.ecg-calc-container {
max-width: 800px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
color: #333;
line-height: 1.6;
}
.ecg-calc-box {
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 25px;
margin-bottom: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.ecg-calc-header {
text-align: center;
margin-bottom: 25px;
color: #2c3e50;
}
.ecg-form-group {
margin-bottom: 20px;
}
.ecg-form-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #495057;
}
.ecg-input-row {
display: flex;
gap: 20px;
flex-wrap: wrap;
}
.ecg-col-half {
flex: 1;
min-width: 250px;
}
.ecg-form-control {
width: 100%;
padding: 10px 12px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.ecg-form-control:focus {
border-color: #e74c3c;
outline: none;
box-shadow: 0 0 0 3px rgba(231, 76, 60, 0.2);
}
.ecg-btn {
background-color: #e74c3c;
color: white;
border: none;
padding: 12px 20px;
font-size: 18px;
border-radius: 4px;
cursor: pointer;
width: 100%;
transition: background-color 0.2s;
font-weight: bold;
}
.ecg-btn:hover {
background-color: #c0392b;
}
.ecg-result-box {
background-color: #fff;
border: 1px solid #dee2e6;
border-radius: 6px;
padding: 20px;
margin-top: 25px;
display: none;
}
.ecg-result-header {
font-size: 20px;
font-weight: bold;
color: #2c3e50;
border-bottom: 2px solid #e74c3c;
padding-bottom: 10px;
margin-bottom: 15px;
}
.ecg-result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
padding-bottom: 10px;
border-bottom: 1px dashed #eee;
}
.ecg-result-label {
color: #6c757d;
}
.ecg-result-value {
font-weight: bold;
font-size: 18px;
}
.ecg-interpretation {
margin-top: 15px;
padding: 10px;
border-radius: 4px;
font-weight: 500;
text-align: center;
}
.status-normal { background-color: #d4edda; color: #155724; }
.status-warning { background-color: #fff3cd; color: #856404; }
.status-danger { background-color: #f8d7da; color: #721c24; }
.ecg-article h2 { color: #2c3e50; margin-top: 30px; border-bottom: 2px solid #eee; padding-bottom: 10px; }
.ecg-article h3 { color: #e74c3c; margin-top: 25px; }
.ecg-article ul { margin-bottom: 20px; }
.ecg-article li { margin-bottom: 10px; }
.ecg-note { font-size: 0.9em; color: #666; font-style: italic; }
function calculateECGRates() {
var method = parseInt(document.getElementById('ecgMethod').value);
var rrCount = parseFloat(document.getElementById('rrInput').value);
var ppCount = parseFloat(document.getElementById('ppInput').value);
var resultDiv = document.getElementById('ecgResult');
// Displays
var vDisplay = document.getElementById('ventricularRateDisplay');
var aDisplay = document.getElementById('atrialRateDisplay');
var vInterp = document.getElementById('ventricularInterp');
var aInterp = document.getElementById('atrialInterp');
// Show results box
resultDiv.style.display = 'block';
// Calculate Ventricular Rate
if (rrCount && rrCount > 0) {
var vRate = Math.round(method / rrCount);
vDisplay.innerHTML = vRate + " bpm";
var vClass = "status-normal";
var vText = "Normal Sinus Rhythm Rate";
if (vRate 100) {
vClass = "status-danger";
vText = "Tachycardia (Fast)";
}
vInterp.className = "ecg-interpretation " + vClass;
vInterp.innerHTML = vText;
} else {
vDisplay.innerHTML = "No data entered";
vInterp.className = "ecg-interpretation";
vInterp.innerHTML = "";
}
// Calculate Atrial Rate
if (ppCount && ppCount > 0) {
var aRate = Math.round(method / ppCount);
aDisplay.innerHTML = aRate + " bpm";
var aClass = "status-normal";
var aText = "Normal Atrial Rate";
if (aRate 100) {
aClass = "status-danger";
aText = "Atrial Tachycardia";
}
aInterp.className = "ecg-interpretation " + aClass;
aInterp.innerHTML = aText;
} else {
aDisplay.innerHTML = "No data entered";
aInterp.className = "ecg-interpretation";
aInterp.innerHTML = "";
}
// Specific check for Heart Block or Conduction issues
if ((rrCount > 0 && ppCount > 0) && (Math.abs(rrCount – ppCount) > 1)) {
// Simple logic check: if Rates differ significantly, flag it
// This is just a UI hint, not a diagnosis
}
}
How to Calculate Atrial and Ventricular Rate from an ECG
Calculating heart rates from an Electrocardiogram (ECG/EKG) strip is a fundamental skill for medical professionals. The heart rate is derived from the electrical activity of the heart, specifically measuring the frequency of the P waves (atrial activity) and the QRS complexes (ventricular activity).
Why measure both Atrial and Ventricular Rates?
In a healthy heart (Normal Sinus Rhythm), the atrial rate and ventricular rate are identical because every electrical impulse from the sinus node triggers exactly one ventricular contraction. However, in various arrhythmias such as Atrial Flutter, Atrial Fibrillation, or 3rd-Degree Heart Block, these rates usually dissociate. Calculating them separately helps identify the specific type of arrhythmia.
Method 1: The 1500 Method (Small Box Method)
This is the most precise method for calculating heart rate on a regular rhythm strip.
- Step 1: Identify two consecutive R waves (for ventricular rate) or P waves (for atrial rate).
- Step 2: Count the number of small boxes (1mm squares) between them.
- Step 3: Divide 1,500 by this number.
Formula: Rate = 1500 ÷ Number of Small Boxes
Example: If there are 20 small boxes between two R waves, the heart rate is 1500 / 20 = 75 bpm.
Method 2: The 300 Method (Big Box Method)
This method is faster but slightly less precise, useful for quick bedside estimation.
- Step 1: Identify two consecutive complexes.
- Step 2: Count the number of big boxes (5mm squares) between them.
- Step 3: Divide 300 by this number.
Formula: Rate = 300 ÷ Number of Big Boxes
Sequence to Memorize: 300, 150, 100, 75, 60, 50. (e.g., 1 big box = 300 bpm, 2 big boxes = 150 bpm).
Calculating Ventricular Rate (R-R Interval)
The ventricular rate is what we typically refer to as the "pulse" or "heart rate." It reflects the contraction of the ventricles, which pumps blood to the lungs and body. To calculate it, measure the distance between the peaks of two consecutive QRS complexes (the R waves).
Calculating Atrial Rate (P-P Interval)
The atrial rate reflects the frequency of atrial depolarization. To calculate it, measure the distance between the peaks of two consecutive P waves. In Atrial Flutter, you may see "sawtooth" waves; counting these allows you to determine the flutter rate, which is often between 250 and 350 bpm.
Interpreting the Results
- Normal Sinus Rhythm: 60 – 100 bpm.
- Bradycardia: Less than 60 bpm.
- Tachycardia: Greater than 100 bpm.
Note: Standard ECG paper speed is 25mm/second. The formulas (1500 and 300) are based on this standard speed. If the paper speed is 50mm/second, you must double the result.