4.4 Substance Use Screening: Alcohol, Cannabis, Stimulants & Cardiac Risk
Key Takeaways
- A US standard drink contains 14 grams of pure alcohol: 12 oz of regular beer, 5 oz of wine, or 1.5 oz of distilled spirits.
- AUDIT-C is a validated three-item alcohol screen, positive at a score of 4 or higher in men and 3 or higher in women.
- Binge drinking precipitates atrial fibrillation in structurally normal hearts — the pattern known as holiday heart syndrome — while sustained heavy intake causes dilated alcoholic cardiomyopathy, hypertension, and hypertriglyceridemia.
- Cocaine causes coronary vasospasm and accelerates atherosclerosis; benzodiazepines and nitrates are first-line for cocaine-associated chest pain, and beta-blockers are traditionally avoided because of unopposed alpha-adrenergic stimulation.
- SBIRT — Screening, Brief Intervention, and Referral to Treatment — is the framework that converts a positive substance use screen into a documented CR action.
4.4 Substance Use Screening: Alcohol, Cannabis, Stimulants & Cardiac Risk
[!NOTE] Blueprint anchor: Domain 1 (Patient Assessment), task 1.16 — Assess substance use (e.g., alcohol, tobacco, recreational drugs). Tobacco is developed separately under Domain 7; this section addresses alcohol and other substances.
Substance use is a modifiable contributor to the event that brought the patient to cardiac rehabilitation, and it interacts directly with the exercise prescription, medication management, and psychosocial care. It is also the assessment domain patients are least likely to disclose voluntarily. Structured, non-judgmental screening is therefore an explicit competency.
Alcohol: Definitions and Thresholds
The US standard drink contains 14 grams of pure alcohol:
| Beverage | Volume | Typical ABV |
|---|---|---|
| Regular beer | 12 oz | ~5% |
| Malt liquor | 8-9 oz | ~7% |
| Table wine | 5 oz | ~12% |
| Distilled spirits (80 proof) | 1.5 oz | ~40% |
Patients systematically underestimate intake because home pours bear little relationship to these volumes. A useful counseling move is to have the patient describe the actual glass and pour, then convert together.
Consumption limits commonly referenced for cardiovascular counseling are no more than 2 standard drinks per day for men and no more than 1 per day for women, with the strong caveat that current guidance does not recommend initiating or increasing alcohol consumption for cardiovascular benefit. The older claim that moderate drinking is cardioprotective has weakened substantially, and any perceived benefit does not offset harms in patients with hypertension, arrhythmia, cardiomyopathy, or hypertriglyceridemia.
Cardiovascular consequences of alcohol
| Effect | Mechanism and relevance |
|---|---|
| Hypertension | Dose-dependent blood pressure elevation; reduction produces measurable BP lowering and is a first-line lifestyle intervention |
| Holiday heart syndrome | Binge drinking precipitating atrial fibrillation or other atrial arrhythmias, classically in a structurally normal heart |
| Alcoholic cardiomyopathy | Sustained heavy intake causing dilated cardiomyopathy with reduced ejection fraction; partially reversible with abstinence |
| Hypertriglyceridemia | Alcohol markedly raises triglycerides; a key target when triglycerides are elevated |
| Weight | ~7 kcal/g with no satiety value, undermining energy-balance goals |
| Interactions | Additive hypotension with antihypertensives and nitrates; hepatotoxicity risk considerations with statins; increased bleeding with anticoagulants; masks and worsens hypoglycemia by impairing gluconeogenesis |
[!WARNING] Alcohol impairs hepatic gluconeogenesis and can cause delayed hypoglycemia many hours after intake — a serious risk for patients on insulin or sulfonylureas who drink in the evening and exercise the next morning. This interaction is a frequent exam target.
Screening Instruments
| Tool | Format | Positive threshold |
|---|---|---|
| AUDIT-C | 3 items (frequency, typical quantity, frequency of 6+ drinks) | 4 or more in men; 3 or more in women |
| Single-item NIAAA screen | "How many times in the past year have you had 5 (men) / 4 (women) or more drinks in a day?" | 1 or more |
| CAGE | 4 items: Cut down, Annoyed, Guilty, Eye-opener | 2 or more suggests problem drinking |
| NIDA Quick Screen / DAST-10 | Non-alcohol drug use | Any positive prompts further assessment |
Ask in a normalized, non-judgmental frame: "Many people drink to relax, especially after a health scare. In a typical week, how many days do you have a drink, and how many on those days?" Leading with a presumption of use reduces defensive under-reporting relative to "You don't drink, do you?"
