Hugh A. McCann

Alcohol consumption and idiopathic dilated cardiomyopathy: a case control study.

BACKGROUND Alcohol has been implicated as a risk factor for idiopathic dilated cardiomyopathy (DCM), but a causal relation has not been established. The objective of this study was to determine the association between alcohol consumption and DCM. METHODS Questionnaires detailing average weekly intake of alcohol, total lifetime consumption, and alcohol abuse were administered in a cohort of well-defined patients with DCM and a randomly selected, population-based control group. RESULTS Significantly more of the 100 patients with DCM than the 211 members of the control group drank greater than the recommended weekly intake of alcohol (40% vs 24%; p < 0.01) and were alcohol abusers according to the CAGE questionnaire (27% vs 16%; p < 0.05). The average total lifetime consumption measured in units of alcohol was also significantly greater in cases than in the control group (31,200 vs 7,904; p < 0.01). Patients with familial DCM were not significantly more likely to consume alcohol above recommended limits or to be alcohol abusers compared with nonfamilial cases. CONCLUSIONS This study confirms previous suspicion of a causal association between alcohol and DCM, with significantly more patients than members of the control group either abusing alcohol or drinking it in excess of recommended limits.

Gender differences in the management and outcome of acute myocardial infarction in unselected patients in the thrombolytic era

This study compares the clinical features, management, and outcome in men and women from a consecutive, unselected series of patients with acute myocardial infarction (AMI) who were admitted to a university cardiac center over a 3-year period. It is a retrospective observational study of 1,059 admissions with AMI identified through the Hospital In-Patient Enquiry (HIPE) registry, validated according to Minnesota Manual criteria, and followed for a period of up to 5 years (median 36 months). Women comprised 40% of all admissions, had a higher hospital mortality (24% vs. 16%, p<0.001), and were less likely to receive thrombolysis (23% vs. 33%, p<0.01), admission to coronary care (65% vs. 77%, p<0.001), or subsequent invasive or noninvasive investigations (55% vs. 63%, p<0.01). However, women with AMI were older than men with AMI (71 vs. 65 years, p<0.001). After adjusting for age, differences that remained significant were prevalence of hypertension (odds ratio [OR] 2.12, 95% confidence intervals [CI] 1.56 to 2.88) and cigarette smoking (OR 0.47, 95% CI 0.35 to 0.65), management in coronary care (OR 0.66, 95% CI 0.49 to 0.88), and hospital mortality (OR 1.48, 95% CI 1.07 to 2.04). Excess mortality occurred predominantly in women <65 years old (18% vs. 8%, OR [multivariate] 2.35, 95% CI 1.19 to 4.56), among whom multivariate analysis demonstrated a significantly lower thrombolysis rate (OR 0.48, 95% CI 0.27 to 0.86). In this group, lack of thrombolysis independently predicted hospital mortality (OR 5.37, 95% CI 1.45 to 19.82). Female gender was not an independent predictor of mortality following AMI (OR 1.42, 95% CI 0.90 to 2.26). Thus, among unselected patients, female gender is associated with, but not an independent predictor of, reduced survival after AMI. Gender differences in mortality are greatest in younger patients, who are less likely to receive thrombolysis and in whom lack of thrombolysis is independently associated with mortality after AMI.

Hospital mortality of acute myocardial infarction in the thrombolytic era

OBJECTIVE To examine the management and outcome of an unselected consecutive series of patients admitted with acute myocardial infarction to a tertiary referral centre. DESIGN A historical cohort study over a three year period (1992–94) of consecutive unselected admissions with acute myocardial infarction identified using the HIPE (hospital inpatient enquiry) database and validated according to MONICA criteria for definite or probable acute myocardial infarction. SETTING University teaching hospital and cardiac tertiary referral centre. RESULTS 1059 patients were included. Mean age was 67 years; 60% were male and 40% female. Rates of coronary care unit (CCU) admission, thrombolysis, and predischarge angiography were 70%, 28%, and 32%, respectively. Overall in-hospital mortality was 18%. Independent predictors of hospital mortality by multivariate analysis were age, left ventricular failure, ventricular arrhythmias, cardiogenic shock, management outside CCU, and reinfarction. Hospital mortality in a small cohort from a non-tertiary referral centre was 14%, a difference largely explained by the lower mean age of these patients (64 years). Five year survival in the cohort was 50%. Only age and left ventricular failure were independent predictors of mortality at follow up. CONCLUSIONS In unselected consecutive patients the hospital mortality of acute myocardial infarction remains high (18%). Age and the occurrence of left ventricular failure are major determinants of short and long term mortality after acute myocardial infarction.

