Synchronous cardiac arrest in monozygotic twins with hypertrophic cardiomyopathy--is sudden cardiac death genetically pre-programmed?

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a myocardial disorder characterised by left ventricular hypertrophy (LVH) in the absence of another cardiac or systemic disease capable of producing the magnitude of LVH evident. HCM causes variable symptoms and is one of the leading causes of sudden cardiac death (SCD) in young adults. While various phenotypic features of HCM among monozygotic twin pairs are not uncommonly reported, occurrence of synchronous cardiac arrest among them is not known from literature. CASE PRESENTATION: We present a case of monozygotic twins with HCM who both had a cardiac arrest post physical exertion in 63rd year of their lives. CONCLUSION: This case highlights potential genetics predisposition of cardiac arrest in patients with HCM despite having different phenotypic expression. SCD may be the only manifestation of patients with HCM. Decision of implantable cardioverter-defibrillator (ICD) placement for primary prevention of SCD should be based on the recommended guidelines, clinical judgment and patient's preference.

Left ventricular torsional dynamics post exercise for LV diastolic function assessment.

AIMS: 2D speckle tracking echocardiography allows for assessment of left ventricular (LV) torsional deformation as a composite function of the radial, longitudinal and circumferential fibres. We test the hypothesis that post-exercise LV torsional dynamics are more sensitive markers for myocardial dysfunction than resting measures, and better predictors for exercise capacity compared to post-exercise LV diastolic filling pressure (E/e'). METHODS: We studied 88 patients referred for stress echocardiogram. Treadmill exercise was performed using Bruce protocol, and echo images were acquired using GE Vivid 7. LV rotational dynamics were analysed by speckle tracking method using the GE ECHOPAC software. Tertiles were defined according to exercise capacity measured by the achieved metabolic equivalents (METS) adjusted for age and gender. Comparison was made between LV torsional dynamics and E/e' to correlate with METS to predict exercise capacity. RESULTS: Mean age of the study population was 58 years, 48% females. Patients with systolic dysfunction or evidence of ischaemia were excluded from the analysis. No significant correlation was found between METS and LV torsion measures at rest. There was statistically significant correlation between METS and post-exercise LV torsion (r=0.34, p=0.001), twist velocity increase (r=0.27, p=0.01), and incremental change in torsion (r=0.22, p<0.05). In addition, a correlation was also shown between post-exercise E/e' and METS (r=-0.33, p=0.002). CONCLUSION: Post-exercise LV torsional dynamics correlate with exercise capacity and may be a useful tool for assessing LV myocardial function in subjects with normal LVEF.

A twist in the transradial coronary catheterisation.

The transradial approach for coronary angiography was first described in 1989. With the advent of modern equipment and improved technology it has recently gained significant interest amongst interventional cardiologists. As compared to femoral access, the radial approach has the major advantages of lower access site complication rates, cost-effectiveness, and shorter hospital stays. Further clinical benefits of lower morbidity and cardiac mortality in patients with ST-elevation myocardial infarction have been shown recently. Rare vascular complications may include radial artery spasm, dissection, occlusion, perforation or compartment syndrome. Here, we present two unusual cases of an entrapped catheter in the radial artery and their outcomes.

Cardiac resynchronisation therapy for reversal of new-onset left bundle branch block and heart failure after surgical aortic valve replacement.

Left bundle branch block (LBBB) is not an uncommon complication following both surgical aortic valve replacement and transcatheter aortic valve implantation. LBBB can cause interventricular and intraventricular dyssynchrony that can lead to development of heart failure as demonstrated by a decline in left ventricular ejection fraction (LVEF). It is known that change in QRS duration has significant correlation with change in LVEF. In a study involving 202 consecutive patients with no baseline ventricular conduction disturbances or previous permanent pacemaker implantation who underwent transcatheter aortic valve replacement (TAVR) with a balloon-expandable valve, it was found that around 30% of patients develop new LBBB.

