Reduced left atrial function on exercise in patients with heart failure and normal ejection fraction.

AIMS: The cardinal symptom of heart failure with a normal ejection fraction (HFNEF) is exertional dyspnoea. The authors hypothesised that failure of left atrial (LA) compensatory mechanism particularly on exercise contributes to the genesis of symptoms in HFNEF patients. METHODS AND RESULTS: Fifty HFNEF patients, 15 asymptomatic hypertensive subjects and 30 healthy controls underwent rest and submaximal exercise echocardiography. Rest and exercise systolic, early diastolic and late diastolic (Am) mitral annular velocities were assessed using colour tissue Doppler echocardiography. Left atrial functional reserve index was calculated. Am at rest was comparable between all three groups, but exercise Am was significantly lower in HFNEF compared with hypertensive subjects and healthy controls resulting in a lower LA functional reserve index (0.84 (1.34) vs 2.39 (1.27) and 1.81 (1.39), p<0.001). LA volume index was significantly higher in HFNEF patients (30.4 (9.2) vs 27.9 (6.3) and 23.2 (7.1) ml/m(2), p=0.002). There was a significant correlation between Am on exercise with peak VO(2) max (r=0.514, p<0.001) and E/Em on exercise (r=-0.547, p<0.001). Area under the receiver operating characteristic for Am on exercise was 0.768 (95% CI=0.660 to 0.877). CONCLUSION: HFNEF patients have reduced LA function on exercise in addition to left ventricular systolic and diastolic dysfunctions. Reduced LA function probably contributes significantly to exercise intolerance and breathlessness in HFNEF patients.

Cardiovascular magnetic resonance at 0.5T in five patients with permanent pacemakers.

BACKGROUND: Cardiovascular magnetic resonance (CMR) yields important clinical information which often cannot be obtained from other imaging modalities. Cardiac pacemakers have conventionally been considered a contraindication to CMR, and relatively few data exist on CMR in such patients. METHODS AND RESULTS: We present 5 patients who underwent 6 CMR scans in a 0.5 Tesla scanner. The patients were non-pacemaker dependent, and the pacemakers were reprogrammed prior to scanning to have sub-threshold output. Spin echo, gradient echo and real-time sequences were used with specific absorption rates of up to 0.1 W/kg. A cardiologist was present during each scan, and the patient had continuous electrocardiographic and non-invasive monitoring of vital signs. Five of the scans were carried out without incident providing useful diagnostic information, which was not compromised by obvious artifact from the pacemaker box. In one case, the pacemaker began pacing at maximum voltage at a fixed rate of 100. This patient was removed from the magnet, and there were no clinical sequelae. The mean pre-and post-scan ventricular lead voltage threshold was the same (2.28 V vs 2.28 V). CONCLUSION: Our experience is that CMR at 0.5T in non-pacemaker dependent patents can be performed in closely supervised circumstances where the benefit-risk assessment is considered positive.

Left ventricular aneurysm: comprehensive assessment of morphology, structure and thrombus using cardiovascular magnetic resonance.

AIM: To demonstrate that cardiac magnetic resonance (CMR) techniques provide unique and definitive information on the presence, location, size and nature of left ventricular aneurysm and pseudoaneurysm, the presence of thrombus and the viability of myocardium. METHOD: A retrospective study of 27 patients with a final diagnosis of left ventricular aneurysm or pseudoaneurysm, who underwent CMR at a tertiary referral centre in the period between 2000 and 2003. RESULTS: In 7 cases the correct diagnosis of true aneurysm was confirmed; in 7 cases previously unsuspected thrombus was identified; in 7 cases an unsuspected pseudoaneurysm was identified; and in a further 6 cases a previously unsuspected aneurysm was identified. CONCLUSION: CMR refined the diagnosis in the majority of patients with left ventricular aneurysm, and should be considered in all cases of confirmed or suspected left ventricular aneurysm.

Echocardiography and the general physician.

Doctors from many medical specialties request echocardiography as part of their assessment of patients with a wide range of pathology. Recent advances in the technology and techniques of echocardiography are discussed. The role of echocardiography in acute medicine is reviewed and its place in general medicine is also discussed.

Cardiac magnetic resonance imaging.

Recent advances in technology have allowed magnetic resonance imaging to be exploited in cardiology. It is capable of giving high definition structural and functional information. The current applications of this technique and how it may develop in the future are reviewed.