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1.
Int J Clin Pract ; 65(12): 1259-66, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22093532

ABSTRACT

AIMS: The aim of this study was to compare rates of target lesion revascularisation (TLR) and total mortality between South Asians (SAs) and White Europeans (WEs) following percutaneous coronary intervention (PCI). METHODS: We followed a cohort of 293 SAs and 865 WEs patients admitted for elective or urgent PCI to de novo lesions. For each patient, baseline cardiovascular risk factors and angiographic data were obtained. Patients had long-term follow-up for all-cause mortality and TLR. RESULTS: Patients were followed up over a median period of 54 months (inter-quartile range: 47-65). SAs were younger (62 ± 12 years vs. 66 ± 11 years; p < 0.0001), with a higher prevalence of diabetes, greater social deprivation [Carstairs score: 10.2 (IQR 6.5-12.1) vs. 3.3 (IQR 0.9-6.5); p < 0.0001] and presented more acutely (urgent PCI procedure). During the follow-up period, a total of 119 deaths and 111 TLR [94 repeat PCI and 17 coronary artery bypass grafting (CABG)] occurred. There was no significant difference in the rate of long-term all-cause mortality between SA and WE [31 (10.6%) vs. 107 (12.4%); OR: 0.84 (0.55-1.28); p = 0.47]. However, SA ethnicity was an independent predictor of long-term TLR, after adjusting for baseline clinical and procedural characteristics [54 (18.4%) vs. 57 (6.6%); OR: 2.83 (1.87-4.29); p < 0.0001]. CONCLUSIONS: South Asian patients were more likely to require re-admission to treat clinical restenosis of the index lesion. There was no significant long-term difference in all-cause mortality between SA and WE patients.


Subject(s)
Asian People/ethnology , Coronary Artery Disease/ethnology , Myocardial Infarction/ethnology , White People/ethnology , Aged , Angioplasty, Balloon, Coronary/mortality , Angioplasty, Balloon, Coronary/statistics & numerical data , Asia, Southeastern/ethnology , Coronary Artery Bypass/mortality , Coronary Artery Bypass/statistics & numerical data , Coronary Artery Disease/therapy , England/epidemiology , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Myocardial Infarction/mortality , Myocardial Infarction/therapy , Myocardial Revascularization , Stents , Treatment Outcome
2.
Int J Clin Pract ; 64(9): 1245-51, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20653800

ABSTRACT

It is becoming increasingly common to offer primary percutaneous coronary intervention as first line treatment for ST elevation myocardial infarction (STEMI). In a subset of patients presenting with suspected STEMI, coronary arteries appear normal at coronary angiography. In this article, the current literature of this group of patients is reviewed. The incidence of 'normal' angiography, the clinical and electrocardiographic features of this group of patients and the alternative diagnoses for presentation are discussed. This article reviews the factors leading to such presentation, the clinical characteristics of such patients and the implications, clinical and economic.


Subject(s)
Coronary Angiography , Myocardial Infarction/diagnostic imaging , Aged , Angioplasty, Balloon, Coronary , Diagnosis, Differential , Electrocardiography , Female , Humans , Male , Medical Audit , Middle Aged , Myocardial Infarction/therapy
3.
Int J Clin Pract ; 63(12): 1693-701, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19694835