Clinical characteristics and outcomes of octogenarians presenting with ST elevation myocardial infarction in the Australian population.

AIM: To investigate the characteristics and outcomes of octogenarians who presented with ST-elevation myocardial infarction (STEMI) compared to non-octogenarians and to investigate the outcomes of octogenarians that received primary percutaneous coronary intervention (PCI) compared to those managed conservatively. METHODS: We performed a single center retrospective case controlled study. All octogenarians who presented with STEMI to a tertiary referring hospital between 2007 and 2012 were included. The subsequent non-octogenarian patient who presented with a STEMI following the octogenarian patient was assigned to the control group in a 1:1 manner. The outcomes measured were peri-procedural cardiac arrest, death on table, cerebrovascular accidents (CVA), in-hospital and 30-d mortality. RESULTS: A total of 146 patients were analyzed. The octogenarian group had a higher percentage of females, higher overall comorbidities, higher Charlson Comorbidity Index score, worse renal function and were more likely to require residential care and home help. The octogenarian group were also less likely to have PCI attempted and had a longer symptom onset to PCI time. Mortality rate was high amongst octogenarians who presented with STEMI. However, those managed conservatively had a higher in-hospital and 30-d mortality rate. CONCLUSION: Octogenarians who presented with STEMI that were managed conservatively had a higher mortality rate compared to those who had primary PCI. Therefore, we propose that revascularization may be beneficial to patients in this age group.

Giant coronary aneurysm presenting as a cardiac mass on transthoracic echocardiogram.

A 69-year-old man with a history of ischaemic heart disease and previous stent implantation in the right coronary artery (RCA) was found to have a large well-encapsulated mass attached to the right atrium on a routine transthoracic echocardiogram. Subsequent investigations including transoesophageal echocardiography and CT coronary angiogram suggested an RCA aneurysm formation in relation to the prior stented segment, further confirming on coronary angiogram a large ectatic vessel with a giant aneurysm measuring 2.4×2.7 cm. Giant coronary artery aneurysms are rare and here we present interesting images of a case initially picked up on transthoracic echocardiography.

Effects of intravenous caffeine on fractional flow reserve measurements in coronary artery disease.

BACKGROUND: Intravenous adenosine is used to minimise the coronary micro-resistance to achieve maximal hyperaemia along with nitrates for optimal fractional flow reserve (FFR) measurements. We hypothesise that caffeine, being a competitive inhibitor of adenosine, would influence adenosine-mediated FFR readings. METHODS: Consecutive patients undergoing angiogram and FFR measurements were enrolled after abstaining from caffeine for 24 h. Patients with any contraindications to intravenous adenosine or caffeine were excluded. FFR measurements were taken using nitrates and adenosine pre and post 4 mg/kg intravenous caffeine administration and results were compared. RESULTS: 10 patients were analysed (80% men, age 59.9±9.4, weight 87.5±15.6). Baseline caffeine levels were undetectable in all patients and increased significantly postintravenous caffeine administration (16.4±5.5 µg/mL). Baseline preadenosine FFR values were similar before and after caffeine administration (0.91±0.06 vs 0.91±0.07; p=0.41). Postadenosine FFR readings were 0.79±0.07, which increased non-significantly to 0.82±0.11 postcaffeine (p=0.15). Two significant FFR readings (≤0.8) changed to non-significant after caffeine administration (0.77-0.93 and 0.8-0.91). CONCLUSIONS: Caffeine may affect FFR results in some patients. Larger studies are warranted to clarify the extent and magnitude of caffeine/adenosine interaction particularly due to ubiquitous nature of caffeine and increasing importance of FFR in clinical practice.

Platypnoea orthodeoxia after hepatic surgery.

