Ferreira T

Usefulness of Doppler myocardial imaging for identification of mutation carriers of familial hypertrophic cardiomyopathy

Because myocyte dysfunction and disarray are early abnormalities in hypertrophic cardiomyopathy (HC), we tested if Doppler myocardial imaging (DMI) could identify systolic and diastolic dysfunction in mutation carriers (MC) (genotype positive patients without hypertrophy, defined as phenotype negative after conventional screening tests). In a single family with a missense mutation in the myosin binding protein C gene (Arg 502 Gln) we identified 5 MCs; these subjects were asymptomatic and had normal physical examination, normal electrocardiogram, treadmill stress test, ambulatory Holter electrocardiogram, and normal conventional M-mode, 2-dimensional, and Doppler echocardiography. In each patient we performed a DMI study and measured the peak velocities of the systolic (S), rapid filling (E), and atrial contraction (A) waves in the 4 sides of the mitral annulus, in 8 left ventricular segments (apical views), in the tricuspid annulus, and in 2 right ventricular segments. These data were compared with those from 10 normal volunteers matched for sex, age, and body surface. Compared with the normal volunteers, the MCs had lower left ventricular systolic velocities and higher right ventricular systolic velocities; lower diastolic rapid filling velocities; higher or similar atrial contraction velocities; reduced E/A; lower percentage of annular sides and segments with E/A >1 and lower average number of sides and/or segments with E/A >1 per patient; similar right ventricular rapid filling velocities; and similar or higher atrial contraction wave velocities. Thus, DMI detects important left and right ventricular annular and regional myocardial contraction and relaxation abnormalities independently of the presence of hypertrophy, in HC. These results show that DMI is more sensitive than conventional echocardiography and establishes a new and highly accurate method for the noninvasive screening of MCs of the disease.

Avaliação da função dos músculos respiratórios em doentes com falência ventricular esquerda

The decrease in strength of respiratory muscles, determined by measuring the maximal respiratory pressures in the mouth, has been evoked as a mechanism of dyspnoea in patients with left ventricular failure (LVF). Knowing the limitations of this technique in the evaluation of the “real” strength, we propose to apply in this group of patients the different techniques available to study the maximal respiratory pressures. We studied 20 male patients, with LVF (GI), classes II and III of New York Heart Association (NYHA), and we compared them with 19 male aged-matched controls without cardiopulmonary disease (GII). We assessed the maximal respiratory pressures at the mouth level, expiratory (PME) and inspiratory (PMI), the nasal Sniff (SNIF-N) and the esophageal Sniff (SNIF-E). We have obtained the following results: PME: GI – 138.7 ± 42.1 cmH2O; GII – 152.5 ± 40.8.8 cmH2O; p:NS; PMI: GI – 74.1 ± 22.2 cmH2O; GII – 85.8 ± 16.6 cmH2O; p < 0.03; SNIF-N: GI – 95.6 ± 22.2 cmH2O; GII – 96.6 ± 16.6 cmH2O; p:NS; SNIF-E: GI – 96.2 ± 20.6 cmH2O; GII – 97.5 ± 18.5 cmH2O; p:NS. When comparing PMI with SNIF-N we found a statistical significant difference between the groups: GI – p < 0.0002 e GII – p < 0.009. There was no statistical difference between SNIF-N and SNIF-E. In conclusion, PMI underestimates the strength of inspiratory muscles. LVF patients in NYHA classes II and III did not present a decrease in the global strength of respiratory muscles, once there were no significant differences in PME and SNIF values, between patients and control group. Finally we did not detect differences between SNIFF-N and SNIFF-E pressures so we think that the assessment of SNIFF-N pressure can be used as a non-invasive method to evaluate the strength of inspiratory muscles. REV PORT PNEUMOL 2001; VII (6):

Importância da avaliação funcional do controle da ventilação

RESUMO Estudamos o controle da respiracao com a finalidade primordial de avaliar a dispneia. A presente abordagem deve ser feita a varios niveis, uma vez que o centro respiratorio pode estar integro mas os efectores a nivel dos circuitos neuronais podan eocontrar-se comprometidos. Utilizamos um estimulo hipercapnico para o centro respiratorio e medimos a resposta venrilatoria, a pressao de oclusao e escalas analogicas visuais. Tambem avaliamos as pressoes respiratorias maximas e os movimentos toraco-abdominais utilizando plerismografia por variacao de inductancia. Com esta metodologia somos capazes de localizar qual o efector responsavel pela dispneia e avaliar a integridade do centro respiratorio em doentes com patologia cardiac ou respiratoria. REV PORT PNEUMOL 1999; V (2): 237-246

Control of breathing, respiratory patterns and dyspnoea in patients with congestive heart failure

Abstract The aim of this paper was the evaluation of the control of breathing and respiratory patterns in patients with congestive heart failure (CHF) and its relation with the genesis of dyspnoea. Forty seven patients were studied with CHF, with a mean age of 60.9±12.5 years and compared them with 35 age-matched controls, free of cardiopulmonary diseases. The evaluation included: (a) measurements of lung function using the helium dilution method; (b) determination of occlusion pressure (P0.1) at rest; (c) noninvasive breathing pattern at rest assessed by means of respiratory inductive plethysmography (RIP); (d) CO 2 re-breathing test with the simultaneous recording of ventilation, P0.1 and dyspnoea perception using a visual analogue scale. A mild restrictive ventilatory defect was found in CHF patients, together with an abnormal breathing pattern at rest defined by a significant increase in respiratory frequency and a decrease in tidal volume, when compared with the control group. However, the mean pulmonary ventilation at rest did not differ between the two groups whereas the baseline P0.1 was higher in CHF, (median 1.6; range 2.00 cmH 2 O), than in controls (median 1.20; range 1.00 cmH 2 O), ( P 2 ), than in controls (median 1.30; range 1.29), ( P

Fisiopatologia da Dispneia em doentes cardíacos com Congestão Pulmonar

The purpose of this study was to evaluate whether pulmonary congestion (PC) in cardiac patients may induce changes in the control of breathing or in the respiratory muscles strength, that could be implicated in the genesis of dyspnea in this group of patients. We have compared 48 patients (GI), with a mean age of 61 years and a mean pulmonary capillary (wedge) pressure of 19.9 mmHg, with a group of 35 controls (GII) with a mean age of 62 years. We have performed the following measurements: pulmonary volumes and capacities using the helium dilution method, airway flows by pneumotachography. We also determined the occlusion pressure and the ventilatory response to C02, with simultaneous quantification of dyspnea using a visual analogue scale. Measurements of maximal inspiratory and expiratory pressures were also performed. PC patients underwent right heart catheterization and assessment of cardiac output by thermodilution technic. Cardiac patients had an increase in the central output to breathing (P0.1 GI-1.7 cmH20/GII - l.35 cmH20; < 0.001), probably due to the respiratory restrictive pattern. Because we found no changes in the P0.1, during C02 stimulation, we admit that the central command is not altered. During the C02 stimulation, and for a similar increase in ventilation, the cardiac patients showed a higher degree of dyspnea. The reduction of maximal respiratory pressures and the increased basal respiratory drive can be important factors in the generation of dyspnea presented by these patients.