The 'A' wave of the apex cardiogram in aortic valve disease and cardiomyopathy

Effect of cardioselective beta-blockade on heart function and chest pain in acute myocardial infarction

Systolic time intervals and the a/H ratio were recorded in 20 patients with uncomplicated acute myocardial infarction over a period of five days. The initial high heart rate and systolic blood pressure and the short PEP and ICT indicating a sympathetic overactivity were spontaneously normalized during the first week of infarction. LVET was reduced indicating a fall in stroke volume and the a/H ratio was unchanged at the high levels suggestive of elevated preload or LVEDP. In 10 patients with acute myocardial infarction and recurrent chest pain recordings on noninvasive parameters were made before and 30 min after intravenous injection of practolol. In addition, 7 patients with chest pain, classified as acute myocardial infarction, were given practolol. The average dose of practolol was 17.9 mg ranging from 5 to 30 mg. An almost immediate and pronounced relief of pain was observed in all patients and no signs of impaired left ventricular function appeared. The product of systolic blood pressure and heart rate was decreased by practolol and the PEP and the ICT were prolonged to normal values while no changes were seen in LVET and a/H ratio. On 126 occasions practolol was given in dosages ranging from 5 to 30 mg (mean 8 mg) to 75 patients with acute myocardial infarction and recurrent chest pain. A satisfactory pain relief was seen on 108 occasions. It is suggested that an inappropriate sympathetic overactivity is an important factor in provoking recurrent chest pain in acute myocardial infarction. Administration of the beta-adrenergic blocking agent practolol resulted in pain relief due to reduction of heart work and in severity of myocardial ischemia. The beta-blocking agent was well tolerated in the present study. Continuous beta-blockade during the whole hospital stay to patients with acute myocardial infarction seems to be a very attractive therapy in order to preserve the ischemic myocardium and limit the size of infarction.

Noninvasive assessment of cardiac motion: comparison of the apexcardiogram and cardiokymorgram

The apexcardiogram (ACG) and cardiokymogram (CKG) (displacement cardiogram) tracings were compared in 45 patients with a variety of cardiac diseases and in 16 normal subjects. The ACG and CKG were generally comparable in waveform and timing of standard tracing intervals; however, on a case by case comparison frequent discrepancies between the ACG and CKG were observed. In 13 patients where no ACG could be recorded, an interpretable CKG tracing was obtained. However, the CKG produced frequent artifacts, mirror images, was very sensitive to probe position, and was judged to be of limited advantage over the ACG.

Use of apexcardiography to evaluate left ventricular diastolic compliance in human beings

The relation between various relative amplitude measurements of the left apexcardiogram and internally derived indexes of diastolic compliance of the left ventricle was studied in 29 patients. Simultaneous high fidelity recordings of the left apex tracing and left ventricular pressure were obtained in 11 patients without left ventricular disease (group I) and 18 patients with congestive cardiomyopathy (group II). In 204 normal subjects the ratio of the A wave amplitude to the total diastolic deflection (A/D ratio) of the left apexcardiogram was 31.4 +/- 11.4 (mean +/- standard deviation) percent, the ratio of the A wave amplitude to the total height (A/H ratio) 8.9 +/- 4.3 percent and the D/H ratio 30.4 +/- 14.7 percent. The A/D and A/H ratios were significantly (P less than 0.001 and P less than 0.005) increased in group II (69.2 +/- 12.2 percent and 16.8 +/- 8.2 percent, respectively); they were within normal limits in group I. In contrast, the D/H ratio was within normal limits in both groups of patients. The A/D ratio correlated significantly better with specific compliance (deltaV/deltaP.V) (r = -0.87) than did the A/H ratio (r = -0.53), whereas similar correlations were obtained with end-diastolic volume compliance (dV/dPV) (r = -0.61 and r = - 0.64, respectively). In contrast, the D/H ratio correlated significantly only with end-diastolic distensibility index (dV/dP) (r = -0.52). It is concluded that A wave amplitude/total diastolic deflection (A/D) ratio and, to a lesser degree, the A wave amplitude/total height (A/H) ratio of the left apexcardiogram correspond best to diastolic compliance and are useful noninvasive measurements of this property of the left ventricle.

