Section 5 Pacemakers Ventricular pacemaker Dual chamber pacing (AV sequential pacing) Problems with pacemakers – failure to sense Problems with pacemakers – failure to capture Polymorphic VT with cardioversion and pacing by an implantable cardioverter defibrillator (ICD) Case 52 An 82-year-old man who had presented with collapse Ventricular pacemaker • There is a pacing spike before the QRS complex. • The paced complexes are wide and of abnormal morphology (usually resembles LBBB as the tip of the pacing wire is most commonly placed at the apex of the right ventricle). Features of this ECG • Paced rhythm, ventricular rate 42 b.p.m.: – atrial rate 66 b.p.m., AV dissociation is present • There are pacing spikes before each QRS complex (Fig. 52.1) • An occasional pacing spike is obscured by a P wave (Fig. 52.2) • Abnormal QRS complexes with a LBBB pattern Fig. 52.1 Ventricular pacing. Fig. 52.2 Rhythm strip. Clinical Note This was a patient with a temporary pacing wire inserted for symptomatic complete heart block (CHB). He needed permanent pacing. This ECG was taken when the paced rate was slowed to allow assessment of the underlying rhythm which has remained as CHB. Pacemaker nomenclature Case 53 A 60-year-old lady with a history of ischaemic heart disease and blackouts Dual chamber pacing (AV sequential pacing) • Pacing spikes may precede the P wave and/or the QRS complex. Dual chamber pacemakers sense intrinsic atrial and ventricular activity and pace the appropriate chambers as required. The morphology of the induced P wave may be abnormal or closely resemble the normal P wave depending on the position of the pacing electrode in the right atrium. The morphology of the induced QRS also depends on the position of the ventricular wire but usually resembles a LBBB pattern. Features of this ECG • Dual chamber paced rhythm, 60 b.p.m. Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Hypertrophy patterns Bundle branch block Ventricular rhythms Ischaemic heart disease Stay updated, free articles. Join our Telegram channel Join Tags: ECGs by Example Aug 29, 2016 | Posted by admin in CARDIOLOGY | Comments Off on Pacemakers Full access? Get Clinical Tree
Section 5 Pacemakers Ventricular pacemaker Dual chamber pacing (AV sequential pacing) Problems with pacemakers – failure to sense Problems with pacemakers – failure to capture Polymorphic VT with cardioversion and pacing by an implantable cardioverter defibrillator (ICD) Case 52 An 82-year-old man who had presented with collapse Ventricular pacemaker • There is a pacing spike before the QRS complex. • The paced complexes are wide and of abnormal morphology (usually resembles LBBB as the tip of the pacing wire is most commonly placed at the apex of the right ventricle). Features of this ECG • Paced rhythm, ventricular rate 42 b.p.m.: – atrial rate 66 b.p.m., AV dissociation is present • There are pacing spikes before each QRS complex (Fig. 52.1) • An occasional pacing spike is obscured by a P wave (Fig. 52.2) • Abnormal QRS complexes with a LBBB pattern Fig. 52.1 Ventricular pacing. Fig. 52.2 Rhythm strip. Clinical Note This was a patient with a temporary pacing wire inserted for symptomatic complete heart block (CHB). He needed permanent pacing. This ECG was taken when the paced rate was slowed to allow assessment of the underlying rhythm which has remained as CHB. Pacemaker nomenclature Case 53 A 60-year-old lady with a history of ischaemic heart disease and blackouts Dual chamber pacing (AV sequential pacing) • Pacing spikes may precede the P wave and/or the QRS complex. Dual chamber pacemakers sense intrinsic atrial and ventricular activity and pace the appropriate chambers as required. The morphology of the induced P wave may be abnormal or closely resemble the normal P wave depending on the position of the pacing electrode in the right atrium. The morphology of the induced QRS also depends on the position of the ventricular wire but usually resembles a LBBB pattern. Features of this ECG • Dual chamber paced rhythm, 60 b.p.m. Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Hypertrophy patterns Bundle branch block Ventricular rhythms Ischaemic heart disease Stay updated, free articles. Join our Telegram channel Join Tags: ECGs by Example Aug 29, 2016 | Posted by admin in CARDIOLOGY | Comments Off on Pacemakers Full access? Get Clinical Tree
