Atrial fibrillation is associated with a lower exercise capacity in male chronic heart failure patients

Objective—To study the influence of atrial fibrillation on peak oxygen uptake (peak O₂) in chronic heart failure. An unfavourable effect of atrial fibrillation has been shown in several patient populations, but the results have not been consistent in chronic heart failure.
Methods—Data were analysed from male heart transplant candidates who were able to perform graded bicycle ergometry until exhaustion with respiratory gas analysis and measurement of heart rate. Patients in atrial fibrillation (n = 18) were compared with patients in sinus rhythm (n = 93).
Results—Age, weight, height, and aetiology of chronic heart failure did not differ significantly between the two groups. Cardiac catheterisation at supine rest showed that heart rate was comparable, but that stroke volume and cardiac output were lower (p < 0.05) in atrial fibrillation. Systolic and diastolic left ventricular function, assessed by radionuclide angiography at rest, were not significantly different. Peak O₂ (mean (SD): 13.8 (3.6) v 17.1 (5.6) ml/kg/min; p < 0.01) and peak work load (78 (27) v 98 (36) W; p < 0.05) were lower in the patients with atrial fibrillation, though respiratory gas exchange ratio and Borg score were similar in the two groups. Patients with atrial fibrillation had a higher heart rate sitting at rest before exercise (93 (16) v 84 (16) beats/min) and at peak effort (156 (23) v 140 (25) beats/min) (p < 0.05).
Conclusions—Atrial fibrillation is associated with a 20% lower peak O₂ in patients with chronic heart failure, suggesting that preserved atrial contraction or a regular rhythm, or both, are critical to maintain cardiac output and exercise performance.

Keywords: peak oxygen uptake;  exercise capacity;  chronic heart failure;  atrial fibrillation     

Assessment of ventricular diastolic function in AIDS patients from Congo: a Doppler echocardiographic study

Objective—To investigate the prevalence of left ventricular dysfunction in African patients infected with the human immunodeficiency virus (HIV). The hypothesis was that HIV infected patients with left ventricular dysfunction are asymptomatic.
Methods—M mode, cross sectional, and Doppler echocardiography were performed in 49 consecutive patients (30 HIV positive (HIV+) carriers and 19 AIDS patients). None of the patients or 58 controls had a medical history of cardiovascular abnormalities.
Results—Cardiac abnormalities were not suspected on physical, electrocardiographic, and radiological examination. Forty two of the HIV infected patients had left ventricular diastolic dysfunction; this was more pronounced in AIDS patients than in HIV+ carriers. Systolic function was normal in both stages of HIV infection. Left ventricular isovolumic relaxation time (mean (SD)) increased from 87.2 (12.4) ms in the carrier state to 103.9 (19.3) ms in AIDS (p < 0.05, Bonferoni correction), peak early filling velocity declined from 0.54 (0.1) to 0.44 (0.1) m/s (p < 0.05), and late velocity increased from 0.64 (0.1) to 0.69 (0.2) m/s. A restrictive filling pattern was explained by concentric hypertrophy in 23 HIV infected patients, and by systemic amyloidosis with left ventricular dilatation in 12 of 49 HIV infected patients.
Conclusions—Echocardiography is a useful technique for detecting left ventricular diastolic dysfunction in HIV infected patients with clinically unsuspected cardiac lesions. Systolic function was normal despite the presence of such cardiac abnormalities.

Keywords: HIV infection; AIDS; diastolic dysfunction; black Africans; echocardiography     

Comparison of early diastolic mitral annular velocity and flow propagation velocity in detection of mild to moderate left ventricular diastolic dysfunction.