Measurement of diastolic events by apexcardiogram: correlation with hemodynamic state and prognosis after myocardial infarction

Apexcardiograms and hemodynamic studies were performed in 32 postmyocardial infarction patients. Group 1 patients (5) had markedly elevated left ventricular end diastolic (LVED) pressures but normal LVED volumes; apexcardiograms included tall A waves (31 percent of the E to O points), prolonged A-wave durations of 134 msec or greater, short rapid filling wave durations (55 msec) and slow-filling waves replaced by plateaus in three patients. Group 2 patients (10) had markedly elevated LVED pressures and elevated LVED volumes, and had similar apexcardiographic findings: A-wave heights had a mean of 23.4 percent of E to O points, A-wave durations were 113 msec or more, rapid filling wave (RFW) durations were 93 msec and diastolic plateaus occurred in five patients. Group 3 patients (11) had intermediate hemodynamic findings and the apexcardiograms were varied; three patients with mild congestive heart failure (CHF) had apexcardiograms similar to Group 1 and five without CHF had apexcardiograms similar to those in Group 4. Group 4 patients (6) had normal hemodynamic findings; the mean A-wave height was 6 percent of the E to O point height, A-wave durations 90 msec or less RFW durations were 117.5 msec or more and the slow-filling wave duration (SFW) was normal in the configuration. Fourteen of 15 patients in Groups 1 and 2 developed CHF and six died on follow-up. Group 4 patients showed no evidence of CHF on follow-up and there were no deaths. Group differences were significantly different for A-wave height and duration, and for RFW duration at 0.05 or 0.01.Tall prolonged A waves and short RFWs were associated with poor left ventricular (LV) compliance and dysfunction, and diastolic plateau immediately following the RFW when present were confirmatory. Thus, the apexcardiogram is a reproducible useful noninvasive tool for clinical assessment, and predicting prognosis in postmyocardial infarction patients.

Relationship between duration of systolic upstroke of apexcardiogram and internal indexes of myocardial function in man

In 11 patients with nonobstructive cardiomyopathy and coronary heart disease and decreased myocardial function of the left ventricle, as well as in nine patients without left heart valvular or myocardial disease, left apexcardiograms were recorded during diagnostic heart catheterization, wherein micromanometers were used; ACG's were registered additionally in 54 healthy volunteers in order to establish the normal range of apexcardiographic parameters. In all cases the apex tracings were recorded by means of a pulse transducer with infinite time constant. The most important finding of this study was the close correlation between the duration of the systolic upstroke (SUT) of the apex tracing and some accepted isovolumic indexes of left heart function (isovolumic contraction time, time interval from the onset to peak of the first derivative of left ventricular pressure, maximal value of the first derivative of left ventricular pressure, and the peak measured velocity of shortening of the contractile elements). Further, the mean value of SUT in patients with impaired left myocardial function was significantly prolonged, compared to the control subjects; an overlap was apparent due to the fact that some of these patients showed a normal left myocardial performance at rest, having an abnormal response only to exercise tests. The apexcardiographic SUT can practically always be measured when the first derivative of apex tracing is simultaneously recorded. It showed itself to be only slightly influenced by the resting heart rate. The mentioned relationship of the systolic upstroke time of the ACG to internal isovolumic indexes of myocardial function makes this noninvasive measurable parameter an additional excellent tool for the evaluation of the left myocardial state, thus supporting a new aspect of the value of quantitative apexcardiography.