ABSTRACT

OBJECTIVES: To evaluate reduction of door-to-balloon (DTB) time and its impact on in-hospital mortality of high-risk infarct patients in a collaboration of district general hospitals (DGH) with a physician-to-patient model. METHODS: Primary percutaneous coronary interventions (PPCI) with short DTB time offer mortality benefit for ST-segment elevation myocardial infarction but literatures are conflicting on this benefit for high- vs. low-risk patients. In a unique model at Sandwell and West Birmingham Hospitals, five interventional cardiologists provide 24-h PPCI at whichever one of its two DGH that patients present to. A retrospective audit was performed on 3 years (July 2005-June 2008) of PPCI data in the British Cardiovascular Intervention Society database. Data were analysed in four periods corresponding to change from daytime-only to 24-h PPCI. DTB time and in-hospital mortality were the main outcome measures. RESULTS: Of the 459 patients, median DTB time improved from 89 min (interquartile range: 49-120) to 68 min (50-91) (p = 0.005) and proportion of patients achieving target 90-min DTB time increased from 53% (21/40) to 75% (93/124) (p = 0.005). In-hospital mortality was less for short DTB time [4.6% (13/284) vs. 11.5% (20/174); odds ratio (OR) 0.37, 95% confidence interval (CI): 0.18-0.75; p = 0.008]. With the proviso that our study was limited in power, long DTB time (> 90 min vs. < or = 90 min) was associated with higher in-hospital mortality in high-risk patients [15.6% (20/128) vs. 7.1% (12/168); OR 2.41, 95% CI: 1.14-5.06; p = 0.024] and not in low-risk patients [0% (0/46) vs. 0.9% (1/117); OR 0, 95% CI: 0-9.88; p = 1.000]. CONCLUSIONS: A collaboration of DGH with a physician-to-patient model can deliver timely PPCI that appear to translate into mortality benefit more so in high-risk patients. Low-risk patients would therefore probably tolerate delays associated with transfer to large centres while high-risk patients would not and need alternative strategy. A collaboration of smaller hospitals with a pool of mobile interventional cardiologists could be such an alternative.


Subject(s)
Angioplasty, Balloon, Coronary/mortality , Emergency Medical Services , Myocardial Infarction/therapy , Abciximab , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Monoclonal/therapeutic use , Emergency Medical Services/statistics & numerical data , England , Female , Hospital Mortality , Humans , Immunoglobulin Fab Fragments/therapeutic use , Male , Middle Aged , Myocardial Infarction/drug therapy , Myocardial Infarction/mortality , Myocardial Revascularization/mortality , Platelet Aggregation Inhibitors/therapeutic use , Risk Factors , Time Factors , Treatment Outcome , Young Adult
4.
Int J Clin Pract ; 61(4): 680-3, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17394440

ABSTRACT

A high prevalence of newly detected diabetes mellitus (DM) and impaired glucose tolerance (IGT) has been reported in patients with acute myocardial infarction (AMI) and no previous diagnosis of DM. However, the prevalence of newly detected DM is grossly underestimated by using fasting plasma glucose (FPG). We determined the prevalence of DM and IGT in patients post-AMI from our local mixed ethnicity population, and evaluated the usefulness of oral glucose tolerance testing in such patients. All non-diabetic subjects admitted with AMI underwent a standardised oral glucose tolerance test (OGTT) with 75 g glucose load predischarge in our institution. Fasting and 2-h postchallenge plasma glucose levels were recorded, in addition to admission plasma glucose, serum cholesterol, triglycerides, HDL cholesterol and haemoglobin A1(C)levels. We studied 61 patients [38 (62%) male; mean (SD) age, 64 (12.5) years], of whom 70% were white European and 30% South Asians. Mean (SD) plasma glucose concentration on admission was 6.9 (1.7; range, 5.8-8.1) mmol/l. Newly diagnosed DM and IGT were detected in 31% (95% CI 10-52) and 33% (95% CI 12-53) of patients respectively. Of those with newly detected diabetes only 32% (95% CI 0-69) had FPG > 6.1 mmol/l. The 12 month major adverse cardiac event rate was 4.5%, 15% and 32% in those with normal glucose tolerance, IGT and DM respectively. Previously undiagnosed DM and IGT in patients with AMI is common. The false reassurance of a normal FPG denies a significant proportion of undiagnosed diabetics the chance of early treatment. The importance of OGTT in the diagnostic work up of this vulnerable high-risk group cannot be over-emphasised.


