Assessment of cardiovascular risk: a return to basics.
Explore the source record for details and available documents.
Coronary Disease↗
Biomedical subjects
W K Laskey
Publications and source records attributed to W K Laskey.
Prolonged heparin therapy for occlusive intracoronary thrombus.
The presence of intracoronary thrombus is associated with increased complications during coronary angioplasty. Such thrombus may also mimic the appearance of a critical stenosis. We report a case of nearly occlusive intracoronary thrombus which resolved after prolonged heparin therapy, revealing only a minimal underlying stenosis. The recognition and treatment of this entity is discussed.
Coronary Angiography↗
Intravascular ultrasonographic assessment of the results of coronary artery stenting.
We studied 12 patients undergoing elective coronary stent implantation for either recurrent restenosis or adverse lesion appearance. By use of a 4.8F 20 MHz intravascular ultrasound catheter, the conventional angioplasty site was examined before and after coronary stent implantation. Quantitative angiographic analysis revealed the expected excellent final result with a group mean poststent diameter reduction of 14 +/- 9% and a cross-sectional area reduction of 22 +/- 13%. Angiographic analysis also indicated an increase in minimum stenosis diameter from 1.8 +/- 0.6 mm after conventional balloon angioplasty to 2.8 +/- 0.3 mm after coronary stent implantation. Quantitative analysis of the corresponding intravascular ultrasound images, however, revealed significant residual endoluminal obstruction. Fractional plaque area remained unchanged from 30 +/- 12% after conventional balloon angioplasty to 32 +/- 11% after stent implantation. The circumferential distribution of plaque increased significantly from 0.44 +/- 0.17 to 0.55 +/- 0.15 (p = 0.03) after stent implantation. Despite the lack of significant change in the ultrasound-determined minimum stenosis diameter after stent placement, there was a borderline significant increase in the plaque-free lumen area (before stent, 6.35 +/- 1.55 mm2; after stent, 7.25 +/- 1.6 mm2; p = 0.06). Thus, in contrast to the substantial improvement in the angiographically assessed residual luminal obstruction after stent implantation compared with the prestent condition, considerably less improvement was found by intravascular ultrasound-assessed examination. Morphometric analysis indicated a tendency toward circumferential remodeling of plaque. The inherently different approaches to vascular imaging represented by contrast angiography and intravascular ultrasound techniques appear to provide complementary information.(ABSTRACT TRUNCATED AT 250 WORDS)
Coronary Angiography↗
Pulmonary artery hemodynamics in primary pulmonary hypertension.
OBJECTIVES: The present investigation compared and contrasted steady and pulsatile pulmonary hemodynamics at rest and during exercise in patients with primary pulmonary hypertension and normal control subjects. BACKGROUND: A complete description of the relation between pressure and flow in the pulmonary circulation includes both steady and pulsatile hemodynamic behavior. Patients with primary pulmonary hypertension provide a unique opportunity to study the effects of primary alterations in pulmonary vasculature on pulmonary artery vascular hydraulic load. METHODS: Catheter tip pressure and velocity recordings from the main pulmonary artery in 8 patients with primary pulmonary hypertension and 10 control subjects were used to derive the pulmonary artery input impedance spectrum and the extent of pulse wave reflection at rest and during exercise. RESULTS: As expected, in patients with primary pulmonary hypertension, mean pulmonary artery pressure (50 +/- 10 mm Hg) and pulmonary vascular resistance (880 +/- 446 dynes.s.cm-5) were markedly elevated at rest and remained so during exercise (mean pressure 71 +/- 15 mm Hg, mean resistance 750 +/- 530 dynes.s.cm-5). Pulmonary artery characteristic impedance was elevated at rest and did not change with exercise (rest 55 +/- 25 dynes.s.cm-5; exercise 66 +/- 33 dynes.s.cm-5). Measures of arterial wave reflection indicated that the extent of wave reflection in the pulmonary bed in those with primary pulmonary hypertension is large at rest (reflection coefficient 0.89 +/- 0.09) and that the composite reflected wave arrived during the midportion of right ventricular ejection. Although the extent of wave reflection decreased with exercise (reflection coefficient 0.81 +/- 0.10, p < 0.05), the magnitude and timing of these reflections remained adverse. Furthermore, in patients with primary pulmonary hypertension, the stroke volume response to exercise was strongly related to rest levels of pulmonary artery diastolic pressure, pulmonary vascular resistance and the reflection factor, whereas no such relation was found in the control subjects. CONCLUSIONS: In addition to the expected abnormalities in steady measures of pulmonary artery hemodynamics at rest in patients with primary pulmonary hypertension, rest and exercise measures of oscillatory behavior (characteristic impedance and pulse wave reflection) are perturbed. Measures of steady and pulsatile behavior, particularly wave reflection, appear to have an important role in the exercise response of these patients.
