**3. QT heart rate correction formulas**

When the lengths of the different waves, intervals, and segments are greater or lesser than the values considered normal, the heart is much more vulnerable to arrhythmias. Any of these may be truly lethal, and accesses to ventricular fibrillation may develop.

As we have already mentioned, Breijo et al. published a new electrocardiographic pattern consisting of a short PR and QT intervals in the same electrocardiogram tracing.

People who had this kind of electrocardiographic pattern had also suffered from a wide variety of symptoms. Nocturnal tachycardias, dizziness, seizures, and unexplained syncopal accesses were the main symptoms common to all patients. They were diagnosed as people with epilepsy and treated with specific drugs for epilepsy; the results of such treatment were null.

However, the electroencephalographic registers did not provide any visualization for epileptic focus in any of the assessed patients. The patient age ranged from 16 to 40 years. The male gender was predominant. All previous electrocardiographic studies were considered within normal ranges.

As we have previously mentioned, the typical features of the **Breijo pattern** are:


The great controversy that persists to this date is about which should be considered as an average length of the QT interval since it is related to the heart rate, that is, the QT value is

Several formulas are used to correct the QT interval (QTc). The most used are those of *Bazett* 

However, for these authors, typical values would be between 0.40 and 0.44 s, regardless of the

The discrepancies among the different authors about the typical values of corrected QT are immense. These controversies are producing an authentic catastrophe when it comes to cata-

For us, in accordance with Gollop [9]—any QT value corrected interval less than 0.360 s must

When the lengths of the different waves, intervals, and segments are greater or lesser than the values considered normal, the heart is much more vulnerable to arrhythmias. Any of these

As we have already mentioned, Breijo et al. published a new electrocardiographic pattern

People who had this kind of electrocardiographic pattern had also suffered from a wide variety of symptoms. Nocturnal tachycardias, dizziness, seizures, and unexplained syncopal accesses were the main symptoms common to all patients. They were diagnosed as people with epilepsy and treated with specific drugs for epilepsy; the results of such treatment were null.

However, the electroencephalographic registers did not provide any visualization for epileptic focus in any of the assessed patients. The patient age ranged from 16 to 40 years. The male gender was predominant. All previous electrocardiographic studies were considered within

may be truly lethal, and accesses to ventricular fibrillation may develop.

consisting of a short PR and QT intervals in the same electrocardiogram tracing.

frequency—dependent.

person's age and sex.

be considered as "short QT."

**QT heart rate correction formulas**

**Table 1.** Formulas for QTc measure.

loging when it is or not a short QTC [4–8].

**Exponential Formula** Bazett QT/ RR1/2 Fridericia QT/ RR1/3 **Linear Formula**

Framingham QT + 0.154 (1-RR) Hodges QT + 1.75 (HR-60)

**3. QT heart rate correction formulas**

normal ranges.

The most commonly used formulas are as follows (**Table 1**):

*and Fridericia.*

148 Cardiac Arrhythmias

Both on the same electrocardiographic tracing.

As we have mentioned previously, we agree with Gollop et al. [9] on when the QTc interval duration ought to be considered as "**short**."

Gollop et al. have written over 61 cases of Short QT Syndrome. Their cohort of 61 cases was predominantly male (75.4%) and had a mean QTc value of 0.306 s with values ranging from 0.248 to 0.381 s in symptomatic cases. For Gollop et al., the overall median age at clinical presentation was 21 years (adulthood) [IQR: 17–31.8 years) with a value of 20 years (IQR: 17–29 years) in males and 30 years (IQR: 19–44 years) in females].

These authors developed the ECG characteristics of the general population, and in consideration of clinical presentation, family history and genetic findings, a highly sensitive diagnostic using a scoring system.

This "scoring system" includes:


Since then, the patient referred multiple accesses of nocturnal palpitations, accompanied by intense sweating that wet the pajamas. Feelings of gait instability. He liked to play sports, but at the minimum effort, he felt severe palpitations that impeded him from continuing with it. The patient was anxious about his heart and visited numerous specialists in the field. He underwent a lot of diagnostic tests, and all of them were considered normal. The doctors

Breijo Electrocardiographic Pattern

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http://dx.doi.org/10.5772/intechopen.75446

In two occasions, the patient suffered two syncope events that were considered vase-vagal

A thorough compilation of patients with this kind of symptoms such as infantile convulsions non-responders to conventional treatments, bouts of nocturnal tachycardia with sudden char-

An exhaustive study of personal antecedents, as well as your current clinical situation, was

An exhaustive measurement of intervals, segments, and electrocardiographic waves. Measure-

By way of example, we will expose the following case: A 37-year-old man with much nocturnal tachycardia crisis (since childhood) and three syncopal events observed and related to physical stress. In his family background, two sudden deaths were found: father died at age

He was diagnosed in his Reference Hospital (where he was transferred by emergency services) with supraventricular tachycardia to 195–200 beats/min (**Figure 3**), with narrow QRS

55 of sudden cardiac, and a brother died at 22 months by sudden infant death.

believed him to be a patient with intense anxiety and hypochondriasis.

acter, and syncopal events related to the effort.

**Figure 3.** The full basal electrocardiogram tracing.

ment technique: MioLaserTool®, Pixruler® & Cardiocaliper®.

etiology.

performed.

**Figure 2.** Boston Diagram.

Of all the current layouts, this is the one we consider as the most reliable and the most accurate.

We have seen cases of a short QT interval (QTc ≤ 0.350 s) in asymptomatic patients and without a positive family history thereto for congenital (and non-genetic) character.

We also think it is worthy to mention an interesting paradoxical ECG phenomenon called deceleration-dependent shortening of QT interval (shortening of QT interval associated with a decrease in heart rate); this should also be considered in a differential diagnosis [1–3].

In order to know precisely if the corrected QT value—by the different existing formulas—is in ranges, we use the **Boston diagram** (**Figure 2**).
