David Chase

Transition from image intensifier to flat panel detector in interventional cardiology: Impact of radiation dose

Flat panel detector (FPD) technology in interventional cardiology is on the increase due to its varied advantages compared to the conventional image intensifier (II) systems. It is not clear whether FPD imparts lower radiation doses compared to II systems though a few studies support this finding. This study intends to compare radiation doses from II and FPD systems for coronaryangiography (CAG) and Percutaneous Transluminal Coronary Angioplasty (PTCA) performed in a tertiary referral center. Radiation doses were measured using dose area product (DAP) meter from patients who underwent CAG (n = 222) and PTCA (n = 75) performed using FPD angiography system. The DAP values from FPD were compared with earlier reported data using II systems from the same referral center where the study was conducted. The mean DAP values from FPD system for CAG and PTCA were 24.35 and 63.64 Gycm 2 and those from II system were 27.71 and 65.44 Gycm 2 . Transition from II to FPD system requires stringent dose optimization strategies right from the initial period of installation.

Zero fluoroscopy radiofrequency ablation for Typical Atrioventricular Nodal Reentrant Tachycardia (AVNRT)

A twenty nine year old primigravida at two months of gestation, working as a medical professional, presented with recurrent hour long episodes of symptomatic palpitations, associated with extreme fatigue. Within a month, she had four admissions to the emergency department for the same. On examination during tachycardia, she was diaphoretic, with a regular heart rate of 220 beats per minute (bpm), blood pressure of 80/60 mmHg in the upper limbs, and prominent neck pulsations. Systemic examination was normal. The electrocardiogram (ECG) revealed narrow QRS regular tachycardia at 220 bpm, with a pseudo R0 in lead V1 and a pseudo S in lead II, consistent with a diagnosis of typical AVNRT. The tachycardia terminated with 12mg of intravenous adenosine. She had not reported any episodes prior to her pregnancy. The nature of her illness and management options were discussed with

Response to "Anatomic Twist to a Straightforward Ablation"

David Chase, A Devi, Bobby JohnDepartment of Cardiac Pacing and Electrophysiology, Christian Medical College Hospital, Vellore, Tamilnadu, India, PIN 632004.Address for Correspondence: Dr. David Chase, Associate Professor, Department of Cardiology, Christian Medical College Hospital, Vellore, India. E-mail: davsuchi@gmail.com

Three-dimensional echocardiography with left ventricular strain analyses helps earlier prediction of right ventricular pacing-induced cardiomyopathy

Background and objectives Right ventricular (RV) pacing can lead to progressive ventricular dysfunction over a certain period. This pacemaker-induced cardiomyopathy (PiCMP) may be more common than previously reported. Speckle tracking imaging is a recent development in echocardiography that can identify left ventricular (LV) dysfunction even before the LV ejection fraction (LVEF) value decreases. Three-dimensional (3D) echocardiography has made more accurate assessment of LVEF possible. The objectives of this study are to study the incidence of RV PiCMP using 3D echocardiography and LV strain analysis over a follow-up of 6 months, and to identify its predictors. Methods This is an observational study of consecutive patients without structural heart disease and with a baseline EF of more than 45% who received a permanent pacemaker. They were observed over a 6-month period. PiCMP was defined as a decrease in LVEF by 10 percentage points or a decrease in LV strain by 15% from baseline in the absence of other known causes of cardiomyopathy. PiCMP incidence and its associations were analyzed over a 6-month period. Results The incidence of PiCMP was not only significant over a period of 6 months but also at 24 hours. Significant drops in 3D EF were noted in one (2.8%) patient at 24 hours and in another four (11.1%) patients at 6 months. A significant decrease in LV global longitudinal strain was noted in 23 (63.9%) patients by 6 months. In seven of these patients, there was significant decrease in global longitudinal strain 24 hours after implantation. In analyzing longitudinal strain, the parameter significantly influencing a decrease was a pacing percentage of ≥20% (p = 0.023). Conclusions PiCMP is not uncommon in patients undergoing pacemaker implantation and is associated with RV pacing. PiCMP was associated with a ventricular pacing percentage of ≥20%. 3D echocardiography with LV strain analysis plays a vital role in identifying LV dysfunction at an earlier stage compared to EF. PiCMP, if picked up and intervened upon early, can help impede its progression.

