Left ventricular diastolic filling in patients with coronary artery disease and normal left ventricular function

Abnormal left ventricular diastolic filling (DF) has been noted in coronary disease (CD) patients with normal left ventricular function (NLVF). Inclusion of patients with regional wall disease, hypertension, and left ventricular hypertrophy may be responsible for abnormal DF. We evaluated left ventricular DF curves derived from gated blood pool scans in 21 normals (group 1), in 38 CD patients with NLVF specifically defined (group 2), and in 28 CD patients with ejection fractions greater than 50% and regional disease (group 3). The peak filling rate (PFR), mean filling rate (MFR), the percentage of stroke volume filled at one third of diastole (%SV-1/3 DT) and at the end of the rapid filling period (%SV-RFP) were determined. Groups 1 and 2 had similar DF parameters. Group 2 patients with 75% obstructive left anterior descending disease (LAD) had a reduced %SV-RFP and PFR (2.56 +/- 0.56 end-diastolic volumes/sec [EDV/S]) as compared to normals (3.11 +/- 0.65 EDV/S, p less than 0.01). Group 3 patients had a reduced PFR (2.14 +/- 0.53 EDV/S, p less than 0.001), MFR, %SV-1/3 DT, and %SV-RFP. DF in CD patients with NLVF was similar to normals in a select group of patients but was abnormal in patients with regional disease and greater than 75% LAD disease with NLVF.

MDL 17,043 therapy in severe congestive heart failure: characterization of the early and late hemodynamic, pharmacokinetic, hormonal and clinical response

MDL 17,043, an agent with both inotropic and vasodilator properties, was evaluated in the treatment of chronic severe heart failure. The early and late hemodynamic, hormonal, pharmacokinetic and clinical responses to oral MDL 17,043 were studied in 20 patients. MDL 17,043 acutely increased cardiac output from 3.6 +/- 0.9 to 4.6 +/- 1.0 liters/min (+28%, p less than 0.001) and decreased mean pulmonary artery wedge pressure from 24 +/- 8 to 13 +/- 8 mm Hg (-46%, p less than 0.001), mean right atrial pressure from 10 +/- 5 to 4 +/- 4 mm Hg (-60%, p less than 0.001) and mean arterial pressure from 78 +/- 9 to 70 +/- 11 mm Hg (-10%, p less than 0.001). Hemodynamic improvement was sustained for 8 hours. Plasma renin activity tended to increase (0.10 less than p greater than 0.05), plasma norepinephrine tended to decrease (0.10 less than p greater than 0.05) and arginine vasopressin did not show any directional change. Elimination half-life for MDL 17,043 was approximately 20 hours. Hemodynamic responsiveness was maintained in six patients undergoing restudy at 4 weeks. Initial subjective improvement in the 20 patients occurred in 90%, was present at 4 weeks in 50% and continued longer than 3 months in 25%. Side effects occurred in 75% and required cessation of treatment in 10%. Thirteen (93%) of 14 patients on long-term therapy died (median time after start of MDL 17,043 therapy 39 days). Deaths were sudden in 69%. It is concluded that oral MDL 17,043 produces early and late hemodynamic improvement in patients with severe heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Investigation of genesis of gallop sounds in dogs by quantitative phonocardiography and digital frequency analysis

Several investigators have noted external gallop sounds to be of higher amplitude than their corresponding internal sounds (S3 and S4). In this study we hoped to determine if S3 and S4 are transmitted in the same manner as S1. In 11 closed-chest dogs, external (apical) and left ventricular pressures and sounds were recorded simultaneously with transducers with identical sensitivity and frequency responses. Volume and pressure overload and positive and negative inotropic drugs were used to generate gallop sounds. Recordings were made in the control state and after the various interventions. S3 and S4 were recorded in 17 experiments each. The amplitude of the external S1 was uniformly higher than that of internal S1 and internal gallop sounds were inconspicuous. With use of Fourier transforms, the gain function was determined by comparing internal to external S1. By inverse transform, the amplitude of the internal gallop sounds was predicted from external sounds. The internal sounds of significant amplitude were predicted in many instances, but the actual recordings showed no conspicuous sounds. The absence of internal gallop sounds of expected amplitude as calculated from the external gallop sounds and the gain function derived from the comparison of internal and external S1 make it very unlikely that external gallop sounds are derived from internal sounds.

