Lown and his colleagues proposed a classification of premature ventricular beats based on risk of death after myocardial infarction.
|
Finding |
Grade |
|
no ventricular premature beats |
0 |
|
less than 30 ventricular premature beats per hour |
1 |
|
30 or more ventricular premature beats per hour |
2 |
|
multiform/polymorphic ventricular premature beats |
3 |
|
repetitive ventricular premature beats • couplets (2 consecutive ventricular extrasystoles) • monomorphic ventricular tachycardia runs (salvos, 3 or more consecutive ventricular extrasystoles) |
4a 4b |
|
R on T phenomenon (ventricular premature beat on preceding T wave) |
5 |
Interpretation:
• In general, the prognosis worsens as the grade increases.
• Bigger and Weld (1981) found that grade 4 arrhythmias had greater risk than grade 5 arrhythmias:
|
Grade |
Mortality Rate |
|
0 |
14% |
|
1 |
11% |
|
2 |
0% (only 2 patients) |
|
3 |
15% |
|
4A |
20% |
|
4B |
33% |
|
5 |
29% |
(Table 2, page 719, Bigger and Weld, 1981)
where:
• The R on T phenomenon is now considered especially dangerous only in the presence of acute ischemia.
Specialty: Cardiology
ICD-10: ,
