ST segment depression: Definition, causes, treatments Health ConditionsHealth ConditionsAlzheimer's & DementiaAnxietyArthritisAsthma & AllergiesBreast CancerCancerCardiovascular HealthCOVID-19Dermatology & SkincareDiabetesEnvironment & SustainabilityExercise & FitnessEye HealthHeadache & MigraineHealth EquityHIV & AIDSHuman BiologyInflammatory Bowel DiseaseLeukemiaLGBTQIA+Men's HealthMental HealthMultiple Sclerosis (MS)NutritionParkinson's DiseasePsoriasisSexual HealthWomen's HealthDiscoverNewsLatest NewsOriginal SeriesMedical MythsHonest NutritionThrough My EyesNew Normal HealthPodcastsHow to understand chronic painWhat is behind vaccine hesitancy?The amazing story of hepatitis C, from discovery to cureNew directions in dementia researchCan psychedelics rewire a depressed, anxious brain?Why climate change matters for human healthToolsGeneral HealthDrugs A-ZHealth HubsHealth ToolsBMI Calculators and ChartsBlood Pressure Chart: Ranges and GuideBreast Cancer: Self-Examination GuideSleep CalculatorHealth ProductsAffordable Therapy OptionsBlood Pressure MonitorsDiabetic SuppliesFitness TrackersHome GymsGreen Cleaning ProductsHow to Shop for CBDQuizzesRA Myths vs FactsType 2 Diabetes: Managing Blood SugarAnkylosing Spondylitis Pain: Fact or FictionConnectAbout Medical News TodayWho We AreOur Editorial ProcessContent IntegrityConscious LanguageNewslettersSign UpFollow UsMedical News TodayHealth ConditionsDiscoverToolsConnectSubscribe Everything to know about ST segment depressionMedically reviewed by Uzochukwu Ibe, MD, MPH — By Jenna Fletcher on September 28, 2022The ST segment is the line between the “S” and the “T” on the readout of an EKG. If a person is in good health, the line appears at or close to the baseline level. A depressed or elevated ST segment can indicate the presence of an underlying health condition. An EKG creates a readout with what looks like a zig-zagging line moving up and down. The line has several plateaus, peaks, and values with P, Q, R, S, and T labels from left to right. The ST segment occurs between the depression of S and the peaking of T on the readout. A generally flat line that occurs around the baseline indicates that a person has a good health status. However, a depressed ST segment may be due to an underlying health condition. This article explains what a depressed ST segment is and considers the possible causes and treatments. It also looks at the outlook for people who receive this test result. What is an ST segment depression on an EKG Share on PinterestTo many people, the readout that an EKG produces will just look like a scribbled line that goes up and down across graph paper or a screen. However, doctors, nurses, and technicians can interpret this line, which shows the heart’s rhythm and electrical activity. They can use the EKG readout to look for abnormalities and help diagnose several potential underlying heart conditions, such as heart attack, heart blocks, and atrial or ventricular tachycardia, among others. An EKG has several points representing different waves that appear above or below the baseline. There are three waves:P waveQRS complexT wave The ST segment occurs between the end of the QRS complex and the start of the T wave. In healthy individuals, the ST segment is generally flat and appears at or close to the baseline level, although variations are possible. In some cases, a person may have a depressed ST segment. When this occurs, their readout shows a valley or a dip below the baseline. Experts recommend that doctors use the PQ junction as a reference point when determining whether a person has an ST segment depression. This plateau occurs between the P wave and the QRS complex. If the ST segment appears below the level of the PQ junction, a doctor will likely confirm that the person has an ST segment depression. Causes Several underlying conditions and other factors can cause an ST segment depression. These include:Hypokalemia: Hypokalemia occurs when a person’s body excretes an excessive amount of potassium. This can result in the person not having enough potassium in their blood, which can cause several symptoms, including muscle weakness that can lead to paralysis.Left bundle branch block: When this condition occurs, the electrical impulses to the heart’s left ventricle slow, which can make it harder for the heart to pump blood efficiently through the body.Myocardial ischemia: Myocardial ischemia is a term that describes an imbalance in the oxygen supply to the heart. An obstruction of blood flow to the heart can cause this condition. A partial