Læknablaðið : fylgirit - 01.06.1982, Page 28

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THE FREQUENCY OF VENTRICULAR ECTOPIC BEATS IN PATIENTS WITH
ESSENTIAL HYPERTENSIŒ, TREATED VJIIH THIAZIDES OR BETABLOCKERS.
Johann Raqnarsson, Thordur Hardarson, Snorri P. Snorrason,
Sigurdur Samuelsson. The Hypertension Clinic, Ihe Departments
of tfedicine, Reykjavik City Hospital and University Hospitals,
Reykjavik.
Hypokalemia is a common problem in diuretic treated pat-
ents. There is a general agreement regarding the need for
potassium supplementation in digitalis-treated patients. In
patients with essential hypertension and treated with diuret-
ics,the need for potassium supplementation is more contro-
versial, since little information is available about ventric-
ular irritability in those who develop hypokalemia.
We investigated the frequency of ventricular ectopic
beats by 24-hour ambulatory Holter monitoring in patients
with well controlled essential hypertension.
Ihe patients were all males who were randomised into
treatment groups. In one group (mean age 58.7 yrs), the
treatment was betablocker (metoprolol). Ihe other group
(mean age 58.3 yrs) was treated only with diuretic (bendro-
flumethiazide), and received either potassium supplementation
or potassium sparing diuretic. Serum potassium measurement was
obtained on the day of the ambulatory Holter monitoring.
Ventricular arrhythmias were classified according to Lown.
Results are shown in table I.
Table I
Class________________________0 I II III iVa IVb
B-blocker group (n=22) 10 9 1 2 0 0
Diuretic group (n=22) 571 6 1 2
Ihe mean serum potassium was 3.6 + 0.3 meq/1 in the diu-
retic group, but 4.1 + 0.2 meq/1 in the betablocker group.
P<0.01. Ihese results indicate that potentially serious
ventricular arrhythmias (9 pts versus 2 pts) are more corrmon
in diuretic-treated patients than patients on betablocking
treatment.
In the patients with the most frequent ventricular ectopic
beats (n 5) the mean serum potassium was 3.4 meq/1. All were
in group III or IV and on diuretic treatment.