Platypnoea orthodeoxia is a rare clinical syndrome characterised by dyspnoea and deoxygenation exhibited in upright position with improvement in supine posture. Previously described aetiologies include cardiac (pericardial effusion or constrictive pericarditis), pulmonary (pneumonectomy, emphysema or amiodarone toxicity), abdominal (cirrhosis or ileus) or vascular (abdominal aortic aneurysm) causes. We report an unusual case of platypnoea orthodeoxia associated with patent foramen ovale and partial hepatic resection.

Usefulness of enhanced stent visualization imaging technique in simple and complex PCI cases.

Stent underexpansion and underdeployment are associated with unfavorable outcomes including stent thrombosis, in-stent restenosis, and geographical miss. Visualization of coronary stents is increasingly difficult due to the reduction in stent strut thickness to improve deliverability. The gold standard evaluation method for stent expansion is intravascular ultrasound (IVUS), but its routine use is costly, time-consuming, and not without risk. Enhanced stent visualization is a novel fluoroscopy-based technique that improves visualization of deployed stents in the coronary arteries. We present a case series highlighting the use of this technique in percutaneous coronary intervention.

Heart failure with preserved ejection fraction - unwinding the diagnosis mystique.

A precise diagnosis of diastolic dysfunction is often difficult and requires invasive techniques to determine left ventricular volume, relaxation, and compliance properties. At this current point of time there is no single non-invasive index available to adequately reflect diastolic function, perhaps because of the numerous factors that can alter diastolic function. In most clinical settings, diastolic function is estimated using Doppler echocardiography. Cardiac magnetic resonance imaging (CMRI) is yet another emerging modality for diastolic function analysis. Here we present a comprehensive review of the various parameters used to assess diastolic function as part of diagnosis of clinical syndrome "Heart failure with preserved ejection fraction (HFPEF)".

Use of ivabradine and atorvastatin in emergent orthopedic lower limb surgery and computed tomography coronary plaque imaging and novel biomarkers of cardiovascular stress and lipid metabolism for the study and prevention of perioperative myocardial infarction: study protocol for a randomized controlled trial.

BACKGROUND: The incidence of perioperative myocardial infarction (PMI) globally is known to be around 2 to 3% and can prolong hospitalization, increased morbidity and mortality. Little is known about the pathophysiology and risk factors for PMI. We investigate the presence of elevated novel cardiac markers and preoperative coronary artery plaque through contemporary laboratory techniques to determine the correlation with PMI, as well as studying ivabradine and atorvastatin as protective pharmacotherapies against PMI in the context of orthopedic surgery. METHODS/DESIGN: We aim to enroll 200 patients aged above 60 years who suffer from neck of femur fracture requiring surgery. Patients will be randomized to four arms (no study drugs, atorvastatin only, ivabradine only and ivabradine and atorvastatin). Our primary outcome is incidence of PMI. All patients will receive an electrocardiogram, cardiac echocardiography, measurement of novel cardiac biomarkers and computed tomography (CT) coronary angiography. A telephone interview post discharge will be conducted at 30 days, 60 days and 1 year. DISCUSSION: We postulate that ivabradine and atorvastatin will reduce the rate and magnitude of PMI following surgery by reducing heart rate and attenuating catecholamine-induced tachycardia postoperatively. Secondly, we postulate that postoperative reduction in heart rate and catecholamine-induced tachycardia with ivabradine will correlate with a reduction in cardiovascular novel biomarkers which will reduce atrial stretch and postoperative incidence of arrhythmia. We aim to demonstrate that treatment with ivabradine and atorvastatin will cause a reduction in the incidence and magnitude of PMI, the benefit of which is derived primarily in patients with greater atherosclerotic burden as measured by higher CT coronary calcium scores. TRIAL REGISTRATION: This study protocol has been listed in the Australia New Zealand Clinical Trial Registry (registration number: ACTRN12612000340831) on 23 March 2012.

Therapeutic interventions for heart failure with preserved ejection fraction: A summary of current evidence.