or full blockage of the coronary artery can lead to a potentially fatal heart attack.Use of certain medications: Some medications that treat heart failure and arrhythmias, such as digitalis, can cause an ST segment depression. Treatment The treatment options will vary depending on the exact underlying condition affecting the person. Hypokalemia treatment Hypokalemia occurs as a symptom of another condition. A doctor will need to determine the underlying condition and provide treatment to address the root cause. During treatment, they may recommend the use of potassium supplements or have the person include more potassium in their diet. In severe cases, they may prescribe potassium chloride, which comes in oral and IV forms. Left bundle branch block treatment Currently, no standard of care exists for left bundle branch blocks. Instead, a doctor will make recommendations for treating any underlying causes. Experts at the American Heart Association (AHA) recommend that doctors maintain watchful waiting and schedule regular examinations with people. This can help ensure that they can address any changes that occur. Myocardial ischemia treatment Experts indicate that the best treatment option for myocardial ischemia is a type of medication known as beta-blockers. Beta-blockers help decrease a person’s heart rate, thereby reducing stress on their heart. Other therapies and medications that may help with myocardial ischemia include:psychotherapy, to help manage and reduce stresscalcium channel blockersstatinsaspirin In some cases, if myocardial ischemia is responsible for an ST segment depression, a person may need to undergo cardiac catheterization so that the doctor can visualize the coronary arteries. If this reveals any significant narrowing, the doctor may recommend stents. Outlook A person’s outlook is dependent on the underlying condition and their overall health. Some causes require only minimal intervention, such as medication or dietary changes, while others may require more intensive treatment. A person can make some changes to improve their overall heart health. This may help reduce the risk of complications, such as stroke or heart attack. People can take steps to lower their risk of heart disease. These include:staying active or increasing their activity levelseating a nutritious, balanced dietreaching or maintaining a moderate weightquitting or not starting smokingmoderating alcohol consumption or completely avoiding itpracticing stress management techniques Making these changes may help control blood pressure and cholesterol levels and decrease the risk of certain heart conditions that can lead to an ST segment depression or potentially fatal complications, such as a heart attack. Summary ST segment depression typically indicates that a person has an underlying condition that affects the heart. The condition may be relatively benign or potentially life threatening. The treatment options typically involve medication and lifestyle changes. A person’s outlook will depend on several factors, including the underlying condition affecting them, their response to treatment, and their overall health. Last medically reviewed on September 28, 2022Heart DiseaseCardiovascular / CardiologyMedical Devices / Diagnosticsheartvalvedisorders 8 sourcescollapsedMedical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.Castro, D., et al. (2022). Hypokalemia. https://www.ncbi.nlm.nih.gov/books/NBK482465/Gul, Z., et al. (2022). Silent myocardial ischemia. https://www.ncbi.nlm.nih.gov/books/NBK536915/Heart conduction disorders. (2016). https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/conduction-disordersHow do beta blocker drugs affect exercise? (2017). https://www.heart.org/en/health-topics/consumer-healthcare/medication-information/how-do-beta-blocker-drugs-affect-exerciseKashou, A. H., et al. (2021). ST segment. https://www.ncbi.nlm.nih.gov/books/NBK459364/Keep your heart healthy. (2022). https://health.gov/myhealthfinder/health-conditions/heart-health/keep-your-heart-healthyMeyers, H. P, et al. (2021). Ischemic ST‐segment depression maximal in V1–V4 (versus V5–V6) of any amplitude is specific for occlusion myocardial infarction (versus nonocclusive ischemia). https://www.ahajournals.org/doi/10.1161/JAHA.121.022866Scherbak, D., et al. (2022). Left bundle branch block.https://www.ncbi.nlm.nih.gov/books/NBK482167/FEEDBACK:Medically reviewed by Uzochukwu Ibe, MD, MPH — By Jenna Fletcher on September 28, 2022 Latest newsWhat sets 'SuperAgers' apart? 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