Premature ventricular contractions can be classified based upon the number of normal beats between them.

• There are four different named patterns of regularly occurring PVCs.
• Depending whether there are 1, 2, or 3 normal beats between each PVC, the rhythm is called bigeminy, trigeminy, or quadrigeminy.
• Unifocal PVCs are triggered from a single site in the ventricle, causing the peaks on the ECG to look the same.
• Multifocal PVCs arise when more than one site in the ventricles initiate depolarization, causing each peak on the ECG to have a different shape. If 3 or more PVCs occur in a row it may be called ventricular tachycardia.

There is no established system for the classification of [disease name].

OR

[Disease name] may be classified according to [vcbvgbfggbnto [number] subtypes/groups: [group1], [group2], [group3], and [group4].

OR

[Disease name] may be classified into [large number > 6] subtypes based on [classification method 1], [classification method 2], and [classification method 3]. [Disease name] may be classified into several subtypes based on [classification method 1], [classification method 2], and [classification method 3].

OR

Based on the duration of symptoms, [disease name] may be classified as either acute or chronic.

OR

If the staging system involves specific and characteristic findings and features: According to the [staging system + reference], there are [number] stages of [malignancy name] based on the [finding1], [finding2], and [finding3]. Each stage is assigned a [letter/number1] and a [letter/number2] that designate the [feature1] and [feature2].

OR

The staging of [malignancy name] is based on the [staging system].

OR

There is no established system for the staging of [malignancy name].

There is no established system for the classification of [disease name].

OR

[Disease name] may be classified according to [classification method] into [number] subtypes/groups:

• [Group1]
• [Group2]
• [Group3]
• [Group4]

OR

[Disease name] may be classified into [large number > 6] subtypes based on:

• [Classification method 1]
• [Classification method 2]
• [Classification method 3]

[Disease name] may be classified into several subtypes based on:

• [Classification method 1]
• [Classification method 2]
• [Classification method 3]

OR

Based on the duration of symptoms, [disease name] may be classified as either acute or chronic.

OR

If the staging system involves specific and characteristic findings and features:

According to the [staging system + reference], there are [number] stages of [malignancy name] based on the [finding1], [finding2], and [finding3]. Each stage is assigned a [letter/number1] and a [letter/number2] that designate the [feature1] and [feature2].

OR

The staging of [malignancy name] is based on the [staging system].

OR

There is no established system for the staging of [malignancy name].

There is no established system for the classification of [disease name].

OR

[Disease name] may be classified according to [classification method] into [number] subtypes/groups: [group1], [group2], [group3], and [group4].

OR

[Disease name] may be classified into [large number > 6] subtypes based on [classification method 1], [classification method 2], and [classification method 3]. [Disease name] may be classified into several subtypes based on [classification method 1], [classification method 2], and [classification method 3].

OR

Based on the duration of symptoms, [disease name] may be classified as either acute or chronic.

OR

If the staging system involves specific and characteristic findings and features: According to the [staging system + reference], there are [number] stages of [malignancy name] based on the [finding1], [finding2], and [finding3]. Each stage is assigned a [letter/number1] and a [letter/number2] that designate the [feature1] and [feature2].

OR

The staging of [malignancy name] is based on the [staging system].

OR

There is no established system for the staging of [malignancy name].

There is no established system for the classification of [disease name].

OR

[Disease name] may be classified according to [classification method] into [number] subtypes/groups:

• [Group1]
• [Group2]
• [Group3]
• [Group4]

OR

[Disease name] may be classified into [large number > 6] subtypes based on:

• [Classification method 1]
• [Classification method 2]
• [Classification method 3]

[Disease name] may be classified into several subtypes based on:

• [Classification method 1]
• [Classification method 2]
• [Classification method 3]

OR

Based on the duration of symptoms, [disease name] may be classified as either acute or chronic.

OR

If the staging system involves specific and characteristic findings and features:

According to the [staging system + reference], there are [number] stages of [malignancy name] based on the [finding1], [finding2], and [finding3]. Each stage is assigned a [letter/number1] and a [letter/number2] that designate the [feature1] and [feature2].

OR

The staging of [malignancy name] is based on the [staging system].

OR

There is no established system for the staging of [malignancy name].