Q-second sound interval in acute myocardial infarction.

Abstract

In clinical practice an objective measurement of cardiac function is desirable in following patients with acute myocardial infarction. Jegek (1963) and Weissler, Harris, and Schoenfeld (1968) have suggested that the Q-S2 time interval expressed as a fraction of the cardiac cycle length may be of value in the assessment of cardiac function. We have measured this interval in a series of normal patients and in those who have had a myocardial infarction. The purpose of this paper is to evaluate the practical value of this measurement. SUBJECTS AND METHODSOne hundred normal subjects and 20 patients who had had acute myocardial infarction were studied. The normals consisted of 69 men and 31 women between the ages of 31 and 70. Clinical examination, electrocardiogram, and chest x-ray were done in each case. A group of 3 normal controls was studied daily for 10 days before and after exercise to note any deviation of Q-S2 interval from the normal range.The patients with acute myocardial infarction were included if they showed the typical signs of acute myocardial infarction with chest pain, diagnostic changes in electrocardiogram, and elevation of serum lactic dehydrogenase. Patients with bundle-branch block on the electrocardiogram were excluded from this study.The patients were grouped clinically according to absence (Group I) or presence (Group II) of cardiac abnormalities, including the presence of a third heart sound, cardiomegaly, and pulmonary congestion. The maximum level of serum lactic dehydrogenase rise was also recorded.The electrocardiogram and phonocardiogram were recorded simultaneously on 3-channel Elema Schonander Mingograph recorder at a paper speed of 100 mm./ sec. Two electrocardiographic leads were used to determine the onset of ventricular depolarization as one lead only could be misleading, as illustrated in Fig. 1. The crystal microphone was placed in the position which clearly showed the onset of initial high frequency vibrations of the first and second heart sounds. The Q-S2 interval was measured from the onset of Q wave to the onset of aortic component of the second heart sound, which was taken as the beginning of first high frequency vibrations. Five consecutive cycles were measured in each tracing and averaged. The measurements were made during held quiet expiration in the supine position. The records in which the onset of ventricular depolarization or onset of second heart sound was not clear were discarded.The patients were studied daily at a fixed time from 440 m.sec. 420 m. sec. 462 -1 Il 52 FIG. 1.-Simultaneous phonocardiogram and two leads of electrocardiogram, showing the value of recording two leads of electrocardiogram in measurement of Q-S2 interval.

Systolic Time Intervals in Acute Myocardial Infarction

“…On the 21st day the values were approximately the same as on the 1st day. These findings are in agreement with several other studies (1, 3, 4, 6, 8, 10, I I , 13,14,15,16). QS2 and especially LVET have been found to be correlated to stroke volume (6).…”

“…In our patients with AMI, we found a strong correlation between LVET and HBDH serum levels. Another study has shown good correlation between QS2 and the LDH level in serum (14). The rise in HBDH has been shown to be in direct relationship to the development of heart failure and cardiogenic shock (2).…”

“…In patients with AM1 there is an excellent correlation between left ventricular ejection time (LVET) and stroke volume (6). A lot of investigators have used STI in the evaluation of patients with AM1 ( I , 3 ,4 ,6 ,8 ,9 ,10,I I ,13,14,IS,16).…”

Effect of isocapnic hypoxia on systolic time intervals in conscious man.

“…The indices determined using these methods are primarily measures of left ventricular performance (Weissler et al, 1969;Lewis et al, 1976). Though STI have limited use in differential diagnosis, they serve to quantify the effects on the cardiovascular system of various pharmacological interventions (Harris et al, 1966(Harris et al, , 1967 or disease states (Weissler et al, 1968;Toutouzas et al, 1969;Lewis et al, 1976), as multiple observations in the same individual are possible.…”

Χρονικες Φασεις Της Συστολικης Περιοδου Της Αριστερας Κοιλιας Επι Κολποκοιλιακου Αποκλεισμου Προ Και Μετα Ηλεκτρικην Βηματοδοτησιν Της Καρδιας

“…Εις τους ασθενείς εκείνους, ο'ΐτινες εμφανίζουν ήλαττωμένην καρδιακήν παροχήν, ό βαθμός τών μεταβολών του χρόνου εξωθήσεως και τής προεξωθητικής περιόδου τής αριστεράς κοιλίας είναι ανάλογος προς τον βαθμόν ελαττώσεως τοϋ όγκου παλμοΰ και τής καρδιακής παροχής. Έπί μικράς ελαττώσεως τής καρδιακής παροχής και τοϋ όγκου παλμού αί πΐχρατηρούμεναι μεταβολαί τών ώς άνω δύο χρονικών φάσεων τοϋ καρδιακού κύκλου είναι μικρού βαθμού, ενώ επί σοβαράς πτώσεως τής παροχής και τοϋ όγκου παλμοΰ αύται είναι έκσεσημασμέναι 55 , 56 .…”