Cardiac strangulation by epicardial pacing wires in adults.

Like children, adult patients with active or abandoned epicardial pacing leads are also at risk of developing life-threatening cardiac ischemia due to mechanical compression of the coronary arteries. As this complication is amenable to surgical removal, these patients require periodic evaluation for myocardial ischemia even if they are asymptomatic.

What is Chapman's sign?

Chapman's (electrographic) sign is of a notch on the ascending limb of the R wave in leads I, aVL and V6. It has been used in the diagnosis of myocardial infarction (MI) during left bundle branch block (LBBB) and cardiac pacing. A number of studies have yielded divergent results about its diagnostic usefulness.

Variability of the PR intervals in Wenckebach atrioventricular block.

The duration of the PR intervals in atypical Wenckebach atrioventricular block before and after a non-conducted P wave can exhibit a wide range of values and patterns. Understanding the different or at times puzzling manifestations of Wenckebach atrioventricular block in terms of its PR intervals can avoid diagnostic errors, especially the erroneous more serious diagnosis of Mobitz type II atrioventricular block.

Misinterpretation of sleep-induced second-degree atrioventricular block.

A number of publications have claimed that Mobitz type II atrioventricular block (AVB) may occur during sleep. None of the reports defined type II AVB and representative electrocardiograms were either misinterpreted or missing. Relatively benign Wenckebach type I AVB is often misdiagnosed as Mobitz type II which is an indication for a pacemaker.

Clinical use of CRT-D devices with left ventricular sensing: Impact of the desynchronization-detection algorithm.

The use of CRT-D devices with left ventricular (LV) sensing has created controversy about programming various parameters especially the left ventricular T wave protection (LVTP) designed to prevent the delivery of a pacing stimulus into the LV vulnerable period. Such devices are available from two manufacturers. This review focuses only on those provided by Biotronik.

Centennial of the original description of Mobitz type II second-degree atrioventricular block.

The year 2024 marks the centenary of Mobitz's description of type II second-degree atrioventricular block. Its definition remains valid to this day with only minor modification for the diagnosis of infranodal conduction block. Mobitz a century ago indicated that his type II atrioventricular block was associated with Stock-Adams attacks and a prolonged duration of the QRS complex before the eventual description of bundle branch block.

Pseudo-2:1 bundle branch block. "Fusion causes confusion".

The fusion of narrow-QRS sinus-generated beats with end-diastolic ventricular extrasystoles occurring in bigeminy can produce an electrocardiographic pattern difficult to differentiate from parasystole. Such an ECG should not be interpreted as 2:1 RBBB because of the variability of the PR intervals.

Sensing of concealed ventricular extrasystoles by pacemakers. Fifty years later.

Whether a pacemaker can sense concealed ventricular extrasystoles still remains debatable since its occurrence was first proposed in 1972. It must remain a diagnosis of exclusion if it really exists. Isoelectric complexes and all the causes of oversensing especially discrete false signals generated by a defective pacemaker lead must be excluded before concealed ventricular extrasystoles can be postulated.

Incomplete (partial) left anterior hemiblock.

This report describes two electrocardiograms (ECGs) showing unusual manifestations of left anterior hemiblock (LAH). One revealed different degrees of incomplete LAH and the other documented the occurrence of 2:1 LAH. Understanding different degrees of LAH helps to interpret the ECG with regard to intraventricular conduction disorders and other ECG abnormalities.

Transient loss of atrial capture: the "atrial pacemaker stunning" phenomenon.

Atrial loss of capture in the chronic phase after implantation may be permanent due to various causes, e.g. technical lead problems or increased scar tissue formation around the lead tip.

Definitions and Pitfalls in the Diagnosis of Atrioventricular Block.

The widespread use of disparate definitions of atrioventricular block has created important diagnostic problems. Adherence to the correct definitions provides a logical and simple framework for clinical evaluation. This review focuses on the clinical importance of the definitions in the diagnosis of the various types of atrioventricular (AV) block and the associated diagnostic pitfalls.

Mobitz type II second-degree atrioventricular block during sleep: true or false?

A number of publications have claimed that Mobitz type II second-degree atrioventricular (AV) block can occur during sleep apnea. None has provided a definition of type II block used in the articles, and representative electrocardiograms have been generally missing. Despite these reports, the existence of type II AV block during sleep must remain questionable.

Unusual manifestation of atypical type I second degree atrioventricular block.

A 25 year-old woman exhibited atypical type I second degree atrioventricular block characterized by constant PR intervals except the PR interval of the beat after the block. This was attributed to vagally induced AV block with failure of the vagal effect to depress the sinus node.

Problematic definitions of Mobitz type II second degree AV block: Historical aspects.

Problems with the definition of type II second degree AV block are best understood by reviewing the historical aspects that include Mobitz's original description, the contributions of the Chicago Arrhythmia School and the growing importance of excluding slowing of the sinus rhythm.

Diagnosis of slow ventricular tachycardia by cardiac resynchronization devices utilizing a desynchronization detection algorithm.

Some cardiac resynchronization therapy (CRT) devices equipped with left ventricular (LV) sensing can develop a specific desynchronization rhythm. Contemporary BIOTRONIK devices are designed with an algorithm called "CRT pacing interrupt" exclusively designed to record the occurrence of the specific form of desynchronization. We report six patients in whom the CRT pacing interrupt function permitted the diagnosis of slow ventricular tachycardia (VT).