Catecholaminergic polymorphic ventricular tachycardia
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a form of inherited
cardiac disease associated with sudden cardiac death. It is inherited in an
autosomal dominant fashion and has a prevalence of around 1:10,000.
Pathophysiology
● the most common cause is a defect in the ryanodine receptor (RYR2) which is
found in the myocardial sarcoplasmic reticulum
Features
● exercise or emotion induced polymorphic ventricular tachycardia resulting in
syncope
● sudden cardiac death
● symptoms generally develop before the age of 20 years
Management
● beta-blockers
● implantable cardioverter-defibrillator
Percutaneous coronary intervention
Percutaneous coronary intervention (PCI) is a technique used to restore myocardial
perfusion in patients with ischaemic heart disease, both in patients with stable
angina and acute coronary syndromes. Stents are implanted in around 95% of
patients - it is now rare for just balloon angioplasty to be performed
Following stent insertion migration and proliferation of smooth muscle cells and
fibroblasts occur to the treated segment. The stent struts eventually become
covered by endothelium. Until this happens there is an increased risk of platelet
aggregation leading to thrombosis.
Types of stent
, ● bare-metal stent (BMS)
● drug-eluting stents (DES): stent coated with paclitaxel or rapamycin which
inhibit local tissue growth. Whilst this reduces restenosis rates the stent
thrombosis rates are increased as the process of stent endothelisation is
slowed
Following insertion, the most important factor in preventing stent thrombosis is
antiplatelet therapy. Aspirin should be continued indefinitely. The length of
clopidogrel treatment depends on the type of stent, reason for insertion and
consultant preference. Antiplatelets should only be stopped following discussion
with the cardiology team (e.g. if the patient is due to have surgery) due to the risk of
stent thrombosis.
Complications
Periprocedural complications
● minor bleeding/haematoma at the site of vascular access
● retroperitoneal haematoma
○ may occur if the puncture site occurs proximal to the inguinal ligament
○ may be asymptomatic or present with flank pain/hypotension
● femoral pseudoaneurysm
○ pulsatile mass, femoral bruit and compromised distal pulses
● cholesterol embolisation
○ occurs due to embolisation of cholesterol released from
atherosclerotic plaques
○ purpura, livedo reticularis
○ renal impairment
○ blue toes
Longer term complications
● restenosis
○ due to excessive tissue proliferation around the stent
○ occurs in around 5-20% of patients, most commonly in the first 3-6
months
○ usually presents with the recurrence of angina symptoms
, ○ risk factors include diabetes, renal impairment and stents in venous
bypass grafts
● stent thrombosis
○ due to platelet aggregation as above
○ occurs in 1-2% of patients, most commonly in the first month
○ usually presents with acute myocardial infarction
Amiodarone
Amiodarone is a class III antiarrhythmic agent used in the treatment of atrial, nodal
and ventricular tachycardias. The main mechanism of action is by blocking
potassium channels which inhibits repolarisation and hence prolongs the action
potential. Amiodarone also has other actions such as blocking sodium channels (a
class I effect)
The use of amiodarone is limited by a number of factors
● very long half-life (20-100 days). For this reason, loading doses are frequently
used
● should ideally be given into central veins (causes thrombophlebitis)
● has proarrhythmic effects due to lengthening of the QT interval
● interacts with drugs commonly used concurrently (p450 inhibitor) e.g.
Decreases metabolism of warfarin
● numerous long-term adverse effects (see below)
Monitoring of patients taking amiodarone
● TFT, LFT, U&E, CXR prior to treatment
● TFT, LFT every 6 months
Adverse effects of amiodarone use
● thyroid dysfunction: both hypothyroidism and hyper-thyroidism
● corneal deposits
● pulmonary fibrosis/pneumonitis
, ● liver fibrosis/hepatitis
● peripheral neuropathy, myopathy
● photosensitivity
● 'slate-grey' appearance
● thrombophlebitis and injection site reactions
● bradycardia
● lengths QT interval
Amiodarone has a long half-life - it is highly lipophilic and widely absorbed by tissue,
which reduces its bioavailability in serum. Therefore, a prolonged loading regime is
required to achieve stable therapeutic levels
Hypertension: management
NICE published updated guidelines for the management of hypertension in 2019.
Some of the key changes include:
● lowering the threshold for treating stage 1 hypertension in patients < 80 years
from 20% to 10%
● angiotensin receptor blockers can be used instead of ACE-inhibitors where
indicated
● if a patient is already taking an ACE-inhibitor or angiotensin receptor blocker,
then a calcium channel blocker OR a thiazide-like diuretic can be used.
Previously only a calcium channel blocker was recommended
Blood pressure classification
This becomes relevant later in some of the management decisions that NICE
advocates.