BACKGROUND: Pulsed wave tissue Doppler echocardiography (PW-TDE) and color M-mode are new Doppler methods for left ventricular (LV) diastolic function assessment. To date, few studies have compared the data obtained by these methods in the same series of patients and compared them to the current clinical reference method of detecting LV diastolic function. AIMS: To determine the utility of PW-TDE and color M-mode parameters in the assessment of LV diastolic function in the typical patient population encountered in daily clinical practice and to compare their discriminating power. METHODS: Early diastolic septal mitral annular velocity (Em) determined by PW-TDE and color M-mode flow propagation velocity (Vp) were measured in 86 male patients and compared to LV filling patterns obtained using standard Doppler indices. Values of Em < 0.08 m s(-1) and Vp < 0.5 m s(-1) were considered as markers of abnormal LV diastolic function. RESULTS: A value of Em < 0.08 m s(-1) distinguished mild to moderate LV diastolic dysfunction with higher sensitivity and specificity than Vp < 0.5 m s(-1) (96% and 87% vs. 73% and 84%, respectively). A comparison of receiver operating characteristic curves showed a significant difference for areas under the curve in favor of Em (P < 0.01). In a stepwise multiple logistic regression analysis, a pseudonormal filling pattern and an EF > 60% were identified as significant predictors of Vp false negative results (p < 0.05). CONCLUSIONS: Em appears to be superior to Vp in the detection of mild to moderate LV diastolic dysfunction. Vp failed to detect abnormal LV diastolic function in particular in patients with preserved LV systolic function and a pseudonormal filling pattern type.     

The clinical quandary of left and right ventricular diastolic dysfunction and diastolic heart failure

Summary

Diastolic heart failure is a common clinical entity that is indistinguishable from systolic heart failure without direct evaluation of left ventricular function. Diastolic heart failure is a clinical diagnosis in patients with signs and symptoms of heart failure but with preserved left ventricular function and normal ejection fraction, and is often seen in patients with a long-standing history of hypertension or infiltrative cardiac diseases. In contrast, diastolic dysfunction represents a mechanical malfunction of the relaxation of the left ventricular chamber that is primarily diagnosed by two-dimensional transthoracic echocardiography and usually does not present clinically as heart failure. The abnormal relaxation is usually separated in different degrees, based on the severity of reduction in passive compliance and active myocardial relaxation. The question whether diastolic dysfunction ultimately will lead to diastolic heart failure is critically reviewed, based on data from the literature. Treatment recommendations for diastolic heart failure are primarily targeted at risk reduction and symptom relief. Currently, few data only are reported on diastolic dysfunction and its progression to systolic heart failure.     

Reversal of severe pulmonary hypertension with beta blockade in a patient with end stage left ventricular failure

A 52 year old man with severe chronic left ventricular failure (New York Heart Association class IV) was considered unsuitable for cardiac transplantation because of high and irreversible pulmonary vascular resistance (PVR). In an attempt to produce symptomatic improvement, metoprolol was cautiously introduced, initially at 6.25 mg twice daily. This was slowly increased to 50 mg twice daily over a two month period and continued thereafter. After four months of treatment the patient's symptoms had improved dramatically. His exercise tolerance had increased and diuretic requirements reduced to frusemide 160 mg/day only. Assessment of right heart pressures was repeated and, other than a drop in resting heart rate, there was little change in his pulmonary artery pressure or PVR. His right heart pressures were reassessed showing a pronounced reduction in pulmonary artery pressure and a significant reduction in PVR, which fell further with inhaled oxygen and sublingual nitrates. He was then accepted onto the active waiting list for cardiac transplantation. A possible mechanism of action was investigated by assessing responses to beta agonists during treatment. Not only was there pronounced improvement in PVR but it was also demonstrated that beta receptor subtype cross-regulation may have contributed to the mechanism of benefit.     