Influence of ethnic background on left atrial markers of inflammation, endothelial function and tissue remodelling

Background It has been suggested that ethnicity can make a significant difference to the likelihood of thromboembolic stroke related to atrial fibrillation. Ethnic differences have been shown to alter inflammatory and haemostatic factors; however, this may all be confounded by differences in cardiovascular risk factors between different ethnicity. The impact of different ethnicities on the thrombogenic profile is not known. The aim of this study was to investigate differences in markers of inflammation, endothelial function and tissue remodelling between Caucasian and Indian populations with supraventricular tachycardia (SVT). Methods Patients with structurally normal hearts undergoing catheter ablation for SVT were studied. This study included 23 Australian (Caucasian) patients from the Royal Adelaide Hospital, Adelaide, Australia and 24 Indian (Indian) patients from the Christian Medical College, Vellore, India. Blood samples were collected from the femoral vein, and right and left atria. Blood samples were analysed for the markers of endothelial function (ADMA, ET-1), inflammation (CD40L, VCAM-1, ICAM-1), and tissue remodelling (MMP-9, TIMP-1) using ELISA. Results The study populations were well matched for cardiovascular risk factors and the absence of structural heart disease. No difference in the echocardiographic measurements between the two ethnicities was found. In this context, there was no difference in markers of inflammation, endothelial function or tissue remodelling between the two SVT populations. Conclusion Caucasian and Indian populations demonstrate similar inflammatory, endothelial function or tissue remodelling profiles. This study suggests a lack of an impact of different ethnicity in these populations in terms of thrombogenic risk.

Association between a prolonged corrected QT interval and outcomes in patients in a medical Intensive Care Unit

Introduction: Patients admitted into a medical Intensive Care Unit (ICU) have varying illnesses and risk factors. An electrocardiogram (ECG) is a useful tool to assess the cardiac status. The aim of the study was to determine the prevalence of QT prolongation of the ECG in patients admitted to a medical ICU in a tertiary hospital, to assess outcomes in terms of mortality, cardiovascular events, and duration of ICU stay. Materials and Methods: Prospective observational study, 6 months duration, assessing the prevalence of prolonged corrected QT interval (QTc) at admission into a medical ICU. A QTc calculated by Bazetts formula, of >440 ms for males and >460 ms for females was considered prolonged. Details of illness, clinical and lab parameters were monitored. Results: The total number of patients screened was 182. There was a high prevalence of prolonged QTc (30%) on admission to the ICU. This reduced to 19% on day 3 (P = 0.011). In patients with a prolonged QTc the odds ratio of adverse outcome from ICU was 3.17 (confidence interval [CI]: 1.52–6.63) (P = 0.001) and of adverse outcome for hospital stay was 2.27 (CI: 1.11–4.66) (P = 0.014). In the study, 35% of all patients received drugs with QT prolonging action. Of patients with a prolonged QTc at admission 18 (35%) received a QT prolonging drug. Conclusions: We found that prolonged QTc is common (30%) in our medical ICU at admission and a large proportion (35%) received drugs capable of prolonging QT interval. These patients with QTc prolongation have a higher odds ratio for adverse outcomes.

Right-sided ECG chest leads and native heart ventricular fibrillation evaluation in a heterotopic cardiac transplant recipient

ECG diagnosis of Ventricular Fibrillation (VF) in Heterotopic Cardiac transplant recipients is complemented by using right-sided precordial chest leads placed in the right-sided mirror image positions of the standard left-sided precordial leads position. In this particular patient with terminal native heart cardiac failure and VF based on a standard twelve lead ECG (Fig. 1) as evidenced by the irregular rapid VF waves seen in the background in the left-sided chest leads V2 &3 with regular donor heart QRS complexes interspersed in between, almost akinetic native heart ventricles with hardly any excursions of the mitral valve or the aortic valve leaflets on echocardiography was demonstrable, and progressively worsening hemodynamic status resulting from increasing dependence on the smaller donor heart was seen (a heterotopic cardiac transplant was performed in the first place for the same reason – a small donor heart). These irregular waves could be easily considered artefactual especially if associated with tremors, rigors etc. Obtaining the left precordial leads ECG allowed demonstrating progressively smaller regular donor heart ‘R’ waves in the lateral leads (leads further away from the donor heart), associated with ‘VF’ complexes interspersed in V2&3 leads (left sided parasternal leads). The right-sided precordial leads (Fig. 2) demonstrated a ‘normal’ V1–V6 donor heart ‘R’ wave progression and the left parasternal lead (mirror image right precordial leads position V-1) once again showed evidence of the native heart VF. Since only one of the two precordial lead sets (right-sided or left-sided) showed a ‘normal’ R-wave progression, the question as to which heart – the left-sided normal position native heart, or the right-sided piggy-back donor heart, was fibrillating, could be resolved. Native heart VF in a heterotopic cardiac transplant recipient being an uncommon condition, the usefulness of a simple maneuver involving procuring a right-sided precordial lead ECG in addition to the standard twelve lead ECG is demonstrated (Figs. 1 and 2). Fig. 1 Heterotopic cardiac transplant recipient – standard twelve-lead ECG. Standard twelve-lead ECG showing what appears to be noise, best seen in V 2 & 3 leads but found to have an almost akinetic native heart with hardly any mitral and aortic ... Fig. 2 Heterotopic cardiac transplant recipient twelve-lead ECG with right-sided precordial leads. Right-sided precordial leads showing narrow QRS complexes (right superior axis) in right lateral chest leads favouring a narrow QRS rhythm in the donor heart. ... Acknowledegment The Austin Hospital Emergency Department, Heidelberg, Melbourne, Australia.