Small but significant

 

The QT interval is the beginning of the QRS complex to the end of the T wave. It is the electrocardiographic representation of ventricular depolarisation and repolarisation.

QTi Cropped For Blog

The heart’s electrical system operates through channels within the myocardial cell membrane, regulating the flow of ions (electrically charged atoms) in and out of the cell.

 

In a normally conducted heart, a rapid influx of positive sodium and calcium ions results in a normal myocardial depolarisation. When this influx is exceeded by an outflow of potassium ions, repolarisation occurs.

 

If this balance is disturbed by a channel malfunction, ventricular repolarisation can be prolonged and therefore the QT interval becomes prolonged on the ECG.

 

Alongside channel malfunctions caused by certain medications, there are also genes that can affect normal functioning of the QT interval.

 

The QT’s relevance in Mental Health Care

 

Prior to taking certain medications for conditions such as attention deficit hyperactivity disorder and schizophrenia, amongst other mental health conditions, ECG screening can be undertaken. The main purpose is to assess whether there are underlying cardiac conditions that may affect medication decisions.

 

Regular ECG monitoring is also performed within mental health care to monitor the QT interval during pharmacological treatment. ECG On-Demand offers portable ECG machines that can help healthcare professionals monitor heart health in the comfort of a patient’s own surroundings, whether out in the community or receiving inpatient care. This has the potential to make an often intrusive procedure a better experience for vulnerable patients.

 

If the QT interval is abnormal, it can become a risk factor for ventricular arrhythmias such as torsades de pointes. 

 

Every Millisecond Counts

 

Obtaining the most accurate measurement of the QT interval is sometimes challenging due to the presence of U waves, a deflection of the ECG representing ventricular repolarisation seen after the T wave. Patients with resting sinus tachycardia may also pose a challenge.

 

ECG On-Demand uses the raw ECG data transmitted from our cloud connected ECG machines, in order to provide the most accurate measurement possible. Automated ECG interpretation is often unreliable due to normal variations in ECG waveforms. Furthermore, QT intervals need to be adjusted to account for the heart rate to give an accurate estimation of risk. 

By having the raw data, our team of experienced cardiac physiologists can provide a manually adjusted measurement complete with a traffic light risk rating. For repeated tests, our PDF ECG reports display the patient’s previous QT interval measurements to help you manage patients with ease.

 

Are you looking to improve your diagnostic quality in a mental health setting? Get in touch with a member of our team below!

Laura And Zoe