Subject(s)
Diabetes Mellitus, Type 2/diagnosis , Diabetic Angiopathies/diagnosis , Glucose Intolerance/diagnosis , Glucose Tolerance Test , Myocardial Infarction/etiology , Aged , Blood Glucose/analysis , False Negative Reactions , Female , Humans , Male , Mass Screening/methods , Middle Aged , Myocardial Infarction/physiopathology
8.
Am Heart J ; 149(1): 13-9, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15660030

ABSTRACT

BACKGROUND: Patients with diabetes have an increased incidence and severity of ischemic heart disease, which leads to an increased requirement for coronary revascularization. Comparative information regarding mode of revascularization--coronary artery bypass graft surgery surgery (CABG) or percutaneous coronary intervention (PCI)--is limited, mainly confined to a subanalysis of the Bypass Angioplasty Revascularization (BARI) trial, suggesting a mortality benefit of CABG over PCI. No prospective trial has specifically compared these modes of revascularization in patients with diabetes. OBJECTIVE: The Coronary Artery Revascularisation in Diabetes (CARDia) trial is designed to address the hypothesis that optimal PCI is not inferior to modern CABG as a revascularization strategy for diabetics with multivessel or complex single-vessel coronary disease. The primary end point is a composite of death, nonfatal myocardial infarction, and cerebrovascular accident at 1 year. METHOD: A total of 600 patients with diabetes are to be randomized to either PCI or CABG, with few protocol restrictions on operative techniques or use of new technology. This gives a power of 80% to detect non-inferiority of PCI assuming that the PCI 1-year event rate is 9%. A cardiac surgeon and a cardiologist must agree that a patient is suitable for revascularization by either technique prior to recruitment into the study. Twenty-one centers in the United Kingdom and Ireland are recruiting patients. Data on cost effectiveness, quality of life, and neurocognitive function are being collected. Long-term (3-5 year) follow-up data will also be collected.


Subject(s)
Angioplasty, Balloon, Coronary , Coronary Artery Bypass , Coronary Disease/therapy , Diabetes Complications , Coronary Disease/complications , Coronary Disease/surgery , Humans , Immunosuppressive Agents/administration & dosage , Multicenter Studies as Topic , Myocardial Infarction , Randomized Controlled Trials as Topic , Research Design , Sirolimus/administration & dosage , Stents
9.
Cochrane Database Syst Rev ; (3): CD004394, 2003.
Article in English | MEDLINE | ID: mdl-12918013

ABSTRACT

BACKGROUND: Adult and adolescent congenital heart disease is increasing in prevalence as better medical care means more children are surviving to adulthood. People with chromic disease often also experience depression. There are several non-pharmacological treatments that might be effective in treating depression and improving quality of life for adults and young adults with congenital heart disease. The aim of this review was to assess the effects of treatments such as psychotherapy, cognitive behavioural therapies and talking therapies for treating depression in this population. OBJECTIVES: To assess the effects (both harms and benefits) of psychological interventions for treating depression in young adults and adults with congenital heart disease. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register (CCTR) (on The Cochrane Library issue 4, 2002), MEDLINE (1966 to August 2002), EMBASE (1980 to August 2002), PsycLIT (1887 to August 2002), the Database of Abstracts of Reviews of Effectiveness (DARE) (Issue 4, 2002 of the Cochrane Library), Biological Abstracts (January 1980 to August 2002), and CINAHL (January 1980 to August 2002). Abstracts from national and international cardiology and psychology conferences and dissertation abstracts were also searched. SELECTION CRITERIA: Randomised controlled trials comparing psychological interventions with no intervention for people over 15 years with depression who have congenital heart disease. DATA COLLECTION AND ANALYSIS: Two reviewers independently screened titles and abstracts of studies that were potentially relevant to the review. Studies that were clearly ineligible were rejected. Two reviewers independently assessed the abstracts or full papers for inclusion criteria. Further information was sought from the authors where papers contained insufficient information to make a decision about eligibility. MAIN RESULTS: No randomised controlled trials were identified. REVIEWER'S CONCLUSIONS: Depression is common in patients with congenital heart disease and can exacerbate the physical consequences of the illness. There are effective pharmacological and non-pharmacological treatments for depression, but we have not been able to identify any trials showing the effectiveness of non-pharmacological treatments. A well designed randomised controlled trial is needed to assess the effects of psychological interventions for depression in congenital heart disease.