Stimulants
Cocaine
Cocaine blocks catecholamine reuptake, producing tachycardia, hypertension, and — most importantly for CR — coronary vasospasm. It also accelerates atherosclerosis, promotes thrombosis, and is associated with left ventricular hypertrophy, aortic dissection, and cardiomyopathy. Myocardial infarction can occur in young patients with minimal atherosclerotic burden.
[!IMPORTANT] In cocaine-associated chest pain, benzodiazepines and nitrates are first-line, and beta-blockers are traditionally avoided because beta blockade leaves alpha-adrenergic vasoconstriction unopposed, potentially worsening coronary vasospasm and hypertension. This "unopposed alpha" principle is a classic testable item. Recent ongoing use should prompt discussion with the medical director before high-intensity exercise progression.
Methamphetamine
Methamphetamine causes sustained sympathetic activation and is a recognized cause of methamphetamine-associated cardiomyopathy, often in younger patients with severely reduced ejection fraction, along with pulmonary hypertension, arrhythmia, and accelerated coronary disease. Abstinence can produce meaningful recovery of ventricular function, which makes referral to treatment a genuinely disease-modifying intervention rather than a formality.
Cannabis
Cannabis use is increasingly common in the CR population, including among older adults using it for pain or sleep, and patients frequently do not consider it a drug worth mentioning. Cardiovascular effects include dose-dependent tachycardia, increased myocardial oxygen demand, transient blood pressure changes with orthostatic hypotension, and a documented transient elevation in myocardial infarction risk in the hour following use. Smoked cannabis also delivers combustion products with effects analogous to tobacco smoke. Practical counseling: ask specifically, advise against use within several hours of an exercise session, favor non-smoked routes if the patient continues use, and note that a resting tachycardia at intake may reflect recent use rather than deconditioning.
Anabolic-Androgenic Steroids
More relevant in younger patients and those in fitness settings. Effects include marked HDL suppression with LDL elevation, left ventricular hypertrophy with diastolic dysfunction, hypertension, polycythemia with thrombotic risk, and premature atherosclerosis. Non-prescribed testosterone and supplement products containing undeclared stimulants should be asked about specifically, since patients rarely classify them as drugs.
SBIRT: Converting a Positive Screen Into Action
SBIRT — Screening, Brief Intervention, and Referral to Treatment — is the framework that keeps CR action within scope:
- Screening — validated tool at intake, repeated as indicated.
- Brief Intervention — a short motivational-interviewing-consistent conversation: give personalized feedback linking the substance to the patient's own cardiac event and lab values, elicit the patient's view, offer clear advice, and negotiate a concrete step. This is squarely within CR scope.
- Referral to Treatment — for high-risk scores, dependence, or withdrawal risk, refer to addiction medicine, behavioral health, or the primary physician. CR professionals do not manage withdrawal. Alcohol withdrawal in particular can be life-threatening and requires medical management.
Document the screen, the score, the brief intervention delivered, and the referral in the individualized treatment plan, and re-assess at the 30-day update.
Realistic Clinical Scenario
Scenario: A 52-year-old man enters Phase II after NSTEMI. Resting HR is 96 bpm, triglycerides are 420 mg/dL, and BP runs 148/92 despite lisinopril. He reports "a couple of beers most nights." On AUDIT-C he scores 6. He also mentions using cannabis nightly for sleep. He is on metformin and glipizide.
Assessment: AUDIT-C of 6 is positive. His "couple of beers" is likely a substantial underestimate given a positive screen, and alcohol plausibly contributes to all three of his uncontrolled findings: hypertension, hypertriglyceridemia, and elevated resting heart rate. The glipizide plus evening alcohol combination creates real delayed hypoglycemia risk, particularly before morning sessions. Nightly cannabis may also contribute to the resting tachycardia.
Plan: Deliver a brief intervention linking his own triglyceride value and blood pressure to alcohol intake, clarify standard drink sizes against his actual pour, and negotiate a specific reduction target rather than abstinence-or-nothing. Explicitly teach the delayed hypoglycemia interaction with glipizide and instruct on pre-exercise glucose checking after evenings with alcohol. Ask directly about timing of cannabis use relative to sessions and advise separation from exercise. Communicate the triglyceride level and alcohol history to the prescribing clinician, refer to a registered dietitian, and document the AUDIT-C score, brief intervention, and referrals in the ITP for reassessment at 30 days.
A patient on glipizide reports drinking three to four beers most evenings. He exercises at the program each weekday morning. Which risk requires specific teaching?
A 38-year-old patient presents with chest pain and admits to cocaine use two hours earlier. Which pharmacologic principle is most important for the CR professional to understand?
A patient scores 5 on the AUDIT-C. Which action correctly reflects the SBIRT framework and CR scope of practice?