Pathological view of sudden cardiac death

Epidemiological Changes in Transthyretin Cardiac Amyloidosis: Evidence from In Vivo Data and Autoptic Series

Cardiac amyloidosis is an infiltrative disease that causes progressive myocardial impairment secondary to amyloid fibril deposition in the extracellular space of the myocardium. Many amyloid precursors, including transthyretin protein, are known to determine cardiac damage by aggregating and precipitating in cardiac tissue. Transthyretin cardiac amyloidosis may be either caused by rare genetic mutations of the transthyretin gene in the hereditary variant, or may arise as a consequence of age-related mechanisms in the acquired form. Although it has been labeled as a rare disease, in recent years, transthyretin cardiac amyloidosis has stood out as an emerging cause of aortic stenosis, unexplained left ventricular hypertrophy and heart failure with preserved ejection fraction, particularly in the elderly. Indeed, the integration of data deriving from both in vivo imaging techniques (whose advancement in the last years has allowed to achieve an easier and more accessible non-invasive diagnosis) and forensic studies (showing a prevalence of amyloid deposition in cardiac tissue of elderly patients up to 29%) suggests that cardiac amyloidosis is a more common disease than traditionally considered. Thanks to all the improvements in non-invasive diagnostic techniques, along with the development of efficacious therapies offering improvements in survival rates, transthyretin cardiac amyloidosis has been transformed from an incurable and infrequent condition to a relatively more diffuse and treatable disease, which physicians should take into consideration in the differential diagnostic processes in daily clinical practice.

Sudden arrhythmic death and cardiomyopathy are important causes of sudden cardiac death in the UK: results from a national coronial autopsy database

AIMS

Sudden cardiac death (SCD) is defined as natural unexpected death in witnessed cases occurring < 1 h and in unwitnessed cases as last seen alive < 24 h. SCD due to ischaemic heart disease (IHD) is frequent in older age groups; in younger people genetic cardiac causes, including channelopathies and cardiomyopathies, are more frequent. This study aimed to present the causes of SCD from a large specialist pathology registry.

METHODS AND RESULTS

Cases were examined macroscopically and microscopically by two expert cardiac pathologists. The hearts from 7214 SCD cases were examined between 1994 and 2021. Sudden arrhythmic death syndrome (SADS), a morphologically normal heart, which can be underlaid by cardiac channelopathies, is most common (3821, 53%) followed by the cardiomyopathies (1558, 22%), then IHD (670, 9%), valve disease (225, 3%), congenital heart disease (213, 3%) and myocarditis/sarcoidosis (206, 3%). Hypertensive heart disease (185, 3%), aortic disease (129, 2%), vascular disease (97, 1%) and conduction disease (40, 1%) occur in smaller proportions.

DISCUSSION

To our knowledge, this is the largest SCD cohort with autopsy findings ever reported from one country. SADS and cardiomyopathies predominate. This study highlights the importance of the autopsy in SCD, which is a significant public health concern in all age groups. Knowing the true incidence in our population will improve risk stratification and develop preventative strategies for family members. There is now a national pilot study integrating molecular autopsy and family screening into the assessment of SCD victims.

Real-time three-dimensional echocardiography and two-dimensional speckle tracking imaging in the evaluation of left atrial function in patients with triple-vessel coronary artery disease without myocardial infarction

OBJECTIVE

To evaluate left atrial function in patients with triple-vessel disease (TVD) without myocardial infarction by real-time three-dimensional echocardiography (RT-3DE) and two-dimensional speckle tracking imaging (2D-STE).

METHODS

Sixty patients with coronary artery disease (CAD) without myocardial infarction were classified into two groups in accordance with the coronary angiography results: group B (all triple-vessel stenosis ≥ 50% and < 75%) and group C (all triple-vessel stenosis ≥ 75%). Thirty healthy individuals were selected as group A. LA volume related parameters including left atrial maximum volume index (LAVImax), LA passive and active ejection fraction (LAPEF, LAAEF) and LA total ejection fraction (LATEF) were measured by RT-3DE. The global peak atrial longitudinal systolic strain (LASRs), early and late diastolic LA strain (LASRe and LASRa) rates were measured by 2D-STE.

RESULTS

We found statistically significant differences between 2D-STE and RT-3DE related parameters of these three groups. Furthermore, in groups B and C, N-terminal fragment brain natriuretic peptides (NT-pro-BNP) and left ventricular end-diastolic pressure (LVEDP) were found to be significantly correlated with LASRs and LASRa. And NT-pro-BNP had a moderate correlation with LVEDP.

CONCLUSIONS

2D-STE and RT-3DE can assess the LA function in patients with TVD without myocardial infarction. And LA strain values may provide additional information for predicting increased LVEDP and NT-pro-BNP.

The British Cardiovascular Society and clinical studies in ischaemic heart disease: from RITA to ORBITA, and beyond

In this article, we provide a historical view of key aspects of British Cardiovascular Society (BCS) influence in clinical trials of ischaemic heart disease (IHD) followed by key research and developments, notable publications and future perspectives. We discuss the role of the BCS and its members. The scope of this article covers clinical trials in stable IHD and acute coronary syndromes, including interventions relating to diagnosis, treatment and management. We discuss the role of the BCS in supporting the original RITA trials. We highlight the changing face of angina and its management providing contemporary and future insights into microvascular disease, ischaemic symptoms with no obstructive coronary arteries and, relatedly, myocardial infarction with no obstructive coronary arteries. The article is presented as a brief overview of the BCS in IHD research, relationships with stakeholders, patient and public involvement and clinical trials from the perspective of past, present and future possibilities.

The role of coronary angiography in out-of-hospital cardiac arrest patients in the absence of ST-segment elevation: A literature review

Out-of-hospital cardiac arrest (OHCA) is a major cause of death. Although the aetiology of cardiac arrest can be diverse, the most common cause is ischaemic heart disease. Coronary angiography and percutaneous coronary intervention, if indicated, has been associated with improved long-term survival for patients with initial shockable rhythm. However, in patients without ST-segment elevation on the post-resuscitation electrocardiogram, the optimal timing of performing this invasive procedure is uncertain. One important challenge that clinicians face is to appropriately select patients that will benefit from immediate coronary angiography, yet avoid unnecessary delay of intensive care support and targeted temperature management. Observational studies have reported contradictory results and until recently, randomised trials were lacking. The Coronary Angiography after Cardiac Arrest without ST-segment elevation (COACT) was the first randomised trial that provided comparative information between coronary angiography treatment strategies. This literature review will provide the current knowledge and gaps in the literature regarding optimal care for patients successfully resuscitated from OHCA in the absence of ST-segment elevation and will primarily focus on the role and timing of coronary angiography in this high-risk patient population.