Blood Flow Velocity↗
Repeated reflection of waves in the systemic arterial system.
Traditional analysis of pulse-wave propagation and reflection in the arterial system treats measured pressure and flow waves as the sum of a single forward wave (traveling away from the heart) and a single backward wave (traveling toward the heart). The purpose of this study was to develop a more general wave reflection theory that allows repeated reflection of these waves. The arterial system was modeled as a uniform viscoelastic tube terminating in a complex load with reflections occurring at the tube load interface and the heart tube interface. The resulting framework considers the forward wave to be the sum of an initial wave plus a series of antegrade waves. Similarly, the backward wave is the sum of a series of retrograde waves. This repeated reflection theory contains within it the traditional forward/backward wave reflection analysis as a special case. In addition, the individual antegrade and retrograde waves, at the tube entrance, are shown to be independent of the tube length. Aortic pressure and flow data, from dog experiments, were used to illustrate the phenomenon of repeated reflections. Alteration of the arterial system loading conditions, brought about through pharmacological intervention, affected the number and morphology of repeated waves. These results are compared with those found in traditional forward/backward reflection analysis.
Animals↗
Pulmonary impedance and right ventricular-vascular coupling during coronary angioplasty.
Right ventricular ejection may be modified by alterations in pulmonary vascular properties during acute pulmonary hypertension. Pulmonary artery impedance and reflection properties were analyzed during coronary angioplasty in nine patients with single-vessel disease involving the left anterior descending artery by use of high-fidelity catheter recordings of pulmonary pressure and flow made before angioplasty balloon inflation and at peak ischemia. Acute pulmonary hypertension in this resting model resulted in a significant decrease in pulmonary vascular resistance (142 +/- 54 to 92 +/- 64 dyn.s.cm-5, P < 0.05), increase in low-frequency impedance (67 +/- 36 to 101 +/- 43 dyn.s.cm-5, P < 0.05), and no change in high-frequency (characteristic) impedance (38 +/- 14 to 41 +/- 13 dyn.s.cm-5). Pulmonary wave reflection amplitudes were increased, and the amount of hydraulic power expended per unit of net forward flow significantly increased (3.1 +/- 0.7 to 4.3 +/- 0.7 mW.ml-1.s-1, P < 0.001). These findings indicate that, during acute pulmonary hypertension in humans, 1) recruitment of additional resistance vessels can occur, 2) pulsatile pulmonary artery properties are significantly altered, and 3) right ventricular power output requirements are increased. Because episodic pulmonary hypertension occurs frequently in coronary artery disease, these changes may help explain eventual right ventricular hypertrophy or failure.
Adult↗
Right ventricular-vascular interaction in congestive heart failure. Importance of low-frequency impedance.
BACKGROUND: Vasodilator agents are widely used in congestive heart failure. These agents may have important effects on the pulsatile aspects of right ventricular hydraulic load. METHODS AND RESULTS: Fifteen patients with severe congestive heart failure were studied during cardiac catheterization by use of high-fidelity pressure transducers and a catheter-mounted flow velocity probe. Three graded doses of nitroprusside were infused as pulmonary artery (PA) pressure and flow were continuously recorded. From Fourier transforms of signal-averaged waves, PA impedance, hydraulic power, and wave reflection indices were derived. At the highest dose of nitroprusside (66 +/- 41 micrograms/min), cardiac output was significantly improved, whereas PA mean and wedge pressure, resistance, impedance at the first harmonic, characteristic impedance, and wave reflection amplitude were all reduced. At the dose (32 +/- 20 micrograms/min) at which cardiac output first showed improvement, only PA mean pressure and first-harmonic impedance were significantly reduced. Hydraulic power cost per unit of forward flow was also lowered at this dose, despite lack of significant change in pulmonary vascular resistance. At the lowest dose of nitroprusside (11 +/- 4 micrograms/min), six patients experienced a decrease in stroke volume, whereas the other nine were either unchanged (n = 1) or showed an increase (n = 8). Multiple regression revealed that only the change in first-harmonic impedance correlated with this effect, increasing when stroke volume decreased and decreasing when stroke volume increased (P = .02). The change in first-harmonic impedance at this dose appeared to be caused by alterations in the amplitude of PA wave reflections. At higher doses, changes in mean PA pressure (but not in pulmonary vascular resistance) correlated with changes in stroke volume. CONCLUSIONS: Nitroprusside vasodilation at low doses alters PA hemodynamics in congestive heart failure primarily through changes in low-frequency impedance. In some patients, this effect is associated with decreased stroke output. At higher doses, favorable alterations in resistance, low- and high-frequency impedance, and wave reflections all contribute to increased forward flow and decreased power requirement per unit forward flow. These findings show that ventricular-vascular interaction is importantly affected by pulmonary vasodilation and that appreciation of pulsatile properties is required to understand the effects of pulmonary vasodilation on cardiac output.