Impact of left ventricular diastolic function on exercise capacity in patients with chronic mitral regurgitation: an exercise echocardiography study

BACKGROUND: Mitral regurgitation (MR) is known as one of the most frequent causes of heart failure and sudden death. In spite of increasing prevalence of MR, there have been no available data on cardiac determinants of exercise capacity in patients with chronic MR. HYPOTHESIS: This study aimed to investigate cardiac determinants of exercise capacity in patients with chronic MR. METHODS: We consecutively enrolled 32 patients (11 men, mean age: 44 +/- 14 years) who had greater than moderate MR with normal left ventricular (LV) systolic function (LV ejection fraction >50%). Conventional echocardiographic indices and parameters measured by Doppler tissue imaging at septal side of mitral annulus were obtained before exercise. Mitral regurgitation fraction, forward stroke volume, pulmonary venous flow velocities, and systolic pulmonary artery pressure (sPAP) were also obtained with standard methods. RESULTS: Left ventricular ejection fraction was 61 +/- 6% and MR fraction was 48 +/- 13%. All patients finished a symptom-limited treadmill exercise test with a peak heart rate of >85% of predicted maximum heart rate. Mean exercise time was 9.95 +/- 2.17 min, corresponding to 11 +/- 2 metabolic equivalents. Among pre-exercise echocardiographic variables, only early diastolic mitral annulus velocity (E') and pulmonary venous reversal flow velocity (PVa) showed a significant correlation with exercise time (r = 0.44, p = 0.011, and r = -0.40, p = 0.040, respectively), which persisted after multivariate analysis (p = 0.011 and 0.038, respectively). Other parameters such as systolic mitral annulus velocity, resting and postexercise sPAP, forward stroke volume, LV size, LV ejection fraction, left atrial size, and regurgitant fraction showed no significant correlation. CONCLUSIONS: Left ventricular diastolic function is an important determinant of exercise capacity in patients with chronic MR. Both E' and PVa, accepted surrogate estimates for LV diastolic function, may be useful for identifying patients with chronic MR and with poor exercise capacity.     

Recovery and recurrence of left ventricular systolic dysfunction in patients with idiopathic dilated cardiomyopathy

BACKGROUND:

Some patients with nonischemic left ventricular (LV) systolic failure recover to have normal LV systolic function. However, few studies on the rates of recovery and recurrence have been reported, and no definitive indicators that can predict the recurrence of LV dysfunction in recovered idiopathic dilated cardiomyopathy (IDCMP) patients have been determined. It was hypothesized that patients who recovered from nonischemic LV dysfunction have a substantial risk for recurrent heart failure.

METHODS:

Forty-two patients (32 men) with IDCMP (mean [± SD] age 56.9±8.7 years) who recovered from systolic heart failure (LV ejection fraction [LVEF] of 26.5±6.9% at initial presentation) to a near-normal state (LVEF of 40% or greater, and a 10% increase or greater in absolute value) were monitored for recurrence of LV systolic dysfunction. Patients with significant coronary artery disease were excluded. Patients were monitored for 41.0±26.3 months after recovery (LVEF 53.4±7.6%) from LV dysfunction.

RESULTS:

LV systolic dysfunction reappeared (LVEF 27.5±8.1%) during the follow-up period in eight of 42 patients (19.0%). No significant difference between the groups with or without recurrent heart failure was observed in the baseline clinical and echocardiographic characteristics. However, more patients in the recurred IDCMP group than those in the group that maintained the recovery state had discontinued antiheart failure medication (62.5% versus 5.9%, P<0.05).

CONCLUSIONS:

LV dysfunction recurs in some patients with reversible IDCMP. The recurrence was significantly correlated with the discontinuation of antiheart failure drugs. The results suggest that continuous medical therapy may be mandatory in patients who recover from LV systolic dysfunction.     

Long term ventricular performance after intra-atrial correction of transposition: left ventricular filling is the major limitation