Subject(s)
Depression/therapy , Heart Defects, Congenital/psychology , Psychotherapy , Adolescent , Adult , Depression/etiology , Humans
10.
Heart ; 88(1): 71-5, 2002 Jul.
Article in English | MEDLINE | ID: mdl-12067950

ABSTRACT

OBJECTIVE: To examine the quality of life of adults with congenital heart disease. DESIGN AND SETTING: Observational, cross sectional study conducted at one general hospital in Birmingham, UK. PATIENTS: All 471 patients registered at the adult congenital heart disease clinic were sent the 36 item short form health survey (SF-36) to assess their quality of life. Questionnaires were completed by 276 (58.6%) patients (41.7% men; median (interquartile range) age 31.0 (26.3-36.0) years, range 16-85 years). RESULTS: Surprisingly, patients deemed surgically cured (for example, atrial septal defect repair) had significantly poorer quality of life in all domains (all p < 0.05), except for pain, than the general population, as determined from population normative data. Patients who had received palliative treatment reported quality of life scores similar to those who had never required cardiac surgery and to the general population, although both patient groups had significantly poorer physical functioning and overall general health perception than the general population (all p < 0.01). Patients with inoperable conditions had significantly poorer physical functioning (all p < 0.01) and overall general health perception (all p < 0.05) than all other patients, and significantly worse quality of life in all domains than the similarly aged general population. Patients with cyanotic conditions had significantly worse quality of life than age and sex matched acyanotic patients (all p < 0.01). CONCLUSIONS: Patients with inoperable or cyanotic conditions and, paradoxically, those deemed surgically cured, had the poorest quality of life among adults with congenital heart disease. However, all adults with congenital heart disease had significantly poorer levels of physical functioning and overall general health perception then similarly aged people in the general population.


Subject(s)
Heart Defects, Congenital/psychology , Quality of Life , Adolescent , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Health Status , Health Surveys , Heart Defects, Congenital/therapy , Humans , Male , Middle Aged , Palliative Care , Surveys and Questionnaires
12.
J Am Coll Cardiol ; 35(6): 1661-8, 2000 May.
Article in English | MEDLINE | ID: mdl-10807474

ABSTRACT

OBJECTIVES: This study was conducted to assess whether myocardial ischemia and/or infarction are involved in the pathogenesis of late right ventricular dysfunction in adult survivors of atrial baffle repair for transposition of the great arteries in infancy. BACKGROUND: The medium-term success of intraatrial baffle repair for transposition of the great arteries is good, with many patients surviving into adult life, but prognosis can be limited by progressive right ventricular dysfunction. We hypothesized that ongoing myocardial ischemia and/or infarction are important factors in the pathogenesis of this complication. Radionuclide techniques offer an opportunity to study both myocardial perfusion and concomitant ventricular wall motion. METHODS: Dipyridamole sestamibi single-photon emission computed tomography followed by rest sestamibi single-photon emission computed tomography was used to assess right ventricular myocardial perfusion, wall motion, wall thickening and ejection fraction in 22 adolescents/young adults who had undergone atrial baffle repair for simple transposition of the great arteries at median 6.7 (range 0.5 to 54) months of age. The patients were aged 10 to 25 (median 15.5) years; 19 in New York Heart Association class I, 2 in class II and 1 in class III. All were in a regular cardiac rhythm during the studies. The right ventricular tomographic images were examined in three parallel and two orthogonal planes, analyzed in 12 segments. RESULTS: Perfusion defects were evident in all patients in at least one segment, in either the rest or stress images. Twelve patients (55%) demonstrated fixed defects only, nine (41%) had fixed and reversible defects and one (4.5%) had reversible defects only. Concomitant wall-thickening abnormalities occurred in 83% of segments with fixed perfusion defects, mirrored by a reduction in wall motion in 91% of segments analyzed. Right ventricular ejection fraction was correlated with age (R = 0.62; p = 0.002), and with wall-thickening abnormalities (R = 0.60; p < 0.005). CONCLUSIONS: Reversible and fixed perfusion defects with concordant regional wall motion abnormalities occur in the right (systemic) ventricle 10 to 20 years after Mustard repair for transposition of the great arteries; this may be important in the pathogenesis of late right ventricular dysfunction in this group.