Relation of intensity of cardiac sounds to age

The absolute intensity of the first (S1), third (S3), and fourth (S4) heart sounds (in mm Hg) and the relative intensity of S4 compared with S1 were measured in 146 normal persons, aged 8 to 91 years, using an infinite time-constant, calibrated pressure mechanocardiograph applied to the chest wall with a loading pressure of 400 mm Hg. The absolute intensity of S1 (r = 0.28) and S3 (r = 0.43) decreases with age, but the absolute intensity of S4 does not increase with age (r = 0.06). Therefore, the relative intensity of S4 compared with S1 increases with age (r = 0.31). This finding may explain the increased frequency of S4 in qualitative phonocardiograms in older persons.

Heart sound propagation in the human thorax

Simultaneous quantitative recordings of pressure in the aorta near a prosthetic valve and at two locations externally on the chest provide data on certain aspects of sound propagation in the human thorax. On the basis of the different speeds of propagation, it is possible to distinguish between the longitudinal and transverse vibrations contributing to the external phonocardiographic signal. Digital signal processing was employed to derive transfer functions, correlations and power spectra.

The third heart sound

A unitary concept is proposed to explain the genesis of the third heart sound and associated "rapid filling wave" of the apexcardiogram in physiological and pathological states including constrictive pericarditis. This theory not only clarifies the hitherto unexplained phenomenon such as presence of S3 in significant mitral stenosis, but also places in proper perspective the hemodynamic significance of S3 in physiological and various pathological states.

Long-term hemodynamic follow-up of cardiac transplant patients treated with cyclosporine and prednisone

To evaluate the long-term hemodynamic results in cardiac transplant patients treated with cyclosporine and prednisone, 19 patients were studied by cardiac catheterization and endomyocardial biopsy 13 +/- 3 months after transplantation. Immunosuppression consisted of 6 +/- 4 mg/kg/day cyclosporine and 20 +/- 8 mg/day prednisone. Eighteen patients were asymptomatic but had developed postoperative systemic hypertension (17 on antihypertensive therapy). These patients were compared with a normotensive control group of 18 patients without cardiovascular disease. Significant differences were found in heart rate; right atrial, pulmonary arterial, pulmonary arterial wedge, systemic arterial, and left ventricular end-diastolic pressures; cardiac index and stroke volume index; systemic and pulmonary vascular resistance; and end-diastolic volume index and left ventricular ejection fraction. The most frequent hemodynamic abnormalities included an elevated arterial pressure in 10 patients (56%), an elevated left ventricular end-diastolic pressure in six patients (33%), and a reduced ejection fraction in five patients (28%). Hemodynamic abnormalities tended to resolve or improve in the five patients restudied 2 years after transplantation. There was no significant relationship between fibrosis or inflammation on endomyocardial biopsy and hemodynamic abnormalities. We conclude that mild-to-moderate hemodynamic abnormalities are common in asymptomatic cardiac transplant patients receiving cyclosporine and prednisone.

Plasma vasopressin response to osmotic and hemodynamic stimuli in heart failure

Arginine vasopressin (AVP) regulation was studied in 42 patients with severe heart failure (CHF) and 10 patients without CHF during cardiac catheterization. Plasma AVP levels were elevated in CHF compared with non-CHF patients (2.98 +/- 2.48 vs. 1.01 +/- 0.44 pg/ml, P less than 0.01). In non-CHF patients, osmotic loading with angiographic contrast caused increases in plasma osmolality (283 +/- 4 to 290 +/- 5 mosmol/l, P less than 0.05) and AVP (1.01 +/- 0.44 to 1.79 +/- 0.20 pg/ml, P less than 0.001). In 10 CHF patients, similar osmotic loading produced an increase in plasma osmolality (275 +/- 13 to 288 +/- 17 mosmol/l, P less than 0.05) and an exaggerated rise in plasma AVP (3.61 +/- 3.17 to 16.30 +/- 12.17 pg/ml, P less than 0.001). The increase in plasma AVP per unit increase in osmolality was greater (P less than 0.01) in the CHF patients (1.36 +/- 1.25 pg . mosmol-1 . 1(-1)) than in non-CHF patients (0.18 +/- 0.17). To determine whether improved cardiac performance would lower AVP levels, 18 CHF patients received the experimental agent MDL 17,043, with improved cardiac index (1.9 +/- 0.4 to 3.3 +/- 0.7 1 . min-1 . m-2, P less than 0.001). Plasma AVP levels did not change significantly (1.99 +/- 0.74 to 2.81 +/- 2.06 pg/ml), but significant inverse correlations were found between changes in plasma AVP and changes in mean (r = -0.53) and systolic (r = -0.65) arterial pressure after MDL 17,043 infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypotension and sinus arrest with nifedipine in pulmonary hypertension

An adverse reaction to the acute administration of sublingual nifedipine is reported. Subsequent reversal was by intravenous administration of calcium chloride.

