Thanh T Phan

• BMedSc (Hons) MBChB (Hons) PhD FRCP FACC FESC
• Consultant at University Hospitals of North Midlands

Hypertrophic cardiomyopathy patients exhibit myocardial energetic impairment, but a causative role for this energy deficiency in the pathophysiology of hypertrophic cardiomyopathy remains unproven. We hypothesized that the metabolic modulator perhexiline would ameliorate myocardial energy deficiency and thereby improve diastolic function and exerci...

Asymptomatic subjects with diabetes mellitus have an impaired cardiac energetics status that may play a significant role in the development of heart failure. In the present study, we assessed the role of microvascular dysfunction in the development of impaired cardiac energetics in subjects with type 1 diabetes mellitus. Twenty-five asymptomatic su...

This study assessed the chronotropic response to exercise and heart rate (HR) recovery after exercise in a carefully phenotyped group of patients with heart failure with preserved left ventricular ejection fraction (HfpEF) and a control group of similar age and gender distribution. We studied 41 patients with HfpEF, 41 healthy controls, and 16 hype...

Cardiac resynchronization therapy produces both short-term hemodynamic and long-term symptomatic/mortality benefits in symptomatic heart failure patients with a QRS duration >120 ms. This is conventionally believed to be due principally to relief of dyssynchrony, although we recently showed that relief of external constraint to left ventricular fil...

We sought to evaluate the role of exercise-related changes in left ventricular (LV) relaxation and of LV contractile function and vasculoventricular coupling (VVC) in the pathophysiology of heart failure with preserved ejection fraction (HFpEF) and to assess myocardial energetic status in these patients. To date, no studies have investigated exerci...

Aims: Treatment options for patients with non-obstructive hypertrophic cardiomyopathy (HCM) are limited. We sought to determine whether biventricular (BiV) pacing improves exercise capacity in HCM patients, and whether this is via augmented diastolic filling. Methods and results: Thirty-one patients with symptomatic non-obstructive HCM were enro...

Aim This new laser facilitated ‘inside-out’ technique was used for transvenous pacemaker insertion in a pacemaker-dependent patient with bilateral subclavian occlusion and a failed epicardial system who is not suitable for a transfemoral approach. Method and results Procedure was undertaken under general anaesthesia with venous access obtained fro...

Background: A pacemaker dependent 49-year-old male with bilateral subclavian vein occlusions and a failing epicardial system, who was felt unsuitable for transiliac approach, successfully underwent transvenous pacemaker implantation using a Laser-facilitated ‘insideout’ approach. Method: Pre-procedure CT venography confirmed long occlusions of both...

Techniques to overcome challenging venous anatomy have become an increasingly important part of modern day cardiac device implantation. Complete superior vena cava (SVC) obstruction, however, is a rare and serious clinical entity, and consequently there is limited clinical experience in addressing this pathology in the context of transvenous pacema...

The recovery of LV function in patients with severe LV impairment in the acute phase following primary percutaneous coronary intervention (PPCI) is not well established. The indication for a primary prevention ICD post-STEMI is dependent on which screening guidance, NICE or ESC, is followed. The potential impact of the new NICE guidance is estimate...

Introduction In high-risk patients with severe symptomatic aortic stenosis (AS) surgical AVR (sAVR) or Transcatheter Aortic Valve Implanation (TAVI) are established treatment options. Rates of permanent pacemaker (PPM) insertion post TAVI are dependent on valve type and vary from22.5% for Medtronic CoreValve to 5.9% for the Edwards heart valve syst...

Introduction Indications for cardiac resynchronisation therapy (CRT) are expanding; included in this are patients with symptomatic heart failure and chronic right ventricular pacing undergoing upgrade procedures. Previously reported data from the REPLACE registry suggest a much higher complication rate (18.7% overall) associated with CRT upgrade pr...

Introduction The response to cardiac resynchronisation therapy (CRT) can be heterogeneous. Most studies aim to improve patient selection in order to achieve better outcomes.However, the adjustment of device timing intervals in conjunction with optimisation of medical therapy may maximise the effectiveness of CRT. This approach provides a new paradi...