Urban informal settlements as hotspots of antimicrobial resistance and the need to curb environmental transmission

Antimicrobial resistance (AMR) is a growing public health challenge that is expected to disproportionately burden lower- and middle-income countries (LMICs) in the coming decades. Although the contributions of human and veterinary antibiotic misuse to this crisis are well-recognized, environmental transmission (via water, soil or food contaminated with human and animal faeces) has been given less attention as a global driver of AMR, especially in urban informal settlements in LMICs-commonly known as 'shanty towns' or 'slums'. These settlements may be unique hotspots for environmental AMR transmission given: (1) the high density of humans, livestock and vermin living in close proximity; (2) frequent antibiotic misuse; and (3) insufficient drinking water, drainage and sanitation infrastructure. Here, we highlight the need for strategies to disrupt environmental AMR transmission in urban informal settlements. We propose that water and waste infrastructure improvements tailored to these settings should be evaluated for their effectiveness in limiting environmental AMR dissemination, lowering the community-level burden of antimicrobial-resistant infections and preventing antibiotic misuse. We also suggest that additional research is directed towards developing economic and legal incentives for evaluating and implementing water and waste infrastructure in these settings. Given that almost 90% of urban population growth will occur in regions predicted to be most burdened by the AMR crisis, there is an urgent need to build effective, evidence-based policies that could influence massive investments in the built urban environment in LMICs over the next few decades.

Pathoanatomic Findings Associated With Duty-Related Cardiac Death in US Firefighters: A Case-Control Study

Background Sudden cardiac death accounts for the greatest proportion of duty-related deaths among US firefighters. Increased understanding of the pathoanatomic causes of sudden cardiac death and the risk associated with underlying cardiac pathologies is needed to develop evidence-based screening recommendations. Methods and Results Using autopsy data for duty-related firefighter fatalities occurring between 1999 and 2014, this retrospective case-control study compared cardiac findings of male firefighters aged 18 to 65 years who died on duty of cardiac-related causes with those who died of noncardiac trauma-related causes. Data from 276 cardiac cases and 351 noncardiac trauma controls were analyzed. Among cardiac cases, the most prevalent (82%) underlying pathoanatomic substrate was comorbid coronary heart disease and cardiomegaly/left ventricular hypertrophy. Cardiac cases had a higher prevalence of cardiomegaly (heart weight >450 g), left ventricular hypertrophy (left ventricular wall thickness ≥1.2 cm), and severe coronary artery stenosis (≥75%) than trauma controls (all P<0.001). In multivariate analyses, heart weight >450 g, coronary artery stenosis ≥75%, and evidence of a prior myocardial infarction were strong independent predictors of cardiac death, with odds ratios of 6.1 (95% confidence interval, 3.6-10.4), 9.3 (95% confidence interval, 5.3-16.1), and 6.2 (95% confidence interval, 3.4-11.3), respectively. Conclusions The majority of cardiac fatalities had evidence of both coronary heart disease and increased heart mass, and each condition was independently associated with a markedly elevated risk of cardiac death. Targeted screening for coronary heart disease, increased heart mass, and evidence of prior myocardial infarction should be considered to reduce duty-related cardiac deaths among firefighters.

Circadian Rhythm in Sudden Cardiac Death: A Retrospective Study of 2,665 Cases

Several studies have reported a circadian variation in sudden cardiac death. The aim of this study was to determine whether in northern Greece sudden cardiac death shows a circadian rhythm and/or a weekly and seasonal distribution. We studied 2,665 sudden deaths due to coronary heart disease from 13,832 sudden deaths that merited autopsy; 1,429 (53.6%) of them were due to acute myocardial infarction (AMI) and 1,236 (46.4%) to chronic ischemic heart disease (IHD). The time of death was determined on the basis of autopsy results and witness interviews. There was a circadian rhythm of sudden cardiac death (p<0.010), with a low incidence during the hours 04.00-08.00 (13.1%) and an increased incidence during 20.00-24.00 (19.8%) (p<0.05). Women did not show the same significant circadian variation. Time of occurrence of sudden cardiac death attributed either to AMI or to IHD showed a similar 24-hour distribution (lowest incidence during 04.00-08.00 hours, 12.8% and 13.5%, respectively, and higher during 20.00-24.00, 19.5% and 20.3%, respectively). Weekday distribution of sudden cardiac death showed a significant statistical variation (p<0.005) with the highest frequency on Monday (21.1%) and the lowest on Sunday (7.5%). The same distribution was observed in men, whereas in women the lower frequency was also on Sunday but the higher was on Tuesday. Sudden cardiac death was evenly distributed over the months of the year, with the highest incidence in summer (27.3%) and the lowest in autumn (22%). Sudden cardiac death shows a circadian rhythm and a significant variation during the week.

Shensong Yangxin capsules prevent ischemic arrhythmias by prolonging action potentials and alleviating Ca2+ overload

Shensong Yangxin capsules (SSYX) are an effective traditional Chinese medicine that has been used to treat coronary heart disease clinically. The present study aimed to establish whether SSYX prevent ischemic arrhythmias in rats, and to explore the underlying mechanisms. Male rats were pretreated with distilled water, SSYX and amiodarone for one week. Acute myocardial ischemia (AMI) was performed to induce ischemic arrhythmias. The incidence and severity of ischemic arrhythmias were evaluated. The action potential, transient outward K+ current (Ito) and inward rectifier K+ current (IK1) of rat cardiomyocytes were measured using the patch‑clamp technique. The intracellular Ca2+ concentration of the cardiomyocytes was measured using a laser scanning confocal microscope. The results revealed that SSYX lowered the incidence of arrhythmia markedly during AMI. Furthermore, SSYX delayed the appearance, and reduced the severity, of ischemic arrhythmias compared with the control. In addition, SSYX markedly decreased the ratio of the myocardial infarction region to the whole heart. In an in vitro study, SSYX prolonged the action potential duration of rat cardiomyocytes, and inhibited Ito and IK1 markedly. Additionally, SSYX inhibited Ca2+ elevation induced by KCl in cardiomyocytes. These results suggested that SSYX prevents ischemic arrhythmia, and the underlying mechanism responsible for this process may include prolonging the action potential and alleviating Ca2+ overload.

Coronary microvascular dysfunction is associated with baseline QTc prolongation amongst patients with chest pain and non-obstructive coronary artery disease

BACKGROUND

Coronary microvascular dysfunction (CMD) causes ischemia and is linked to adverse cardiovascular events. Acute transmural ischemia is associated with QT prolongation, but whether CMD affects repolarization is unknown. The aim of this study was to determine if CMD is associated with prolongation of resting heart rate corrected QT interval (QTc).