Blood Flow Velocity↗
Gender differences in the management of coronary artery disease: bias or good clinical judgement?
Explore the source record for details and available documents.
Coronary Disease↗
Right ventricular-pulmonary arterial interactions.
The application of pulsatile models to hemodynamic data has made possible a more complete understanding of the relationship of pulmonary pressure and flow. To review the genesis of these concepts, the unique characteristics of the pulmonary artery and right ventricle are outlined as a basis for understanding why differences in their pulsatile properties from the systemic circuit must exist. The pulmonary impedance spectrum is introduced and the concept of optimal right ventricular-pulmonary artery coupling is explored based on a review of extensive experimental data. Finally, available studies of normal pulmonary impedance in man and abnormal impedance in human disease states are reviewed, with emphasis on disturbances in optimal ventricular-vascular coupling. The important implications of these concepts for understanding and treatment of cardiovascular disease are developed.
Coronary Disease↗
Management and immediate outcome of patients with intracoronary thrombus during percutaneous transluminal coronary angioplasty.
A retrospective analysis of our experience with intraprocedural thrombus complicating percutaneous transluminal coronary angioplasty (PTCA) was undertaken. Of 983 PTCA procedures reviewed, 62 (6.3%) were complicated by thrombus. Patients were managed conservatively (group I, n = 18), with redilation (group II, n = 17), or with intracoronary urokinase and redilation (group III, n = 27). The three groups did not differ with respect to demographic or baseline angiographic variables, but complications, defined as death, myocardial infarction, bypass surgery, or threatened occlusion requiring emergency stenting, occurred in 11% of patients in group I, 24% in group II, and 48% in group III. Occlusive thrombus behavior was observed in 80% of these 62 patients. Patients with complications were less likely to have received antecedent antiplatelet therapy (79% vs 95% of patients without complications), had more complex baseline lesion morphology, more often had thrombus present at baseline (42% vs 19%), and more often had a low activated clotting time at the start of PTCA (53% vs 8%). Thrombi that led to complications more frequently exhibited occlusive behavior before therapy was begun (95% vs 71%) and more often occurred in the setting of intimal dissection (42% vs 14%). Patients undergoing PTCA at the time of diagnostic catheterization were more likely to have complications than those in whom PTCA was delayed. A successful outcome was more likely (83% vs 27%, p = 0.03) in group III if at least 140,000 U of urokinase were administered within 50 minutes of the appearance of thrombus. Thus intracoronary thrombus formation during PTCA remains a significant source of morbidity.(ABSTRACT TRUNCATED AT 250 WORDS)
Angioplasty, Balloon, Coronary↗
Effects of pacing tachycardia and balloon valvuloplasty on pulmonary artery impedance and hydraulic power in mitral stenosis.
