Alan Gordon Fraser

The effect of pharmacological stress on intraventricular dyssynchrony in left ventricular systolic dysfunction

Cardiac resynchronisation therapy (CRT) improves symptoms and exercise capacity in many patients with heart failure (HF) who have left ventricular systolic dysfunction (LVSD) and markers of dyssynchrony. LV dyssynchrony is conventionally measured at rest but the symptoms of heart failure occur predominantly on exercise. Induction or exacerbation of dyssynchrony during stress might identify additional patients who could benefit from CRT.

Follow-up of chronic thoracic aortic dissection: comparison of transesophageal echocardiography and magnetic resonance imaging

Because survivors of thoracic aortic dissection require follow-up to detect prognostic factors such as intimal tears, persistent flow in the false lumen, and complications associated with grafts, we compared transesophageal echocardiography (TEE) with magnetic resonance imaging (MRI) prospectively in 14 patients 1 year after their initial examination. Residual dissection was identified by both techniques in 11 patients. Flow and/or thrombus in the false lumen were detected by TEE in 10 (91 %) and 6 (55%) patients, respectively, and by MRI in 9 (82%) and 5 (45%), respectively (p = NS); more tears were detected by TEE (2.5 +/- 1.4 per patient vs 0.2 +/- 0.4; p < 0.005). Satisfactory delineation of a graft in the ascending aorta was noted in all 8 (100%) of the surgically treated patients by TEE compared with 4 (50%) by MRI (p < 0.005). The upper ascending aorta was visualized clearly in fewer patients by TEE than by MRI (7 [50%] vs 13 [93%]; p < 0.05), as were the origins of the head and neck vessels (10 [71%] vs 13 [93%], p = NS). We conclude that TEE and MRI are both suitable techniques for the follow-up of patients with aortic dissection. TEE is more sensitive in identifying prognostic factors. MRI has a complementary role, particularly in visualization of the upper ascending aorta and the head and neck vessels.

Adenosine provokes diastolic dysfunction in microvascular angina

Adenosine stress echocardiography was performed in nine patients (58 (±3) years, eight women) with documented microvascular angina. Global ventricular function was assessed by Tc99m blood pool imaging and Doppler, whereas longitudinal ventricular function was assessed by simultaneous tissue Doppler echocardiography of the lateral mitral annulus. Adenosine was infused incrementally to onset of chest pain in all patients. There was no significant change in global or longitudinal systolic function. Adenosine induced global diastolic dysfunction, demonstrated by blood pool imaging and by Doppler of the transmitral flow. All patients had long axis diastolic dysfunction at peak adenosine, revealed by a ratio of early to late diastolic velocity of lateral mitral annulus <1, which was absent at rest. Adenosine, as a stress agent, provokes regional and global diastolic dysfunction in microvascular angina, which may be a consequence of subendocardial ischaemia. Long axis diastolic dysfunction can be easily revealed by tissue Doppler of the lateral annular motion.

Progression of Subclinical Myocardial Dysfunction in Type 2 Diabetes after 5 years Despite Improved Glycemic Control

Background: Patients with uncomplicated diabetes have reduced left ventricular long‐axis function, related to poor glycemic control and increased conduit arterial stiffness, with increased radial function. It is unknown if improved control of risk factors can reverse these subclinical changes. Patients and methods: We studied 27 patients with type 2 diabetes (18 men) 57 ± 1 months (mean ± SD) after an initial visit when they were compared with healthy age‐ and sex‐matched controls. On both visits patients had detailed echocardiographic studies including tissue Doppler, noninvasive tests of conduit arterial function, and metabolic and lipid profiling. Results: Mean age at this second review was 63.4 ± 8.1 years; 48% of patients received insulin. Mean HbA1c had decreased by 13% to 8 ± 1.6% and cholesterol by 17% to 4.3 ± 1.3 mmol/L (both, P < 0.01), but long‐axis systolic and early diastolic myocardial velocities had also declined, by 13% and 20%, respectively (both, P < 0.001). Body mass index had increased by 4%, arterial pulse pressure by 17% (both P < 0.01), and carotid arterial stiffness by 49% (P < 0.01). Fractional shortening (by 21%, P < 0.001), radial systolic velocity (by 13%, P < 0.05), and ejection fraction (by 9% to 68 ± 7%, P < 0.01) had all declined. Reductions in longitudinal function were best predicted by its baseline measurements, duration of diabetes, fasting triglycerides, and arterial stiffness (epsilon index). Conclusions: Despite improved diabetic control, subclinical left ventricular dysfunction progressed over 5 years. Radial compensation was reversed. Prevention of subclinical myocardial dysfunction in diabetes might require more intensive control of net cardiovascular risk.

Delays by patients in seeking treatment for acute chest pain: implications for achieving earlier thrombolysis

A study was set up to identify why patients delay seeking medical assistance after myocardial infarction. The study was performed in 100 consecutive patients with suspected acute myocardial infarction admitted to either the University Hospital of Wales, Cardiff, UK, or the Royal Jubilee Hospital, Victoria, British Columbia, Canada (50 patients from each centre). The main outcome measure was the delay from the onset of symptoms to admission to hospital. The mean total delay before admission was 385 minutes (SEM 45). The mean delay incurred by the patient in seeking assistance was 172 minutes (SEM 27), representing 45% of the total. Delay was longer in patients with crescendo angina and shorter in those later confirmed to have myocardial infarction. Patients with prior ischaemic heart disease (74% of patients) presented later than those with no such history. No other demographic or clinical factors predicted early or late presentation. Delays in seeking medical assistance after the onset of severe chest pain contribute significantly to total delays in patients hospital admission and thrombolysis. The unexpected observation that patients with known ischaemic heart disease delay longer before seeking help in spite of their frequent contact with doctors, suggests that opportunities for educating patients are being wasted. Major efforts are needed to understand and modify behaviour of patients with chest pain to further reduce delays in treatment.