METHODS

In patients presenting to the catheterization laboratory with chest pain and non-obstructive coronary artery disease (CAD) at angiography, coronary flow reserve (CFR) in response to intracoronary adenosine was measured and compared to baseline to give a CFR ratio. The Bazett's-derived QTc was manually derived from patients' 12-lead ECG obtained prior to the procedure. QTc was compared between patients with normal and abnormal (CFR ratio≤2.5) coronary microvascular function.

RESULTS

Of the 926 patients included in this study, 281 patients (30%) had CMD (mean age 53.2 years [SD 12.7], 25% male). QTc was significantly longer in those with an abnormal CFR response to adenosine (median [Q1, Q3] ms: 420 [409, 438] vs. 416 [405, 432]; p value<0.001) and patients in the lowest quartile of CFR had a significantly longer QTc compared to those in the highest quartile (median [Q1, Q3] ms: 420 [409, 439] vs. 413 [402, 426]; p<0.001). In a linear regression model adjusting for age and sex, CMD was associated with an increase in QTc of 3.09 ms (p=0.055).

CONCLUSION

Our data suggest that CMD may be associated with an increase in baseline QTc, however the precise clinical relevance of this finding needs to be better investigated in larger clinical studies.

Sudden death due to coronary artery insufficiency as a result of massive cardiomegaly--a case report

Forensic pathologists encounter a wide range of deaths due to natural causes. Natural deaths can be sudden and unexpected, occurring in apparently healthy people. All such cases have to be investigated and a medico-legal autopsy should be conducted to ascertain the cause of death, and to rule out any criminal cause of death. Here, we report a case of a 46-year-old male who collapsed at his workplace and died. There was no history of significant natural disease. The case was investigated due to the suddenness of his death and absence of a history of significant medical illness. An autopsy revealed that the death was due to coronary artery insufficiency as a result of massive cardiomegaly, although there was absence of significant occlusion of the coronary arteries.

Sudden adult death

In the investigation of sudden death in adults, channelopathies, such as long QT syndrome, have risen to the fore in the minds of forensic pathologists in recent years. Examples of these disorders are touched upon in this review as an absence of abnormal findings at postmortem examination is characteristic and the importance of considering the diagnosis lies in the heritable nature of these conditions. Typically, a diagnosis of a possible channelopathy is evoked as an explanation for a 'negative autopsy' in a case of apparent sudden natural death. However, the one potential adverse effect of this approach is that subtle causes of sudden death may be overlooked. The intention of this article is to review and discuss potential causes of sudden adult death (mostly natural) that should be considered before resorting to a diagnosis of possible channelopathy. Nonetheless, it becomes apparent that many of the potential causes of sudden death can have a genetic basis. Thus, it becomes an important consideration that there may be a genetic basis to sudden death that extends beyond the negative autopsy.

Implications of the Turing completeness of reaction-diffusion models, informed by GPGPU simulations on an XBox 360: cardiac arrhythmias, re-entry and the Halting problem

In the arsenal of tools that a computational modeller can bring to bare on the study of cardiac arrhythmias, the most widely used and arguably the most successful is that of an excitable medium, a special case of a reaction-diffusion model. These are used to simulate the internal chemical reactions of a cardiac cell and the diffusion of their membrane voltages. Via a number of different methodologies it has previously been shown that reaction-diffusion systems are at multiple levels Turing complete. That is, they are capable of computation in the same manner as a universal Turing machine. However, all such computational systems are subject to a limitation known as the Halting problem. By constructing a universal logic gate using a cardiac cell model, we highlight how the Halting problem therefore could limit what it is possible to predict about cardiac tissue, arrhythmias and re-entry. All simulations for this work were carried out on the GPU of an XBox 360 development console, and we also highlight the great gains in computational power and efficiency produced by such general purpose processing on a GPU for cardiac simulations.

Effect of timolol on late ventricular arrhythmias after acute myocardial infarction

This is a subproject of the Norwegian timolol myocardial infarction study carried out at one of the clinical centers. High risk patients surviving either a reinfarction or large initial infarction were randomized to placebo (44 pts) or timolol (37 pts). A 24 hour ECG was obtained the day before randomization (at baseline, 7-28 days after the acute attack) then 3 days, 1 month and 6 months after start of therapy. During this period the number of patients with one or more of ventricular couplets, bigemini, ventricular tachycardia or early cycle premature ventricular contractions (PVC) (i.e. complex ventricular arrhythmias) and the average number of PVC per hour increased significantly in the placebo group but not in the timolol group. The results indicate that there is an increased severity and incidence of ventricular arrhythmias in the first 6 months after myocardial infarction. Timolol effectively inhibited this trend. The importance of timolol as an antiarrhythmic agent may therefore be to prevent subclinical infarction extension and secondary ventricular arrhythmias related to the size of the myocardial damage.

Effect of slow coronary flow on electrocardiographic parameters reflecting ventricular heterogeneity

QT interval dispersion reflects regional variations in ventricular repolarization and cardiac electrical instability. Previous studies have showed that QT interval dispersion changes during episodes of myocardial ischemia. Slow coronary flow (SCF) in epicardial coronary arteries is a rare and unique angiographic finding. Whether this pattern of flow is associated with electrocardiographic abnormalities is unknown. Therefore, this study was designed to investigate whether SCF results in electrocardiographic (ECG) changes compared to normal coronary flow. For this aim 24 patients with angiographically proven SCF who had no obstructive coronary lesion (group I) and 25 patients without coronary artery disease (group II) were included in the study. Both groups underwent a routine standard 12-lead surface electrocardiogram recorded at 50 mm/s during rest. QT dispersion (QTd), corrected QT (QTc), and corrected QT dispersion (QTcd) were calculated. Distributions of sex, age, body mass index (BMI), and cardiac risk factors were similar in the 2 groups. Mean heart rate was similar in the 2 groups (74 +/-8 vs 77 +/- 7 p > 0.05). Mean QRS interval durations were similar in the groups (92 +/-7 vs 90 +/-6 ms p > 0.005). In group I, QTd, QTcd, and QTc, were significantly higher than in group II (QTd: 73 +/-14 vs 40 +/-14; QTcd: 71 +/-15 vs 42 +/-9; QTc: 414 +/-14 vs 388 +/-13, respectively p <0.05). In conclusion, SCF was found to be associated with prolonged QT interval and increased QT dispersion. Ischemia in microvascular level and/or altered autonomic regulation of the heart may be responsible mechanisms.