Subject(s)
Myocardial Infarction/diagnosis , Myocardial Ischemia/diagnosis , Postoperative Complications/diagnosis , Transposition of Great Vessels/surgery , Ventricular Dysfunction, Right/diagnosis , Adolescent , Adult , Child , Female , Heart Atria/surgery , Humans , Male , Predictive Value of Tests , Prognosis , Risk Factors , Tomography, Emission-Computed, Single-Photon
14.
Pediatr Cardiol ; 20(2): 143-6, 1999.
Article in English | MEDLINE | ID: mdl-9986893

ABSTRACT

A 3-year-old girl presented with a febrile illness complicated by right ventricular outflow tract tachycardia, which persisted after resolution of the presumed viral infection. The tachycardia was intermittent, but was significantly exacerbated by exercise. Radiofrequency ablation (RFA) of the ectopic focus was successfully performed and the child remains free of tachycardia 12 months later. A review of the literature suggests that RFA in children is increasingly seen as a safe and convenient option for the treatment of supraventricular tachycardia, whereas the management of ectopic ventricular tachycardia in pediatric practice has not been well defined.


Subject(s)
Catheter Ablation , Tachycardia, Ventricular/surgery , Ventricular Premature Complexes/surgery , Child, Preschool , Electrocardiography, Ambulatory , Exercise Test , Female , Humans , Tachycardia, Ventricular/diagnosis , Treatment Outcome , Ventricular Premature Complexes/diagnosis
15.
J R Coll Physicians Lond ; 32(2): 122-4, 1998.
Article in English | MEDLINE | ID: mdl-9597626

ABSTRACT

OBJECTIVES: To shorten the stay in hospital of patients admitted with chest pain of uncertain origin, using clinical history and an unchanging ECG as a basis to inform patients on the post-take ward round of imminent discharge that same day (pending normal cardiac enzyme results), thereby facilitating actual discharge on the same day. DESIGN: A prospective observational study over a two-month period of consecutive patients admitted with chest pain of uncertain origin. SETTING: District general hospital in North-West England with a regional cardiothoracic centre on site. RESULTS: Of the 115 patients enrolled in the study (15% of acute medical admissions), 43 (37%) were identified by the investigators as likely to have normal cardiac enzymes and only one of them had evidence of important cardiac ischaemia (median actual length of stay, 3 days). The specificity of the protocol was 98%, with a sensitivity of 89%. CONCLUSIONS: A careful clinical history taken by experienced junior staff together with two sequential ECGs, can identify patients who may be discharged within 24 hours of admission with chest pain of uncertain origin. Significant bed savings would result from the instigation of this practice, with minimal requirement for extra resources.


