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TEE is a useful tool to investigate patients undergoing ablation therapy of atrial fibrillation. The technique provides important information about the presence of thrombus and SEC in the left atrium and LAa, and about minor IAS abnormalities, which seem to occur more frequently than in the normal population. Such information is necessary for planning the approach to the PV by catheters that must cross the septum and the atrial cavity.

After ablation, TEE can be used to monitor possible minor complications, such as a residual IAS shunt or pericardial effusion. It also allows the detection of PV stenosis, a rare but dreaded complication of PVAI. A control TEE examination 3 months after the ablation procedure is probably adequate for this purpose.

In summary, the SMU is uncommon in North America. Furthermore, relatively few arrhythmia specialty centres are contemplating establishment of such a facility, although most survey respondents believe that an SMU would be helpful. The survey findings suggest that establishment of such a unit is impeded by lack of leadership, resource limitations within medical centres, and absence of convincing published data regarding SMU effectiveness. Thus, at least in the near term, the SMU will remain the exception rather than the rule in North American medical practice.

Cardiac resynchronisation therapy improves HF symptoms and reduces HF-related hospitalisations and total mortality in patients with moderate to severe HF and ventricular dyssynchrony. In smaller studies, CRT has also been shown be beneficial in patients with less symptomatic HF. The effects of CRT on HF outcomes is therefore currently being studied in patients with NYHA II heart failure or ALVD.

Available evidence supports the hypothesis that CRT results in favourable structural and electrical remodeling. Whether this effect would obviate the need for back-up defibrillation capability in CRT devices is unclear and should be the focus of further studies.

Upon completion of the chapter, the student will be able to:

In patients with structurally normal hearts and unexplained syncope or cardiac arrest, Brugada syndrome is considered a frequent underlying condition. In patients with suspected Brugada syndrome but inconclusive or normal ECG findings at baseline, drug challenge with intravenous administration of sodium channel blockers according to a standardised protocol is a powerful tool to unmask diagnostic type-1 Brugada ECG features and thereby identify patients at risk of sudden death. The additional impact of drug challenge in the risk stratification algorithms of patients already diagnosed with Brugada syndrome is less well-established and requires additional studies.

As discussed above, the more frequently the RV apex is paced, the more likely cardiac performance will be compromised. This explains why, although maintenance of AV synchrony afforded by conventional DDDR is intuitively superior to VVIR, this has been surprisingly difficult to prove. Large randomised clinical trials have reached a consensus that there is no survival benefit in patients conventionally DDDR paced; furthermore, DDDR pacing may be associated with an increased risk of death among ICD patients.

These trials have highlighted the importance of developing sophisticated pacemakers and ICDs capable of minimising, in patients without AV block, RV pacing, thus preserving normal ventricular activation while providing physiologic pacing support.

A reliable alternative to RV pacing may well be biventricular pacing, which seems to be a valid option to preserve LV function in patients who present with LV dysfunction and heart failure symptoms. In addition, there is the option to use CRT for ‘primary prevention’ in selected patients who require ventricular pacing for electrical reasons.

In summary, the SMU is uncommon in North America. Furthermore, relatively few arrhythmia specialty centres are contemplating establishment of such a facility, although most survey respondents believe that an SMU would be helpful. The survey findings suggest that establishment of such a unit is impeded by lack of leadership, resource limitations within medical centres, and absence of convincing published data regarding SMU effectiveness. Thus, at least in the near term, the SMU will remain the exception rather than the rule in North American medical practice.

Cardiac resynchronisation therapy improves HF symptoms and reduces HF-related hospitalisations and total mortality in patients with moderate to severe HF and ventricular dyssynchrony. In smaller studies, CRT has also been shown be beneficial in patients with less symptomatic HF. The effects of CRT on HF outcomes is therefore currently being studied in patients with NYHA II heart failure or ALVD.

Epicardial VT may occur in ischaemic, non-ischaemic, and idiopathic VT. Truly subepicardial VT can preferentially be ablated from the epicardial surface. The percutaneous subxiphoid approach to the pericardial space is easy and can be done safely in the EP laboratory by an electrophysiologist. This approach may improve the results of the catheter ablation procedure.