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Risk Stratification in Cardiac Rehabilitation

Definition / Explanation

Risk stratification in cardiac rehabilitation is the process of classifying a patient's risk of adverse cardiac events during exercise, based on clinical history, diagnostic test results, and functional capacity. The AACVPR risk stratification algorithm is used to determine the level of monitoring required — including whether continuous ECG telemetry is necessary, whether GXT is required before prescription, and when the patient can safely transition to unsupervised exercise.

Risk Categories

Low Risk (AACVPR Class A)

Criteria: - Uncomplicated MI, CABG, PCI, or valve surgery - Normal left ventricular function (LVEF ≥ 50%) - No resting or exercise-induced complex arrhythmias - Normal hemodynamic response to exercise - Functional capacity ≥ 7 METs

Implications: Telemetry may be discontinued after initial 6–12 sessions; patient may transition to Phase III earlier.

Moderate Risk (Class B)

Criteria: - LVEF 35–49% - Mild-to-moderate left ventricular dysfunction - History of MI or revascularization without complications - Exercise capacity 5–6 METs - Presence of controlled atrial fibrillation or occasional PVCs

Implications: Telemetry required for 12–18 sessions; GXT required before intensity > 40–60% HRR.

High Risk (Class C)

Criteria: - LVEF < 35% or severe left ventricular dysfunction - Complex ventricular arrhythmias at rest or with exercise - Survived sudden cardiac death or cardiac arrest - MI complicated by heart failure, shock, or malignant arrhythmias - Functional capacity < 5 METs with abnormal hemodynamics - Significant silent ischemia on GXT

Implications: Continuous ECG telemetry for all supervised sessions; no unsupervised exercise until cleared by cardiology; GXT mandatory before any prescription beyond light activity.

Clinical Application

Risk stratification directly determines: - Telemetry requirements — Low risk: may discontinue after initial sessions; Moderate risk: 12–18 sessions; High risk: all sessions - GXT necessity — Required for Moderate and High risk before prescribing exercise above 40–60% HRR - Supervision requirements — High-risk patients must remain under direct clinical supervision - Exercise intensity ceiling — High-risk patients capped at RPE 11–13 until cleared