Subject(s)
Chest Pain/diagnosis , Electrocardiography , Length of Stay , Medical History Taking/standards , Patient Discharge/standards , Adult , Age Distribution , Aged , Aged, 80 and over , Chest Pain/epidemiology , Chest Pain/etiology , Chest Pain/physiopathology , England/epidemiology , Evaluation Studies as Topic , Female , Humans , Male , Middle Aged , Policy Making , Prospective Studies , Risk Factors , Sensitivity and Specificity
17.
Eur Heart J ; 15(5): 608-19, 1994 May.
Article in English | MEDLINE | ID: mdl-8055999

ABSTRACT

The purpose of this randomized controlled study was to assess the haemodynamic effects, safety and tolerability in acute myocardial infarction (AMI) of one month of oral captopril, one month of oral isosorbide mononitrate and 24 h of intravenous magnesium. It was carried out in four United Kingdom and six Polish hospitals in consecutive phases: oral captopril vs oral mononitrate vs placebo were compared among 400 patients in a 'three-way' study; and then oral captopril vs placebo and oral mononitrate vs placebo were compared among 474 patients in '2 x 2' and '2 x 2 x 2' factorial studies (with 208 patients in the latter study also randomized between intravenous magnesium and open control). The factorial studies differed from the three-way study in that one group of patients was allocated both oral captopril and oral mononitrate, a higher maintenance dose of captopril was used (following the same initial dose), and once daily controlled-release mononitrate was used. In the three-way study, the mean of the lowest systolic blood pressures recorded during the first 4 h after randomization were (mmHg +/- standard error): 104 +/- 2 captopril vs 105 +/- 1 mononitrate vs 112 +/- 2 placebo (P < 0.001 for captopril or for mononitrate vs placebo), and in the factorial studies were 105 +/- 1 captopril vs 110 +/- 1 placebo (P < 0.01) and 106 +/- 1 mononitrate vs 108 +/- 1 placebo (NS). There was an excess of hypotension recorded among patients allocated active treatment (captopril > mononitrate > placebo) and there was a small, but significant, excess of cardiogenic shock with captopril compared with control in the factorial study. However, in these studies, neither captopril nor mononitrate were associated with any overall increase in the incidence of hypotension considered severe enough to lead to treatment being stopped. No other serious complications were observed, and compliance with study tablets at hospital discharge was not significantly different between the active and placebo groups. Patients allocated magnesium in the 2 x 2 x 2 factorial study had a slightly lower mean systolic blood pressure just after the initial 15 min bolus injection (126 +/- 2 magnesium vs 134 +/- 3 control; P < 0.05) but there were no significant differences during the subsequent 24 h maintenance infusion period. Apart from some facial flushing, magnesium did not appear to be associated with any complications.(ABSTRACT TRUNCATED AT 400 WORDS)


Subject(s)
Captopril/therapeutic use , Hemodynamics/drug effects , Isosorbide Dinitrate/analogs & derivatives , Magnesium Sulfate/therapeutic use , Myocardial Infarction/drug therapy , Vasodilator Agents/therapeutic use , Captopril/administration & dosage , Drug Administration Schedule , Drug Therapy, Combination , Female , Humans , Isosorbide Dinitrate/administration & dosage , Isosorbide Dinitrate/therapeutic use , Magnesium Sulfate/administration & dosage , Male , Middle Aged , Myocardial Infarction/mortality , Patient Compliance , Pilot Projects , Research Design , Safety , Time Factors , Vasodilator Agents/administration & dosage
18.
J Heart Lung Transplant ; 13(3): 473-80, 1994.
Article in English | MEDLINE | ID: mdl-8080589

ABSTRACT

Intramitochondrial calcification has been reported in heart transplant recipients treated with high-dose cyclosporine. Myocardial magnesium depletion is common in this group and, on the basis of extensive data from animal studies, would be expected to produce similar mitochondrial deposition of calcium. This prospective study investigated the occurrence of such calcification in biopsy specimens obtained serially in nine heart transplant recipients with simultaneous analysis of myocardial magnesium. During a mean follow-up of 32 weeks, 24 biopsy specimens were analyzed from nine patients. Mitochondrial calcium deposition was more marked in biopsy specimens from recipients with magnesium depletion (p < 0.025). Early toxic cyclosporine levels occurred in three recipients associated with a significant but reversible increase in mitochondrial calcification (p < 0.0001). Histologic rejection and use of calcium antagonists did not modify these findings. It is concluded that although cyclosporine toxicity does induce mitochondrial calcium deposition, such deposition can occur in the absence of toxicity should myocardial magnesium depletion be concurrent. Long-term follow-up will establish the clinical sequelae of such observations. However, when taken together with the results of this study, recent reports of attenuation of accelerated graft atherosclerosis by calcium antagonists may suggest that cyclosporine-induced myocardial magnesium depletion may have an etiologic role in this multifactorial process.