BACKGROUND: Mitral stenosis is characterized by progressive pulmonary hypertension and eventual right ventricular failure. However, the correlation between right ventricular failure and the level of pulmonary hypertension is poor, suggesting that factors other than those recognized from nonpulsatile hemodynamic parameters may contribute to impaired right ventricular performance in this condition. METHODS AND RESULTS: We studied 16 patients with severe mitral stenosis (mean valve area, 1.0 +/- 0.2 cm2) at supine rest and during pacing tachycardia using high-fidelity catheter recordings of pulmonary artery (PA) pressure and flow velocity. Pulmonary impedance spectra, wave reflection properties, and hydraulic power data were derived from Fourier analysis of signal-averaged data. Pacing tachycardia (baseline heart rate, 81 +/- 11 beats per minute; pacing, 132 +/- 11 beats per minute) significantly raised pulmonary wedge and mean PA pressures. There was no change in pulmonary vascular resistance (209 +/- 144 to 232 +/- 164 dyne-sec/cm5) or PA characteristic impedance (62 +/- 25 to 55 +/- 28 dyne-sec/cm5). However, first harmonic impedance (Z1) significantly decreased (134 +/- 71 to 100 +/- 68 dyne-sec/cm5; p < 0.001). Accordingly, oscillatory and total dissipated hydraulic power per unit forward flow (WT/CO) fell during tachycardia (2.6 +/- 1.6 to 2.3 +/- 1.4 mW/ml.sec-1; p = 0.06) despite acute pulmonary hypertension. Reflected pressure waves returned earlier to the proximal PA, suggesting increased vessel stiffness. Immediately after percutaneous balloon mitral valvuloplasty (PBV) in eight of the patients, baseline and pacing data were again recorded. Compared with the pre-PBV baseline state, post-PBV resting data demonstrated no change in resistance or characteristic impedance, but there was a significant fall in Z1 (166 +/- 75 to 103 +/- 45 dyne-sec/cm5; p < 0.05) and in the magnitude of pulmonary wave reflections. WT/CO tended to decrease after PBV, and pacing after PBV produced a further decrease in WT/CO, again in association with lower Z1. CONCLUSIONS: These data demonstrate that 1) increased pulmonary characteristic impedance, although a feature of mitral stenosis, is not exacerbated by the acute effects of increased distending pressure; 2) pacing tachycardia in mitral stenosis causes little change in the pulmonary impedance spectrum except at low frequencies, where decreased impedance lowers power requirements per unit flow; and 3) relief of mitral stenosis produces immediate improvement in low-frequency impedance and in hydraulic power requirements. These findings suggest that although characteristic impedance may be a measure of the long-term effects of pulmonary hypertension on the pulmonary circulation, acute increases and decreases in PA pressure produce effects on right ventricular load that are best described in terms of the low-frequency properties of the PA system. Improvement in low-frequency impedance diminishes hydraulic power requirements and thus reflects improved ventricular-vascular coupling, irrespective of distending PA pressure. Efforts to treat or prevent right heart failure in the presence of pulmonary hypertension should take account of the potential benefit of changes in low-frequency impedance characteristics of the pulmonary vascular bed.
Adult↗
Influence of heparin therapy on percutaneous transluminal coronary angioplasty outcome in unstable angina pectoris.
The acute procedural outcome of percutaneous transluminal coronary angioplasty in 304 patients with unstable angina was retrospectively examined with respect to the influence of prolonged preprocedural intravenous heparin therapy. Clinical and angiographic success in 135 patients receiving heparin therapy for greater than or equal to 24 hours was 91% while such success was noted in 81% of patients not treated with heparin (p = 0.02). The incidence of immediate postprocedural thrombotic vessel occlusion was higher in the nonheparin group than in the heparin-treated group (8.3 vs 1.5%, respectively, p less than 0.01). In addition, the overall rate of thromboembolic target and branch or distal vessel occlusion was 12.4% in the nonheparin group and 1.5% in the heparin-treated group (p less than 0.001). Thus, prolonged preprocedural intravenous heparin administration in this well-defined group of patients with unstable angina resulted in an improved procedural success rate and a significant decrease in the risk of abrupt vessel closure. These observations are concordant with current understanding of the pathophysiology of unstable angina.
Aged↗
Influence of heparin therapy on percutaneous transluminal coronary angioplasty outcome in patients with coronary arterial thrombus.
The clinical and angiographic outcome of 18 patients with coronary thrombus undergoing percutaneous transluminal coronary angioplasty without antecedent heparin therapy was compared to that of a group of 35 patients receiving pre-procedural heparin therapy. The former group had a significant reduction in angiographic success (61 vs 94%, p less than 0.05) and a significant increase in immediate postprocedural thrombotic arterial occlusion (33 vs 6%, p less than 0.05). This difference existed despite equivalent frequencies of antiplatelet therapy. Prolonged intravenous heparin therapy before angioplasty in the setting of coronary thrombus improves the overall success rate and lessens the likelihood of periprocedural coronary arterial thrombosis.
