Dependency of premature ventricular contractions on heart rate.
To identify a method for characterizing the dynamic behavior of ventricular arrhythmias at different heart rates, 201 consecutive patients with frequent premature ventricular contractions (PVCs) underwent two 24-hour electrocardiographic monitoring periods. The percentage of PVCs for each cycle length was calculated and then analyzed by linear regression analysis. On the basis of the significance of the p value, and the positive or negative value of the slope, we identified three trends: a tachycardia-enhanced pattern (p < 0.01, slope negative), a bradycardia-enhanced pattern (p < 0.01, slope positive), and an indifferent pattern (p > 0.01). During the first monitoring period, a tachycardia-enhanced pattern was present in 56 patients (28%), a bradycardia-enhanced pattern was present in 49 patients (24%), and an indifferent pattern was present in 96 patients (48%). This relationship was reproducible in 41 of the patients with a tachycardia-enhanced pattern (73%), in 29 of the patients with a bradycardia-enhanced pattern (59%), and in 70 patients with an indifferent pattern (72%). In conclusion, it is possible to identify a spontaneous trend between the incidence of ventricular arrhythmias and the length of the preceding cardiac cycle that seems to remain stable over time.
Pitzalis
M V
MV
Institute of Cardiology, University of Bari, Italy.
Mastropasqua
F
F
Massari
F
F
Passantino
A
A
Forleo
C
C
Luzzi
G
G
Totaro
P
P
De Nicolò
M
M
Rizzon
P
P
D000328:Adult; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D002908:Chronic Disease; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006339:Heart Rate; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013997:Time Factors; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*