Effects of isolated coronary artery ectasia on electrocardiographic parameters reflecting ventricular heterogeneity

Isolated coronary ectatic but otherwise normal epicardial coronary arteries are an infrequent angiographic finding. We sought to determine whether coronary artery ectasia (CAE) may alter QT-interval duration and dispersion. The study population consisted of 24 patients with isolated CAE and otherwise normal epicardial coronary arteries (group 1) and sex- and age-matched subjects with atypical chest pain and otherwise normal coronary flow (group 2). Both groups underwent a routine standard 12-lead surface electrocardiogram recorded at 50 mm/s during rest. QT dispersion (QTd), corrected QT (QTc), and corrected QT dispersion (QTcd) were calculated. Distribution of sex, age, body mass index, and cardiac risk factors were similar in the 2 groups. Mean heart rate was similar in the 2 groups (74 +/- 10 vs 70 +/- 7, P > .05). In group 1, QTd, QTcd, and QTc were significantly higher than those of group 2 (QTd, 40 +/- 17 vs 29 +/- 10 milliseconds [P < .05]; QTcd, 43 +/- 19 vs 30 +/- 10 milliseconds [P < .05]; QTc, 410 +/- 21 vs 397 +/- 19 milliseconds [P < .05]). In conclusion, CAE was found to be associated with prolonged QT interval and increased QTd. Microvascular dysfunction and/or ischemia may be responsible mechanisms.

Initiation of re-entry in an excitable medium: structural investigation of cardiac tissue using a genetic algorithm

The detailed mechanisms by which re-entry and ventricular fibrillation are initiated in the heart remain poorly understood because they are difficult to investigate experimentally. We have used a simplified excitable media computational model of action potential propagation to systematically study how re-entry can be produced by diffuse regions of inexcitable tissue. Patterns of excitable and inexcitable tissue were generated using a genetic algorithm. The inexcitable tissue was modeled in two ways: (i) diffusive, electrically connected but inexcitable tissue, or (ii) zero-flux, areas of tissue electrically disconnected in the same way as zero-flux boundary conditions. We were able to evolve patterns of diffuse inexcitable tissue that favored re-entry, but no single structure or pattern emerged. Diffusive inexcitable regions were inherently less arrhythmogenic than zero-flux inexcitable ones.

The association of QT dispersion and QT dispersion ratio with extent and severity of coronary artery disease

BACKGROUND

Although prolongation of the QT intervals in acute ischemic conditions, such as acute myocardial infarction, intracoronary balloon inflation, and exercise induced ischemia, has been shown, association of rest QT intervals with extent and severity of stable coronary artery disease (CAD) has not been assessed so far. The effects of extent and severity of stable CAD on rest QT interval were analyzed in this study.

METHODS

Rest 12-lead electrocardiograms (ECG) were recorded in 162 clinically stable subjects undergoing coronary angiography before the angiography for measurement of corrected QT dispersion (cQTd) and the QT dispersion ratio (QTdR) defined as QT dispersion divided by cycle length and expressed as a percentage. Angiographic "vessel score,""diffuse score," and "Gensini score" were used to evaluate the extent and severity of coronary atherosclerosis. Subjects were grouped as follows: those with normal angiogram (Group 1), those with insignificant (<50%) coronary stenosis (Group 2), and those with 1- (Group 3), 2- (Group 4), or 3-vessel disease (Group 5).

RESULTS

cQTd and QTdR were higher in Group 3 compared with Group 1 (P < 0.001 and P = 0.001, respectively), in Group 4 compared with Group 1 (P < 0.001 for both) and Group 2 (P = 0.001 and P = 0.003, respectively), and in Group 5 compared with Group 1 (P < 0.001 for both) and Group 2 (P < 0.001 and P = 0.003, respectively). cQTd and QTdR were positively correlated with the vessel score (r = 0.422, P < 0.001; r = 0.358, P < 0.001, respectively), diffuse score (r = 0.401, P < 0.001; r = 0.357, P < 0.001, respectively) and Gensini score (r = 0.378, P < 0.001; r = 0.373, P < 0.001, respectively). In multiple linear regression analyses, cQTd was found to be independently associated only with diffuse score (beta= 0.325, P = 0.038). Also, QTdR was independently associated with diffuse score (beta= 0.416, P = 0.006) and Gensini score (beta= 0.374, P = 0.011).

CONCLUSIONS

Rest cQTd and QTdR are increased, and related to the extent and severity of coronary atherosclerosis in patients with stable CAD.

Alternating conduction in the ischaemic border zone as precursor of reentrant arrhythmias: a simulation study

AIMS

Here, we investigate the mechanisms underlying the onset of conduction-related arrhythmias in a three-dimensional (3D) computational model of acute regional ischaemia.

METHODS

Ischaemia was introduced by realistic gradients of potassium, pH, oxygen and electrical coupling in a 3D slab of ventricular tissue using the LRd model. We focused on a specific stage (10-15 min after occlusion) at which an intramural non-conductive ischaemic core (IC) surrounded by a border zone (BZ) has formed.

RESULTS

At pacing frequencies greater than 4.5 Hz, we observed narrow areas (0.5 mm wide) of 2:1 conduction blocks at the periphery of the IC. As the pacing frequency increased, the area of block widened to 9 mm and gave rise to reentry at the periphery of the BZ. Alternating conduction blocks produced discordant action potential duration (APD) alternans throughout the slab and T-wave alternans in pseudo-ECG. Slowing the recovery of the calcium current broadened the range of pacing frequencies at which blocks were observed. Hyperkalaemia alone was sufficient to induce the alternating blocks.

CONCLUSION

Computer modelling predicts that ischaemia-related arrhythmias are triggered by calcium-mediated alternating conduction blocks in the ischaemic border zone. Alternating conduction blocks lead to intramural reentry and APD alternans.

Phytanic acid accumulation is associated with conduction delay and sudden cardiac death in sterol carrier protein-2/sterol carrier protein-x deficient mice

INTRODUCTION

The sterol carrier protein-2 gene encodes two functionally distinct proteins: sterol carrier protein-2 (SCP2, a peroxisomal lipid carrier) and sterol carrier protein-x (SCPx, a peroxisomal thiolase known as peroxisomal thiolase-2), which is involved in peroxisomal metabolism of bile acids and branched-chain fatty acids. We show in this study that mice deficient in SCP2 and SCPx (SCP2null) develop a cardiac phenotype leading to a high sudden cardiac death rate if mice are maintained on diets enriched for phytol (a metabolic precursor of branched-chain fatty acids).

