.calc-section { margin-bottom: 25px; padding: 20px; border: 1px solid #f0f2f5; border-radius: 6px; background-color: #f8f9fa; }
.calc-header { font-size: 24px; font-weight: 700; color: #2c3e50; margin-bottom: 15px; border-bottom: 2px solid #0073aa; padding-bottom: 10px; }
.input-group { margin-bottom: 15px; }
.input-group label { display: block; font-weight: 600; margin-bottom: 5px; color: #444; }
.input-group input { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 4px; font-size: 16px; box-sizing: border-box; }
.calc-button { background-color: #0073aa; color: white; border: none; padding: 12px 20px; font-size: 16px; font-weight: 600; border-radius: 4px; cursor: pointer; width: 100%; transition: background-color 0.2s; }
.calc-button:hover { background-color: #005177; }
.result-box { margin-top: 20px; padding: 15px; border-radius: 4px; background-color: #e7f3ff; border: 1px solid #b3d7ff; display: none; }
.result-title { font-weight: 700; color: #004085; margin-bottom: 5px; }
.result-value { font-size: 20px; font-weight: 700; color: #0073aa; }
.article-content { margin-top: 30px; }
.article-content h2 { color: #2c3e50; font-size: 22px; margin-top: 25px; }
.article-content p { margin-bottom: 15px; }
.article-content ul { margin-bottom: 15px; padding-left: 20px; }
.example-box { background-color: #fff3cd; border-left: 5px solid #ffeeba; padding: 15px; margin: 20px 0; }
function calculateRR() {
var hr = document.getElementById('heartRateInput').value;
var rr = document.getElementById('rrIntervalInput').value;
var resultBox = document.getElementById('rrResultBox');
var resultValue = document.getElementById('rrResultValue');
var resultTitle = document.getElementById('rrResultTitle');
if (hr !== "" && !isNaN(hr)) {
var hrNum = parseFloat(hr);
if (hrNum <= 0) {
alert("Please enter a heart rate greater than zero.");
return;
}
var calculatedRR = 60000 / hrNum;
resultTitle.innerHTML = "Calculated RR Interval:";
resultValue.innerHTML = calculatedRR.toFixed(2) + " ms";
resultBox.style.display = "block";
}
else if (rr !== "" && !isNaN(rr)) {
var rrNum = parseFloat(rr);
if (rrNum <= 0) {
alert("Please enter an RR interval greater than zero.");
return;
}
var calculatedHR = 60000 / rrNum;
resultTitle.innerHTML = "Calculated Heart Rate:";
resultValue.innerHTML = calculatedHR.toFixed(1) + " BPM";
resultBox.style.display = "block";
}
else {
alert("Please enter either a Heart Rate or an RR Interval value.");
}
}
RR Interval Calculator
Calculate the RR interval (ms) from heart rate or vice versa.
– OR –
Conversion Result:
What is the RR Interval?
In electrocardiography (ECG/EKG), the RR interval is the time elapsed between two successive R waves of the QRS signal on the cardiac cycle. It represents the duration of one complete heartbeat and is primarily used to determine the heart rate and evaluate heart rate variability (HRV).
While heart rate is typically measured in beats per minute (BPM), the RR interval provides a more granular look at cardiac timing, measured in milliseconds (ms).
The Calculation Formula
The relationship between Heart Rate (HR) and the RR interval is inverse. Since there are 60,000 milliseconds in one minute, the formulas are:
- RR Interval (ms) = 60,000 / Heart Rate (BPM)
- Heart Rate (BPM) = 60,000 / RR Interval (ms)
Calculation Example:
If a patient has a heart rate of 60 BPM:
Calculation: 60,000 / 60 = 1,000 ms.
Therefore, the RR interval is exactly 1,000 milliseconds (1 second).
If a patient has a heart rate of 60 BPM:
Calculation: 60,000 / 60 = 1,000 ms.
Therefore, the RR interval is exactly 1,000 milliseconds (1 second).
Why is RR Interval Important?
The RR interval is a critical metric for several reasons:
- Heart Rate Variability (HRV): By looking at the variation between consecutive RR intervals, clinicians and athletes can assess the health of the autonomic nervous system and recovery levels.
- QT Correction (QTc): Calculating the RR interval is the first step in determining the corrected QT interval, which is vital for diagnosing potential arrhythmias.
- Arrhythmia Detection: Irregularities in the RR interval can signal conditions like Atrial Fibrillation (AFib) or premature ventricular contractions.
Standard RR Interval Reference Table
| Heart Rate (BPM) | RR Interval (ms) |
|---|---|
| 50 (Bradycardia) | 1,200 ms |
| 60 (Normal) | 1,000 ms |
| 75 (Normal) | 800 ms |
| 100 (Tachycardia) | 600 ms |
| 150 (Exercise) | 400 ms |