.ecg-calculator-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
background: #fff;
padding: 20px;
border-radius: 8px;
box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
.ecg-header {
text-align: center;
margin-bottom: 30px;
border-bottom: 2px solid #0073aa;
padding-bottom: 15px;
}
.ecg-header h2 {
color: #23282d;
margin: 0;
font-size: 24px;
}
.ecg-input-group {
margin-bottom: 20px;
}
.ecg-input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #444;
}
.ecg-input-group input, .ecg-input-group select {
width: 100%;
padding: 12px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.ecg-input-group .help-text {
font-size: 12px;
color: #666;
margin-top: 5px;
}
.ecg-btn {
background-color: #0073aa;
color: white;
border: none;
padding: 15px 30px;
font-size: 16px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
transition: background-color 0.3s;
}
.ecg-btn:hover {
background-color: #005177;
}
.ecg-results {
margin-top: 30px;
background-color: #f9f9f9;
border: 1px solid #e5e5e5;
padding: 20px;
border-radius: 4px;
display: none;
}
.ecg-result-item {
display: flex;
justify-content: space-between;
align-items: center;
margin-bottom: 15px;
padding-bottom: 10px;
border-bottom: 1px solid #eee;
}
.ecg-result-item:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.ecg-result-label {
font-weight: 600;
color: #555;
}
.ecg-result-value {
font-size: 24px;
font-weight: 700;
color: #0073aa;
}
.ecg-interpretation {
margin-top: 15px;
padding: 10px;
background: #fff;
border-left: 4px solid #0073aa;
font-size: 14px;
}
.status-brady { color: #d32f2f; }
.status-normal { color: #2e7d32; }
.status-tachy { color: #d32f2f; }
.ecg-article {
margin-top: 50px;
line-height: 1.6;
color: #333;
}
.ecg-article h3 {
color: #23282d;
border-bottom: 1px solid #ddd;
padding-bottom: 10px;
margin-top: 30px;
}
.ecg-article ul {
padding-left: 20px;
}
.ecg-article li {
margin-bottom: 10px;
}
.ecg-note {
background: #fff3cd;
border: 1px solid #ffeeba;
color: #856404;
padding: 10px;
border-radius: 4px;
font-size: 0.9em;
margin-bottom: 20px;
}
function calculateECGRate() {
// Get inputs
var rWavesInput = document.getElementById('ecg_r_waves');
var durationInput = document.getElementById('ecg_duration');
var resultsContainer = document.getElementById('ecg_results_container');
var bpmDisplay = document.getElementById('ecg_bpm_result');
var classDisplay = document.getElementById('ecg_class_result');
var interpDisplay = document.getElementById('ecg_interpretation_text');
// Parse values
var rWaves = parseFloat(rWavesInput.value);
var duration = parseFloat(durationInput.value);
// Validation
if (isNaN(rWaves) || rWaves < 0) {
alert("Please enter a valid number of R-waves.");
return;
}
if (isNaN(duration) || duration <= 0) {
alert("Please enter a valid strip duration greater than 0.");
return;
}
// Calculation Logic: (Count / Seconds) * 60
var bpm = (rWaves / duration) * 60;
// Round to nearest whole number for clinical relevance
bpm = Math.round(bpm);
// Determine Classification
var classification = "";
var interpText = "";
var colorClass = "";
if (bpm < 60) {
classification = "Bradycardia";
colorClass = "status-brady";
interpText = "The rate is slower than normal (= 60 && bpm 100 BPM). If this is Atrial Fibrillation, it indicates Rapid Ventricular Response (RVR). Assess for symptoms such as palpitations, shortness of breath, or chest pain.";
}
// Display Results
resultsContainer.style.display = "block";
bpmDisplay.innerHTML = bpm + " BPM";
classDisplay.innerHTML = classification;
classDisplay.className = "ecg-result-value " + colorClass;
interpDisplay.innerHTML = interpText;
interpDisplay.style.borderColor = (bpm 100) ? "#d32f2f" : "#2e7d32";
}
ECG Irregular Rhythm Rate Calculator
Calculate heart rate using the 6-Second Method for arrhythmias like Atrial Fibrillation.
Count the number of complete QRS complexes within the strip duration. Don't include premature beats that don't generate a pulse if checking pulse deficit, but for ECG rate, count all conducted beats.
Standard rhythm strips are 6 seconds (30 large squares at 25mm/s).
Calculated Heart Rate:
— BPM
Classification:
—
How to Calculate Heart Rate for Irregular Rhythms
Calculating the heart rate from an electrocardiogram (ECG) is a fundamental skill for medical professionals. While the "300 method" (dividing 300 by the number of large squares between R-R intervals) works perfectly for regular rhythms, it is inaccurate for irregular rhythms such as Atrial Fibrillation (AFib), Multifocal Atrial Tachycardia, or significant Sinus Arrhythmia.
Clinical Note: For irregular rhythms, the ventricular rate varies from beat to beat. Therefore, we must calculate an average rate over a set period rather than measuring the distance between just two beats.
The 6-Second Method
The standard approach for calculating rate in an irregular rhythm is the 6-Second Method. This is widely accepted because it is quick, simple, and provides a clinically useful average of the ventricular rate.
Step-by-Step Calculation:
- Identify a 6-second strip: On standard ECG paper running at 25 mm/sec, a 6-second interval consists of 30 large squares. Most ECG strips have hash marks at the top or bottom indicating 3-second intervals; two of these intervals make 6 seconds.
- Count the QRS Complexes: Count the number of R-waves (the spikes) that fall completely within this 6-second period.
- If a QRS complex falls exactly on the start or end line, it is generally counted, but consistency is key.
- Multiply by 10: Since 6 seconds is one-tenth of a minute (60 seconds), multiplying the count by 10 gives the average Beats Per Minute (BPM).
Example: If you count 8 QRS complexes in a 6-second strip:
8 complexes × 10 = 80 BPM.
Interpreting the Results
Once you have the rate, it helps to categorize the rhythm to determine immediate clinical stability:
- Bradycardia: Heart rate < 60 BPM. In irregular rhythms (like slow AFib), this requires monitoring for hemodynamic stability.
- Normal Range: Heart rate between 60 and 100 BPM. This is often described as "Controlled Ventricular Response" in the context of AFib.
- Tachycardia: Heart rate > 100 BPM. In AFib, this is called "Rapid Ventricular Response" (RVR) and often requires rate-controlling medication.
Why the "300 Rule" Fails for Irregular Rhythms
The 300 Rule (300 / large squares between R-waves) assumes every heartbeat is equidistant. In an irregular rhythm, one interval might represent a rate of 120 BPM while the next represents 50 BPM. Using the 300 rule on a single interval would give a wildly inaccurate snapshot of the patient's actual cardiac output. The 6-second method averages these fluctuations for a realistic assessment.