METHODS AND RESULTS

In 210 surface and 305 telemetric ECGs recorded in wild-type (C57BL/6; wt; n = 40) and SCP2 null mice (n = 40), no difference was observed at baseline. However, on diet, cycle lengths were prolonged in SCP2 null mice (262.9 +/- 190 vs 146.3 +/- 43 msec), AV conduction was prolonged (58.3 +/- 17 vs 42.6 +/- 4 ms), and QRS complexes were wider (19.1 +/- 5 vs 14.0 +/- 4 ms). In 11 gene-targeted Langendorff-perfused hearts isolated from SCP2 null mice after dietary challenge, complete AV blocks (n = 5/11) or impaired AV conduction (Wenckebach point 132 +/- 27 vs 92 +/- 10 msec; P < 0.05) could be confirmed. Monophasic action potentials were not different between the two genotypes. Left ventricular function studied by echocardiography was similar in both strains. Phytanic acid but not pristanic acid accumulated in the phospholipid fraction of myocardial membranes isolated from SCP2 null mice.

CONCLUSION

Accumulation of phytanic acid in myocardial phospholipid membranes is associated with bradycardia and impaired AV nodal and intraventricular impulse conduction, which could provide an explanation for sudden cardiac death in this model.

Psychotropic drugs, cardiac arrhythmia, and sudden death

A variety of drugs targeted towards the central nervous system are associated with cardiac side effects, some of which are linked with reports of arrhythmia and sudden death. Some psychotropic drugs, particularly tricyclic antidepressants (TCAs) and antipsychotic agents, are correlated with iatrogenic prolongation of the QT interval of the electrocardiogram (ECG). In turn, this is associated with the arrhythmia (TdP). This review discusses the association between psychotropic agents, arrhythmia and sudden death and, focusing on TCAs and antipsychotics, considers their range of cellular actions on the heart; potentially pro-arrhythmic interactions between psychotropic and other medications are also considered. At the cellular level TCAs, such as imipramine and amitriptyline, and antipsychotics, such as thioridazine, are associated with inhibition of potassium channels encoded by In many cases this cellular action correlates with ECG changes and a risk of TdP. However, not all psychotropic agents that inhibit HERG at the cellular level are associated equally with QT prolongation in patients, and the potential for QT prolongation is not always equally correlated with TdP. Differences in risk between classes of psychotropic drugs, and between individual drugs within a class, may result from additional cellular effects of particular agents, which may influence the consequent effects of inhibition of repolarizing potassium current.

The epidemiology of out-of-hospital 'sudden' cardiac arrest

It is difficult to assemble data from an out-of-hospital cardiac arrest since there is often lack of objective information. The true incidence of sudden cardiac death out-of-hospital is not known since far from all of these patients are attended by emergency medical services. The incidence of out-of-hospital cardiac arrest increases with age and is more common among men. Among patients who die, the probability of having a fatal event outside hospital decreases with age; i. e. younger patients tend to more often die unexpectedly and outside hospital. Among the different initial arrhythmias, ventricular fibrillation is the most common among patients with cardiac aetiology. The true distribution of initial arrhythmias is not known since several minutes most often elapse between collapse and rhythm assessment. Most patients with out-of-hospital cardiac arrest have a cardiac aetiology. Out-of-hospital cardiac arrests most frequently occur in the patient's home, but the prognosis is shown to be better when they occur in a public place. Witnessed arrest, ventricular fibrillation as initial arrhythmia and cardiopulmonary resuscitation are important predictors for immediate survival. In the long-term perspective, cardiac arrest in connection with acute myocardial infarction, high left ventricular ejection fraction, moderate age, absence of other heart failure signs and no history of myocardial infarction promotes better prognosis. Still there is much to learn about time trends, the influence of patient characteristics, comorbidity and hospital treatment among patients with prehospital cardiac arrest.

Effects of Valsalva maneuver on QT dispersion in patients with ischemic heart diseases

Previous studies showed that increased QT dispersion (QTd) has been observed during episodes of myocardial ischemia or infarction and identify the patients at risk of arrhythmia or sudden death. The objective of this study is to investigate the relationship between coronary artery disease and QTd during the Valsalva maneuver. The study population included 85 subjects (21 with normal coronary arteries, 35 with stable angina pectoris, and 29 with unstable angina pectoris). Twelve-lead surface ECGs were recorded at 50-mm/sec paper speeds and were obtained before the Valsalva maneuver and during the strain phase. The results indicate a significant difference in mean time increase between the control group and the group with stable angina pectoris (mean difference = 16.10 milliseconds, p<0.000), and between the control group and the group with unstable angina pectoris (mean difference = 35.26 milliseconds, p<0.000). The mean difference in time between these groups was also compared (mean difference = 19.17 milliseconds), and was statistically significant (p<0.000). There are some conditions like constipation, severe coughing spells, nausea, vomiting, and carrying or lifting heavy objects that increase intrathoracic pressure and may increase QT dispersion. Therefore, all these conditions should be treated appropriately and carrying or lifting heavy objects is forbidden, especially in patients with coronary artery disease.

Effects of atrial pacing on QT dispersion in patients with coronary artery disease without angina pectoris and ST segment depression

The aim of this study was to investigate QT dispersion during atrial pacing in patients with coronary artery disease (CAD) without clinical ischemia, such as angina pectoris and ST segment depression. Thirteen patients with normal coronary arteries and 42 patients with CAD (12 with single-vessel, 16 with two-vessel and 14 with three-vessel disease) having no angina pectoris or ST segment depression during atrial pacing with maximum rate of 120/minute were enrolled in the study. Twelve-lead surface ECGs were recorded at 100 mm/second paper speed before pacing, at maximum pacing rate, and during the recovery period for measurement of QT interval parameters. Corrected QTd (QTcd) increased from 43.4 +/- 8.1 to 49.3 +/- 9.5 ms (p < 0.05) in the control group, from 46.1 +/- 8.1 to 74.3 +/- 7.7 ms (p < 0.0001) in the single-vessel disease group, from 48.5 +/- 10.4 to 93.8 +/- 22.1 ms in the two-vessel disease group (p < 0.0001), and from 49.7 +/- 13.6 to 128.5 +/- 31 ms (p < 0.0001) in the three-vessel disease group at peak atrial pacing period. A positive correlation was found between the severity of CAD and QTcd (r = 0.49, p < 0.0001). It was found that pacing-induced QTc dispersion identifies coronary disease extent, even when there is no ST depression or T wave inversion during pacing.

