to hypertension and damage to coronary artery intima. Here is some more detail on how stress increases the risk of CVD.

Psychiatric conditions and symptoms are commonly comorbid with depression, and this applies in particular to those patients with CVD. Following are the key aspects:

Quality of Life –

Quality of Life (QOL) is an important parameter when managing the rehabilitation of CVD patients.  CVD patients with poor QOL are more likely to develop anxiety or depressive disorders. Furthermore, depression in the presence of CVD is specifically associated with an increased risk of morbidity and mortality.

Anxiety –

Diagnosis of anxiety after an AMI is a reliable marker for the future development of depression. Anxiety is also independently associated with increased mortality in cardiac disease patients. Therefore, when planning a comprehensive cardiac rehabilitation program, consideration of anxiety risk factors must be done to prevent adverse cardiac outcomes.

Psychosocial Issues –

Social isolation and depression are strongly correlated and are associated with poor QOL. If CVD patients develop depression, then there is the likelihood of developing psychosocial issues that will compound QOL as well as the health status of an individual. To prevent this, a strong social support network that includes healthcare professionals, family members and caregivers can help in preventing social isolation.

Adherence to medication –

Non-adherence to medication is a common outcome of depression and comes with a significant clinical burden. In CVD patients the rate of non-adherence to medication is double when in the presence of depression. Adherence to medication and lifestyle changes after an AMI is crucial for recovery. Therefore, careful monitoring is required to ensure patients adhere to their new lifestyle behaviours and ongoing medication.

Cardiologists:

In Australia, only 3% of cardiologists routinely screen for depression in their patients. When screening for depression, self-report questionnaires are comprehensive tools that assist in clinical diagnoses. The Beck Depression Inventory is the most commonly used in cardiac patients. However, it was designed for psychiatric patients and not specifically for cardiac patients. A more relevant test is the Cardiac Depression Scale, as this was designed specifically for detecting depression in CVD patients and has been shown to have excellent sensitivity.

Two core questions that cardiologists can ask to screen for depression are:

• Do you feel down or depressed? (Low mood)
• Have you lost interest and pleasure in life? (Anhedonia)

These two questions may go a long way in identifying patients that may need a psychiatric input.

Psychiatrists:

Psychiatrists have an important clinical responsibility in the assessment of cardiovascular risk factors. At a minimum lifestyle history (smoking alcohol and exercise) , Weight, BP and blood tests to rule out hyperlipidemia and high blood glucose are essential aspects of cardiovascular evaluation in psychiatry.

For more detailed examination see the video below. (Source: psychinterview.com

The development of depression after a cardiac event is quite common if a comprehensive cardiac rehabilitation program is not in place. Strategies for cardiac patients should include a variety of approaches, including exercise, cognitive behavioural therapy, and if necessary, antidepressant medication.

Cardiac Rehabilitation

Cardiac rehabilitation programs are an essential component of recovery that can reduce the emotional, psychosocial and physical issues that affect individuals after experiencing a life-threatening event. Key elements of these programs are exercise, education on lifestyle changes and professional support. In particular, group exercises are a physical and psychosocial activity that can significantly help prevent depression and thereby assist in reducing mortality rates.

Psychotherapies

There is considerable empirical evidence that supports the use of psychological treatments for patients suffering from depression. Although talking therapies are beneficial components of any cardiac rehabilitation program, the results have been variable. Nevertheless, it is reasonable to recommend that depressed cardiac patients could benefit if psychotherapy treatments are optimised to the individual.

Pharmacotherapy

Antidepressants have differing potency and a variable side effect profile particularly regarding the predisposition to serious cardiac arrhythmias. Some key points are as follows:

• SSRI’s are considered the first line in depression with CVD. However, citalopram and escitalopram are associated with prolonged QTc. Read about QTc prolongation in Psychiatry. 
• In the elderly, start low and go slow particularly if there are electrolyte abnormalities (K and Mg), have Congestive Cardiac Failure or have certain medications that can inhibit CYP2D6 (Amiodarone) and CYP2C19 (Omeprazole). Sertraline is metabolised via CYP2D6; Escitalopram and Citalopram are metabolised via CYP2C19.
• Tricyclic Antidepressants should not be used first-line due to the risk of Ventricular Arrhythmias.
• Monitor the QTc intervals closely. (Borderline levels 450ms for male and 470 ms for females)

Check out our quick tool for mechanisms of action and side effects of antidepressants and antipsychotics including cardiac side effects

The relationship between depression and CVD is of great clinical concern because patients who exhibit both depression and CVD have worse health-related quality of life, recurrent cardiac events, and increased mortality. Because of the potential impact on morbidity and mortality outcomes, screening for depression is highly recommended after a cardiac event. Psychiatrists and Cardiologists should familiarise themselves with the main interdisciplinary issues and work together closely for better patient outcomes.