The anesthetist as cardiologist: a case of heart block identified in the peripartum period.

We describe a case of undiagnosed heart block which was detected during the postpartum surgical repair of a vaginal tear, and the subsequent investigations that confirmed diagnosis of atrio-ventricular heart block.

Towards understanding the cause of stroke in young adults utilising a new stroke classification system (A-S-C-O).

BACKGROUND: Stroke in younger people is relatively common and frequently unexplained. While understanding of the causes of young stroke has improved, there remains uncertainty over the role of low-risk lesions such as a patent foramen ovale (PFO). The TOAST criteria are often used to describe stroke aetiology, but in younger people in whom PFOs are frequent, there is a very high proportion of cases attributed to cardiac embolism. The impact of using the newer A-S-C-O criteria on stroke aetiology was investigated. METHODS: Consecutive patients with ischaemic stroke were investigated and categorised by the TOAST and ASCO1 criteria. Stroke aetiology was presented and compared by the different classification systems. RESULTS: Of the 106 ischaemic stroke cases, by TOAST 6% were 'large artery atheroma', 11% 'small vessel occlusion', 28% 'cardioembolic', 22% 'other determined cause' and 33% 'undetermined cause'. The vascular territory and associated causes are presented. With the ASCO1 criteria, there were more cases of unclassified stroke (51.9 vs. 34.0%; p < 0.001) and fewer cases of cardiac embolism. Kappa ranged from 0.5 for 'undetermined aetiology' to 1.0 for both 'large artery atheroma' and 'other determined aetiology'. Younger cases (<45 years) were less likely to be either 'large artery atheroma' or 'small vessel occlusion'. CONCLUSION: Using the ASCO criteria, more patients fall into the undetermined group which more accurately reflects our current uncertainty regarding the pathogenic relevance of PFOs in this age group.

Increased incidence of interatrial block in younger adults with cryptogenic stroke and patent foramen ovale.

BACKGROUND: Stroke is often unexplained in younger adults, although it is often associated with a patent foramen ovale (PFO). The reason for the association is not fully explained, and mechanisms other than paradoxical embolism may be involved. Young stroke patients with PFO have more atrial vulnerability than those without PFO. It is plausible that stretching of the interatrial septum may disrupt the interatrial conduction pathways causing interatrial block (IAB). IAB is associated with atrial fibrillation, dysfunctional left atria and stroke. METHODS: Electrocardiogram (ECG) characteristics of prospectively recruited young patients (≤55 years of age) with unexplained stroke (TOAST and A-S-C-O) were compared with control data. All stroke cases underwent bubble contrast transthoracic and transoesophageal echography. IAB was defined as a P-wave duration of ≥110 ms. ECG data were converted to electronic format and analysed in a blind manner. RESULTS: Fifty-five patients and 23 datasets were analysed. Patients with unexplained stroke had longer P-wave duration (p = 0.013) and a greater prevalence of IAB (p = 0.02) than healthy controls. Case status was an independent predictor of P-wave duration in a significant multivariate model. There was a significant increase in the proportion of cases with a PFO with IAB compared with cases without PFO and with controls (p = 0.005). CONCLUSIONS: Young patients with unexplained stroke, particularly those with PFO, exhibit abnormal atrial electrical characteristics suggesting atrial arrhythmia or atrial dysfunction as a possible mechanism of stroke.

Stroke in younger patients: the heart of the matter.

Stroke in young adults is not a rare entity, and often provides difficult management decisions for neurologists. The knowledge gained from stroke in older adults does not transfer easily to this younger group given the different causes of stroke observed. Cardiac causes of stroke are common in this group, but often consist of low risk cardiac lesions such as a patent foramen ovale. Appropriate investigation should follow a stepwise approach to initially exclude higher risk pathology for recurrent stroke such as arterial dissection. Similarly, stepwise application of cardiac investigations will allow early identification of significant pathology, with investigation for abnormalities of the inter-atrial septum reserved for those with no other identified cause of stroke. Bubble contrast echo is now widely available, and with improved image quality may be performed with either transthoracic or transoesophageal echo, as well as with transcranial Doppler. Following this approach, patients can be best categorised by the expected rate of recurrent stroke, as informed by observational studies. Appropriate secondary prevention can then be tailored to the recurrence rate, with anticoagulation and possibly device closure reserved for those at highest risk of recurrence.

The electromechanical effects of pacing at different sites within the right atrium.

AIMS: To compare high right atrium (HRA) with right atrial appendage (RAA) pacing with respect to atrial electromechanical function. METHODS: Eleven patients undergoing elective electrophysiological studies were studied in order directly to compare atrial conduction acutely associated with HRA and RAA pacing. Twenty-five patients with chronically implanted, active fixation leads in the HRA were compared with an age and sex matched group of 25 patients with chronically implanted, passive fixation leads in the RAA. For both studies recordings were taken in sinus rhythm then repeated when paced. Measured time intervals were intra- and interatrial activation times. P wave duration and time to onset of atrial systolic blood flow. RESULTS: Right atrial pacing, when compared with sinus rhythm, significantly prolongs the interatrial activation time, the P wave duration and the time to onset of right and left atrial blood flow irrespective of site paced. Comparing the RAA group with the HRA group, there were no statistical differences for any of the measured parameters. CONCLUSION: High right atrial free wall or the right atrial appendage pacing, when compared with sinus rhythm, is significantly detrimental to atrial electromechanical function. There is, however, no demonstrable difference between the two sites.