14.7
Teste de estresse por exercício
Introdução
O teste de estresse por exercício, comumente conhecido como teste de esteira, é um procedimento não invasivo usado para avaliar a função ca…
O teste ergométrico avalia a função cardiovascular e diagnostica as condições cardíacas medindo a resposta do coração ao esforço usando uma esteira ou bicicleta ergométrica.
Antes do teste, a enfermeira informa o paciente sobre o procedimento, instrui-o a usar roupas confortáveis e calçados esportivos e garante que o paciente jejue por três horas, evitando cafeína, álcool e tabaco por vinte e quatro horas antes.
A enfermeira anexa dez derivações de ECG, colocando-as em posições padrão. Em seguida, os eletrodos do braço direito e esquerdo são colocados dois cm abaixo da clavícula e os eletrodos da perna direita e esquerda são colocados abaixo da caixa torácica na parte inferior do tronco.
Durante o teste, o exercício começa com uma fase de aquecimento de baixa intensidade e aumenta gradualmente, com monitoramento contínuo de ECG, frequência cardíaca e pressão arterial.
O teste para na frequência cardíaca alvo quando ocorrem alterações significativas no ECG ou aparecem sintomas como dor no peito ou dispneia.
Um resultado negativo não mostra alterações no ECG. Uma interpretação positiva pode incluir infradesnivelamento do segmento ST, inversão da onda T ou outras alterações no ECG indicando isquemia ou arritmia, que podem exigir tratamento adicional.
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Q1: What is the purpose of an exercise stress test?
An exercise stress test evaluates cardiovascular function and diagnoses heart conditions by measuring the heart's response to exertion using a treadmill or stationary bicycle. The test discovers coronary artery disease symptoms, assesses existing heart condition severity, determines safe exercise levels, and evaluates the effectiveness of heart treatments.
Q2: How should patients prepare for an exercise stress test?
Patients should wear comfortable clothing and athletic shoes, fast for three hours before the test, and avoid caffeine, alcohol, and tobacco for 24 hours prior. Some medications like beta-blockers and calcium channel blockers may need to be paused 48 hours before testing. The nurse cleans the skin and obtains a resting 12-lead ECG for comparison.
Q3: What parameters are monitored during an exercise stress test?
During the test, continuous monitoring includes electrocardiogram (ECG) to detect ischemic changes and arrhythmias, heart rate to ensure target levels are reached, blood pressure to assess cardiovascular response, and symptoms like chest pain or dyspnea. Physical appearance, skin color, sweating, and perceived exertion are also observed throughout the procedure.
Q4: When does an exercise stress test stop?
The test stops when the patient reaches their target heart rate, which is 85% of maximum heart rate calculated by subtracting age from 220. It also terminates if significant ECG changes occur or symptoms develop, including severe chest pain, dyspnea, dizziness, leg cramps, or other abnormalities requiring immediate cessation.
Q5: What do positive and negative exercise stress test results indicate?
A negative result shows no ECG changes, indicating normal heart function during exertion. A positive result may include ST-segment depression, T-wave inversion, or other ECG changes indicating myocardial ischemia or arrhythmia, which may require further diagnostic testing or treatment interventions.
Q6: What happens after the exercise stress test is completed?
After exercise, the patient is monitored for 10 to 15 minutes until heart rate returns to normal. Monitoring continues until the patient is stable with no concerning symptoms. If myocardial ischemia signs like chest pain or ECG changes such as ST-segment depression or T-wave inversion occur, additional monitoring and interventions may be necessary.
Q7: What are the risks associated with exercise stress testing?
Stress tests are generally safe, but minimal risks include chest pain, fainting, or rarely myocardial infarction. Medical personnel and emergency equipment are available throughout the procedure to manage adverse events. Patients are informed about potential post-test symptoms and specific instructions for abnormal results.