Cardiac Devices: Pacemakers, VADs, and ICDs Overview

Pacemaker - Definition

A small device placed in the chest/abdomen to help control abnormal heart rhythm.

Pacemaker - Indications

Used for patients with bradycardia, heart blocks, or congenital heart disease.

Pacemaker - How it works

Electrodes detect electrical activity → data sent to generator → if abnormal rhythm → sends electrical pulses to heart.

Pacemaker - Exercise Considerations

Improves exercise tolerance, but stay below ischemic threshold to avoid issues.

Pacemaker - Exercise Testing

• Low level Bruce protocol • Naughton protocol • Bike ergo with small increments per stage

Pacemaker - Exercise Programming

• No above shoulder work for first 3 weeks • Resistance training at 50% 1RM after 4-6 weeks • Use RPE and HR to monitor intensity

Pacemaker - Issues

• May under/over sense • Pacemaker syndrome • Risk of infections

Ventricular Assist Device (VAD) - Definition

A surgically attached device with external power source supporting LV and aorta.

VAD - Indications

• Bridge to Transplant (waiting for transplant) • Bridge to Recovery (unload heart pressure) • Destination Therapy (permanent, transplant-ineligible)

VAD - Contraindications for Exercise

Do not exercise if: • MAP < 65 mmHg • Device alarm is activated

VAD - Exercise Testing

• 6-Minute Walk Test (6MWT) • Use RPE and Arterial BP

VAD - Exercise Programming

• RPE 11-13 • Start at very low levels • No chest compression • Exercise with someone familiar with the device

Implantable Cardioverter Defibrillator (ICD) - Definition

Pulse generator that restores electrical synchrony with shocks.

ICD - Indications

Used in patients with: • Severe/unstable ventricular tachycardia (VT) • LV dysfunction • Hypertrophic cardiomyopathy (HCM) • Congestive heart failure (CHF)

ICD - Conditions Treated

• Ventricular tachycardia (VT) • Ventricular fibrillation (VF)

ICD - Programmed Therapies

• Low energy shock: converts abnormal rhythm • High energy shock: used if arrhythmia is severe

ICD - Risk During Exercise

Inappropriate shock may occur if HR exceeds programmed threshold.

ICD - Exercise Testing

• Low level Bruce protocol • Naughton protocol • Bike ergo with small increments per stage

ICD - Exercise Programming

• Safe to exercise soon after implantation (with cardiologist approval) • Full knowledge of ICD programming required • Adherence to medications essential • No above shoulder work for first 3 weeks • Resistance training at 50% 1RM after 4-6 weeks • Use RPE and HR to monitor intensity