Objective—To establish the incidence of systolic and diastolic dysfunction of the right and left ventricle in a large cohort of patients after Mustard or Senning operations and to assess changes in the incidence on long term follow up.
Design—Postoperative case-control study using radionuclide ventriculography. Ejection fractions, peak filling rates, rapid filling periods and fractions, slow filling periods and fractions, and atrial contraction periods and fractions were studied.
Setting—Tertiary care centre, ambulatory and hospital inpatient care.
Patients—A convenience sample of 153 patients studied at median age of 6.9 years (median 4.4 years after surgery). In 99 cases another study was available at a median age of 15.3 years (median 13 years after surgery and 8.8 years after the first study).
Results—Respective incidences of dysfunction in the first and the second study were as follows: ejection fraction-right ventricle 7.8% and 8.1%, left ventricle 7.2% and 10.1%; peak filling rate-right ventricle 0% and 4.2%, left ventricle 14.3% and 29.5% (p < 0.05); rapid filling period- right ventricle 18.3% and 11.6%, left ventricle 30.2% and 30.5%; slow filling period—right ventricle 4.8% and 3.2%; left ventricle 11.9% and 23.2%; atrial contraction period-right ventricle 0.8% and 4.2%, left ventricle 15.1% and 26.3%; rapid filling fraction-right ventricle both 0%, left ventricle 82.5% and 79.0%; slow filling fraction-right ventricle 0.8% and 4.2%, left ventricle 37.3% and 30.5%; atrial contraction fraction-right ventricle both 0%, left ventricle 79.4% and 71.6%.
Conclusions—The incidence of systolic ventricular dysfunction is 8% (right ventricle) and 10% (left ventricle) 13 years after surgery, without a significant increase over the eight year follow up. Diastolic filling is abnormal in up to 80% of patients and left ventricular peak filling rate deteriorates with time.

Keywords: congenital heart defects; transposition of the great arteries; radionuclide ventriculography; ventricular function     

Relation between left ventricular function and oxidative stress in patients undergoing bypass surgery

Objective—To determine whether preoperative left ventricular ejection fraction (LVEF) is related to the degree of myocardial oxidative stress during bypass surgery in man.
Design—Observational study.
Setting—Tertiary care centre.
Patients and interventions—31 patients (LVEF range was 20% to 68%) undergoing elective coronary bypass surgery with blood cardioplegic reperfusion were studied. Arterial and coronary sinus blood was collected before aortic cross clamping (T0) and at 0 (T1), 15 (T2), and 30 (T3) minutes after unclamping. Transmural left ventricular biopsies were also obtained from 15 patients at T0 and at T1.
Main outcome measures—Glutathione and adenine nucleotides were measured in myocardial biopsies, while coronary sinus-artery differences for glutathione, nucleotides, and products of lipid peroxidation were calculated from blood specimens. Creatine kinase (myocardial band; CK-MB) was measured in plasma at four and 12 hours after operation.
Results—Myocardial glutathione and adenine nucleotides were correlated (p < 0.02) with preoperative LVEF both at T0 (r = 0.909 and 0.672) and T1 (r = 0.603 and 0.605). Oxidised glutathione released from the heart during reperfusion was inversely correlated with LVEF (r = −0.448, −0.466, and −0461 at T1, T2, and T3, p < 0.01), while reduced glutathione (r = 0.519 and 0.640 at T1 and T2) and glutathione redox ratio (r = 0.647, 0.714, 0.645, and 0.702 at T0, T1, T2, and T3) showed a direct correlation (p < 0.01). Lipid peroxidation at T1 was negatively related to LVEF (r = −0.492). CK-MB was also negatively related to LVEF (r = −0.440 at 4 h and −0.462 at 12 h).
Conclusions—The capacity to counterbalance oxidative burst following ischaemia and reperfusion appears to be related to the functional ability of the heart.

Keywords: oxidative stress; glutathione; lipid peroxidation; aortocoronary bypass     