Echophonocardiographic estimates of pulmonary artery wedge pressure in mitral stenosis

The efficacy of noninvasive indexes for predicting pulmonary artery wedge (PAW) pressure was reviewed in 77 patients with mitral stenosis. M-mode echocardiography and phonocardiography were used to measure the aortic valve closure-mitral valve E-point interval (A2-E) and the electrocardiographic Q wave-mitral valve closure interval (Q-C) close to the time of diagnostic cardiac catheterization. During catheterization, in 65 patients PAW pressure was measured and in 12 left atrial (LA) pressure was measured. The A2-E and Q-C intervals taken alone had only modest correlation with PAW pressure (r = -0.54 and r = 0.46, respectively). The correlation was weakest in patients with atrial fibrillation and best in sinus rhythm when heart rate variation between invasive and noninvasive studies was within +/- 5 beats. Substitution of V-wave pressure for mean PAW pressure and correction for variation in blood pressure improved the A2-E correlation (r = -0.64), as did combining the A2-E and Q-C intervals into a ratio [(Q-C)/(A2-E)] (r = 0.62). However, the best results were obtained in patients where LA pressure was measured directly (r = -0.91 for A2-E), suggesting the PAW pressure is not always an accurate reflection of LA pressure. In conclusion, many factors in addition to LA pressure affect the Q-C and A2-E intervals which, in many situations, decrease their predictive value. However, if used appropriately, these intervals may allow an estimation of PAW pressure.

Modeling the isovolumic relaxation period

The isovolumic relaxation period of the left ventricular pressure curve in man has been assumed to be best represented by an exponential decay. To determine which model most closely approximates the empiric pressure data of isovolumic relaxation in man, several models were compared. They included linear, exponential with a zero mmHg pressure asymptote, exponential with a variable asymptote, and second-to fifth-order polynomials. In addition, four different methods of computing parameters of isovolumic relaxation by the exponential model with a variable asymptote were tested. It was found that the isovolumic relaxation period approximates an exponential, that the theoretic asymptote is variable, and that the Levenburg-Marquardt algorithm can be used efficiently to model this period.

Pattern of left ventricular diastolic filling in chronic aortic regurgitation: a gated blood pool assessment

Limited information exists regarding the pattern of left ventricular diastolic filling in moderate to severe chronic aortic regurgitation (AR). The left ventricular diastolic filling curve derived from gated blood pool scans was evaluated in 24 normal subjects and 29 patients with AR. The peak filling rate (PFR), mean filling rate (MFR), peak ejection rate (PER), PFR/MFR, PFR/PER, and the time of the rapid filling period divided by the diastolic time were determined. PFR, MFR and PER were calculated as end-diastolic volumes per second (EDV/s). PFR was lower in the AR group than in the normal subjects (2.24 +/- 0.70 vs 3.09 +/- 0.71 EDV/s, p less than 0.001). Similarly, MFR was lower in the AR group (1.31 +/- 0.40 vs 1.63 +/- 0.29 EDV/s, p less than 0.01). PER was also reduced in the AR group. Both PFR/MFR and PFR/PER were reduced, while the ratio of rapid filling period to diastolic time was longer in the AR group than in normal subjects. Clinical evidence of congestive heart failure occurred in 8 patients in the AR group. Diastolic filling variables were not significantly different from the asymptomatic subgroup of patients with AR, but were abnormal when compared with those of normal subjects. In patients with AR, an abnormal pattern of diastolic filling was noted, consisting of a reduced PFR, MFR and PFR/ with a more linear pattern of filling (reduced PFR/MFR) during a longer rapid filling period.