Angiography↗
Estimation of total systemic arterial compliance in humans.
Systemic arterial compliance, a major component of aortic input impedance, was determined in 10 patients with congestive heart failure secondary to idiopathic dilated cardiomyopathy and 11 age-matched control subjects found free of detectable cardiovascular disease. Total arterial compliance was determined from high-fidelity ascending aortic pressure and velocity recordings using 1) the traditional monoexponential aortic diastolic pressure decay and 2) the direct solution of the equation, which describes the three-element windkessel model of the arterial system. Resting values for total arterial compliance (x10(-3) cm5/dyn) derived from method 1 were significantly correlated with compliance derived from method 2 (r = 0.89, P less than 0.01). However, method 1 values (control mean 1.15 +/- 0.27, heart failure mean 1.18 +/- 0.54) were consistently and significantly lower (P less than 0.001) than method 2 values (control mean 1.59 +/- 0.50, heart failure mean 1.38 +/- 0.60). Resting total arterial compliance in heart-failure patients was not significantly different from control subjects. Total arterial compliance did not significantly change with exercise in either group despite increases in arterial pressure. However, nitroprusside administration in the heart-failure group increased total arterial compliance both at rest and on exercise compared with the unmedicated state. These different methodological approaches to the estimation of total arterial compliance in humans resulted in significantly different absolute values for compliance, although both methods provided concordant results with respect to the response of arterial compliance to physiological and pharmacological interventions.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Adaptation to ischemia during percutaneous transluminal coronary angioplasty. Clinical, hemodynamic, and metabolic features.
The clinical, electrocardiographic, and coronary hemodynamic responses to sequential 90-second occlusions of the left anterior descending coronary artery in 12 patients undergoing elective percutaneous transluminal coronary angioplasty were examined. Transmyocardial lactate metabolism was examined in an additional group of seven patients with clinical and hemodynamic features similar to the first group. We noted that in comparison with the initial balloon occlusion the second occlusion was characterized by less subjective anginal discomfort, less ST segment shift (0.44 +/- 0.13 versus 0.21 +/- 0.07 mV, p = 0.01), and lower mean pulmonary artery pressure (25 +/- 1.0 versus 20 +/- 1.7 mm Hg, p = 0.005). In addition, for the same heart rate-blood pressure product, cardiac vein flow during the second inflation was significantly lower than that recorded during the first inflation (96 +/- 1.4 versus 83 +/- 2.4 ml/min, p = 0.005). Finally, there was significantly less myocardial lactate production during the second inflation (lactate extraction ratio: first inflation, -0.11 +/- 0.03; second inflation, -0.03 +/- 0.02; p = 0.04). We conclude that the lessened clinical, electrocardiographic, hemodynamic, and metabolic evidence of myocardial ischemia during the second of two periods of coronary artery occlusion during percutaneous transluminal coronary angioplasty supports the concept of adaptation to myocardial ischemia (ischemic preconditioning).
Adaptation, Physiological↗
Percutaneous aortic balloon valvuloplasty in octogenarians: morbidity and mortality.