Subject(s)
Calcium/metabolism , Cyclosporine/therapeutic use , Heart Transplantation/pathology , Magnesium Deficiency/metabolism , Mitochondria, Heart/metabolism , Myocardium/metabolism , Biopsy , Calcinosis/chemically induced , Calcinosis/metabolism , Calcinosis/pathology , Calcium Phosphates/metabolism , Cardiomyopathies/blood , Cardiomyopathies/chemically induced , Cardiomyopathies/metabolism , Cardiomyopathies/pathology , Cyclosporine/adverse effects , Cyclosporine/blood , Follow-Up Studies , Graft Rejection/pathology , Heart Transplantation/physiology , Humans , Magnesium/blood , Magnesium Deficiency/blood , Magnesium Deficiency/chemically induced , Magnesium Deficiency/pathology , Microscopy, Electron , Mitochondria, Heart/ultrastructure , Myocardium/pathology , Nifedipine/adverse effects , Nifedipine/therapeutic use , Prospective Studies
19.
Magnes Res ; 6(4): 361-8, 1993 Dec.
Article in English | MEDLINE | ID: mdl-8155488

ABSTRACT

Magnesium deficit in man is very difficult to detect and even more difficult to study. However, a chance observation led to the investigation of cardiac transplant recipients as an in vivo model of drug-induced magnesium depletion. Clinical circumstances were such that the question of the correlation of serum and tissue magnesium levels might be addressed. Using the same model, investigation of myocardial calcium levels was undertaken. Significant myocardial magnesium depletion accompanied persistent hypomagnesaemia in over 50 per cent of cardiac transplant recipients. Repletion of myocardial magnesium occurred some weeks later than normalization of serum levels; these time lags may explain the lack of correlation of serum and tissue magnesium levels in these circumstances. Myocardial calcium levels were generally higher than expected from control studies, and were particularly high in magnesium-depleted subjects. These findings are keeping with those predicted from animal studies. Electrophysiological studies in the transplanted denervated heart are free of many of the confounding features of such studies in the native heart. Preliminary work involving pacing protocols designed to induce abnormalities of phase 4 of the action potential suggests that myocardial magnesium deficit does not produce a clinical arrhythmogenic substrate in the denervated heart. However, shortening of the effective ventricular refractory period in hypomagnesaemic patients was observed, and it was noted that concurrent hypokalaemia in this circumstance would be particularly disadvantageous. The data collected in the course of these studies is discussed, and mechanisms for the observed benefit of magnesium as a possible anti-ischaemic agent in the period following acute myocardial infarction are proposed.


Subject(s)
Heart Transplantation/physiology , Heart/physiology , Magnesium Deficiency/physiopathology , Magnesium/physiology , Adult , Age Factors , Aged , Arrhythmias, Cardiac/physiopathology , Calcium/chemistry , Humans , Magnesium/chemistry , Middle Aged , Myocardium/chemistry
20.
Clin Cardiol ; 15(12): 928-30, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1473310

ABSTRACT

This report describes a patient who developed acute severe exacerbation of mild rheumatic mitral regurgitation caused by ischemia in the territory of a small, non-dominant circumflex coronary artery without myocardial infarction.


Subject(s)
Mitral Valve Insufficiency/physiopathology , Myocardial Ischemia/physiopathology , Rheumatic Heart Disease/physiopathology , Coronary Disease/physiopathology , Humans , Male , Middle Aged , Papillary Muscles/physiopathology
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