Evaluation of patients with diabetes mellitus for coronary artery disease using dobutamine stress echocardiography.

BACKGROUND There is a high prevalence of coronary artery disease (CAD) in patients with diabetes mellitus. Detection of inducible ischaemia using treadmill exercise testing may be limited by the relatively poor inherent predictive accuracy of the test. The purpose of this study was to determine the value of dobutamine stress echocardiography (DSE) for the detection of CAD in patients with diabetes mellitus. METHODS Patients with diabetes mellitus referred for cardiac assessment were considered eligible for study. DSE was performed in a standard fashion. Significant CAD was defined as a > 50% luminal diameter stenosis on coronary angiography. RESULTS A total of 52 patients (mean age 59 years) with diabetes mellitus were studied prospectively using DSE. Risk factors for CAD included hypertension in 19, family history in 21, hypercholesterolaemia in 14, history of smoking in 38. The sensitivity, specificity, positive and negative predictive values of DSE for detection of CAD were 82, 54, 84 and 50% respectively. CONCLUSION The specificity of DSE for CAD in patients with diabetes mellitus is low. Whether this reflects an underdetection of small vessel disease by contrast coronary angiography or whether it relates to test performance is unclear.

Serial changes in cardiac output during normal pregnancy: a Doppler ultrasound study

OBJECTIVES To determine the direction and magnitude of change in cardiac output (CO) during pregnancy. STUDY DESIGN We performed serial measurements of CO on five occasions from 24 weeks gestation to term and once during the puerperium in 26 normal pregnancies (156 measurements) using Doppler ultrasound measurement of flow velocity profiles and aortic root cross sectional area. RESULTS CO increased to 7.0 l/min by 32 weeks gestation, 49% above baseline values. It fell to 5.7 l/min by term, 21% above baseline. The peak in CO corresponded with an increase in heart rate to 91 beats/min, 32% above baseline. Stroke volume peaked at 36 weeks gestation, by which time CO had already begun to decline. CONCLUSIONS CO increased in a linear fashion until 32 weeks gestation and then declined to term, but to a value still greater than the postpartum baseline. These findings have obvious management implications for patients with serious heart disease complicating pregnancy.

Dobutamine stress echocardiography in the detection of coronary artery disease: Importance of the pretest likelihood of disease ☆ ☆☆

Although the accuracy of dobutamine stress echocardiography for the detection of coronary artery disease in a high-risk population is known, it has not been well defined for lower risk groups. Two probability groups, high (>75%; n = 199) and intermediate (>10% but < or =75%; n = 118), were studied. Dobutamine stress echocardiography was performed in a standard fashion. Significant coronary artery disease was defined as a >50% luminal diameter stenosis on coronary angiography. The positive predictive accuracy of dobutamine stress echocardiography for the detection of coronary artery disease was greater in the high-probability group (96% vs 86%), as was the sensitivity (89% vs 78%), whereas the negative predictive value was greater in the intermediate-probability group (50% vs 23%), as was the specificity (63% vs 50%). Dobutamine stress echocardiography does have a diagnostic role in the evaluation of patients with an intermediate probability of coronary artery disease.

Dobutamine stress echocardiography in the detection of coronary artery disease in a clinical practice setting

UNLABELLED In this prospective study, patients referred for coronary angiography for detection of disease underwent dobutamine stress echocardiography to define its value in a clinical practice setting. RESULTS Of 219 patients studied, 170 (78%) had significant coronary artery disease. The overall sensitivity and specificity of dobutamine stress echocardiography for coronary artery disease were 82 and 65%, respectively. The sensitivity was 88% for detection of triple-vessel disease, 83% for double-vessel disease, and 74% for single-vessel disease. Positive and negative predictive values for coronary artery disease were 89 and 51%, respectively. Dobutamine stress echocardiography correctly identified only 72 of 138 patients with significant stenosis of the left anterior descending coronary artery. In 219 patients, 345 of 657 major epicardial vessels had significant disease. Dobutamine stress echocardiography could only correctly identify the vessel involved in 188. Triple-vessel disease was present in 65 patients. Dobutamine stress echocardiography correctly categorised 18% (n = 12) of these. The remainder were incorrectly classified as having double-vessel disease or single-vessel disease (n = 45), or no disease at all (n = 8). CONCLUSION Dobutamine stress echocardiography performs well. However, lower specificity may lead to unwarranted referrals for coronary angiography, and the low NPV give false reassurance as to the absence of disease.

