What is a handheld device that gives the QTc (corrected QT interval), QRS (QRS complex), PR (PR interval), and QT (QT interval) intervals?

Handheld Devices for ECG Interval Measurement

The AliveCor KardiaMobile 6L is the only FDA-approved handheld device that provides reliable measurements of QTc, QRS, PR, and QT intervals comparable to standard 12-lead ECGs. 1

Device Options and Capabilities

The AliveCor KardiaMobile 6L stands out as the primary option for portable ECG interval measurement:

• FDA-approved specifically for QTc monitoring 1
• Provides 6-lead ECG recordings (more comprehensive than single-lead alternatives)
• Enables remote monitoring of critical ECG intervals including QTc, QRS, PR, and QT
• Connects to smartphones/tablets for easy data transmission and interpretation

Clinical Validation

Multiple studies have demonstrated the reliability of the KardiaMobile 6L:

• Mean differences between KardiaMobile 6L and standard 12-lead ECGs for QTcF, heart rate, PR, and QRS were minimal (2.6 ms, -5.5 bpm, 1.0 ms, and 1.2 ms respectively) 2
• Good agreement for QT interval measurements with standard 12-lead ECGs 3
• Acceptable agreement for PR interval, QRS duration, and cardiac axis measurements 3
• Demonstrated reliability in critically ill patients, with QTc measurements comparable to standard 12-lead ECGs 4

Clinical Applications

The KardiaMobile 6L is particularly valuable in several clinical scenarios:

• QTc monitoring for patients on QT-prolonging medications 1

  • Allows for remote assessment of QTc intervals when medications are maintained after hospital discharge
  • Enables detection of significant QTc prolongation that may require medication adjustment

• Remote patient monitoring during telehealth visits 1

  • Patients can record ECGs at home and transmit data to healthcare providers
  • Particularly useful during situations requiring minimal patient contact (e.g., COVID-19 pandemic)

• Clinical trials requiring ECG interval monitoring 1

  • Provides an economical solution for monitoring QTc in outpatient trials
  • Allows participants to record ECGs at baseline and specified follow-up intervals

Limitations to Consider

Despite its utility, the KardiaMobile 6L has important limitations:

• Not a replacement for standard 12-lead ECG in emergency situations 5
• Limited ability to detect ST-segment deviations that might indicate myocardial ischemia 5
• Reduced accuracy during movement or with improper electrode placement 5
• Less reliable for detecting left ventricular hypertrophy, certain QRS amplitude measurements, and ischemic changes 3

Best Practices for Use

To optimize accuracy when using the KardiaMobile 6L:

• Ensure proper electrode placement and minimize patient movement during recording 5
• Consider patient position (recordings typically done sitting rather than supine) 2
• Confirm significant findings with a standard 12-lead ECG when clinically indicated 5
• Use as a supplementary tool rather than the sole diagnostic method for comprehensive cardiac evaluation 5

Practical Implementation

For clinical implementation of KardiaMobile 6L:

1. Patient training: Provide simple instructions on device use - most patients can successfully record ECGs after basic training 6
2. Data transmission: ECGs can be uploaded to monitoring platforms or emailed directly to providers 1
3. Interpretation: QTc intervals of ≥500 ms or increases of ≥60 ms should prompt reassessment of medication risks/benefits 1

The KardiaMobile 6L represents an important advancement in portable ECG technology, offering a reliable method for monitoring critical ECG intervals outside traditional healthcare settings.