左室舒张性心功能障碍超声左心形态、功能及运动耐量的改变50例分析

对核素心血池扫描证实的５０例左室舒张性心功能障碍（ＬＶＤＤ）病例、２６例左室收缩性心功能障碍（ＬＶＳＨＦ）病例进行Ｍ型、二维、多普勒超声心动图及活动平板运动试验检测，并以２０例正常人为对照组（ＣＧ）。结果表明：（１）左心形态学改变：与ＬＶＳＨＦ组比较，ＬＶＤＤ组左房内径（ＬＡＤ）、左室内径（ＬＶＤ）无明显增加，室间隔厚度（ＩＶＳＴ）、左室后壁厚度（ＰＷＴ）增加。与ＣＧ组比较，ＬＶＤＤ组ＬＡＤ、ＩＶＳＴ、ＰＷＴ增加，但ＬＶＤ差异无显著性。（２）ＬＶＤＤ组收缩功能指标：左室射血分数（ＬＶＥＦ）、心脏指数（ＣＩ）与ＣＧ组比较差异无显著性，ＬＶＳＨＦ组与ＣＧ组比较，ＬＶＳＨＦ组ＬＶＥＦ、ＣＩ减低。与ＣＧ组比较，ＬＶＤＤ组左室舒张功能指标：二尖瓣舒张早期流速峰值（ＥＰＦＶ）、二尖瓣舒张早、晚期流速峰值比（Ｅ／Ａ）、舒张早期减速度（ＤＣ）比ＣＧ组减低，二尖瓣舒张晚期流速峰值（ＡＰＦＶ）、等容舒张时间（ＩＲＴ）较ＣＧ组增高。ＬＶＤＤ组各左室舒张功能指标与ＬＶＳＨＦ组差异无显著性。（３）ＬＶＤＤ组运动时间、运动当量显著低于ＣＧ组，但高于ＬＶＳＨＦ组。     

Prolonged left ventricular dysfunction occurs in patients with coronary artery disease after both dobutamine and exercise induced myocardial ischaemia

OBJECTIVE: To determine whether pharmacological stress leads to prolonged but reversible left ventricular dysfunction in patients with coronary artery disease, similar to that seen after exercise. DESIGN: A randomised crossover study of recovery time of systolic and diastolic left ventricular function after exercise and dobutamine induced ischaemia. SUBJECTS: 10 patients with stable angina, angiographically proven coronary artery disease, and normal left ventricular function. INTERVENTIONS: Treadmill exercise and dobutamine stress were performed on different days. Quantitative assessment of systolic and diastolic left ventricular function was performed using transthoracic echocardiography at baseline and at regular intervals after each test. RESULTS: Both forms of stress led to prolonged but reversible systolic and diastolic dysfunction. There was no difference in the maximum double product (p = 0.53) or ST depression (p = 0.63) with either form of stress. After exercise, ejection fraction was reduced at 15 and 30 minutes compared with baseline (mean (SEM), -5.6 (1.5)%, p < 0.05; and -6.1 (2.2)%, p < 0. 01), and at 30 and 45 minutes after dobutamine (-10.8 (1.8)% and -5. 5 (1.8)%, both p < 0.01). Regional analysis showed a reduction in the worst affected segment 15 and 30 minutes after exercise (-27.9 (7.2)% and -28.6 (5.7)%, both p < 0.01), and at 30 minutes after dobutamine (-32 (5.3)%, p < 0.01). The isovolumic relaxation period was prolonged 45 minutes after each form of stress (p < 0.05). CONCLUSIONS: In patients with coronary artery disease, dobutamine induced ischaemia results in prolonged reversible left ventricular dysfunction, presumed to be myocardial stunning, similar to that seen after exercise. Dobutamine induced ischaemia could therefore be used to study the pathophysiology of this phenomenon further in patients with coronary artery disease.     

Usefulness of P‐wave peak time as an electrocardiographic parameter in predicting left ventricular diastolic dysfunction in patients with mitral regurgitation

