Major depression is also associated with excessive sympathetic and diminished parasym-pathetic nervous system activity, potentially contributing to hypertension, increased resting heart rate, decreased heart rate variability, and altered endothelial function.2,21,22 Each of these factors facilitates arterial plaque formation.
Depression may also exacerbate chronic anxiety and other forms of distress. The combined effects of an overtaxed central nervous system, neuroendocrine dysregulation, and unhealthy behaviors may eventually overwhelm the cardiovascular system.
CVD’s effect on depression. How does CVD contribute to depression? The vascular depression hypothesis23 proposes that diffuse heart and brain atherosclerosis restricts perfusion of limbic and cortical structures that regulate mood. A first depressive episode after acute MI or CABG probably represents exacerbation of cerebrovascular insufficiency that preceded the coronary event.
Table
Four keys to effectively treat depression in patients with heart disease
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In practical terms, this means that pathways linking depression and heart disease include not only biological factors but also:
- psychological factors such as depression, anxiety, and chronic stress
- behavioral factors such as smoking, physical inactivity, and high-fat diet.
How to improve outcomes
Patients with CVD commonly do not receive effective depression treatment:
- Internists and family physicians give preferential attention to physical illness.
- Patients may have insufficient access to mental health specialists.
- Physicians do not adequately monitor depression treatment.
- Patients are reluctant to accept the stigma of mental illness.
By collaborating with primary care physicians, you can improve the likelihood that depression treatment will achieve remission and prevent relapse (Table).
Risk factors for CVD. Depression contributes to heart disease by exacerbating four major CVD risk factors—smoking, diabetes, obesity, and physical inactivity. By effectively treating depression, you may help patients avoid common depressive symptoms—such as overeating and sedentary behaviors—that are related to low energy or fatigue.
Educate middle-aged patients with depression about CVD’s associated risk. Prochaska’s “stages of change” (see Related resources) can help them stop smoking, lose weight, and exercise.
Access to cardiac care. Depressed patients may be less motivated than nondepressed patients to pursue cardiac care.24 Therefore, you may need to:
- encourage your patients to take advantage of indicated state-of-the-art care, including stents, bypass surgery, and medications
- understand patients’ complex cardiac regimens and help them adhere when depression interferes with their motivation.
Effective depression treatment
Patient history. For depressed patients older than 40, take a careful inventory of CVD risk factors:
- family history of heart disease before age 60 for men and age 70 for women
- personal history of smoking, blood pressure >140/90 mm Hg, LDL cholesterol >100 mg/dL, type 2 diabetes, body mass index >30, or physical inactivity (<30 minutes of walking 3 days a week).
In general, the more risk factors, the greater the risk of CVD.
Antidepressant selection. Selective serotonin reuptake inhibitors (SSRIs) are safe and effective for treating major depression in CVD and congestive heart failure.25 Venlafaxine at doses >300 mg/d may increase blood pressure, so use this drug with caution in depressed patients with hypertension.
No controlled clinical trials have gauged the safety and efficacy of bupropion or mirtazapine in patients with CVD.
Tricyclic antidepressants are contraindicated for 6 months post-MI because they may contribute to arrhythmias. Avoid using them in depressed patients with CVD or conduction defects because of their quinidine-like effects on conduction.
Cardiac medications. Contrary to folk wisdom, beta blockers do not cause depression.26 Whether or not a patient is depressed, our primary care and cardiology colleagues can use beta blockers to help regulate the peripheral autonomic nervous system, reducing high blood pressure and the risk of arrhythmias.
SSRIs may increase blood levels of beta blockers, warfarin, and other cardiac medications via cytochrome P-450 isoenzyme inhibition. Make sure warfarin levels and other cardiac drug effects are well monitored when you adjust psychotropic dosages.
Divalproex and SSRIs also may reduce platelet aggregation. Patients who are receiving concomitant aspirin or warfarin may bruise or bleed easily and require dosage reductions or medication changes.
Psychotherapy. All patients with major or minor depression and CVD are considered high-risk and are candidates for a trial of brief psychotherapy. Therapeutic goals are to achieve full remission of depressive symptoms as rapidly as possible, prevent relapse, and maximize adherence to cardiac and depression drug regimens.
Collaborate closely with the cardiologist or primary care physician during the patient’s depressive episode and occasionally during maintenance treatment. Discuss or share notes on the patient’s depressive and cardiac disorders, medication management, symptom monitoring, and behavior changes needed to reduce cardiac risk.