Mechanism and Impact of Left Atrial Dyssynchrony on Long-Term Clinical Outcome During Cardiac Resynchronization Therapy.

Background: Left bundle branch block (LBBB) causes left atrial (LA) dyssynchrony. It is unknown if LA dyssynchrony impacts long-term prognosis.

Objectives: The purpose of this study was to determine mechanisms of LA dyssynchrony in LBBB and if LA dyssynchrony impacts long-term prognosis.

Enhancing cardiac pacing strategies: a review of conduction system pacing compared with right and biventricular pacing and their influence on myocardial function.

Traditional right ventricular pacing (RVP) has been linked to the deterioration of both left ventricular diastolic and systolic function. This worsening often culminates in elevated rates of hospitalization due to heart failure, an increased risk of atrial fibrillation, and increased morbidity. While biventricular pacing (BVP) has demonstrated clinical and echocardiographic improvements in patients afflicted with heart failure and left bundle branch block, it has also encountered significant challenges such as a notable portion of non-responders and procedural failures attributed to anatomical complexities.

Inappropriate Extravascular ICD Shock Due to Wet Car Seat.

Inappropriate shocks from an Intracardiac defibrillator are associated with increased mortality and may be caused by external electromagnetic interference. This case illustrates that water is an excellent conductor of electricity and that determined investigation may reveal the cause of inappropriate shocks.

Mechanical Dyssynchrony Combined with Septal Scarring Reliably Identifies Responders to Cardiac Resynchronization Therapy.

The presence of mechanical dyssynchrony on echocardiography is associated with reverse remodelling and decreased mortality after cardiac resynchronization therapy (CRT). Contrarily, myocardial scar reduces the effect of CRT. This study investigated how well a combined assessment of different markers of mechanical dyssynchrony and scarring identifies CRT responders.

Determinants of the time-to-peak left ventricular dP/dt (Td) and QRS duration with different fusion strategies in cardiac resynchronization therapy.

Background: Cardiac resynchronization therapy (CRT) is helpful in selected patients; however, responder rates rarely exceed 70%. Optimization of CRT may therefore benefit a large number of patients. Time-to-peak dP/dt (Td) is a novel marker of myocardial synergy that reflects the degree of myocardial dyssynchrony with the potential to guide and optimize treatment with CRT.

Shortening of time-to-peak left ventricular pressure rise (Td) in cardiac resynchronization therapy.

Aims: We tested the hypothesis that shortening of time-to-peak left ventricular pressure rise (Td) reflect resynchronization in an animal model and that Td measured in patients will be helpful to identify long-term volumetric responders [end-systolic volume (ESV) decrease >15%] in cardiac resynchronization therapy (CRT).

Methods: Td was analysed in an animal study (n = 12) of left bundle-branch block (LBBB) with extensive instrumentation to detect left ventricular myocardial deformation, electrical activation, and pressures during pacing. The sum of electrical delays from the onset of pacing to four intracardiac electrodes formed a synchronicity index (SI).

Lateral Wall Dysfunction Signals Onset of Progressive Heart Failure in Left Bundle Branch Block.

Objectives: This study sought to investigate if contractile asymmetry between septum and left ventricular (LV) lateral wall drives heart failure development in patients with left bundle branch block (LBBB) and whether the presence of lateral wall dysfunction affects potential for recovery of LV function with cardiac resynchronization therapy (CRT).

Background: LBBB may induce or aggravate heart failure. Understanding the underlying mechanisms is important to optimize timing of CRT.

Imaging predictors of response to cardiac resynchronization therapy: left ventricular work asymmetry by echocardiography and septal viability by cardiac magnetic resonance.

Aims: Left ventricular (LV) failure in left bundle branch block is caused by loss of septal function and compensatory hyperfunction of the LV lateral wall (LW) which stimulates adverse remodelling. This study investigates if septal and LW function measured as myocardial work, alone and combined with assessment of septal viability, identifies responders to cardiac resynchronization therapy (CRT).

Methods And Results: In a prospective multicentre study of 200 CRT recipients, myocardial work was measured by pressure-strain analysis and viability by cardiac magnetic resonance (CMR) imaging (n = 125).

Acute redistribution of regional left ventricular work by cardiac resynchronization therapy determines long-term remodelling.

Aims: Investigating the acute impact of cardiac resynchronization therapy (CRT) on regional myocardial work distribution in the left ventricle (LV) and to which extent it is related to long-term reverse remodelling.