IntroductionConventional Doppler measurements have limitations in predicting left ventricular diastolic dysfunction (LVDD) in patients with mitral regurgitation (MR). Recently, electrocardiographic P‐wave peak time (PWPT) has been proposed as a parameter of detecting LVDD. This study aimed to evaluate the association between PWPT and left ventricular end‐diastolic pressure (LVEDP) in patients with MR.MethodsWe performed echocardiography and cardiac catheterization in 82 patients with moderate or severe MR. We classified patients into two groups: low LVEDP group (L‐LVEDP) (LVEDP <16 mmHg, n = 40) and high LVEDP group (H‐LVEDP) (LVEDP ≥16 mmHg, n = 42). We evaluated LVDD and PWPT based on echocardiographic and electrocardiographic findings in both groups.ResultsThe PWPT in lead II (PWPT_II) was significantly longer in patients in the H‐LVEDP group than in those in the L‐LVEDP group (67 vs. 47 ms, p < .001). Using correlation analysis, LVEDP was positively correlated with PWPT_II (r = .577, p < .001). Using multivariate analysis, PWPT_II was found to be an independent predictor of increased LVEDP (95% CI: 0.1030–0.110; p < .001). Using receiver operating characteristic (ROC) curve analysis, the optimal cutoff value of PWPT_II for predicting elevated LVEDP was 58.9 ms, with a sensitivity of 80.0% and a specificity of 73.8% (area under curve: 0.809, 95% CI: 0.713–0.905).ConclusionTo the best of our knowledge, this is the first study to assess the effect of a significant valvular disease on PWPT in lead II. These findings suggest that prolonged PWPT_II may be an independent predictor of increased LVEDP in patients with moderate or severe MR.     

慢性心力衰竭的左心室舒张功能检测

目的探讨舒张性心力衰竭(心衰)与收缩性心衰的超声特点。方法选择舒张性心衰患者40例为舒张性心衰组,并选择基本情况与之匹配的收缩性心衰患者40例为收缩性心衰组。应用多普勒技术进行舒张功能的检测,进而评价2组在心房、心室容积,二尖瓣口血流舒张早期流速(E)与二尖瓣口血流舒张晚期流速(A)及其比值(E/A)和E峰减速时间,二尖瓣环舒张早期峰值速度(e)和二尖瓣环舒张晚期峰值速度(a)及其比值(e/a),左心房反流入肺静脉血流速度,P波终末电势等方面的差异。结果舒张性心衰组与收缩性心衰组比较,E/A、e/a倒置。舒张性心衰组E峰减速时间延长,左心房反流入肺静脉血流速度增宽。舒张性心衰组左心房增大,左心室舒张末径正常。P波终末电势负值增大。结论肺静脉血流频谱和二尖瓣环组织多普勒可作为二尖瓣血流频谱重要补充。     

Impact of diabetes on left ventricular diastolic function in patients with arterial hypertension

AIMS: To analyse the effect of diabetes (DM) on diastolic function in hypertensive patients. METHODS: 439 hypertensive patients were selected for participation in this study. All participants had an echocardiographic evaluation of systolic and diastolic function. The overall degree of diastolic function and specific parameters (e.g. E/Ea ratio) were analysed. RESULTS: We divided the cohort (63+/-10 years) into those with diabetes mellitus (DM(+), n=124) and without diabetes mellitus (DM(-), n=315). The prevalence of normal diastolic function was lower in DM(+) than DM(-) (19.4% vs. 30.8%); mild (65.3% vs. 60.0%) and moderate/ severe diastolic dysfunction were more frequent in DM(+) (15.3% vs. 9.2%, p=0.022). The E/Ea ratio, an estimate of left ventricular end-diastolic pressure, was significantly higher in DM(+) (12.3+/-4.4) as compared to DM(-) (10.8+/-3.6, p<0.001). Sex-specific analysis revealed that the effect of DM on diastolic function was mainly limited to the male subgroup. Multivariate logistic regression analysis showed that diabetes affected diastolic function in males independent of blood pressure, left ventricular mass index, concomitant medication and prevalence of coronary artery disease. CONCLUSION: Diabetes negatively affects diastolic function in patients with arterial hypertension. This effect is mainly confined to the male subgroup.     

