Heart and vessels
-
Case Reports
Isoproterenol infusion provokes vasovagal response without upright tilt in a patient exhibiting syncopal episodes.
We report a case of a patient with vasovagal syncope, in whom isoproterenol infusion provoked vasovagal response without upright tilting. We subjected the patient, who had had two previous syncopal and several presyncopal episodes, to upright tilting with isoproterenol infusion. Before a control tilt was performed for 10 min (80 degrees), the patient was placed in the supine position for 5 min. ⋯ The patient complained of palpitation and anxiety, and showed profound cold sweating. The drop in the heart rate and the fall in blood pressure occurred when the patient was in the supine position, indicating that, unlike upright tilting with isoproterenol infusion, venous return was not decreased at the beginning of vasovagal response in this setting. This observation suggests that isoproterenol infusion, even without upright tilting, may provoke the vasovagal response in some patients.
-
A 37-year-old female with Marfan's syndrome developed myocardial infarction during a cardiac operation for annuloaortic ectasia and chronic dissecting aneurysm of the aorta. At autopsy, a chronic dissecting aneurysm of the left coronary arterial system (the left main stem, anterior descending branch, first diagonal branch, and circumflex branch) showing a true lumen and a pseudo lumen, which were patent, was found. There was also a hemorrhagic myocardial infarction of the anteroseptal wall and apical portion of the left ventricle.
-
To assess atrial contribution to left ventricular (LV) filling in hypertension, we studied, using pulsed Doppler echocardiography, 22 hypertensive patients without apparent LV hypertrophy (LVH), 12 hypertensive patients with LVH, and 24 age-matched normal subjects. From mitral flow velocity waveform, we determined peak velocity of early diastolic filling flow (peak E), peak velocity of late diastolic filling flow (peak A), and the peak A/peak E ratio (peak A/peak E). Peak E decreased in hypertensives without apparent LVH and showed a further decrease in hypertensives with LVH compared with normal subjects (57 +/- 8 [mean +/- SD]; P less than 0.001, 46 +/- 7; P less than 0.0001, vs 65 +/- 10 cm/s). ⋯ In hypertensives, we found no significant correlation between peak A and the wall thickness index (WTI, determined as mean LV wall thickness normalized by LV diastolic dimension), whereas peak E was significantly correlated with WTI (r = -0.65; P less than 0.001). Our findings indicate that atrial contraction can not fully compensate the decrease in early diastolic filling caused by advanced LVH. We conclude that atrial compensation for reduced early diastolic filling is limited in hypertensive patients with advanced left ventricular hypertrophy.
-
Clinical investigations focused on finding characteristics of noninvasively obtained measurements of pulmonary blood velocity that can be used to quantitate pulmonary blood flow and/or pulmonary pressure have often yielded results whose imprecision has been attributed to flow pattern variability. To determine flow pattern variability in an in vivo animal model in varying hemodynamic states, main pulmonary artery blood velocity waveforms were recorded in 17 dogs at 2-mm intervals along an anterior to posterior wall-oriented axis using a 20-MHz pulsed Doppler needle probe. Control data were obtained before the animals were subjected to altered flow (atrial level shunts) and pressure (10% O2 inhalation) states. ⋯ Elevated pulmonary blood flow tended to increase the maximum velocities along the anterior wall relative to midline velocities. Neither estimate of cardiac output yielded consistently accurate results (r = 0.77 for model-based method, r = 0.80 for area times central velocity method). Findings of this study, which highlight the dependency of waveform characteristics on sampling site, the large degree of intersubject variability, and the need for large or multiple sample volumes for pulmonary blood flow determination, help clarify inconsistencies observed by clinicians and suggest that future work with animal models will facilitate a greater understanding of the determinants of human pulmonary velocity waveforms.
-
The incidence of aortic valve prolapse and aortic regurgitation (AR) among Chinese with ventricular septal defect (VSD) has not been studied, and controversies still exist regarding optimal surgical treatment and timing of operation for this condition. A prospective study of 332 consecutive patients with VSD showed that aortic valve prolapse and AR occurred in 43 (11.9%) patients. Valve lesions occurred more commonly among patients with subpulmonic VSD (28.0%) than with subaortic VSD (8.8%) (P less than 0.005). ⋯ Surgical closure of the subpulmonic VSD may restore the prolapsed valve to normal. Closure of the subaortic VSD has little effect. Valvuloplasty in subaortic VSD may palliate AR, but in all probability cannot restore valve competency.