Ventricular preexcitation in children and young adults: atrial myocarditis as a possible trigger of sudden death

BACKGROUND

Sudden death (SD) in ventricular preexcitation (VP) syndrome is believed to be the result of atrial fibrillation with rapid ventricular response over the accessory pathway. Previous reports are anecdotal and often lack autopsy validation.

METHODS AND RESULTS

Prevalence and clinicopathological features of VP were investigated in a series of 273 SDs in children and young adults (aged <or=35 years). Site of accessory atrioventricular (AV) connection was predicted by 12-lead ECG. Right and left AV ring together with the sinoatrial and AV septal junction were studied in serial histological sections. Ten patients (3.6%; male, mean age 24+/-7 years) had VP: 8 had Wolff-Parkinson-White (WPW) and 2 had Lown-Ganong-Levine (LGL) syndrome. Six patients had previous symptoms, and SD occurred at rest in all but 1. Pathological substrates of LGL consisted of AV-node hypoplasia and right-sided atrio-Hisian tract, respectively. In the 8 WPW patients, 10 total accessory AV pathways consisting of ordinary myocardium were found (7 left lateral, 2 right posterolateral, and 1 septal). These pathways were close to the endocardium (mean distance, 750+/-530 microm) and 310+/-190 microm thick. In 4 WPW patients (50%), isolated acute atrial myocarditis was found, which was polymorphous in 1 and lymphocytic in 3.

CONCLUSIONS

VP accounted for 3.6% of SD in young people and was not preceded by warning symptoms in 40%. A left accessory pathway was the most frequent substrate, and its subendocardial location supports the feasibility of catheter ablation. Isolated atrial myocarditis may act as a trigger of paroxysmal atrial fibrillation that leads to SD.

Clinical Management for Survivors of Sudden Cardiac Death

Sudden cardiac death is believed to affect as many as 400,000 people each year in the United States and is therefore an important public health problem. A common cause of sudden cardiac death is ventricular fibrillation. This article reviews the clinical and electrophysiologic aspects of sudden arrhythmic death and discusses current clinical management for survivors of sudden death. Particular emphasis is placed on the implantable cardioverter-defibrillator (ICD).

Application of noninvasive and invasive tests for risk assessment in patients with ventricular arrhythmias

Sudden cardiac death remains a major public health problem in western society. Because most patients who experience cardiac arrest are not successfully resuscitated, primary prevention of sudden death remains an important challenge. A number of noninvasive risk stratification techniques have been suggested as providing useful information in patients with underlying structural heart defects. Unfortunately, the positive predictive value of most of these techniques has been limited. Left ventricular ejection fraction, the presence of nonsustained ventricular tachycardia on Holter monitoring, and inducible sustained ventricular tachycardia at electrophysiologic testing in patients with coronary artery disease remain the best established prognostic test. However, with the exception of two ICD studies using the combination of these markers, prospective studies have not yet completely validated the use of these and other prognostic markers. Further understanding of the pathophysiology of ventricular fibrillation and other risk stratification techniques will be necessary before a clear algorithm can be developed for application to patients at risk for sudden death.

Risk indicators for out-of-hospital cardiac arrest in patients with coronary artery disease

The objective of this study was to identify risk factors for sudden cardiac arrest (SCA) in patients with coronary artery disease (CAD). A retrospective case-control study was performed consisting of a group of unselected patients who had suffered SCA and had a clinical history of CAD, and a group of unselected age- and gender-matched CAD control patients living in the region of Maastricht. Information about previous myocardial infarction (MI), left ventricular ejection fraction (LVEF), hypertension, hypercholesterolemia, diabetes mellitus, smoking, and coffee and alcohol consumption was collected. A logistic regression model was fitted to all mentioned variables including age and genders. Included were 117 SCA cases (84% men, mean age 65 years [+/-7]) and 144 control patients (83% men, mean age 63 years [+/-8]). Previous MI (odds ratio [OR] 4.0, 95% confidence interval [CI] 1.7-9.3), hypertension (OR 2.9, 95% CI 1.5-6.1), heavy coffee consumption (>10 cups per day) (OR 55.7, 95% CI 6.4-483), and a LVEF <40% (OR 11.2, CI 4.4-28.5) were independent risk indicators for SCA in patients with CAD. Alcohol consumption (1-21 glasses per week) seemed to protect patients with CAD from SCA (OR 0.5, 95% CI 0.2-0.98). These observations suggest that changes in lifestyle factors can be of potential importance in protecting patients with CAD from dying suddenly.

Cardiopulmonary resuscitation: historical perspective to recent investigations

There are at least 300,000 cardiac arrests annually in the United States. Cardiopulmonary resuscitation (CPR) effectively restores hemodynamic stability, return of spontaneous circulation (ROSC), in 40% to 60% of arrests. Prolonged survival is significantly lower because of underlying illness and the postresuscitation syndrome, specifically central nervous system injury and left ventricular stunning after resuscitation. Prognostic variables have been shown to predict survival in multivariate analyses, but no models are sufficiently accurate to predict futility. End-tidal carbon dioxide has prognostic value and can measure the efficacy of CPR. Cardiac arrest outcomes will be most improved with public education and earlier initiation of resuscitative efforts, both Basic Life Support and Advanced Cardiac Life Support, notably defibrillation. Active compression-decompression and interposed abdominal compressions improved ROSC in prospective randomized trials; abdominal compressions have also been shown to increase survival to hospital discharge. Despite 30 years of research, CPR is now performed much as it was initially. Further research into the mechanisms of cardiac arrest, development of predictive models, and improved means to improve cardiac output and survival are needed.

Sudden cardiac death in the young athlete

Sudden cardiac death in athletes is usually due to underlying cardiovascular disease. In the young less than 30 years of age, the most common abnormality is hypertrophic cardiomyopathy, followed by congenital coronary artery anomalies. The final common pathway is usually ventricular fibrillation. Sudden cardiac death in the young is rare but remains a source of concern. A careful screening history and physical examination, especially for potential athletes, should identify the majority of young people at risk.