Occupational radiation exposure in fluoroscopy-guided procedures is highest among medical staff, particularly cardiologists involved in interventional procedures. The danger of radiation-induced cataracts in operators, and the suggestion of a higher incidence of malignancy among interventional cardiologists, have led to a significant focus on radia...

This report describes the successful implantation of a LV lead using balloon venoplasty to overcome a very tight stenosis of the right subclavian vein / brachiocephalic junction for cardiac resynchronisation therapy (CRT-P) in a patient with a right sided CRT-P system and a failed epicardial LV lead. It is important for device implanters to be fami...

Sarcoidosis should always be part of the differential diagnosis when faced with a young patient with significant cardiac conduction disease.

Purpose: Despite waveform optimization, high output devices, dual coil electrodes (DCE) or the addition of a "standard" (Medtronic Transvene) proximal coil (TVCE) high defibrillation thresholds (DFT) continue to be a problem in patients with implantable cardioverter defibrillator (ICD). Placement of a coil electrode (Medtronic 6996) posterior in th...

We present a case of contra-lateral haemopneumothorax and pneumopericardium following a dual chamber ICD implantation using the cephalic vein. The explanation lies in the use of an active fixation atrial (screw-in) lead and not the route of venous access. One should inspect for pneumopericardium when a pneumothorax is present on the CXR and look fo...

Objective Left ventricular torsion is increased in uncomplicated type 2 diabetes (T2DM) which may be an early manifestation of cardiomyopathy. Our aim was to evaluate the relationship of torsion to energetic impairment and microvascular damage in healthy patients with T2DM. Methods 36 patients with T2DM without coronary artery disease as measured...

Background: We evaluated young patients with type 1 diabetes (T1DM) who had normal left ventricular (LV) ejection fraction and used speckle tracking echocardiography to assess changes in LV untwisting. We used cardiac magnetic resonance imaging (MRI) to assess the LV filling patterns in these subjects. Methods: We recruited 33 T1DM patients and...

The pathophysiology of HfpEF is complex. In this review we discuss the molecular aspects of HfpEF as well as the profoundly disturbed haemodynamics with particular focus on exercise haemodynamic abnormalities.

Left ventricular torsion is increased and cardiac energetics are reduced in uncomplicated type 1 diabetes mellitus (T1DM). Our aim was to determine the relationships of these abnormalities to cardiovascular autonomic neuropathy (CAN) in subjects with T1DM. A cross-sectional study was conducted in 20 subjects with T1DM free of known coronary heart d...

Background Patients with hypertrophic cardiomyopathy (HCM) exhibit myocardial energetic impairment, but a causative role for this energy deficiency in the pathogenesis of HCM remains unproven. We hypothesised that the metabolic modulator, perhexiline would ameliorate myocardial energy deficiency and thereby improve diastolic function and exercise c...

Nonobstructive hypertrophic cardiomyopathy (nHCM) is often associated with reduced exercise capacity despite hyperdynamic systolic function as measured by left ventricular ejection fraction. We sought to examine the importance of left ventricular strain, twist, and untwist as predictors of exercise capacity in nHCM patients. Fifty-six nHCM patients...

To the Editor: Dr Prakash has raised an important issue with respect to our recent article “Impaired Heart Rate Recovery and Chronotropic Incompetence in Patients With Heart Failure With Preserved Ejection Fraction,”1 suggesting the possibility that lower intrinsic heart rate (IHR), the heart rate under complete pharmacological blockade of autonom...

Whilst resting disturbances of both diastolic and long-axis systolic function are observed in patients with heart failure who have normal left ventricular ejection fraction, recent evidence suggests that dynamic disturbances in cardiac function occur during exercise. A paradoxical slowing of left ventricular active relaxation during exercise limits...

Using speckle-tracking imaging (STI), the aims of this study were to assess dyssynchrony and quantify the myocardial energy wasted by contractility in delayed segments by determining the longitudinal strain delay index (LSDi) in patients with heart failure with preserved ejection fraction (HFpEF). Thirty-eight patients with HFpEF and 33 matched con...

The role of left atrial (LA) function on exercise remains poorly understood in heart failure with preserved ejection fraction (HfpEF) despite its key role in optimizing left ventricular (LV) diastolic function. We used resting and exercise radionuclide ventriculography to investigate the role of LA function in the pathophysiology of HfpEF. A total...