老年左室舒张性心力衰竭超声心动图观察

目的评价老年左室舒张性心力衰竭超声左心形态、功能的特点。方法对核素心室造影证实的４０例左室舒张性心力衰竭（ＬＶＤＨＦ）及３０例左室收缩性心力衰竭（ＬＶＳＨＦ）进行超声心动图检查，并以２０例正常人为对照组（ＣＧ）。结果ＬＶＤＨＦ组左房内径、室间壁及左室后壁厚度增加，左室内径不大，左室舒张功能参数减低，而左室收缩功能参数正常。ＬＶＳＨＦ组左室内径明显增加，左室收缩、舒张功能参数均异常。结论老年ＬＶＤＨＦ超声心动图特点为左房内径扩大、室壁增厚、左室内径不大，左室收缩功能正常，而左室舒张功能异常。     

Role of orthotopic heart transplantation in the management of patients with recurrent ventricular tachyarrhythmias following myocardial infarction

Objective—To report the outcome of an intention to treat by heart transplantation strategy in two groups of patients after infarction, one with both left ventricular failure (LVF) and ventricular tachyarrhythmias (VTA) (group A) and the other with progressive LVF following antiarrhythmic surgery for VTA (group B).
Patients and methods—Group A comprised 17 consecutive patients for whom transplantation was considered the best primary non-pharmacological treatment; group B comprised five consecutive patients assessed and planned for transplantation after antiarrhythmic surgery.
Results—In group A, eight patients underwent transplantation and all survived the first 30 day period. At median follow up of 55 months (range 11 to 109) seven of this subgroup were still alive. Five patients died of recurrent VTA before transplantation, despite circulatory support. In the face of uncontrollable VTA, four of these underwent "high risk" antiarrhythmic surgery while awaiting transplantation: three died of LVF within 30 days and one was saved by heart transplantation two days after arrhythmia surgery. Mortality for the transplantation strategy in group A patients was 47% by intention to treat analysis. Quality of life in the eight actually transplanted, however, was good and only one died during median follow up of 56 months. The five patients in group B were accepted for transplantation for progressive LVF at a median of 21 months (range 12 to 28) after antiarrhythmic surgery. One died of LVF before transplantation, 22 months after initial surgery; another died of high output LVF three days after transplantation. Thus mortality of the intended strategy was 40%. The three transplanted patients are alive and well at 8-86 months.
Conclusions—Although the short and medium term outcome in category A or B patients who undergo transplantation is good, the overall success of the transplantation strategy in category A patients is limited by lack of donors in the short time frame in which they are required.

Keywords: heart transplantation;  ventricular arrhythmias;  myocardial infarction     

Worsening of left ventricular diastolic dysfunction during exercise causes decreased exercise tolerance in hypertension

BACKGROUND: Exercise tolerance is reduced in hypertension. Hypertension affects left ventricular (LV) diastolic filling by causing abnormal relaxation and decreasing compliance. HYPOTHESIS: This study was designed to determine whether worsening of LV diastolic dysfunction during exercise causes decreased exercise tolerance in hypertension. METHODS: Left ventricular diastolic filling parameters were examined at mitral valve by Doppler echocardiography at rest and at peak exercise in hypertensive patients and were compared with those of age- and gender-matched normotensive individuals. Treadmill exercise stress test was performed according to the Bruce protocol and the exercise time was recorded. RESULTS: Exercise time was significantly shorter in the hypertensive group than that in the normotensive group (320 +/- 29 vs. 446 +/- 38 s, p 0.03). The hypertensive group demonstrated abnormal relaxation pattern of diastolic mitral inflow at rest, which became pseudonormal at peak exercise (E/A velocity ratio, rest 0.86 +/- 0.06 vs. exercise 1.19 +/- 0.09, p < 0.001). The diastolic mitral inflow pattern remained normal at peak exercise in the normotensive group. The deceleration time and the pressure half time of early mitral inflow at peak exercise were significantly shorter in the hypertensive group than those in the normotensive group (deceleration time, 182 +/- 20 vs. 238 +/- 22 ms, p 0.02: pressure half time, 54 +/- 5 vs. 70 +/- 12 ms, p 0.01). CONCLUSIONS: This study demonstrates that reduced exercise tolerance in hypertension is associated with worsening of diastolic dysfunction during exercise consistent with an increase in left atrial pressure.