Acute hemodynamic effect of oral MDL 17,043 in severe congestive heart failure

MDL 17,043, when administered intravenously in humans, produces a significant and salutary hemodynamic response. To determine its acute effect when administered orally (3 mg/kg), 10 patients with severe congestive heart failure were studied by right-sided cardiac catheterization for 8 hours. At 4 hours after drug ingestion, there was significant improvement in several hemodynamic measurements. Cardiac index increased 38% over baseline (from 1.9 +/- 0.4 to 2.6 +/- 0.4 liters/min/m2, p less than 0.01), arteriovenous oxygen difference decreased by 30% (from 8.0 +/- 1.4 to 5.6 +/- 1.2 vol%, p less than 0.01), heart rate increased by 8% (from 85 +/- 16 to 92 +/- 16 beats/min, p less than 0.05), stroke volume index increased by 22% (from 23 +/- 5 to 28 +/- 4 ml/beat/m2, p less than 0.05), left ventricular stroke work increased by 24% (from 18 +/- 5 to 22 +/- 5 g-m/m2, p less than 0.01), mean arterial pressure decreased by 10% (from 79 +/- 6 to 71 +/- 9 mm Hg, p less than 0.01), mean right atrial pressure decreased by 40% (from 10 +/- 5 to 6 +/- 4 mm Hg, p less than 0.01), and mean pulmonary artery wedge pressure decreased by 36% (from 22 +/- 5 to 14 +/- 6 mm Hg, p less than 0.01). Cardiac index, arteriovenous oxygen difference, mean arterial pressure, right atrial pressure, and pulmonary artery wedge pressure remained significantly improved at 8 hours. These findings indicate that MDL 17,043 is active when administered orally and produces beneficial hemodynamic effects for as long as 8 hours.

Subacute stress induced by sumithion on certain biochemical parameters in Oziotelphusa senex senex, the fresh-water rice field crab

Healthy crabs (Oziotelphusa senex senex) were exposed to 3 concentrations of sumithion, with a control group over a 30-day period. The glycogen content of the hepatopancreas was depleted on acute exposure but was elevated after acclimatization. The glycogen phosphorylase activity was elevated on acute exposure, whereas phosphorylase activity decreased after acclimatization. The increase in phosphorylase activity and the decrease in glycogen content indicated increased glycogenolysis at tissue level after acute exposure but on acclimatization the tissue glycogenolysis appeared to be suppressed. Sumithion was found to decrease the activity levels of SDH and MDH and to elevate LDH. The increase in LDH and the decrease in SDH and MDH in the hepatopancreas indicated the development of anaerobic conditions at tissue level in the stressed crabs. In general, acclimatization to a toxic solution seems to result in the elevation of the synthetic phase of carbohydrate metabolism.

The in vivo inhibition and recovery of acetylcholinesterase in the thoracic ganglionic mass of the freshwater rice field crab (Oziotelphusa senex senex) during and after exposure to sumithion

The freshwater crab (Oziotelphusa senex senex) showed a dose-dependent inhibition of thoracic ganglionic mass acetylcholinesterase (AChE) activity during 48 h of exposure to 1, 2 and 4 ppm of sumithion. A progressive recovery of AChE activity from sumithion-induced inhibition was observed in this tissue within 15 days after transferring the crab to toxicant-free clean water.

Intermittent mitral regurgitation due to Beall valve dysfunction: analysis of 13 patients with atrial fibrillation

A unique hemodynamic event was noted in long-term survivors of mitral valve replacement with the Beall prosthesis. The event was a result of intermittent valve dysfunction and transvalvular mitral regurgitation (MR). At cycle lengths longer than 0.9 second that were preceded by shorter cycle lengths, 8 of 13 patients with Beall valve prostheses who had chronic atrial fibrillation (AF) intermittently had a marked unexpected decrease in peak left ventricular systolic pressure and a simultaneous increase in left atrial or pulmonary artery wedge "v" wave pressure. This event, which is a result of intermittent, severe MR, occurred more frequently at longer cycle lengths. In all 8 patients with the finding, severe valve disc wear was found at operation; however, 5 of these patients had only trace or 1+ MR on left ventricular angiography. In contrast, the event did not occur in 11 patients in chronic AF with organic MR or non-Beall valve MR, despite an appropriate number of sufficiently long cycles. The absence of the event in 5 Beall valve patients with significantly faster heart rates than in those with the event may in part be a result of its dependence on cycle length. This hemodynamic event, when present in a Beall valve recipient in AF, is an indication for valve replacement, even in the absence of angiographic evidence of severe MR.

