A normal electrocardiogram precludes the need for left ventriculography in the assessment of coronary artery disease

Prevalence of ECG abnormalities in an international survey of patients with suspected or confirmed heart failure at death or discharge

BACKGROUND

Most patients suspected of having heart failure (HF) will get a 12-lead electrocardiogram (ECG) but its utility for excluding HF or assisting in its management has rarely been investigated.

METHODS

The EuroHeart Failure survey identified 11,327 patients hospitalised with a suspected diagnosis of HF from 115 hospitals in 24 countries. ECGs were obtained from 9315 patients, of whom 5934 had cardiac imaging tests. The utility of the ECG was assessed for excluding or diagnosing major structural heart disease (MSHD) or major left ventricular systolic dysfunction (MLVSD) and for therapeutic decision making.

FINDINGS

MSHD was present in 70% and MLVSD in 54% of patients overall but in only 21% and 5%, respectively, if the ECG was entirely normal. However, <2% of patients had a normal ECG. No single ECG characteristic identified a probability <25% of MSHD or <20% of MLVSD. Patients with QRS width >or=120 ms or anterior pathological Q-waves had a probability >80% of MSHD and >70% of MLVSD. Diagnostic models suggested that electrocardiographic criteria alone were not accurate for the diagnosis or exclusion of important heart disease in this population. However, 2468 patients (42%) had an electrocardiographic finding that should be used to guide the choice of therapy.

CONCLUSIONS

A normal ECG is rare in patients with suspected HF but has limited diagnostic value in this setting. The ECG has an important role in guiding therapy.

Heart rate response during dipyridamole stress as a predictor of mortality in patients with normal myocardial perfusion and normal electrocardiograms

Although it is well established that a blunted chronotropic response to exercise is associated with a higher risk of death, recent data suggest a similar association between mortality risk and blunted heart rate response to vasodilatory stress. We investigated the heart rate response to dipyridamole-induced stress as a predictor of death in the setting of normal myocardial perfusion and a normal electrocardiogram. We followed 1,087 patients for 8 years (range 5.7 to 11.8) who underwent dipyridamole vasodilator stress and had normal perfusion scans and electrocardiograms. None had heart failure, known left ventricular systolic dysfunction, pacemaker implantation, or valve disease. Heart rate response was assessed as the ratio of heart rate at peak stress to heart rate at rest. The primary end point was all-cause mortality. Quartile values for the peak-to-rest heart rate ratio were <1.19, 1.19 to 1.30, 1.31 to 1.44, and >1.44. There were 246 deaths. Death rates according to quartiles of heart rate ratio were 103 of 271 (38%), 64 of 272 (24%), 52 of 272 (19%), and 27 of 272 (10%). After adjusting for age, gender, heart rate at rest, blood pressure response, standard cardiovascular risk factors, and other confounders, a blunted heart rate response remained predictive of death (adjusted hazard ratio for lowest vs highest quartile 3.3, 95% confidence interval 2.1 to 5.1, p <0.0001). When considered as a continuous variable, the logarithm of the heart rate ratio was the strongest predictor of death, aside from age. Thus, among patients who have normal myocardial perfusion and normal electrocardiograms, a blunted heart rate response to vasodilator stress is predictive of a marked increase in risk of death.

Striking similarities in systemic factors contributing to decreased exercise capacity in patients with severe chronic heart failure or COPD

AIMS

Chronic heart failure (CHF) and COPD are both characterized by muscular impairment. To assess whether the severity and functional consequences of muscular impairment are disease specific, we compared skeletal muscle function, body composition, and daily activity level relative to exercise capacity between these two disorders.

METHODS

Twenty-five patients with CHF and 25 patients with COPD, and 36 healthy gender- and age-matched control subjects underwent measurement of fat-free mass (FFM) [by bioelectrical impedance analysis] as an index of muscle mass. Quadriceps and biceps functions were tested by isokinetic methods, and daily activity level was assessed by the Physical Activity Scale for Elderly (PASE) questionnaire. Peak oxygen consumption (O(2)peak) was measured by incremental cycle ergometry.

RESULTS

PASE results were similar in patients with CHF and in patients with COPD, each group scoring lower than control subjects. FFM was also lower in patients than control subjects and correlated closely with quadriceps and biceps strength in all three subgroups, R values ranging from 0.63 to 0.78, with identical slopes. FFM also correlated significantly with O(2)peak (p < 0.05), but slopes were less steep in patients than in control subjects. The type and severity of muscle dysfunction were similar in each group of patients. There were no significant correlations between indexes of cardiopulmonary function and muscle function or exercise performance in patients with CHF or in patients with COPD. In both control subjects and patients, FFM was the most significant determinant of O(2)peak.

CONCLUSION

Muscle dysfunction is not limited to the lower limbs, but generalized and comparable between patients with CHF and patients with COPD with similar exercise capacity. FFM is a strong predictor of peripheral muscle strength, to a lesser extent of O(2)peak, and not at all of peripheral muscle endurance.

Does cardiologist- or radiographer-operated fluoroscopy and image acquisition influence optimization of patient radiation exposure during routine coronary angiography?