Heart failure with preserved ejection fraction (HFPEF) is common and represents a major challenge in cardiovascular medicine. Most of the current treatment of HFPEF is based on morbidity benefits and symptom reduction. Various pharmacological interventions available for heart failure with reduced ejection fraction have not been supported by clinical studies for HFPEF. Addressing the specific aetiology and aggressive risk factor modification remain the mainstay in the treatment of HFPEF. We present a brief overview of the currently recommended therapeutic options with available evidence.

Predictors and outcomes of early coronary angiography in patients with prior coronary artery bypass surgery presenting with non-ST elevation myocardial infarction.

INTRODUCTION: The best strategy in patients with prior coronary artery bypass graft surgery (CABG) who present with non-ST elevation myocardial infarction (NSTEMI) remains less well defined. We compare the characteristics, therapeutic interventions and outcomes of patients with prior CABG presenting with NSTEMI. METHODS: All patients who presented to our hospital during 2007-2012 with available electronic records were analysed retrospectively. Outcomes were compared between patients who underwent coronary angiography or percutaneous coronary intervention (PCI) versus those who were treated medically. RESULTS: A total of 117 patients were analysed. Of that, 79 patients were managed medically while 38 underwent early angiography, of which only 11 (9.5%) received PCI. Patients treated medically (did not undergo angiography) were older (74±10 vs70±8; p=0.05). ECG changes were the only independent predictor for early angiography (OR 0.4, 95% CI 0.15 to 0.99; p=0.05) while recurrent chest pain (OR 0.2, 95% CI 0.05 to 0.97; p=0.05) predicted PCI on multivariate analysis. The PCI group had higher Global Registry of Acute Cardiac Events (GRACE) score (176±29 vs 150±31; p=0.01). No significant difference was found in readmission rates, morbidity (unstable angina pectoris, NSTEMI, ST elevation myocardial infarction (STEMI), or combination) or mortality at 12 months between the groups who underwent angiography, PCI, or treated medically on univariate and multivariate analysis. CONCLUSIONS: The opportunity to intervene in prior CABG patients presenting with NSTEMI is often low. Initial medical management may be a reasonable option in carefully selected patients particularly in the absence of ongoing symptoms, ECG changes or very high GRACE scores. Further studies are required to evaluate the safety of non-invasive strategies in managing this population.

The invasive assessment of coronary atherosclerosis and stents using optical coherence tomography: a clinical update.

Ischaemic heart disease (IHD) remains one of the leading causes of death. Atherosclerosis has been intensely researched given the IHD prevalence and the financial impacts on healthcare systems. More recently, in vivo characterisation of coronary atherosclerotic plaque and tissue responses following stent implantation in a coronary artery has been made possible by a novel technology called optical coherence tomography (OCT). OCT is a light-based, invasive, intracoronary imaging modality long applied to the field of ophthalmology and now in clinical use worldwide. It gives a unique view of within the coronary artery using near-infrared light with a resolution of 15 microns, 10 times higher than other invasive coronary imaging techniques like intravascular ultrasound. The technology is being adopted to comprehensively detect features that make plaques 'vulnerable' (eg, large lipid pool, thin, fibrous-cap atheroma), whether stents are implanted optimally within the artery, and visualise the small layers of tissue that form over stent metal surfaces over time, which in turn may provide surrogate markers for long-term stent safety and help guide the optimal duration of dual antiplatelet therapy, a topic of big discussion at the current point of time.

Multivessel spontaneous coronary artery dissection of left and right coronary systems.

Spontaneous coronary artery dissection (SCAD) involving multiple coronary arteries simultaneously is extremely rare. It should be considered in younger patients, especially who do not have traditional cardiac risk factors. We present a case of young male patient presenting with acute coronary syndrome associated with ST segments elevation on ECG following physical stress whose coronary angiography revealed SCAD of the left anterior descending as well as the right coronary artery and discuss the therapeutic options with a brief review of the limited evidence.