Effect of chronic beta-adrenergic receptor blockade in congestive cardiomyopathy

Adrenergic beta-blocking agents were given to 7 patients with advanced congestive cardiomyopathy who had tachycardia at rest (98 plus or minus 13 beats/min). The patients were on beta-adrenergic receptor blockade for 2 to 12 months (average 5-4 months). One patient was given alprenolol 50 mg twice daily and the other patients were given practolol 50 to 400 mg twice daily. Virus infection had occurred in 6 of the patients before the onset of symptoms of cardiac disease. All patients were in a steady state or were progressively deteriorating at the start of beta-adrenergic receptor blockade. Conventional treatment with digitalis and diuretics was unaltered or reduced during treatment with beta-blocking agents. An improvement was seen in their clinical condition shortly after administration of the drugs. Continued treatment resulted in an increase in physical working capacity and a reduction of heart size. Noninvasive investigations including phonocardiogram, carotid pulse curve, apex cardiogram, and echocardiogram showed improved ventricular function in all cases. The present study indicates that adrenergic beta-blocking agents can improve heart function in at lease some patients with congestive cardiomyopathy. Furthermore, it is suggested that increased catecholamine activity may be an important factor for the development of this disease, as has been shown in animal experiments.

The apical A wave versus the fourth heart sound in assessing the severity of aortic stenosis

The height of the "a" wave of the apexcardiogram was evaluated as a marker for critical aortic stenosis in patients over 40. Critical aoritc stenosis was defined as an aortic valve area less than .75 cm-2 with no more than mild aortic insufficiency. Phonocardiograms and apexcardiograms were performed on 72 patients with catheterization proven aortic stenosis and on 14 normal controls, all over age 40. The height of the "a" wave of the apexcardiogram was measured as a percentage of the e to o excursion (a/e-o). Fourth heart sound gallops ( S4G) were recorded in 71% (11 of 14) of normal controls, 86% (6 of 7) of patients with less than critical aortic stenosis, and 85% ( 55 of 65) of patients with critical aortic stenosis. The a/e-o was less than 16% in all normals or patients with less than critical aortic stenosis. The a/e-o exceeded 16% in 45% (29 of 65) with critical aortic stenosis. Audibility of the S4G bore no relationship to recordability, apical "a" wave geight, or the severity of the aortic stenosis. In conclusion, therefore, we believe that when one is confronted with findings suggestive of aortic stenosis, the finding of a palpable apical "a" wave (or an "a" wave height of greater than 16% of the total complex on the apexcardiogram) is an important positive feature, suggesting severe aortic stenosis. Its absence, however, does not exclude severe valvar obstruction. Probably because of auscultatory inaccuracy in this condition, the apparent presence or absence of an S4G has not been of much aid in this evaluation. This sound, however, might be more useful in a carefully performed prospective study.

The A wave of the apexcardiogram and left ventricular diastolic stiffness

This study was made to determine whether the A wave of the apexcardiogram (ACG), a reflection of the late diastolic response of the left ventricle to atrial systole, corresponded in a quantifiable way to left ventricular late diastolic stiffness (LVDS). Using a combined ultrasonic and hemodynamic technique, the slope of the late diastolic left ventricular pressure/diameter relationship (ΔP/ΔD) was calculated in 25 patients and used as a measure of effective LVDS. Most patients had valvular heart disease, all were in sinus rhythm and none had regional abnormalities of contraction. An ACG was recorded in all and the ratio of the size of the A wave to the total amplitude of the ACG wave (A/H) was calculated. When A/H was more than 11%, left ventricular hypertrophy (LVH) and the presence of a fourth heart sound were the rule in the group of patients studied.

Using A/H as an independent variable, correlation coefficients were obtained for ΔP, ΔD, ΔP/ΔD, left ventricular end diastolic pressure (LVEDP), and left ventricular end diastolic volume (LVEDV). Correlation coefficients ( r ) were: ΔP = 0.68; ΔD = –0.05; ΔP/ΔD = 0.87; LVEDP = 0.73; LVEDV = 0.21. It is concluded that A/H corresponds best to LVDS and is a useful noninvasive measurement of this property of the left ventricle.

