.ecg-calculator-wrapper {
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-calc-container {
background-color: #f8f9fa;
padding: 25px;
border-radius: 8px;
border: 1px solid #e9ecef;
margin-bottom: 30px;
}
.ecg-input-group {
margin-bottom: 20px;
}
.ecg-input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #2c3e50;
}
.ecg-input-group input, .ecg-input-group select {
width: 100%;
padding: 12px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.ecg-input-group .help-text {
font-size: 12px;
color: #6c757d;
margin-top: 4px;
}
.ecg-btn {
background-color: #e74c3c;
color: white;
border: none;
padding: 14px 20px;
font-size: 16px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
transition: background-color 0.3s;
}
.ecg-btn:hover {
background-color: #c0392b;
}
#ecgResult {
margin-top: 25px;
padding: 20px;
background-color: #fff;
border-left: 5px solid #e74c3c;
display: none;
}
.result-title {
font-size: 14px;
text-transform: uppercase;
color: #7f8c8d;
letter-spacing: 1px;
}
.result-value {
font-size: 36px;
font-weight: 700;
color: #2c3e50;
margin: 10px 0;
}
.result-interpretation {
font-size: 16px;
color: #34495e;
padding-top: 10px;
border-top: 1px solid #eee;
}
.article-content h2 {
color: #2c3e50;
margin-top: 30px;
font-size: 24px;
}
.article-content h3 {
color: #34495e;
margin-top: 20px;
font-size: 20px;
}
.article-content p {
line-height: 1.6;
color: #555;
margin-bottom: 15px;
}
.article-content ul {
margin-bottom: 20px;
padding-left: 20px;
}
.article-content li {
margin-bottom: 10px;
color: #555;
line-height: 1.6;
}
.highlight-box {
background-color: #e8f4fd;
border-left: 4px solid #3498db;
padding: 15px;
margin: 20px 0;
color: #2980b9;
}
function toggleCustomDuration() {
var select = document.getElementById("ecgStripDuration");
var customGroup = document.getElementById("customDurationGroup");
if (select.value === "custom") {
customGroup.style.display = "block";
} else {
customGroup.style.display = "none";
}
}
function calculateECGRate() {
// Get inputs
var durationSelect = document.getElementById("ecgStripDuration");
var customSeconds = document.getElementById("customSeconds");
var qrsInput = document.getElementById("qrsComplexes");
var resultDiv = document.getElementById("ecgResult");
var bpmDisplay = document.getElementById("bpmValue");
var interpretationDisplay = document.getElementById("bpmInterpretation");
// Parse values
var qrsCount = parseFloat(qrsInput.value);
var duration = 0;
if (durationSelect.value === "custom") {
duration = parseFloat(customSeconds.value);
} else {
duration = parseFloat(durationSelect.value);
}
// Validation
if (isNaN(qrsCount) || qrsCount < 0) {
alert("Please enter a valid number of QRS complexes.");
return;
}
if (isNaN(duration) || duration <= 0) {
alert("Please ensure the strip duration is valid.");
return;
}
// Calculation: (Beats / Seconds) * 60 Seconds
var bpm = (qrsCount / duration) * 60;
// Round to nearest whole number for clinical relevance
bpm = Math.round(bpm);
// Display Result
resultDiv.style.display = "block";
bpmDisplay.innerHTML = bpm;
// Interpretation Logic
var text = "";
var color = "";
if (bpm < 60) {
text = "Bradycardia: The heart rate is slower than normal (= 60 && bpm <= 100) {
text = "Normal Rate: The heart rate is within normal limits (60-100 BPM).";
color = "#27ae60"; // Green
} else if (bpm > 100) {
text = "Tachycardia: The heart rate is faster than normal (> 100 BPM).";
color = "#c0392b"; // Red
}
interpretationDisplay.innerHTML = text;
interpretationDisplay.style.color = color;
}
Irregular Heart Rate Calculator (6-Second Method)
6 Seconds (Standard)
10 Seconds
30 Seconds
60 Seconds (Full Minute)
Custom Duration
Select the total time duration of the rhythm strip you are analyzing.
Count the number of R-waves (spikes) visible within the selected duration.
Calculated Heart Rate
0 BPM
How to Calculate Rate on ECG if Irregular
Calculating the heart rate from an electrocardiogram (ECG) is a fundamental skill in cardiology. However, standard calculation methods like the 300 Rule (dividing 300 by the number of large boxes between R-waves) or the 1500 Rule only work accurately when the heart rhythm is regular.
When the rhythm is irregular—such as in Atrial Fibrillation (AFib), Multifocal Atrial Tachycardia, or significant Sinus Arrhythmia—the intervals between heartbeats vary. In these cases, using standard methods will produce a highly inaccurate result that fluctuates depending on which specific beat interval you measure.
Key Rule: Do not use box-counting methods for irregular rhythms. Instead, measure the average rate over a fixed period of time.
The 6-Second Method
The most widely accepted and easiest method for calculating an irregular heart rate is the 6-Second Method. This technique calculates the mean heart rate by analyzing a 6-second strip of the ECG.
Step-by-Step Calculation:
- Obtain the Strip: Ensure you have a 6-second rhythm strip. On standard ECG paper (running at 25 mm/sec), 6 seconds equals 30 large boxes.
- Count the R-Waves: Count the number of complete QRS complexes (the tall spikes representing ventricular contraction) within that 6-second window. Do not count incomplete beats at the very start or end of the strip.
- Multiply by 10: Since 6 seconds is one-tenth of a minute (60 seconds), multiply the count by 10 to get the Beats Per Minute (BPM).
Example Calculation
Imagine you are reviewing a telemetry strip for a patient with Atrial Fibrillation:
- You select a 6-second strip (30 large boxes).
- You count 9 R-waves within this period.
- Calculation: 9 x 10 = 90 BPM.
If you used a 10-second strip, you would count the beats and multiply by 6.
Interpreting the Results
Once you have calculated the rate, you can categorize the heart rate clinically:
- Bradycardia: Less than 60 BPM.
- Normal Sinus Rate: 60 to 100 BPM.
- Tachycardia: Greater than 100 BPM.
Note that for highly irregular rhythms, longer strips (e.g., 60 seconds) provide the most accurate average heart rate, though the 6-second method is the standard for rapid clinical assessment.