Stage Criteria
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a form of inherited
cardiac disease associated with sudden cardiac death. It is inherited in an
autosomal dominant fashion and has a prevalence of around 1:10,000.
Pathophysiology
● the most common cause is a defect in the ryanodine receptor (RYR2) which is
found in the myocardial sarcoplasmic reticulum
Features
● exercise or emotion induced polymorphic ventricular tachycardia resulting in
syncope
● sudden cardiac death
● symptoms generally develop before the age of 20 years
Management
● beta-blockers
● implantable cardioverter-defibrillator
Percutaneous coronary intervention
Percutaneous coronary intervention (PCI) is a technique used to restore myocardial
perfusion in patients with ischaemic heart disease, both in patients with stable
angina and acute coronary syndromes. Stents are implanted in around 95% of
patients - it is now rare for just balloon angioplasty to be performed
Following stent insertion migration and proliferation of smooth muscle cells and
fibroblasts occur to the treated segment. The stent struts eventually become
covered by endothelium. Until this happens there is an increased risk of platelet
aggregation leading to thrombosis.
Types of stent
, ● bare-metal stent (BMS)
● drug-eluting stents (DES): stent coated with paclitaxel or rapamycin which
inhibit local tissue growth. Whilst this reduces restenosis rates the stent
thrombosis rates are increased as the process of stent endothelisation is
slowed
Following insertion, the most important factor in preventing stent thrombosis is
antiplatelet therapy. Aspirin should be continued indefinitely. The length of
clopidogrel treatment depends on the type of stent, reason for insertion and
consultant preference. Antiplatelets should only be stopped following discussion
with the cardiology team (e.g. if the patient is due to have surgery) due to the risk of
stent thrombosis.
Complications
Periprocedural complications
● minor bleeding/haematoma at the site of vascular access
● retroperitoneal haematoma
○ may occur if the puncture site occurs proximal to the inguinal ligament
○ may be asymptomatic or present with flank pain/hypotension
● femoral pseudoaneurysm
○ pulsatile mass, femoral bruit and compromised distal pulses
● cholesterol embolisation
○ occurs due to embolisation of cholesterol released from
atherosclerotic plaques
○ purpura, livedo reticularis
○ renal impairment
○ blue toes
Longer term complications
● restenosis
○ due to excessive tissue proliferation around the stent
○ occurs in around 5-20% of patients, most commonly in the first 3-6
months
○ usually presents with the recurrence of angina symptoms
, ○ risk factors include diabetes, renal impairment and stents in venous
bypass grafts
● stent thrombosis
○ due to platelet aggregation as above
○ occurs in 1-2% of patients, most commonly in the first month
○ usually presents with acute myocardial infarction
Amiodarone
Amiodarone is a class III antiarrhythmic agent used in the treatment of atrial, nodal
and ventricular tachycardias. The main mechanism of action is by blocking
potassium channels which inhibits repolarisation and hence prolongs the action
potential. Amiodarone also has other actions such as blocking sodium channels (a
class I effect)
The use of amiodarone is limited by a number of factors
● very long half-life (20-100 days). For this reason, loading doses are frequently
used
● should ideally be given into central veins (causes thrombophlebitis)
● has proarrhythmic effects due to lengthening of the QT interval
● interacts with drugs commonly used concurrently (p450 inhibitor) e.g.
Decreases metabolism of warfarin
● numerous long-term adverse effects (see below)
Monitoring of patients taking amiodarone
● TFT, LFT, U&E, CXR prior to treatment
● TFT, LFT every 6 months
Adverse effects of amiodarone use
● thyroid dysfunction: both hypothyroidism and hyper-thyroidism
● corneal deposits
● pulmonary fibrosis/pneumonitis
, ● liver fibrosis/hepatitis
● peripheral neuropathy, myopathy
● photosensitivity
● 'slate-grey' appearance
● thrombophlebitis and injection site reactions
● bradycardia
● lengths QT interval
Amiodarone has a long half-life - it is highly lipophilic and widely absorbed by tissue,
which reduces its bioavailability in serum. Therefore, a prolonged loading regime is
required to achieve stable therapeutic levels
Hypertension: management
NICE published updated guidelines for the management of hypertension in 2019.
Some of the key changes include:
● lowering the threshold for treating stage 1 hypertension in patients < 80 years
from 20% to 10%
● angiotensin receptor blockers can be used instead of ACE-inhibitors where
indicated
● if a patient is already taking an ACE-inhibitor or angiotensin receptor blocker,
then a calcium channel blocker OR a thiazide-like diuretic can be used.
Previously only a calcium channel blocker was recommended
Blood pressure classification
This becomes relevant later in some of the management decisions that NICE
advocates.
Stage Criteria