The operator of radiation exposure during coronary angiography varies between different centres. The purpose of this study was to explore whether radiation dose was lower during cardiologist- or radiographer-controlled radiation exposure and to determine if the grade of cardiologist performing angiography influenced radiation dose. Patients were randomly allocated either to cardiologist- or radiographer-controlled radiation exposure during coronary angiography. Screening time and radiation dose during fluoroscopy and image acquisition, measured by dose-area product meter, were recorded. Mean radiation dose during cardiologist-controlled radiation exposure (n=176) of 15.6 Gy cm(2) (95% confidence interval (CI), 14.4-16.8) was significantly lower than that produced by the radiographer-controlled group (n=192) of 17.3 Gy cm(2) (95% CI, 16.2-18.6) (p<0.044). There was no significant difference in screening times produced by the two groups of radiation exposure operators. The difference in radiation dose produced by the two operator groups was principally owing to exposure produced at image acquisition. Irrespective of radiation exposure operator, consultant cardiologists produced significantly lower screening times and radiation doses compared with registrars. During routine coronary angiography, radiographer-controlled radiation exposure does not reduce screening time or radiation dose. Senior cardiologists produce the lowest radiation doses during coronary angiography when they are responsible for radiation exposure.

Beta-blockers are associated with lower C-reactive protein concentrations in patients with coronary artery disease

PURPOSE

C-reactive protein is an important risk factor for coronary artery disease, and plasma concentrations are lowered by treatment with pravastatin and aspirin. We examined whether other cardiovascular drugs that are used in the treatment of ischemic heart disease affect C-reactive protein concentrations.

SUBJECTS AND METHODS

Plasma C-reactive protein concentration was measured by high sensitivity immunonephelometric assay in 333 consecutive patients with stable angina and confirmed coronary artery disease who underwent diagnostic angiography.

RESULTS

Patients prescribed beta-blockers had significantly lower mean C-reactive protein concentrations than did patients in whom these were not prescribed (by 1.2 mg/L, or 40% difference in geometric mean concentration; P <0.001). This association remained significant (P = 0.03) after excluding patients with contraindications to the use of beta-blockers, and adjusting for the probability of beta-blocker therapy (propensity score) and other clinical predictors of C-reactive protein concentration, including body mass index, high-density lipoprotein cholesterol level, family history of coronary artery disease, and angiographic severity. No differences among types or dosages of beta-blockers were evident.

CONCLUSION

Beta-blockers may affect C-reactive protein concentrations. Randomized studies are required to confirm these findings.

Factors affecting patient radiation exposure during routine coronary angiography in a tertiary referral centre

Cardiac catheterization is carried out by an increasing number of operators from district hospitals as well as tertiary referral centres. Procedures are not standardized and are at the discretion of individual operators. The purpose of this study was to describe the pattern of patient radiation dose and screening times associated with diagnostic cardiac catheterization, and explore determinants of radiation dose to patients and staff. Data were collected from 1337 diagnostic procedures carried out in two cardiac catheterization laboratories from January to June 1998. Screening time and radiation dose measured by dose-area product (DAP) meter were recorded. Status of the operator and type of investigation were determined. 22 operators had performed at least 15 left ventriculograms with coronary angiography (total 944 procedures). The average (+/- SD) was 40 (+/- 22) per operator. Screening times for individual operators varied from 2.0 (+/- 1.3) min to 5.0 (+/- 4.3) min with no relationship between time and number of cases. Consultants and visiting physicians had longer screening times and greater patient DAP readings. In comparison with 115 cases of coronary angiography alone, left ventriculography increased DAP reading from 14.24 (+/- 11.7) Gy cm2 to 20.26 (+/- 0.47) Gy cm2 (p < 0.0001). In 106 cases of coronary artery bypass graft angiography, an aortogram (n = 53) did not add significantly to radiation dose or screening time. A right heart catheter added approximately 5 min to screening time (9.13 (+/- 0.63) min with right heart (n = 83) vs 3.96 (+/- 0.12) min without right heart (n = 1234)), but did not affect radiation dose significantly. There is a wide range of screening times and radiation doses related to diagnostic cardiac catheterization. Visiting and consultant staff use greater radiation doses. Left ventriculography adds significantly to patients' radiation exposure. Aortography does not add significantly to radiation dose in cases of graft angiography.

Ordering an echocardiogram for evaluation of left ventricular function: level of expertise necessary for efficient use

This prospective study was performed to test the hypothesis that the yield of 2-dimensional echocardiography (2DE) would be higher when it is ordered by a cardiologist than by a noncardiologist. Patients referred for transthoracic 2DE for the evaluation of left ventricular systolic function for the 11-month period between July 10, 1995, and June 10, 1996, were included in the study. Demographic, historical, and clinical findings were recorded. Whether the patient was referred by a cardiologist versus a noncardiologist was used as the predictor variable in a binary logistic regression analysis. To address the possibility that the yield of 2DE may be higher for cardiologists because the prevalence of disease in patients referred to them may be higher (selection bias), the analysis was subjected to a propensity score adjustment. Of 2176 patients referred for 2DE during the study, 1033 were referred for the evaluation of left ventricular function. The test had a positive yield in 52% of patients for cardiologists versus 31% for noncardiologists (chi(2) = 45.5, P <.0001, odds ratio 2.4 [CI = 1. 9-3.1]). This difference remained highly significant even when propensity score risk adjustment was made (chi(2) = 54.2, P <.0001, odds ratio 2.0 [CI = 1.5-2.8]). We conclude that the yield of 2DE is higher for cardiologists compared with noncardiologists and that this result was not related to differences in patient populations examined by the two groups. Thus, more efficient use of 2DE may be achieved if patients are referred to cardiologists rather than directly sent for 2DE.