The hemodynamic effects of intravenous verapamil in patients on chronic propranolol therapy

Concern exists regarding the negative inotropic and chronotropic effects of verapamil given to patients receiving chronic propranolol therapy. In order to evaluate the safety of combined therapy, the hemodynamic effects of verapamil were investigated in a group of 19 patients on chronic propranolol therapy undergoing cardiac catheterization. Hemodynamic measurements and left ventriculography were performed prior to and 30 minutes after initiation of intravenous administration of verapamil. Verapamil doses varied from 0.025 mg/kg to 0.1 mg/kg intravenous bolus injection followed by an infusion of 0.005 mg/kg/min. Following verapamil administration, systolic, diastolic, and arterial mean pressures and systemic vascular resistance decreased significantly. There was no significant change in left ventricular end-diastolic pressure, mean pulmonary capillary wedge pressure, cardiac index, arteriovenous oxygen difference, heart rate, mean velocity of circumferential fiber shortening (VCF), end-diastolic volume index, end-systolic volume index, stroke volume index, and ejection fraction (EF). Stroke work index decreased significantly. Lack of improvement in cardiac index, VCF, and EF and decrease in stroke work index in spite of constant filling pressure and decreased afterload suggest the additive negative inotropic action of verapamil. The depressant action of propranolol itself was not determined by this study. In spite of the negative inotropic effect of verapamil, it can be administered acutely to patients who have been on propranolol therapy with relative safety if the propranolol has not already produced severe left ventricular dysfunction, relative hypotension, bradyarrhythmia, or conduction abnormalities.

Effect of sublethal concentrations of sumithion on limb regeneration of fresh water field crab Oziotelphusa senex senex

The initiation and progress of regeneration following the removal of the left 4th walking leg were altered in the crab (Oziotelphusa senex senex) by exposure to sumithion. Depending on the concentration used, sumithion caused a complete inhibition of regeneration, a delay of initiation of limb bud development or a reduction of limb bud growth rate. Crustacean limb regeneration can also be used as a sensitive bioassay for studying the effects of environmental pollutants.

Tissue sites of aromatization in the female rhesus monkey

Nine female rhesus monkeys (four in the follicular and five in the luteal phases of their cycles) had catheters implanted and were infused iv with [7-3H]androstenedione (A) and [4-14C]estrone (E1) for 4 h. Blood samples were drawn at intervals from the hepatic, renal, jugular, uterine, and brachial veins and the femoral artery. The samples were analyzed for radioactivity as A and E1. The mean +/- SE MCRs for A and E1 were 280 +/- 40 and 270 +/- 30 liters/day, respectively. The mean extractions across the liver measured in six of the monkeys were 0.83 +/- 0.03 for A and 0.71 +/- 0.06 for E1. The percentage of A entering each tissue, which was measured as E1 leaving the tissue (pA,E1AV), was 0.20 +/- 0.10 for splanchnic, 0.21 +/- 0.11 for renal, 0.46 +/- 0.21 for jugular, 2.36 +/- 1.27 for arm, and 0.35 +/- 0.10 for uterine veins. Because of the sampling technique, the value for the uterus may be a reflection of ovarian blood admixture with uterine blood. There were no apparent differences in tissue aromatization between values in the follicular and luteal phases of the cycle. The overall mean value for the percentage of A infused and measured as E1 in arterial blood (pA,E1BB) was 1.01 +/- 0.38%. Using previously reported tissue blood flow, we calculate that the contributions to the overall aromatization rate of tissues drained by the brachial, renal, jugular, hepatic, and uterine veins are 23%, 5%, 5%, 4%, and 0.2%, respectively. Thus, the splanchnic tissue is a minor site for extraglandular aromatization of androgens in the rhesus monkey. An important site appears to be the arm, which reflects aromatization in adipose tissue, muscle, skin, and supporting structures.

In vivo acute physiological stress induced by BHC on hemolymph biochemistry of Oziotelphusa senex senex, the Indian rice field crab

Indian rice field crabs, exposed to a lethal concentration (LC50/24 h = 39 mg/l) of benzene hexachloride (BHC) to study acute toxic effects, showed changes in hemolymph glucose and protein. The effect of BHC resulted in hyperglycemia and hyperproteinemia.