The apexcardiogram in ischemic heart disease

The apexcardiogram (acg), when recorded serially in patients with acute myocardial infarction (ami), preinfarction angina (pia) and stable ischemic heart disease (ihd), appeared to reflect the abnormal patterns of contraction of the left ventricle in these conditions. Thus, paradoxical bulging (dyskinesis) of the systolic wave or increased "a" wave amplitude with gradual recovery over several weeks was found in all 60 patients with documented ami and in 18 of 20 patients with pia. Electrocardiogram changes were noted, however, in only eight of the pia patients. Changes in the acg frequently antedated ischemia in the ecg. Paradoxical bulging of the systolic wave of the acg was additionally noted in patients during the pain of angina pectoris but this promptly disappeared after the administration of nitroglycerine. Patients with classic angina often had normal resting ecg's but abnormal resting acg's. In contrast to the relatively transient abnormalities noted above, the acg remained unchanged in most patients with stable ihd during follow-up of three months to two years. Patients undergoing coronary bypass operations, however, showed immediate improvement in the acg in the postoperative period. These results suggest the acg reflects the contractile pattern of the left ventricle, and may be an indirectly recorded ventriculogram. Its enhanced sensitivity and the earlier development of changes in comparison to the ecg make this a valuable tool in the study of patients with heart disease.

Apex cardiogram and systolic time intervals in acute myocardial infarction

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Electromechanical correlation of leftatrial function after cardioversion

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The Austin Flint murmur and the a wave of the apexcardiogram in aortic regurgitation

Hemodynamic data from 45 patients with either aortic regurgitation (with and without the Austin Flint murmur) or aortic regurgitation and mitral stenosis were correlated with the a -wave percentage amplitude of the apexcardiogram. Changes in the a wave correlated well with corresponding changes in left heart pressures but not with variations in volume. Of 15 patients in whom the ratio of the a wave to the total excursion during systole ( a /H ratio) was [See Equation in PDF file]13%, 11 had left ventricular end-diastolic pressures (LVEDP) >20 mm Hg. All patients with a /H ratios >15% had abnormal LVEDP. The converse was not true; 13 patients had elevated LVEDP with normal a /H ratios. Patients with aortic regurgitation and mitral stenosis had a /H ratios similar to those of normal subjects.

The Flint murmur showed a significant correlation with left ventricular volume changes. Its presence was valuable in prediction of a large regurgitant volume and a high left ventricular stroke volume. It was also present in association with elevated left atrial mean pressure and elevated LVEDP.

Thus, two ancillary findings in aortic regurgitation, a high a wave in the apexcardiogram and the Austin Flint murmur, are of value in anticipating alterations in left ventricular hemodynamics as determined by left-sided catheterization and volume studies.

The use of apexcardiography in the assessment of left ventricular diastolic pressure

A total of 58 observations of simultaneous left ventricular pressure and apex-cardiograms (ACG) was made on 18 patients. An a wave percentage amplitude (aWPA) of greater than 15% of the total deflection of the ACG indicated an increase in left ventricular end-diastolic pressure (LVEDP). In 12 observations on six patients, an aWPA of less than 15% was associated with a high LVEDP. Patients with high LVEDP and aWPA of less than 15% had a high early left ventricular diastolic pressure with further rise in pressure prior to atrial contraction. These patients had small LV a waves ("atrial kick"). The aWPA of the ACG correlated better with the magnitude of the LV a wave than the absolute level of LVEDP in all patients. Correlation was good between changes in aWPA and changes in LVEDP in individual patients; but the ACG as an indirect means of evaluating left ventricular function is limited by the fact that elevations in LVEDP can exist in the presence of a normal aWPA. The ACG is a complex tracing reflecting not only intracardiac pressures, but changes in left ventricular volume, compliance, position, and perhaps left atrial function as well.