The first heart sound in auricular and ventricular extrasystoles

The first heart sound in auricular and ventricular extrasystoles

i\RlEKICAN 630 IlJLkKT JOUKN.\I ‘l‘lw authors have collected forly cases. ‘l‘he age> {A the patirnth varied from 4 to 7.5 years. Amicular flutter ...

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i\RlEKICAN

630

IlJLkKT

JOUKN.\I

‘l‘lw authors have collected forly cases. ‘l‘he age> {A the patirnth varied from 4 to 7.5 years. Amicular flutter and fibrilla‘l‘he auricular form was more common in patients under 40 yearb. lion were more common in adults. The longest l)aroxysmnl etaI(s was ten years. ‘The synlptwl~s consistctl of: I I) palpitation, Organic lessness, and (3) in six, syncopal attacks.

independent of exertion, heart tli~t~asc 1~~s present

The electrocardiographic features consisted of: card& twenty-four cases; (2) repetitive aurirular fibrillation, one case; 13) repetitive nodal tachycardia, tachycdrdia, nine case%

(2) occasional breathin three patients only.

( 1 i repetitive auricular paroxysmal tachyfollr cases and repetitive aurirular t\vn Casey; and (4) repetitive vrntriculat

flutter,

It appears IO 1)~ The nature of this condition is unknown. systoles and ordinary paroxysmal tachycardia. It may be the in the conducting system. The prognosis is good: children tend Treatment is usually of no In adults also it tends to subside. but is usually ineffcctivr.

a connecting link between extraresult of a congenital peculiarity to grow out of it in adolescence. value. Quinidine ma>- be tried SOLOFF.

Cossio, I’., Lknbrosi, in Auricular and

H. G., Ventricular

and

Warnford-Thomson, Extrasystoles.

Rrit.

H. Heart

F.: The First J. 9:275 (Oct.),

Heart 1947.

Sn~rud

This study deals with the causes for the variation in intensity of the first sound of a premature beat. Thirty patients with extrasystoles were studied by means of simultaneous electrocardiographic and phonoc;lrdiographic records. Sixteen patients had arlricular and fourteen, ventricular extrasystoles. iluricrhr Extmsysto/es.--In all but one subject, the extrasystolic than the first sound of the preceding and the following normal heats. onset of QRS and the reinforced first sound varied from 0.05 to 0.08 beats or premature beats without reinforcement of the first sound, The greatest intensity and delay of the first heart sound occurred when systole was in mid-diastole, whereas the less intense sounds occurred tricular systolc was in early or very late diastole.

firht sound was louder The interval between the frond, while in the normal it was 0.03 to 0.05 second. the extrasystolic ventricular when the extrasystolic ven-

Ventriczhr ExtrasystoZes.-The extrasystolic first sound was louder than the normal first sound in nine, of equal intensity in one, of equal or less intensity in one, and of less intensity in three. The interval between the onset of QRS and the increased ventricular extrasystolic first sound was from 0.08 to 0.12 second, while in normal beats it was 0.03 to 0.06 second. Diminished extrasystolic first sounds occurred whenever the premature ventricular systole coincided with the descending limb of the ‘I‘ wave of the preceding cycle or fell just in front of the next P wave of sinus origin. Increased extrasystolic first sounds occurred whenever the premature ventricular systole fell just after the T wave or just after the normal 1’ wave. In four of fourteen cases a split first sound was recordrd in the, premat urc beats. The authors suggest the following explanac ion for these findings: Normally, the onset of a normal ventricular contraction finds the A-V valves in the position of almost complete closure. With premature contraction, the A-V valves are at a lower position; more time must elapse before Their closure, and their movement and, consequently, their vibration is increased. When the onset of premature ventricular extrasystole coincides with aln-icular systole of sinus origin or when a premature systole falls at the end of or immediately after the phase of rapid inflow, the first sound is intensified and delayed; when it falls before the end of the phase rapid inflow, because of incomplete ventricular filling, the valves are insufficiently stretched to intensify the first sound. The asynchronous contraction of the ventricles in prematllre ventricular contraction is the cause for the splitting of 1he first sound. The asynchronous closure of mitral and tricuspid valves also explains why ventrirlllar extrasystnles have a lower incidence of intensified first sound than auricular extrasystoles. SOLOFF.