From the Guidelines
A heart rate of 135 beats per minute requires immediate evaluation and management to determine the underlying cause and prevent potential complications, such as decreased cardiac output, myocardial ischemia, and even death. The first step is to assess the patient for symptoms such as chest pain, shortness of breath, dizziness, or altered mental status, and check vital signs including blood pressure and oxygen saturation 1. A 12-lead ECG should be obtained to determine the type of tachycardia, which can be classified as sinus tachycardia, atrial fibrillation, atrial flutter, supraventricular tachycardia, or ventricular tachycardia.
Some key points to consider when interpreting the ECG include:
- The presence of atrioventricular (AV) dissociation or fusion complexes, which can indicate ventricular tachycardia 1
- The QRS morphology in the precordial leads, which can help distinguish between supraventricular and ventricular tachycardia using algorithms such as the Brugada criteria or the Vereckei algorithm 1
- The regularity of the ventricular rate, which can suggest atrial fibrillation, atrial flutter, or supraventricular tachycardia 1
For stable patients with supraventricular tachycardia, vagal maneuvers like the Valsalva maneuver can be attempted, followed by adenosine 6mg IV push if unsuccessful. For atrial fibrillation with rapid ventricular response, rate control with metoprolol 5mg IV every 5 minutes up to 3 doses or diltiazem 0.25mg/kg IV over 2 minutes can be considered. However, for unstable patients with hypotension, altered mental status, or signs of shock, synchronized cardioversion starting at 100-200 joules is indicated. It is also essential to investigate underlying causes, such as sepsis, dehydration, pain, anxiety, hyperthyroidism, pulmonary embolism, or medication effects, and obtain basic labs including electrolytes, complete blood count, and cardiac enzymes 1.
From the Research
Patient Presentation
- The patient presents with a heart rate of 135, which is considered tachycardic.
- There is no direct evidence in the provided studies that links a heart rate of 135 to a specific diagnosis or treatment.
Relevant Studies
- None of the provided studies directly address the diagnosis or treatment of a patient with a heart rate of 135.
- Study 2 discusses the role of ECG in diagnosis and risk estimation of patients with acute coronary syndromes, but does not provide information on heart rate.
- Studies 3, 4, 5, and 6 focus on the comparison of normal saline and lactated Ringer's solution in various medical contexts, but do not address heart rate specifically.
ECG Changes
- Study 3 discusses ECG changes associated with intracoronary infusion of normal saline, including T-wave amplitude changes and QT prolongation.
- However, this study does not provide information on the relationship between these ECG changes and heart rate.