Methods And Results: One hundred and thirty heart failure patients, referred for CRT implantation, were recruited in our prospective multicentre study. Regional myocardial work was calculated from non-invasive segmental stress-strain loop area before and immediately after CRT.

An image fusion tool for echo-guided left ventricular lead placement in cardiac resynchronization therapy: Performance and workflow integration analysis.

Background: The response rate to cardiac resynchronization therapy (CRT) may be improved if echocardiographic-derived parameters are used to guide the left ventricular (LV) lead deployment. Tools to visually integrate deformation imaging and fluoroscopy to take advantage of the combined information are lacking.

Methods: An image fusion tool for echo-guided LV lead placement in CRT was developed.

Cardiac Mechanical Alterations and Genotype Specific Differences in Subjects With Long QT Syndrome.

Objectives: This study aimed to explore systolic and diastolic function and to investigate genotype-specific differences in subjects with long QT syndrome (LQTS).

Background: LQTS is an arrhythmogenic cardiac ion channelopathy that traditionally has been considered a purely electrical disease. The most commonly affected ion channels are the slow potassium channel, IKs (KCNQ1 gene/LQT1), and the rapid potassium channel, IKr (KCNH2 gene/LQT2).

Reference interval for the index of coronary microvascular resistance.

Aims: The index of microvascular resistance (IMR) is a relatively new tool that is used to assess microvascular function during routinely performed left heart catheterisations. In order to establish a reference interval for IMR, we investigated a subset of arrhythmia patients with structurally normal hearts and no or minimal coronary artery disease.

Methods And Results: Physiological variables, including IMR, were measured in 20 otherwise healthy patients aged 40-60 years (10 males and 10 females) who had been referred for electrophysiological evaluation of suspected atrioventricular nodal re-entry tachycardia.

Cardiac resynchronization by repositioning of a ventricular epicardial lead in a patient with hypoplastic left heart syndrome.

Patients with congenital heart disease and univentricular circulation are vulnerable to ventricular dysfunction. In the context of atrioventricular conduction defects, a ventricular pacemaker may be placed, possibly introducing dyssynchronous wall motion and deterioration of ventricular pump function. We describe such a case in which repositioning of the ventricular lead restored synchronicity.

Near-fatal outcome of late cardiac perforation by a pacemaker lead in a young woman with transposition of the great arteries.

We report a case of ventricular perforation by an active-fixation permanent pacemaker lead in a young woman with congenital heart defect and pacemaker because of atrioventricular block. The rarity of the case is based not only upon the late perforation (as opposed to the more common acute perforations) but also on the near-fatal outcome. The patient experienced sharp chest pain and 1 week later passed out with cardiac arrest.

Assessment of response criteria to cardiac resynchronization therapy (CRT) and prediction of response.

Aims: Approximately 30% of patients treated with cardiac resynchronization therapy (CRT) do not respond. We evaluated response to CRT at six and 12 months, tested a novel response criterion and evaluated different clinical and echocardiographic predictors of response.

Methods And Results: Eighty one patients were enrolled.

[Catecholaminergic polymorphic ventricular tachycardia].

Background: CPVT (catecholaminergic polymorphic ventricular tachycardia) is a condition characterized by syncopes and cardiac arrest that was first described in 1975. CPVT has later been classified as a genetic disease with a great risk for life-threatening arrhythmias that are mainly caused by mutations in the ryanodine receptor 2 gene. Starting with a case report, we present an overview of CPVT.

High prevalence of exercise-induced arrhythmias in catecholaminergic polymorphic ventricular tachycardia mutation-positive family members diagnosed by cascade genetic screening.

Aim: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac disease predisposing to life-threatening arrhythmias. We aimed to determine the prevalence of arrhythmias and efficacy of beta-blocker treatment in mutation-positive family members diagnosed by cascade genetic screening.

Methods And Results: Relatives of six unrelated CPVT patients were tested for the relevant mutation in the ryanodine receptor-2 gene.

[Treatment of cardiac failure with an intra-aortic balloon pump].

Background: Cardiogenic shock is associated with high mortality. This retrospective study examined the effect of an intra aortic balloon pump (IABP) in patients with decompensated heart failure and hypotension, with or without cardiogenic shock.

Material And Methods: 94 patients were treated with IABP from January 1998 to December 2002, at the Department of Cardiology, Rikshospitalet University Hospital, Oslo, Norway.