Denis Graf

Stepwise Evaluation of Unexplained Syncope in a Large Ambulatory Population

Background: Up to 60% of syncopal episodes remain unexplained. We report the results of a standardized, stepwise evaluation of patients referred to an ambulatory clinic for unexplained syncope.

Pacemaker Syndrome During Managed Ventricular Pacing Mode: What is the Mechanism?

A 51-year-old woman underwent implantation of a dual chamber pacemaker 10 years ago, for symptomatic intermittent second-degree type II AV block. She remained free of symptoms during follow-up. Recently, she underwent pacemaker replacement because of battery depletion (Adapta ADDR01, Medtronic Inc., Minneapolis, MN, USA). Given intact AV conduction at the time of intervention, the Managed Ventricular Pacing mode algorithm (MVP, Medtronic), which provides AAI(R) pacing with ventricular monitoring and backup DDD/R pacing as needed, was programmed with a lower rate limit of 60 ppm and an upper rate limit of 130 ppm. Ten days after the procedure, the patient complained of asthenia, dyspnea, and presyncope. ECG at pacemaker interrogation revealed sinus tachycardia with second-degree type II AV block (Fig. 1). Atrial pacing artifacts with atrial capture are seen dissociated from the native QRS complexes. Pacemaker interrogation revealed pacing and sensing thresholds as well as impedances within normal range. In our patient, the repetitive atrial pacing during ventricular systole led to pacemaker syndrome and symptoms resolved by reprogramming the device to AV sequential pacing without MVP. What is the mechanism of atrial stimulation dissociated from the native QRS complexes?

Heart rate never lies: interventional cardiologist and Braude's quote revised

Background Interventional cardiologists may be immune to stress, allowing them to perform complex percutaneous interventions under pressure. Objectives To assess heart rate (HR) variations as a surrogate marker of stress of interventional cardiologists during percutaneous cardiac procedures and in every-day life. Design This is a single-centre observational study including a total of six male interventional cardiologists performing coronary interventions and pacemaker implantations. Participants were asked to record their HR with the Apple Watch Device during procedures, every-day life and control activities such as outpatient consultations, sport, marital conflicts and sexual intercourse. Results Average daily HR was 88±17 bpm. During work days, HR increased significantly during procedures (90±17 bpm) compared with days outside the cathlab (87±17 bpm, p=0.02). The average HR was higher during a regular week working (88±16 bpm) compared with weekends off (84±18 bpm, p=0.002). Complex cardiac procedures were associated with higher HR up to 122 bpm. Peak HR were higher during physical exertion. Of note, participants complained of hypersexuality and mania after night shifts. Conclusions Work and especially percutaneous cardiac procedures increase HR independently of physical exertion suggesting that interventional cardiologists experience mental stress and emotions.

Reduced Desmoplakin immunofluorescence signal in arrhythmogenic cardiomyopathy with epicardial right ventricular outflow tract tachycardia

Introduction Arrhythmogenic cardiomyopathy (ACM), formerly known as arrhythmogenic right ventricular dysplasia, is a primary myocardial disorder characterized by ventricular arrhythmias and sudden cardiac death (SCD). Myocardial desmosomes are cell–cell junctions that reside within the intercalated disc. They consist of members of the cadherin family (desmocollin-2, desmoglein-2), which span the membrane mechanically coupling adjacent cells, and members of the plakin and armadillo families: plakoglobin (PKG), plakophilin-2 (PKP2), and desmoplakin (DSP1), which connect the cadherin complexes to the intermediate cytoskeleton filaments. A reduction in the PKG immunoreactive signal has been shown at intercalated discs of cardiomyocytes in ACM regardless of the underlying pathogenic mutation. Herein we report 2 unusual cases of ACM with digenic heterozygosity showing normal immunoreactive PKG distribution but reduced DSP1 signal at myocardial cell– cell junctions without known pathogenicity in the DSP gene.

Double trouble – a case of atrial fibrillation and pulmonary embolism

Right atrial appendage thrombus is a rare complication of atrial fibrillation that can also lead to cardioembolic pulmonary embolism.

Inappropriate ICD shocks

A patient was implanted with a guidant single-chamber implantable cardioverter-defibrillator (ICD) for episodes of ventricular tachycardia in March 2005. In September, he consulted the outpatient clinic after a shock was delivered. The detailed circumstances, however, remained unclear. The panel shows a print-out of the episode as recorded by the ICD. While the first two beats are of sinus origin, high-frequency discharges (10 Hz) of increasing amplitude are seen before shock delivery. Note that the tracing is compatible with an external electromagnetic source misinterpreted as an episode of ventricular fibrillation. The following day the patient confessed that the physiotherapist he was visiting had asked him to test electro-acupuncture equipment consisting of two metal wands plugged to a 10 Hz–0.9 V electrical generator. The patient reported some tingling sensations before shock delivery. This device, sold by a German company, warns users about its potential side effects in patients with an ICD or pacemaker. Figure 1