Bahman Arrhythmia Clinic

The patient's main complaint was palpitation and symptoms such as exertional dyspnea and orthopnea. The diagnosis of postpartum cardiomyopathy had been mooted because the  beginning of symptoms coincided with her 2nd pregnancy and the symptoms increased during last trimester of 3rd pregnancy. Echocardiography had revealed LV dysfunction (EF:30%)
The symptoms was not relieved after the labor despite drug treatment for heart failure.After 6 months no improvement was found in LV function and she was referred to us due to frequent PVC's and runs of non-sustained VT.
The QRS morphology of bigeminated PVC's (LBBB and inferior axis) was compatible with origination of PVC's from RVOT or aortic cusps and early transition in precordial leads (V2-V3) was in favor of the second one  (figure 1).


      Fig 1 Bigeminated PVC's with LBBB and inferior axis morphology

Although such a QRS morphology can be infrequently produced by PVC's originating from a diseased left ventricular origin, considering the main patient's symptom which was palpitation, we decided to candidate the patient for electrophysiologic study. 
Activation and pace mapping in RVOT did not yield any good potential. So we started to map aortic cusps electrically. Finding some good potentials in left cusp made us hopeful to find the origin of PVC's there. First an aortogram was obtained to show the exact anatomy of cusps and location of the origin of left main artery. (figure 2)

fig 2 Aortogram in LAO and RAO views


The catheter of ablation was then  placed retrogradely from aortic root and careful mapping was performed in left aortic cusp. Meanwhile the ACT was maintained above 250s to prohibit clot formation. The best potential (figure 3) was recorded in a region located at the junction of left and right aortic cusps (figure 4). As seen in the following tracing, the recorded potential at the tip of the ablation catheter begins 52 msec earlier than the onset of PVC on surface ECG (3rd complex) which was quite suitable.   

Fig 3 : The potential recorded in the ablation catheter  (3rd complex) is 52 msec earlier than PVC onset in surface ECG

Figure 4. Position of the catheter on left-right cusp junction in LAO and RAO views.

After acceptable and safe distance from left main orifice was ascertained, RF application at this region abolished PVC's and after 30 minutes no PVC was inducible.The patient was discharged the day after ablation without any recorded PVC on monitor.


Fig 5 .sinus rhythm with no PVC after ablation

Interestingly the echocardiogram obtained just 2 weeks after ablation showed normal LV function and the patient was completely asymptomatic thereafter. So the diagnosis was changed to a reversible PVC induced cardiomyopathy. Naturally the need for ICD implantation was also obviated for this young lady.

Discussion:
Tachycardia-induced cardiomyopathy has been associated with a spectrum of tachyarrhythmias, including atrial fibrillation and flutter, supraventricular tachycardia, and ventricular tachycardia.(we have reported one case of PSVT induced cardiomyopathy before Click to see). However, the mechanism by which isolated ventricular ectopy results in cardiomyopathy is uncertain.

Duffee et al (1) for first time described 4 patients who had more than 20'000 premature ventricular contractions over 24 hours (morphology unknown) and cardiomyopathy (ejection fraction <40%) in whom left ventricular function improved substantially (from mean 27% to mean 49%) after either a B-blocker (n_1) or amiodarone (n_3) was given to suppress ventricular ectopy.
In another study (2) including 8 patients with frequent RVOT PVC's and depressed LV function successful ablation in 7 patients resulted in complete recovery of LV function.Another finding was that ectopy-induced cardiomyopathy was observed in patients with as few as 5500 daily premature beats, which suggests that this underappreciated  entity should be considered in any patient with unexplained cardiomyopathy in whom monomorphic ventricular ectopy is observed. Although day-to-day variability in the burden of ectopy likely plays some part, it is unclear why some patients develop cardiomyopathy and other patients (who often have significantly greater amounts of ectopy) do not.
Although in these studies the PVC's were mainly originated from RVOT, the issue should not differ for PVC's originating from aortic cusps. About 16 % of ventricular idiopathic arrhythmias with inferior axis morphology originate from aortic cusps, more frequently from left cusp and rarely from non coronary cusp . The reason for this discrepancy between cusps is direct contact of left and right cusp with LV ostium but more correlation of non coronary cusp with right atrium which make the electrical activity of this cusp to iduce atrial arrhythmia rather than ventricular one.
It is interesting in our case that the diagnosis of postpartum cardiomyopathy could easily justify the presence of PVC's . In fact the correlation of ventricular arrhythmias and LV dysfunction is reciprocal and can make a viscous cycle. If idiopathic PVC was not suspected as the cause of heart failure and conversely the PVC's were concerned to be caused by LV dysfunction, logically it should be sought enough dangerous to lead us to ICD implantation. However the result of ablation mooted the first scenario. In an interesting case reported recently by Dr Alizadeh in a symposium, ablation of PVC originating from left cusp resulted in improvement of isolated RV dysfunction!  That patient was diagnosed to be affected by ARVD and he was also candidated for ICD implantation.
In conclusion, the correlation of any arrhythmia and CHF should be noticed at both sides and each entity would be sought as potential cause of the another one. The rule should  conclude even isolated and non-sustained arrhythmias.Considering the easier end more effective treatments available for arrhythmias than for heart failure, the patient and physician should  feel lucky if arrhythmia is the cause of heart failure and unlucky if the correlation is reversed.  

Refferences:

1. Duffee DF, Shen WK, Smith HC. Suppression of frequent premature ventricular contractions and improvement of left ventricular function in patients with presumed idiopathic dilated cardiomyopathy. Mayo Clin Proc. 1998;73:430-433.

2. Shah, Jim W. Cheung, Vivian Tan, Bruce B. Lerman and Suneet Mittal Ravi K. Yarlagadda, Sei Iwai, Kenneth M. Stein, Steven M. Markowitz, Bindi K.
Ventricular Ectopy Originating From the Right Ventricular Outflow Tract
Circulation 2005;112;1092-1097; originally published online Aug 15, 2005;