Sympathetic overactivity and sudden cardiac death among hemodialysis patients with left ventricular hypertrophy.
BACKGROUND
We prospectively investigated whether cardiac autonomic imbalance is associated with sudden cardiac death (SCD) among a group of hemodialysis patients with left ventricular hypertrophy (LVH).


METHODS
In a prospective cohort study, we enrolled 196 asymptomatic patients on chronic hemodialysis who had LVH as determined by echocardiography and had undergone twenty-four-hour ambulatory Holter electrocardiography between dialysis sessions (males/females, 114/82; mean age, 65+/-12 years) to analyze heart rate variability. We calculated the percentage difference between adjacent NN intervals more than 50 ms (pNN50) and high-frequency component (HF, 0.15-0.40 Hz) as parameters of cardiac parasympathetic activity, and the low-frequency component (LF, 0.04-0.15 Hz)/HF component ratio as a parameter of sympathetic activity.


RESULTS
During 4.5+/-1.9-year follow-up, 21 patients who had undergone coronary revascularization within 60 days of enrollment were excluded from the analysis. Among the remaining 175 patients (male/female, 105/70; 66+/-12 years), SCD was recognized in 23 patients. On stepwise Cox hazard analysis, SCD was positively associated with age and LF/HF ratio, and tended to be inversely associated with pNN50. On Kaplan-Meier analysis, SCD-free survival rates at 5 years were 29.4% and 98.1% in patients with LF/HF ratios of 1.9 or more and below 1.9, respectively.


CONCLUSIONS
The presence of cardiac sympathetic overactivity may predict the occurrence of SCD in the asymptomatic hemodialysis patients with LVH.
Nishimura
Masato
M
Cardiovascular Division, Toujinkai Hospital, Kyoto, Japan. mnishimura@tea.ocn.ne.jp
Tokoro
Toshiko
T
Nishida
Masasya
M
Hashimoto
Tetsuya
T
Kobayashi
Hiroyuki
H
Yamazaki
Satoru
S
Imai
Ryo
R
Okino
Koji
K
Iwamoto
Noriyuki
N
Takahashi
Hakuo
H
Ono
Toshihiko
T
D000368:Aged; D000369:Aged, 80 and over; D001342:Autonomic Nervous System Diseases / Q000150:complications / Q000401:mortality / Q000503:physiopathology; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000209:etiology* / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000150:complications / Q000401:mortality* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects / Q000401:mortality* / Q000639:trends