Characteristics and outcomes in patients with acute myocardial infarction with ST-segment depression on initial electrocardiogram.

BACKGROUND Acute myocardial infarction (AMI) with nonreciprocal ST-segment depression is said to have a poor prognosis, and early diagnosis and treatment are problematic. The aim of this study was to determine the proportion of unselected consecutive patients admitted to a university center with AMI with nonreciprocal ST-segment depression and to characterize these patients in terms of clinical features, treatment, and short- and long-term prognoses. METHODS AND RESULTS Admission electrocardiographic data on 852 consecutive admissions with AMI were analyzed. Nonreciprocal ST-depression was an admitting feature in 95 (11%) patients, the majority of whom had ST depression >3 mm. These were older (70.3 vs 66.8 years, P <.05), more likely to have had myocardial infarction (40% vs 25%, P <.01), and to have left ventricular failure (56% vs 42%, P <.5), cardiogenic shock (15% vs 9% P =.06), and atrial fibrillation (34% vs 19%, P <.01). Hospital mortality rate was significantly higher (31% vs 17%, P <.01). Patients were less likely to undergo thrombolysis (17% vs 31%, P <.01), angiography (22% vs 35%, P <.05), or percutaneous revascularization (5% vs 9%, P <.01). Patients with ST depression undergoing coronary angiography were more likely to have 3-vessel disease (71% vs 47%, P <.05). Mortality rate at follow-up (median 36 months) was significantly higher in patients with ST depression (56% vs 32%, P <.001). Analysis by individual electrocardiography demonstrated ST-segment depression to be the third most frequent presentation after ST elevation (n = 327) and T-wave changes (n = 258), in whom hospital mortality rates were 24% and 9%, respectively. In multivariate analysis, previous myocardial infarction was an independent predictor of nonreciprocal ST depression at initial examination (odds ratio 2.04 [1.25 to 3.34], P <.005). No electrocardiographic presentation was an independent predictor of death in the hospital after AMI. CONCLUSIONS In unselected cases of AMI, patients with ST-segment depression make up a significant minority (11%), who are likely to be older with a high prevalence of previous myocardial infarction and multivessel disease, and who have a poor prognosis.

Histopathologic changes in asymptomatic relatives of patients with idiopathic dilated cardiomyopathy

Echocardiographic screening of asymptomatic relatives of patients with idiopathic dilated cardiomyopathy identifies a subset with left ventricular enlargement who are assumed to have early familial idiopathic dilated cardiomyopathy. This study shows for the first time that the myocardium in such relatives demonstrates abnormal cellularity.

Safety of dobutamine stress echocardiography in 474 consecutive studies.

BACKGROUND With expanding applications and increasingly aggressive stress protocols, concerns about the safety of dobutamine stress echocardiography (DSE) have arisen. The purpose of this study was to analyse prospectively the safety, adverse event profile and complication rate of DSE. METHODS Prospective data were recorded in a consecutive series of 474 patients undergoing DSE. Dobutamine was administered intravenously in graded infusion, each stage over 3 min, at 10, 20, 40 and, if required, 50 micrograms/kg/min. Atropine (1 mg) was administered thereafter if the response remained suboptimal. RESULTS The mean dose of dobutamine was 42 micrograms/kg/min, with 111 patients (23%) receiving 50 micrograms/kg/min. Atropine was required for 27 patients (6%). No patient died or suffered a myocardial infarction. Sustained ventricular tachycardia occurred in one patient, angina pectoris in 127 (27%), non-sustained ventricular tachycardia in eight (2%) and supraventricular tachycardia in 19 (4%). Profound bradycardia requiring cessation of the test occurred in one patient. Pulmonary oedema developed in one patient. A hypotensive response requiring cessation of the test was seen in one patient. Test termination because the patient complained of nausea, tremor or headache was not required. CONCLUSION DSE is safe. Side effects are rare and when they occur, are usually minor. Ischaemic pain is effectively treated by termination of the test and sublingual administration of nitrates.