Antiarrhythmic therapies for the prevention of sudden cardiac death

Despite remarkable advances in cardiovascular therapeutics, sudden cardiac death remains a significant problem. In this review, data from clinical trials and other studies on antiarrhythmic therapies have been evaluated in order to determine effective strategies for the prevention of sudden cardiac death in high risk patients. Overall, routine prophylactic use of class I antiarrhythmic agents in high risk patients, mostly survivors of acute myocardial infarction, is associated with increased risk of death [61 trials, 23,486 patients: odds ratio (OR) 1.13; 95% confidence interval (CI) 1.01 to 1.27, p < 0.05]. Conversely, beta-blockers are associated with highly significant reductions in risk of death in postinfarction patients (56 trials, 53,521 patients: OR 0.81; 95% CI 0.75 to 0.87, p < 0.00001). Overall data from the amiodarone trials on high risk patients, including postinfarction patients, patients with congestive heart failure or survivors of cardiac arrest, suggest that this agent is effective in reducing the risk of death (14 trials, 5713 patients: OR 0.83; 95% CI 0.72 to 0.95, p = 0.01) although further studies are needed to better define which types of patients will potentially benefit most from this agent. No benefits were seen with calcium channel blockers (26 trials, 21,644 patients: OR 1.03; 95% CI 0.94 to 1.13, p = NS). The implantable cardioverter-defibrillator is a promising option for high risk patients, but definition of its role awaits the completion of ongoing clinical trials. Since causes of sudden death are heterogeneous, the clinician should pursue a multifactorial approach to its prevention. Primary and secondary prevention of cardiac ischaemia, through the treatment of cardiovascular risk factors and maximising the use of aspirin, beta-blockers, lipid-lowering drugs, and angiotensin converting enzyme inhibitors after acute myocardial infarction, should lead to a future decrease in the incidence of sudden cardiac death.

Acute ischaemia: a dynamic influence on QT dispersion

BACKGROUND

The aim of this study was to test the hypothesis that acute myocardial ischaemia increases QT dispersion measured from the 12-lead electrocardiogram.

METHODS

Incremental atrial pacing was used to induce myocardial ischaemia in 18 patients with coronary artery disease and QT dispersion was measured. Six patients with normal coronary arteries served as the control group.

FINDINGS

All the patients with coronary artery disease developed angina and/or ST depression accompanied by marked increases in QT dispersion (mean increase 38 ms, 95% CI 30 to 45 ms, p < 0.001). In contrast, in the six patients with normal coronary arteries who remained without symptoms and without ST changes, there was no significant change in QT dispersion in response to pacing. Baseline QT dispersion did not distinguish those patients with coronary artery disease from those with normal coronary arteries (44 ms [95% Cl 39-49 ms] vs 40 ms [25-55 ms]), respectively.

INTERPRETATION

These results demonstrate that myocardial ischaemia induced by incremental atrial pacing in patients with coronary artery disease causes an acute increase in QT dispersion. Such "inducible" QT dispersion may prove more useful than resting QT dispersion in assessing the individual risk of arrhythmic events in patients with coronary artery disease.

Atrio-ventricular nodal tumor associated with polyendocrine anomalies

We report the clinical and autopsy findings of a young female suffering of complete heart block since the age of 11 and who suddenly died at the age of 32 because of a polycystic atrio-ventricular node tumor. In association with this tumor, we observed a hyperplasia of the islets of Langherans, a true thymic hyperplasia, bilateral multicystic ovaries, adrenal tissue heterotopia and clear cell adenomatosis in the right kidney. We suggest that the polycystic atrio-ventricular node tumor may be part of a complex syndrome with endocrine disorders and heterotopias.

Electrical activation during ventricular fibrillation in the subacute and chronic phases of healing canine myocardial infarction

BACKGROUND

Little information is available regarding the effects of myocardial infarction on the characteristics of ventricular fibrillation (VF). Epicardial activation during VF can be characterized by the cycle length and by the characteristics of activation wave fronts.

METHODS AND RESULTS

VF was induced by programmed stimulation in 6 dogs with subacute healing (1 week) myocardial infarction (MI), 5 dogs with chronic (8 week) healing MI, and 6 dogs without MI. Using a plaque electrode array with a 2.5-mm interelectrode distance, 112 electrograms were recorded and 91 vector loops were created for each cycle of VF from either the anterior (infarcted) or lateral (noninfarcted) wall. Direction of maximum epicardial activation was determined at each site for the first 10 cycles of VF (early) and for 10 cycles after 5 seconds of VF (late). Wave front size was determined based on a similarity in epicardial activation directions within a given area and by a statistical analysis that determined the degree of spatial linking at varying distances over the recording plaque. VF cycle length was defined as the mean interval of 10 consecutive local activation times. Differences among groups and differences between the anterior and posterolateral walls were determined by ANOVA. The mean wave front area was significantly larger in the presence of subacute MI (97 +/- 4 mm2, early; 78 +/- 3 mm2, late) or chronic MI (94 +/- 5 mm2, early; 78 +/- 5 mm2, late) than in noninfarcted animals (73 +/- 5 mm2, early; 61 +/- 3 mm2, late). The degree of linking of epicardial activation directions was similar in the three groups at distances of 2.5 and 5.0 mm but was lower at a distance of 7.5 mm among animals without infarction, confirming a smaller wave front size and suggesting less organization of activation. VF cycle length was significantly longer in the presence of infarction (98 +/- 5 ms, normal control animals; 121 +/- 13 ms, subacute MI; 127 +/- 13 ms, chronic MI). VF cycle length was significantly longer over the anterior than the lateral wall in the presence of subacute MI (131 +/- 8 ms, anterior; 109 +/- 5 ms, lateral) or chronic MI (136 +/- 9 ms, anterior; 119 +/- 6 ms, lateral) but not in noninfarcted animals (99 +/- ms, anterior; 97 +/- 5 ms, lateral). The prolongation of VF cycle length among animals with infarction was associated with slower estimated conduction velocities during VF.

CONCLUSIONS

During VF, in animals with subacute or chronic healing MI, (1) the size of activation wave fronts is larger, (2) the cycle length of VF is longer, (3) the conduction velocities are slower, and (4) the degree of organization is greater than in control animals. Thus, the characteristics of VF throughout the heart are altered by the presence of regional myocardial infarction. The implications of these findings for the initiation and maintenance of VF in the presence of different underlying myocardial substrates require further study.

The conduction system findings in sudden cardiac death

This is a brief review of the findings in the conduction system in cases of sudden death victims who were living "normal" active lives. Twenty-two representative samples from more than 100 cases of sudden cardiac death, especially in young and asymptomatic individuals, revealed a plethora of findings that varied from normal to congenital and acquired changes, in most cases either at the gross or microscopic level, especially in the conduction system to a varying degree. Despite these changes, the individuals were living normal, symptom-free lives and were not clinically diagnosed to have lethal cardiac problems. This suggests that these individuals might have experienced lethal arrhythmias in the past, which might have been "silent" in nature. Innovative new methodologies must be developed to detect the silent lethal arrhythmic focus that may lead to sudden cardiac death.