Muscle nitrogen metabolism of freshwater crab, Oziotelphusa senex senex Fabricius, during acute and chronic sumithion intoxication

Muscle nitrogen metabolism was studied in the crab, Oziotelphusa senex senex Fabricius, following acute (1 day) and chronic (20 days) exposure to 0.1 ppm sumithion solution. Proteolysis in the muscle tissue in acute exposure was increased after exposure for 24 h. The muscle tissue of chronically exposed crabs seemed to develop a more efficient mechanism for the detoxication of ammonia compared with that of acutely exposed crabs. The survival of crabs after chronic sumithion intoxication has been attributed to adaptive changes involving protein synthesis and the metabolism of ammonia.

The acute hemodynamic effects of a new agent, MDL 17,043, in the treatment of congestive heart failure

MDL 17,043 administered intravenously or orally exerts positive inotropic and vasodilator actions in experimental animal preparations. We studied its acute hemodynamic effects in 15 patients with severe congestive heart failure by right-heart catheterization. Intravenous MDL 17,043 at 10 minutes increased cardiac index (3.4 +/- 0.8 vs 1.9 +/- 0.4 l/min/m2), narrowed arteriovenous oxygen content difference (4.6 +/- 0.8 vs 7.8 +/- 2.0 vol%), increased heart rate (98 +/- 14 vs 89 +/- 18 beats/min), and decreased systemic arterial (67 +/- 10 vs 83 +/- 11 mm Hg), pulmonary capillary wedge (12 +/- 5 vs 24 +/- 5 mm Hg) and right atrial (6 +/- 5 vs 12 +/- 7 mm Hg) mean pressures significantly (p less than 0.001). In 11 patients, hemodynamics were monitored hourly for 6 hours. Compared with baseline, the cardiac index and heart rate were higher and mean systemic arterial pressure was lower for 6 hours; pulmonary capillary and right atrial mean pressures were significantly lower for 5 hours. No serious arrhythmias or side effects occurred. These data suggest that MDL 17,043 may be useful for treating congestive heart failure.

Skeletal scintigraphy in carcinoma of the kidney

The scintigrams and radiographs of 32 patients with renal carcinoma were reviewed. False negative skeletal scintigrams were observed in four of 12 symptomatic patients with proven skeletal metastases from carcinoma of the kidney. A negative scintigram therefore does not exclude the possibility of skeletal metastases in this condition.

Chronic sumithion toxicity: effect on carbohydrate metabolism in crab muscle

Chronic sumithion toxicity in experimental crabs was induced by exposing them for 15 and 30 days to 0.04 ppm sumithion solution. The enzymes concerned with glycogenolytic metabolism (phosphorylase), glycolytic metabolism (aldolase), aerobic metabolism [succinate dehydrogenase (SDH), malate dehydrogenase (MDH)], anaerobic metabolism, lactate dehydrogenase (LDH) and alanine amino transaminase (AIAT)], were assayed in the muscle of control and experimental crabs. Glycogen, pyruvic acid, lactic acid were also estimated in the muscle of both control and experimental crabs. The muscle tissue of chronic sumithion-exposed crab exhibited suppressed glycogenolysis and glycolysis with an onset of gluconeogenesis. In general, chronic sumithion exposure seems to result in an elevation of the synthetic phase of muscle carbohydrate metabolism.

Hyperglycemia in the fresh water field crab (Oziotelphusa senex senex) produced by a pesticide (BHC)

Hyperglycemia, Oziotelphusa senex senex, Hyperglycemic Hormone, Hexachlorocyclohexane (BHC) Benzene hexachloride (1,2,3,4,5,6-hexachlorocyclohe-xane) (BHC) produced a significant increase in the hemolymph sugar level of intact crabs. Oziotelphusa senex senex, apparantly by triggering release of the hypergly­ cemic hormone (HGH).

Anterior keratotomy

Anterior keratotomy was analyzed in 200 myopic eyes. The cases were followed postoperatively every day for two weeks, thereafter at weekly intervals for about four months followed by monthly intervals for the rest of the period. There is 51% improvement in the visual acuity during the first week after the surgery. Thereafter up to the period of three months it is observed that 40% of the cases only retain 6/6 visual acuity, as a result of reduction of corneal flatness. This fall of vision in these cases is proportional to the degree of corneal flatness. There is no change in the field of vision. There is no change of accommodation and convergence, there is no change in the corneal thickness and the operation is useful in only 40% of cases.

High-fidelity, infinite time constant calibrated pressure apexcardiogram and its correlation with high-fidelity left ventricular pressure

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