The objective of this study is to report on our 5-year collective experience on the use of perhexiline in the UK, in patients with chronic heart failure (CHF) and/or refractory angina with respect to 'real-life' drug side effects and toxicity, therapeutic drug level monitoring, 5 year mortality outcomes and predictors of response to perhexiline the...

We used speckle tracking echocardiography (STE) to make a comparison between the effects of ageing and of heart failure with normal ejection fraction (HfnEF) on left ventricular (LV) torsion and strain patterns. Forty patients with HfnEF, 27 young controls and 26 older controls, were prospectively recruited. All subjects underwent clinical examinat...

We used speckle tracking echocardiography to study the early changes in left ventricular (LV) torsion in young patients with uncomplicated type 1 diabetes and stress magnetic resonance imaging (MRI) to assess its interrelationships with coronary microangiopathy. We recruited 33 asymptomatic subjects with type 1 diabetes and 32 age-matched healthy c...

We report an unusual and interesting case of a 24-year-old woman with nephropathic cystinosis in association with concomitant isolated noncompaction of the left ventricle. Left ventricular noncompaction usually presents with reduced exercise tolerance as a consequence of ventricular dysfunction, the result of embolus or with palpitations and syncop...

The morbidity and mortality of coronary heart disease and of heart failure remain unacceptably high despite major advances in their management. The main focus of treatment has been revascularisation for ischaemic heart disease and neuro-humoral modification for heart failure. There is an urgent need for new modalities of treatment to improve mortal...

(31)P magnetic resonance spectroscopy (MRS) allows measurement of in vivo high-energy phosphate kinetics in the myocardium. While traditionally (31)P cardiac spectroscopy is performed at 1.5T, cardiac MRS at higher field strength can theoretically increase signal to noise ratio (SNR) and spectral resolution therefore improving sensitivity and speci...

Varieties of artificial antigen presenting cells (aAPCs) with different efficiencies have been introduced to expand whole T cell population or antigen specific ones for the purpose of T cell therapy. From antibody coated beads to gene modified dendritic cells each has some advantages and disadvantages. However, no one can ignore the importance and...

We used Near Infrared Spectrophotometry (NIRS) during arterial occlusion to measure resting skeletal muscle oxygen consumption in chronic heart failure (CHF) patients and in age-matched healthy volunteers (HVs). Fifteen CHF patients (ten males) and eleven HVs (six males) had echocardiographic evaluation followed by measurement of the oxygen consump...

Aim: We used Near Infrared Spectrophotometry (NIRS) during arterial occlusion to measure resting skeletal muscle oxygen consumption in chronic heart failure (CHF) patients and in age-matched healthy volunteers (HVs). Methods: Fifteen CHF patients (ten males) and eleven HVs (six males) had echocardiographic evaluation followed by measurement of the...

Background. Previous studies have reported dyssynchrony using Tissue Doppler in patients with hypertrophic cardiomyopathy (HCM). In this study we assessed dyssynchrony using speckle tracking echocardiography (STE) in patients with non-obstructive hypertrophic cardiomyopathy vs a healthy control group and in a subgroup of highly symptomatic patients...

New researchers may find starting and conducting clinical studies in the UK complicated and time-consuming. In this article, we describe our collective experiences and provide some pointers on how to navigate through the various committees and regulatory bodies. The article is intended to aid junior researchers in understanding the study process an...

New researchers may find starting and conducting clinical studies in the UK complicated and time-consuming. In this article, we describe our collective experiences and provide some pointers on how to navigate through the various committees and regulatory bodies. The article is intended to aid junior researchers in understanding the study process an...

Heart failure continues to have a significant morbidity and mortality rate despite several recent advances in treatment such as additional neurohumoral blockades and cardiac resynchronization therapy. There is emerging evidence that, irrespective of etiology, heart failure is associated with an energetic disorder and that this may contribute to the...

Ventricular tachycardia (VT) can be a life threatening condition which can be caused by an underlying electrolyte disturbance, such as hypomagnesaemia. Causes of electrolyte disturbances, such as magnesium losing nephropathy, should be identified early to allow correct management of the underlying cause of the cardiac arrhythmia.