Evidence of a selective increase in cardiac sympathetic activity in patients with sustained ventricular arrhythmias

BACKGROUND

Although enhanced efferent cardiac sympathetic nervous activity has been proposed as an important factor in the genesis of ventricular arrhythmias and sudden cardiac death, direct clinical evidence has been lacking.

METHODS

We measured the rates of total and cardiac norepinephrine spillover into the plasma, which reflect respectively overall and cardiac sympathetic nervous activity, in 12 patients who had recovered from a spontaneous, sustained episode of ventricular tachycardia or ventricular fibrillation outside the hospital 4 to 48 days earlier. The results were compared with those from three age-matched reference groups without a history of ventricular arrhythmias: 12 patients with coronary artery disease, 6 patients with chest pain but normal coronary arteries, and 12 healthy, normal subjects.

RESULTS

The patients who had had ventricular arrhythmias had reduced left ventricular ejection fractions, as compared with the patients with coronary artery disease or chest pain (mean [+/- SE], 46 +/- 3 percent vs. 58 +/- 4 percent and 69 +/- 5 percent, respectively; P less than 0.003). The rates of total norepinephrine spillover into the plasma were similar in the three reference groups, but 80 percent higher in the patients with ventricular arrhythmias (P less than 0.005). The rate of cardiac norepinephrine spillover was 450 percent higher in these patients (176 +/- 39 pmol per minute, as compared with 32 +/- 8 pmol per minute in the normal subjects; P less than 0.001), a disproportionate increase relative to the increase in total spillover, which indicated selective activation of the cardiac sympathetic outflow. This increase in cardiac norepinephrine spillover was probably caused by a reduction in left ventricular function.

CONCLUSIONS

These results suggest that in some patients major ventricular arrhythmias are associated with and perhaps caused by sustained and selective cardiac sympathetic activation. We speculate that depressed ventricular function was present before the ventricular arrhythmia occurred, and that this resulted in reflex cardiac sympathetic activation, which in turn contributed to the genesis of the arrhythmia.

Arrhythmogenic effects of graded coronary blood flow reductions superimposed on prior myocardial infarction in dogs

BACKGROUND

We studied arrhythmogenesis and its underlying pathophysiology during graded reductions of coronary blood flow, superimposed on prior myocardial infarction to test the hypothesis that spontaneous ventricular fibrillation and induced ventricular tachycardia are dependent on different patterns of coronary flow reduction in hearts with prior myocardial infarction.

METHODS AND RESULTS

In 10 sham-operated dogs (control group) and 24 dogs with 3-week-old experimental apical myocardial infarction, the left circumflex coronary artery was constricted to produce four grades of flow reduction: 25%, 50%, 75%, and 100%. Among the sham-operated control animals, only one of 10 (10%) developed spontaneous ventricular fibrillation and only two of nine (22%) were inducible into sustained ventricular tachycardia during 100% circumflex coronary artery flow reduction. No spontaneous ventricular fibrillation or inducible ventricular tachycardia occurred with lesser grades (25%, 50%, or 75%) of flow reduction among the control animals. In the myocardial infarction group, five of 24 dogs (21%) were inducible before flow reduction. However, 50% flow reduction in the myocardial infarction group resulted in inducibility of ventricular tachycardia in 12 of 24 dogs (50%); nine of 16 (56%) during 75% flow reduction; and six of 11 (55%) with 100% flow reduction. In addition, none of the dogs in the myocardial infarction group developed spontaneous ventricular fibrillation during 25% or 50% flow reduction, whereas six of 22 (27%) developed ventricular fibrillation during 75% flow reduction and 10 of 21 (48%) during 100% flow reduction. In dogs with spontaneous ventricular fibrillation during flow reduction, the total myocardial mass of the ischemic "risk" zone and infarcted zone was significantly greater than in those without spontaneous ventricular fibrillation (68 +/- 5% versus 56 +/- 6% [p less than 0.01]). There was no difference in the total myocardial mass of the ischemic risk zone and infarcted zone between dogs with and without inducible ventricular tachycardia during flow reduction.

CONCLUSIONS

In canine model of subacute myocardial infarction, superimposed ischemia increased the likelihood of inducible sustained ventricular tachycardia with lesser grades of coronary flow reduction compared with that necessary to allow spontaneous ventricular fibrillation. The underlying pathophysiology appears to differ between spontaneous ventricular fibrillation and electrically induced sustained ventricular tachycardia.

Resolved and unresolved issues in the prevention and treatment of coronary artery disease: a workshop consensus statement

Advances in cardiovascular research during the past two decades have resulted in an improved understanding of the chain of events that lead to end-stage coronary artery disease. These developments have been paralleled by therapeutic advances that now make it possible to intervene at virtually every stage in the development of advanced cardiac disease, from asymptomatic persons at risk of developing coronary atherosclerosis to patients with end-stage heart failure. By interrupting this chain of events, perhaps at multiple sites, it may be possible to prevent or slow the development of symptomatic heart disease and hopefully prolong life. Many opportunities exist for obtaining further information regarding the underlying pathophysiology, the fundamental mechanisms of action of interventions designed to prevent and/or treat the development of myocardial ischemia and cardiac failure and for effecting favorably the natural history of various forms of heart disease.

Sudden natural death at the wheel--a particular problem of the elderly?

Thirty-nine autopsy cases of sudden natural death at the wheel were analysed with special respect to the questions if this is a peculiar problem of the elderly and if there are particular pathological features in the elderly. The ages ranged from 33 through 83 years and the median age was 56.4 years. 97% of the deaths were attributable to cardiovascular diseases, about 90% to coronary heart disease. People older than 60 years of age tended to exhibit severe chronical arterio-sclerotic changes of the coronary arteries, especially multiple calcified stenoses and myocardial scars, but there was a low percentage of recent thrombotic occlusion of a coronary artery.

Sudden death in young Aboriginal adults with rheumatic heart disease

A retrospective review for the period 1983 to 1988 was made of all sudden deaths in young Aboriginal adults from the Darwin and East Arnhem regions who had known rheumatic heart disease. A total of five cases was identified from autopsy reports. The age range was between 16 and 35 years. All were being treated for asymptomatic heart disease (grade I). The sudden, unexpected death in each of these patients resulted in their deaths all being reported to the coroner. In all cases there was no evidence at autopsy of significant coronary artery disease or bacterial endocarditis. All had evidence of rheumatic valvular heart disease affecting either one or both mitral and aortic valves to varying degrees. No other cause of death was found. This report serves to illustrate the fact that rheumatic heart disease is still a significant contributor to morbidity and mortality in Aborigines, and that while the usual picture of progressive deterioration in exercise tolerance may be the norm, sudden death without any apparent preceding symptomatology can occur.