R. Scott Millar

Pacemaker induced superior vena cava obstruction: management by spiral vein graft.

A 35‐year‐old male developed superior vena cava (SVC) obstruction due to multiple retained pacemaker leads. This caused cyanosis and suffusion of the head and neck during arm exercise, with desaturation from 99%‐90% demonstrated by ear oximetry. The SVC was bypassed using a spiral vein graft because of worsening symptoms. Dramatic improvement resulted, with desaturation no longer demonstrable.

Hemodynamic effects of nisoldipine, a highly specific calcium antagonist, in patients with acute myocardial infarction.

SummaryThe aim of the study was to investigate the hemodynamic effects of a short-acting, potent, highly specific calcium antagonist, nisoldipine, in patients with acute myocardial infarction. Twenty-four patients were selected on the basis of an elevated wedge pressure and/or elevated blood pressure, less than 12 hours after the onset of symptoms. Patients were randomized to receive either placebo or lowdose nisoldipine (2 μg/kg) as a single intravenous injection over a 3-minute period. Hemodynamic effects were monitored for 20 minutes, and thereafter patients were crossed over to the other agent after the preserved parameters had returned to baseline. An open-label study using double the dose of nisoldipine in 20 patients who had not reacted adversely to low-dose nisoldipine followed. Standard hemodynamic monitoring showed that peak effects of nisoldipine were reached at 5 minutes, with some residual effect at 20 minutes, and it took up to 60 minutes to return to baseline. Both doses of nisoldipine had similar effects: a fall in the systemic vascular resistance by about 600 units, variable tachycardia, little or no change in the wedge pressure, a decrease in the arterial pressure, an unchanged rate-pressure product, and an increase in ejection fraction. Tachycardia of more than 15 beats/min resulted in 5 of 24 patients with low-dose nisoldipine and 6 of 20 patients with high-dose nisoldipine. In view of the risk of tachycardia, nisoldipine seems unsuitable for use in the acute phase of myocardial infarction.

Answer to ECG Quiz 34

What appears to be sinus bradycardia or sinus arrest may be due to non-conducted atrial premature complexes. Premature P-waves may block because they fall within the normal AV nodal refractory period. Voltage criteria for LVH may still apply in the presence of LBBB.

Answer to ECG Quiz no. 32

Trifascicular block cannot be diagnosed from a single ECG showing bifascicular block with prolonged PR. The risk of AV block during anaesthesia and surgery is low. If AV block occurs, it is likely to be vagally induced (Wenckebach), rather than Mobitz II. The risk of a temporary pacemaker is not usually justified.

ECG Quiz 35 Answer

The ventricular rate is around 56/minute and is slightly irregular. The QRS complexes are wide, but are not typical of either left or right bundle branch block. Each QRS is preceded by a P-wave with a short PR interval. Wide, deep Q-waves are present in the inferior leads.

Answer to ECG Quiz no. 31

Regular, wide QRS tachycardia is usually VT, even in young people. QRS morphology is the key to differentiating VT from SVT with bundle branch block. P-waves may help to distinguish VT from pre-excited tachycardias. VT from the right ventricle (pseudo LBBB morphology) requires investigation for ARVC.

Answer to ECG Quiz no. 33

Rapid, bizarre complexes on ECG may be due to artefact. Occasionally, P-waves may be larger than QRS complexes, especially in very abnormal hearts. Muscle tremor from Parkinson’s mimics atrial flutter, but normal P-waves are visible in less affected leads.

Peer review and accreditation in cardiac electrophysiology

In line with the world-wide trend towards peer review and audit in all branches of medical practice,the Cardiac Arrhythmia Society of South Africa (CASSA) has begun a process of voluntary accreditation of Cardiac Electrophysiologists, beginning with those members of the Executive Committee of CASSA in active EP practice. The immediate aim is to provide other practitioners, the public and funders with a list of electrophysiologists who meet agreed standards of experience and competence. The longterm goal is the registration of Cardiac Electrophysiology as a sub-speciality of Cardiology

ECG Quiz no. 31

ECG recorded from a 14-year-old boy who became dizzy with palpitations while playing soccer. He had previously had palpitations with exercise.

ECG Quiz 34

ECG of a 64-year-old man who complained of tiredness, decreased effort tolerance and occasional palpitations.