Impairment of colour vision associated with amiodarone keratopathy

Abstract. Objective changes in colour vision have not been demonstrated previously in patients on long‐term amiodarone therapy, although the occurrence of blurring of vision and seeing coloured haloes around lights has been widely reported. In a masked study, colour vision was assessed in 15 patients who had been treated with amiodarone for 16–72 months. Subjects with extensive corneal microdeposits (Miller stage 3) had worse colour vision than subjects with mild or moderate corneal changes (Miller stages I and 2) (P = 0.02), and higher serum concentrations of the metabolite desethlyamiodarone (P = 0.008). The only subject with marked asymmetry of corneal changes had a long‐standing unilateral ptosis, suggesting that exposure to light might influence the development of corneal changes.

Impact of glycemic control on aortic stiffness, left ventricular mass and diastolic longitudinal function in type 2 diabetes mellitus

BackgroundPoor glycemic control is associated with impaired left ventricular (LV) diastolic function in patients with type 2 diabetes mellitus (T2DM). Inappropriate LV mass increase and accelerated aortic stiffening were suggested to participate on deterioration of diastolic function. The present study investigated the inter-relationships between glycemic control, early diastolic and systolic longitudinal velocity of mitral annulus, LV mass and aortic stiffness in T2DM patients free of cardiovascular disease and with preserved LV ejection fraction, and compared them with those observed in healthy volunteers of similar age and sex distribution.Methods125 T2DM patients and 101 healthy volunteers underwent noninvasive measurement of systolic (s′) and early diastolic (e′) velocities of mitral annulus, LV mass, carotid-femoral pulse wave velocity (cfPWV) and local carotid blood pressure (BP).ResultsForty-four (35.2%) T2DM patients had e′ velocity lower than that expected for age (against 7.9% in healthy volunteers; Pxa0<xa00.0001), 34 (27.2%) had cfPWV higher than that expected for age and mean BP (against 5.9% in healthy volunteers; Pxa0<xa00.0001), and 71 (56.8%) had LV mass higher than that expected for body size and stroke work (against 17.6% in healthy volunteers; Pxa0<xa00.0001). Carotid systolic BP was higher in T2DM patients (124xa0±xa014 vs 111xa0±xa011xa0mmHg; Pxa0<xa00.0001). In multivariate analysis, e′ velocity was independently related to age, carotid BP and s′ velocity in healthy volunteers, and to male sex, age, carotid BP, heart rate and LV mass in T2DM. Glycosylated hemoglobin (HbA1c) was independently related to cfPWV and LV mass in T2DM patients. T2DM patients with HbA1c ≥6.5% (Nxa0=xa085) had higher cfPWV (Pxa0<xa00.05), central BP (Pxa0=xa00.01), prevalence of LV hypertrophy (Pxa0=xa00.01) and lower e′ and s′ velocity (Pxa0=xa00.001 and <0.05, respectively) as compared to those with HbA1c <6.5%.ConclusionsOne-third of T2DM patients with preserved LV ejection fraction has sign of subclinical LV diastolic dysfunction. HbA1c levels are positively associated with LV mass and aortic stiffness, both of which show a negative independent impact on early diastolic velocity e′, the latter through an increase in afterload. T2DM patients with suboptimal glycemic control (HbA1cxa0≥xa06.5%) have lower diastolic and systolic LV longitudinal performance, together with increased aortic stiffness and a higher prevalence of LV hypertrophy.

Acute myocardial infarction related to smoke inhalation and myocardial bridging.

A previously healthy 26 year old woman who was exposed to smoke during a house fire developed acute anterior myocardial infarction complicated by ventricular fibrillation. Subsequent left ventriculography confirmed anterior infarction, but coronary arteriography was normal apart from myocardial bridging over a segment of the left anterior descending artery. The development of acute myocardial infarction in this patient suggests that, in the presence of bridging, carbon monoxide inhalation may cause regional infarction.

Extensive aortic valve ring abscess formation: a rare complication of Q fever endocarditis.

We report the successful management and 2 year follow up of a young patient with Q fever endocarditis on a congenitally bicuspid aortic valve complicated by extensive abscess formation in the aortic valve ring and interventricular septum. Aortic root abscess formation complicating Q fever endocarditis has been reported in only one previous patient. Serological tests may thus be indicated in patients with aortic abscesses. Despite extensive aortic and intramyocardial abscess formation it proved possible to control the progression of disease by open drainage of the abscess and aortic valve replacement. Although the requirement for aortic root replacement was anticipated in this patient, it has not been required.

Towards a consensus on the understanding and analysis of the pulse waveform: Results from the 2016 Workshop on Arterial Hemodynamics: Past, present and future

This paper aims to summarize and map contemporary views on some contentious aspects of arterial hemodynamics that have remained unresolved despite years of research. These were discussed during a workshop entitled Arterial hemodynamics: past, present and future held in London on June 14 and 15, 2016. To do this we formulated a list of potential consensus statements informed by discussion at the meeting in London and quantified the degree of agreement and invited comments from the participants of the workshop. Overall the responses and comments show a high measure of quantitative agreement with the various proposed consensus statements. Taken together, these statements seem a useful basis for proceeding with a more detailed and comprehensive consensus document on the current understanding and approaches to analysis of the pulse waveform. Future efforts should be directed at identifying remaining areas of dispute and future topics for research.