STUDY OBJECTIVE: To examine the morbidity, mortality, and hospital course of an elderly patient sample (mean age, 86 years; 95% CI, 84 to 87) having percutaneous aortic balloon valvuloplasty. DESIGN: Retrospective consecutive case series before and after balloon valvuloplasty. SETTING: Tertiary care referral hospital. PATIENTS: Consecutive sample of 26 patients aged 80 years or older with symptomatic aortic stenosis referred for balloon valvuloplasty from July 1987 to July 1988. MEASUREMENTS AND MAIN RESULTS: Percutaneous aortic balloon valvuloplasty reduced the transvalvular gradient from 59 (95% CI, 51 to 67) to 31 mm Hg (95% CI, 26 to 35; P less than 0.0001) and increased aortic valve area from 0.45 (95% CI, 0.38 to 0.51) to 0.67 cm2 (95% CI, 0.58 to 0.76; P less than 0.0001). The mean length of hospital stay for the entire study population was 11.2 days (95% CI, 7.3 to 15.2) at a total hospital charge per patient of $29,600 (95% CI, 21,050 to 38,150). For patients having procedural complications (11 complications in 8 patients), surgical procedures, or cardiogenic shock, the mean hospital stay increased to 16.2 days (95% CI, 6.2 to 26.2; P less than 0.05) and the hospital charge increased to $44,400 (95% CI, 24,280 to 64,520; P less than 0.01). Two patients who presented with cardiogenic shock died, and 1 patient had an aortic valve replacement before discharge. Four patients were recently discharged (less than 1 month) and follow-up was obtained in the remaining 19 patients at 6.1 months (95% CI, 4.1 to 8.1). Five more patients, including the remaining patient who presented with cardiogenic shock, died after discharge for an overall mortality of 32%. Twelve of the remaining fourteen patients had fewer symptoms and improved an average of 1.1 New York Heart Association classes (95% CI, 0.7 to 1.4; P less than 0.0001). CONCLUSIONS: Percutaneous aortic balloon valvuloplasty in patients 80 years and older improves hemodynamics and symptoms of heart failure during short-term follow-up in most patients, but overall mortality is high in this elderly patient population. Hospital charges and length of stay were much higher in patients with complications or coexisting medical illnesses. Valvuloplasty is a reasonable alternative treatment for patients with aortic stenosis who require palliative treatment of symptoms and have high surgical risk.
Aged↗
Pressure-flow relations in the pulmonary artery during myocardial ischaemia: implications for right ventricular function in coronary disease.
Because exercise induced pulmonary hypertension may disturb optimal coupling between the right ventricle and pulmonary artery in coronary artery disease, high fidelity pulmonary artery and right ventricular pressure and electromagnetic pulmonary artery flow velocity data were recorded at rest and during supine exercise in 10 control subjects free of detectable cardiovascular disease and in 11 patients with coronary artery disease. The pulmonary artery impedance and power spectra were calculated from Fourier analysis of pressure and flow waveforms. Total hydraulic power expended per unit of forward flow was computed as an index of right ventricular-pulmonary artery coupling. In coronary artery disease exercise produced substantial increases in pulmonary artery pressure, pulmonary artery characteristic impedance, and total power per unit flow. These changes did not occur in control subjects. Despite a significant exercise increase in right ventricular end diastolic pressure and peak right ventricular dP/dt, and independent of the presence of right coronary artery involvement, the right ventricular stroke output response during exercise was significantly blunted in the coronary artery disease patients. Pulmonary vascular resistance was unchanged by exercise in either group. Exercise induced ischaemia presents an increased pulsatile hydraulic load to the right ventricle. Increased pulmonary artery input impedance impairs the hydraulic efficiency of right ventricular-pulmonary artery coupling and may contribute to the limitation of right ventricular ejection performance in coronary artery disease.
Adult↗
Effects of exercise and nitroprusside on left ventricular ejection dynamics in idiopathic dilated cardiomyopathy.
To characterize the abnormal pattern of instantaneous left ventricular (LV) ejection in heart failure, proximal aortic pressure, flow, acceleration, power and dW/dt were measured at rest and during supine bicycle exercise using high-fidelity, catheter-mounted pressure and velocity sensors in 16 patients with idiopathic dilated cardiomyopathy (IDC) and 11 normal control subjects. In patients with IDC, peak flow was lower than normal both at rest (454 +/- 155 vs 649 +/- 168 ml/s, p less than 0.01) and during exercise (569 +/- 213 vs 916 +/- 329 ml/s, p less than 0.01). Peak acceleration, power and dW/dt were also significantly reduced in patients with IDC at rest and during exercise. Time to peak flow (as a fraction of LV ejection time) was consistently prolonged in patients with IDC (rest, 0.40 +/- 0.08 vs 0.29 +/- 0.04; exercise, 0.36 +/- 0.06 vs 0.28 +/- 0.04, both p less than 0.01). Exercise-induced increments in peak flow, power and dW/dt were significantly blunted in patients with IDC. Studies during pacing tachycardia and nitroprusside administration failed to reproduce the abnormalities during exercise in patients with IDC. Thus, the instantaneous flow pulse in heart failure is both diminished in magnitude (decreased stroke volume and peak flow) and abnormal in shape (decrease peak acceleration and delayed time to peak flow). Exercise stress in IDC results in abnormalities of LV performance that can be detected using instantaneous ejection information. These abnormalities are unlikely to be explained by changes in heart rate or loading conditions.
Adult↗